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Sample records for methyl ether methacrylate

  1. 76 FR 69659 - Methacrylic Acid-Methyl Methacrylate-Polyethylene Glycol Monomethyl Ether Methacrylate Graft...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-11-09

    ... AGENCY 40 CFR Part 180 Methacrylic Acid-Methyl Methacrylate-Polyethylene Glycol Monomethyl Ether... residues of methacrylic acid-methyl methacrylate- polyethylene glycol monomethyl ether methacrylate graft... permissible level for residues of methacrylic acid-methyl methacrylate-polyethylene glycol monomethyl...

  2. Methyl methacrylate

    Integrated Risk Information System (IRIS)

    TOXICOLOGICAL REVIEW of METHYL METHACRYLATE ( CAS No . 80 - 62 - 6 ) In Support of Summary Information on the Integrated Risk Information System ( IRIS ) January 1998 U.S . Environmental Protection Agency Washington , DC TABLE OF CONTENTS DISCLAIMER . . . . . . . . . . . . . . . . . . . . . . . . .

  3. Dual-Responsive pH and Temperature Sensitive Nanoparticles Based on Methacrylic Acid and Di(ethylene glycol) Methyl Ether Methacrylate for the Triggered Release of Drugs.

    PubMed

    Khine, Yee Yee; Jiang, Yanyan; Dag, Aydan; Lu, Hongxu; Stenzel, Martina H

    2015-08-01

    A series of thermo-and pH-responsive poly(methyl methacrylate)-block-poly[methacrylic acid-co-di(ethylene glycol) methyl ether methacrylate] PMMA-b-P[MAA-co-DEGMA] block copolymers were synthesized by RAFT polymerization and self-assembled into micelles. The molar ratio of MAA was altered from 0-12% in order to modulate the lower critical solution temperature (LCST) of PDEGMA. The release of the drug albendazole from the micelle was strongly dependent on the temperature and the LCST value of the polymer. Systems below the LCST released the drug slowly while increasing the temperature above the LCST or decreasing the pH value to 5 resulted in the burst-like release of the drug. ABZ delivered in this pH-responsive drug carrier had a higher toxicity than the free drug or the drug delivered in a non-responsive drug carrier.

  4. Reactive Poly(Amic Acid)/ Poly(Glycidyl Methacrylate-r-Poly(ethylene Glycol) Methyl Ether Methacrylate) Blends as Gas Permeation Membranes

    NASA Astrophysics Data System (ADS)

    Beaulieu, Michael; Watkins, James

    2012-02-01

    Polymers containing polar moieties, such as ether groups show an affinity for acidic gases, such as CO2 due to dipole-quadrapole interactions. Polymer blends in which one of the components is poly(ethylene glycol) (PEG) have been studied extensively in literature as a CO2/light gas permeation membrane, but due to the crystallization and poor mechanical properties have been difficult to incorporate PEG above 60wt%. In this study, a series of random copolymers containing both glycidyl methacrylate and poly(ethylene glycol) methyl ether methacrylate in different ratios are blended with a poly(amic acid) prepolymer made from 4, 4'-oxydianiline and pyromellitic dianhydride to create gas permeation membranes. By using a reactive blend PEG loadings above 70% have been realized with sufficient mechanical properties, and since the side chain on the PEGMA is short these blends do not suffer from crystallization.

  5. Plasma graft of poly(ethylene glycol) methyl ether methacrylate (PEGMA) on RGP lens surface for reducing protein adsorption

    NASA Astrophysics Data System (ADS)

    Shiheng, Yin; Li, Ren; Yingjun, Wang

    2017-01-01

    Poly(ethylene glycol) methyl ether methacrylate (PEGMA) was grafted on fluorosilicone acrylate rigid gas permissible contact lens surface by means of argon plasma induced polymerization to improve surface hydrophilicity and reduce protein adsorption. The surface properties were characterized by contact angle measurement, x-ray photoelectron spectroscopy (XPS) and atomic force microscopy respectively. The surface protein adsorption was evaluated by lysozyme solution immersion and XPS analysis. The results indicated that a thin layer of PEGMA was successfully grafted. The surface hydrophilicity was bettered and surface free energy increased. The lysozyme adsorption on the lens surface was reduced greatly. The study was supported by National Natural Science Foundation of China (No. 51273072).

  6. Chemical grafting of poly(ethylene glycol) methyl ether methacrylate onto polymer surfaces by atmospheric pressure plasma processing.

    PubMed

    D'Sa, Raechelle A; Meenan, Brian J

    2010-02-02

    This article reports the use of atmospheric pressure plasma processing to induce chemical grafting of poly(ethylene glycol) methyl ether methacrylate (PEGMA) onto polystyrene (PS) and poly(methyl methacrylate) (PMMA) surfaces with the aim of attaining an adlayer conformation which is resistant to protein adsorption. The plasma treatment was carried out using a dielectric barrier discharge (DBD) reactor with PEGMA of molecular weights (MW) 1000 and 2000, PEGMA(1000) and PEGMA(2000), being grafted in a two step procedure: (1) reactive groups are generated on the polymer surface followed by (2) radical addition reactions with the PEGMA. The surface chemistry, coherency, and topography of the resulting PEGMA grafted surfaces were characterized by X-ray photoelectron spectroscopy (XPS), time-of-flight secondary ion mass spectrometry (ToF-SIMS), and atomic force microscopy (AFM), respectively. The most coherently grafted PEGMA layers were observed for the 2000 MW PEGMA macromolecule, DBD processed at an energy dose of 105.0 J/cm(2) as indicated by ToF-SIMS images. The effect of the chemisorbed PEGMA layer on protein adsorption was assessed by evaluating the surface response to bovine serum albumin (BSA) using XPS. BSA was used as a model protein to determine the grafted macromolecular conformation of the PEGMA layer. Whereas the PEGMA(1000) surfaces showed some protein adsorption, the PEGMA(2000) surfaces appeared to absorb no measurable amount of protein, confirming the optimum surface conformation for a nonfouling surface.

  7. Di(ethylene glycol) methyl ether methacrylate (DEGMEMA)-derived gels align small organic molecules in methanol.

    PubMed

    García, Manuela E; Woodruff, Shannon R; Hellemann, Erich; Tsarevsky, Nicolay V; Gil, Roberto R

    2017-03-01

    Residual dipolar couplings (RDCs) constitute an important NMR parameter for structural elucidation in all areas of chemistry. In this study, di(ethylene glycol) methyl ether methacrylate (DEGMEMA)-based gels are introduced as alignment media for the measurement of RDCs of small organic molecules in polar solvents such as methanol. The low viscosity of methanol permits the execution of J-scaled BIRD HSQC experiments that yield very sharp lines in anisotropic conditions. The gels have excellent mechanical properties, and their compression and expansion in the swollen state can be reversed and performed multiple times. This process enables the easy loading and release of analytes. The excellent performance of these new aligning gels is demonstrated by analyzing the structure of the alkaloid retrorsine. Copyright © 2016 John Wiley & Sons, Ltd.

  8. Nonviral Plasmid DNA Carriers Based on N,N'-Dimethylaminoethyl Methacrylate and Di(ethylene glycol) Methyl Ether Methacrylate Star Copolymers.

    PubMed

    Mendrek, Barbara; Sieroń, Łukasz; Żymełka-Miara, Iwona; Binkiewicz, Paulina; Libera, Marcin; Smet, Mario; Trzebicka, Barbara; Sieroń, Aleksander L; Kowalczuk, Agnieszka; Dworak, Andrzej

    2015-10-12

    Star polymers with random and block copolymer arms made of cationic N,N'-dimethylaminoethyl methacrylate (DMAEMA) and nonionic di(ethylene glycol) methyl ether methacrylate (DEGMA) were synthesized via atom transfer radical polymerization (ATRP) and used for the delivery of plasmid DNA in gene therapy. All stars were able to form polyplexes with plasmid DNA. The structure and size of the polyplexes were precisely determined using light scattering and cryo-TEM microscopy. The hydrodynamic radius of a complex of DNA with star was dependent on the architecture of the star arms, the DEGMA content and the number of amino groups in the star compared to the number of phosphate groups of the nucleic acid (N/P ratio). The smallest polyplexes (Rh90°∼50 nm) with positive zeta potentials (∼15 mV) were formed of stars with N/P=6. The introduction of DEGMA into the star structure caused a decrease of polyplex cytotoxicity in comparison to DMAEMA homopolymer stars. The overall transfection efficiency using HT-1080 cells showed that the studied systems are prospective gene delivery agents. The most promising results were obtained for stars with random copolymer arms of high DEGMA content.

  9. Poly(oligo(ethylene glycol) methyl ether methacrylate) Brushes on High-κ Metal Oxide Dielectric Surfaces for Bioelectrical Environments.

    PubMed

    Joh, Daniel Y; McGuire, Felicia; Abedini-Nassab, Roozbeh; Andrews, Joseph B; Achar, Rohan K; Zimmers, Zackary; Mozhdehi, Darush; Blair, Rebecca; Albarghouthi, Faris; Oles, William; Richter, Jacob; Fontes, Cassio M; Hucknall, Angus M; Yellen, Benjamin B; Franklin, Aaron D; Chilkoti, Ashutosh

    2017-02-15

    Advances in electronics and life sciences have generated interest in "lab-on-a-chip" systems utilizing complementary metal oxide semiconductor (CMOS) circuitry for low-power, portable, and cost-effective biosensing platforms. Here, we present a simple and reliable approach for coating "high-κ" metal oxide dielectric materials with "non-fouling" (protein- and cell-resistant) poly(oligo(ethylene glycol) methyl ether methacrylate (POEGMA) polymer brushes as biointerfacial coatings to improve their relevance for biosensing applications utilizing advanced electronic components. By using a surface-initiated "grafting from" strategy, POEGMA films were reliably grown on each material, as confirmed by ellipsometric measurements and X-ray photoelectron spectroscopy (XPS) analysis. The electrical behavior of these POEGMA films was also studied to determine the potential impact on surrounding electronic devices, yielding information on relative permittivity and breakdown field for POEGMA in both dry and hydrated states. We show that the incorporation of POEGMA coatings significantly reduced levels of nonspecific protein adsorption compared to uncoated high-κ dielectric oxide surfaces as shown by protein resistance assays. These attributes, combined with the robust dielectric properties of POEGMA brushes on high-κ surfaces open the way to incorporate this protein and cell resistant polymer interface into CMOS devices for biomolecular detection in a complex liquid milieu.

  10. Encapsulation of glucose oxidase within poly(ethylene glycol) methyl ether methacrylate microparticles for developing an amperometric glucose biosensor.

    PubMed

    Hervás Pérez, J P; López-Cabarcos, E; López-Ruiz, B

    2008-06-15

    Poly(ethylene glycol) methyl ether methacrylate (PEGMEM) microparticles were synthesized and glucose oxidase (GOx) was immobilized within the microparticles. An amperometric biosensor was fabricated using the microparticles with GOx as biological component. The enzyme immobilization method was optimized by investigating the influence of monomer concentration and cross-linker content used in the preparation of the microparticles in the response of the biosensor. The best analytical results were obtained with the microparticles prepared with 0.21 M PEGMEM and 0.74% cross-linking. Furthermore, we have investigated the influence on the biosensor behaviour of parameters such as working potential, pH, temperature and enzymatic load. In addition, analytical properties such as sensitivity, linear range, response time and detection limit were determined. The biosensor was used to determine glucose in human serum samples and to avoid common interferents present in human serum such as uric and ascorbic acids. A Nafion layer was deposited on the electrode surface with satisfactory results. The useful lifetime of the biosensor was at least 520 days.

  11. Radiation-grafting of 2-hydroxyethylmethacrylate and oligo (ethylene glycol) methyl ether methacrylate onto polypropylene films by one step method

    NASA Astrophysics Data System (ADS)

    Ramírez-Jiménez, Alejandro; Alvarez-Lorenzo, Carmen; Concheiro, Angel; Bucio, Emilio

    2012-01-01

    Polypropylene films were modified with 2-hydroxyethylmethacrylate (HEMA) and oligo (ethylene glycol) methyl ether methacrylate (OEGMA) using the pre-irradiation method with gamma-rays (one step method). The effect of absorbed dose from 10 to 100 kGy, temperature (50, 60, and 70 °C), monomer concentration between 12.5% and 62.5%, monomers ratio from 10% to 90% and reaction time from 5 to 50 h; on the degree of grafting was determined. The grafted samples were analyzed by FTIR-ATR, TGA, DSC, swelling, and contact angle. Grafts onto polymeric films between 3% and 109% were obtained at doses from 10 to 100 kGy and a dose rate around 7.4 kGy/h. The graft percent increased with the content in HEMA in the HEMA:OEGMA feed mixture, which indicates a lower reactivity of OEGMA compared to HEMA. The hydrogel layer grafted on the polypropylene substrate increases the hydrophilicity of the surface and also provides certain temperature-responsiveness, which may be of interest for biomedical applications.

  12. Synthesis and characterization of poly(methoxyl ethylene glycol-caprolactone-co-methacrylic acid-co-poly(ethylene glycol) methyl ether methacrylate) pH-sensitive hydrogel for delivery of dexamethasone.

    PubMed

    Wang, Ke; Xu, Xu; Wang, YuJun; Yan, Xi; Guo, Gang; Huang, MeiJuan; Luo, Feng; Zhao, Xia; Wei, YuQuan; Qian, ZhiYong

    2010-04-15

    In this work, a novel pH-sensitive hydrogels based on macromonomer of methoxyl poly(ethylene glycol)-poly(caprolactone)-acryloyl chloride (MPEG-PCL-AC, PCE-AC), poly(ethylene glycol) methyl ether methacrylate (MPEGMA), and methacrylic acid (MAA) were successfully synthesized by heat-initiated free radical polymerization method. The obtained macromonomers and hydrogels were characterized by (1)H NMR and FT-IR, respectively. Morphology study, swelling behavior, in vitro drug release behavior, acute oral toxicity of hydrogels, and cytotoxicity of PCE-AC macromonomer were also investigated in this paper. Finally, the hydrogels demonstrated that the sharp change in different pH value, thus believing to be promising the suitability of the candidate for oral drug-delivery systems.

  13. Drug-loading of poly(ethylene glycol methyl ether methacrylate) (PEGMEMA)-based micelles and mechanisms of uptake in colon carcinoma cells.

    PubMed

    Chang, Teddy; Gosain, Pallavi; Stenzel, Martina H; Lord, Megan S

    2016-08-01

    In this study polymeric micelles formed from poly(poly(ethylene glycol) methyl ether methacrylate)-block-poly(methyl methacrylate) (P(PEGMEMA75)-b-PMMA80) block copolymer of approximately 25nm in diameter were used to encapsulate the model drug, Nile Red, with a loading efficiency of 0.08wt% and a chemotherapeutic drug, doxorubicin (DOX), with an efficiency of 2.75wt%. The release of DOX from the micelles was sufficient to be cytotoxic to human colon carcinoma cells, WiDr, while Nile Red and the unloaded micelles were found not to be cytotoxic when exposed to the cells at polymer concentrations up to 200μg/mL. Nile Red loaded micelles were used to analyze uptake of the micelles into the cells which were rapidly internalized within minutes of exposure. The three major endocytotic pathways were involved in the internalization of micelles; however other passive mechanisms were also at play as the addition of inhibitors to all three pathways did not completely inhibit the uptake of these nanoparticles. These data demonstrate the potential of the P(PEGMEMA)75-b-PMMA80 block copolymer micelles to be rapidly internalized by carcinoma cells and deliver low doses of drugs intracellularly for controlled drug release.

  14. Characterization of tailor-made copolymers of oligo(ethylene glycol) methyl ether methacrylate and N,N-dimethylaminoethyl methacrylate as nonviral gene transfer agents: influence of macromolecular structure on gene vector particle properties and transfection efficiency.

    PubMed

    Uzgün, Senta; Akdemir, Ozgür; Hasenpusch, Günther; Maucksch, Christof; Golas, Monika M; Sander, Bjoern; Stark, Holger; Imker, Rabea; Lutz, Jean-François; Rudolph, Carsten

    2010-01-11

    Oligo(ethylene glycol) methyl ether methacrylates (OEGMA) of various chain lengths (i.e., 9, 23, or 45 EG units) and N,N-dimethylaminoethyl methacrylate (DMAEMA) were copolymerized by atom transfer radical polymerization (ATRP), yielding well-defined P(DMAEMA-co-OEGMA) copolymers with increasing OEGMA molar fractions (F(OEGMA)) but a comparable degree of polymerization (DP approximately 120). Increase of both F(OEGMA) and OEGMA chain lengths correlated inversely with gene vector size, morphology, and zeta potential. P(DMAEMA-co-OEGMA) copolymers prevented gene vector aggregation at high plasmid DNA (pDNA) concentrations in isotonic solution and did not induce cytotoxicity even at high concentrations. Transfection efficiency of the most efficient P(DMAEMA-co-OEGMA) copolymers was found to be >10-fold lower compared with branched polyethylenimine (PEI) 25 kDa. Although OEGMA copolymerization largely reduced gene vector binding with the cell surface, cellular internalization of the bound complexes was less affected. These observations suggest that inefficient endolysosomal escape limits transfection efficiency of P(DMAEMA-co-OEGMA) copolymer gene vectors. Despite this observation, optimized p(DMAEMA-co-OEGMA) gene vectors remained stable under conditions for in vivo application leading to 7-fold greater gene expression in the lungs compared with PEI. Tailor-made P(DMAEMA-co-OEGMA) copolymers are promising nonviral gene transfer agents that fulfill the requirements for successful in vivo gene delivery.

  15. Conjugation of salmon calcitonin to a combed-shaped end functionalized poly(poly(ethylene glycol) methyl ether methacrylate) yields a bioactive stable conjugate.

    PubMed

    Ryan, Sinéad M; Wang, Xuexuan; Mantovani, Guiseppe; Sayers, Claire T; Haddleton, David M; Brayden, David J

    2009-04-02

    Salmon calcitonin (sCT) was conjugated via its N-terminal cysteine to a comb-shaped end-functionalized poly(poly(ethylene glycol) methyl ether methacrylate) (PolyPEG, 6.5 kDa), and to linear PEG (5 kDa). Conjugate molecular weight and purity was assessed by SEC-HPLC and MALDI-TOF MS. Bioactivity of conjugates was measured by cyclic AMP assay in T47D cells. Calcium and calcitonin levels were measured in rats following intravenous injections. Stability of conjugates was tested against serine proteases, intestinal and liver homogenates and serum. Cytotoxicity of conjugates was assessed by lactate dehydrogenase (LDH) assay and by haemolytic assay of rat red blood cells. Results showed that the two conjugates were of high purity with molecular weights similar to predictions. Both conjugates retained more than 85% bioactivity in vitro and had nanomolar EC(50) values similar to sCT. While both sCT-PolyPEG(6.5 K) and sCT-PEG(5 K) were resistant to metabolism by serine proteases, homogenates and serum, PolyPEG (6.5 K) was more so. Although both conjugates reduced serum calcium to levels similar to those achieved with sCT, PolyPEG(6.5 K) extended the T(1/2) and AUC of serum sCT over values achieved with sCT-PEG and sCT itself. None of PolyPEG, PEG or methacrylic acid displayed significant cytotoxicity. PolyPEG may therefore have potential to improve pharmacokinetic profiles of injected peptides.

  16. Synthesis and fluorescence properties of divalent europium-poly(methacrylate containing crown ether structure) complexes

    SciTech Connect

    Higashiyama, N.; Nakamura, H.; Mishima, T.; Shiokawa, J.; Adachi, G. )

    1991-02-01

    This paper reports on divalent europium complexes with poly(methacrylate containing crown ether structure)s, poly(crown ether)s, prepared and their fluorescence properties studied. The polymers used were poly(15-crown-5-methyl methacrylate) (PMA15C5), copoly(15- crown-5-methyl methacrylate-X) (copoly(MA15C5-X)); (X = MMA, EMA, BMA, 2-methoxyethyl methacrylate (MAGI) 3,6,9,12,15- pentaoxahexadecyl methacrylate (MAG5)), poly(18-crown-6- methyl methacrylate) (PMA18C6), and copoly(18-crown-6-methyl methacrylate-MMA) (copoly(MA18C6-MMA)), which were obtained by bulk polymerization. The fluorescence properties of Eu{sup 2+} polymers activated by complexing Eu{sup 2+} ions with crown ether groups were measured in powder form. The Eu{sup 2+}-poly (crown ether)s irradiated by UV light generally gave blue bright emission in the region of 420-465 nm. It was Eu{sup 2+}-copoly(Ma15C5-X); (X = MMA, EMA, and MAG1) that showed the largest emission intensity among the Eu{sup 2+} polymers, and its emission intensity was ca. 20% of that for CaWO{sub 4}:Pb (NBS1026) whose quantum efficiency is about 76%. The intensities of emission for the Eu{sup 2+} polymers containing 15-crown-5 were much larger than that for the ones containing 18-crown-6.

  17. Thin Poly(Di(Ethylene Glycol)Methyl Ether Methacrylate) Homopolymer Brushes Allow Controlled Adsorption and Desorption of PaTu 8988t Cells.

    PubMed

    Voß, Yvonne; Wassel, Ekram; Jiang, Siyu; Song, Qimeng; Druzhinin, Sergey I; Schönherr, Holger

    2016-10-20

    Poly(di(ethylene glycol)methyl ether methacrylate) (PDEGMA) brushes, which are known to suppress protein adsorption and prevent cell attachment, are reported here to possess interesting and tunable thermoresponsive behavior, if the brush thickness is reduced or the grafting density is altered. PDEGMA brushes with a dry ellipsometric thickness of 5 ± 1 nm can be switched from cell adherent behavior at 37 °C to cell nonadherent at 25 °C. This behavior coincides with the temperature-dependent irreversible adsorption of fibronectin from phosphate saline buffer and proteins present in the cell culture medium, as unveiled by surface plasmon resonance measurements. Unlike for tissue culture polystyrene reference surfaces, swelling of the PDEGMA chains below the lower critical solution temperature results in the absence of paxillin and actin containing cellular filaments responsible for cell attachment. These tunable properties of very thin homopolymer PDEGMA brushes render this system interesting as an alternative thermoresponsive layer for continuous cell culture or enzyme-free cell culture systems.

  18. Synthesis and self-assembly of brush-type poly[poly(ethylene glycol)methyl ether methacrylate]-block-poly(pentafluorostyrene) amphiphilic diblock copolymers in aqueous solution.

    PubMed

    Tan, B H; Hussain, H; Liu, Y; He, C B; Davis, T P

    2010-02-16

    Well-defined fluorinated brush-like amphiphilic diblock copolymers of poly[poly(ethylene glycol)methyl ether methacrylate] (P(PEGMA)) and poly(pentafluorostyrene) (PPFS) have been successfully synthesized via atom transfer radical polymerization (ATRP). The self-assembly behavior of these polymers in aqueous solutions was studied using (1)H NMR, fluorescence spectrometry, static and dynamic light scattering and transmission electron microscopy techniques. The micellar structure comprised of PPFS as the core and brush-like (hydrophobic main chain and hydrophilic branches) polymers as the coronas. The hydrodynamic radius (R(h)) of the micelles in aqueous solution was in the nanometer range, independent of the polymer concentration, consistent with a closed association model. Diblock copolymers with a longer P(PEGMA) block formed micelles with smaller R(h) and lower aggregation numbers consistent with an improved solubilization of the core. The micelles possessed a thick hydration layer as verified by the ratio of the radius of gyration, R(g) to the hydrodynamic radius, R(h). The aggregation number and ratio of R(g) to R(h) were observed to increase with temperature (20-50 degrees C), while the R(h) of the micelle decreased slightly over the same temperature range. An increase in temperature induced the brush-like PEG segments in the corona to dehydrate and shrink while forming micelles with larger aggregation numbers.

  19. Chloromethyl methyl ether (CMME)

    Integrated Risk Information System (IRIS)

    Chloromethyl methyl ether ( CMME ) ; CASRN 107 - 30 - 2 Human health assessment information on a chemical substance is included in the IRIS database only after a comprehensive review of toxicity data , as outlined in the IRIS assessment development process . Sections I ( Health Hazard Assessments fo

  20. Self-assembly of brush-like poly[poly(ethylene glycol) methyl ether methacrylate] synthesized via aqueous atom transfer radical polymerization.

    PubMed

    Hussain, Hazrat; Mya, Khine Yi; He, Chaobin

    2008-12-02

    Self-assembly of brush-like well-defined poly[poly(ethylene glycol) methyl ether methacrylate] homopolymers, abbreviated as P(PEGMA-475) and P(PEGMA-1100) is investigated in aqueous solution by employing dynamic/static light scattering (DLS/SLS) and transmission electron microscopy (TEM), whereas 475 and 1100 is molar mass of the respective PEGMA macromonomer. The mentioned brush-like homopolymers are synthesized by aqueous ATRP at room temperature. The critical association concentration (CAC) of the synthesized polymers in water depends on the length of the PEG side chains but not on the overall molar mass of the polymer. Thus, approximately the same CAC of approximately 0.35 mg/mL is estimated for various P(PEGMA-1100) samples, and approximately 0.7 mg/mL is estimated for P(PEGMA-475) series. All the investigated P(PEGMA-1100) samples form multimolecular micelles in aqueous solution, where the hydrodynamic size (Rh) and the aggregation number (Nagg) of micelles decreases as the molecular weight of P(PEGMA-1100) increases. This can be attributed to the increased steric hindrances between the PEG side chains in corona of micelles formed by higher molar mass P(PEGMA-1100). The tendency of micelle formation by samples of P(PEGMA-475) series is significantly lower than that of P(PEGMA-1100) series, as demonstrated by their significantly higher CAC and micelles of lower Nagg. The Rh of micelles does not depend strongly on polymer concentration, which suggests that these micelles are formed via the closed association model. Micelles formed by P(PEGMA-1100) series slightly shrink with increase in temperature from 25 to 60 degrees C, while those of P(PEGMA-475) series are found to be insensitive to the same temperature variation. Finally, TEM is carried out to visualize the formed micelles after transferring the aqueous solution to carbon film.

  1. Phase Behavior of Poly(vinylidene fluoride)-graft-poly(diethylene glycol methyl ether methacrylate) in Alcohol-Water System: Coexistence of LCST and UCST.

    PubMed

    Kuila, Atanu; Maity, Nabasmita; Chatterjee, Dhruba P; Nandi, Arun K

    2016-03-10

    A thermoresponsive polymer poly(diethylene glycol methyl ether methacrylate) (PMeO2MA) is grafted from poly(vinylidene fluoride) (PVDF) backbone by using a combined ATRC and ATRP technique with a high conversion (69%) of the monomer to produce the graft copolymer (PD). It is highly soluble polymer and its solution property is studied by varying polarity in pure solvents (water, methanol, isopropanol) and also in mixed solvents (water-methanol and water-isopropanol) by measuring the hydrodynamic size (Z-average) of the particles by dynamic light scattering (DLS). The variation of Z-average size with temperature of the PD solution (0.2%, w/v) indicates a lower critical solution temperature (LCST)-type phase transition (T(PL)) in aqueous medium, an upper critical solution temperature (UCST)-type phase transition (T(PU)) in isopropanol medium, and no such phase transition for methanol solution. In the mixed solvent (water + isopropanol) at 0-20% (v/v) isopropanol the TPL increases, whereas the T(PU) decreases at 92-100% with isopropanol content. For the mixture 20-90% isopropanol, PD particles having larger sizes (400-750 nm) exhibit neither any break in Z-average size-temperature plot nor any cloudiness, indicating their dispersed swelled state in the medium. In the methanol + water mixture with methanol content of 0-30%, T(PL) increases, and at 40-60% both UCST- and LCST-type phase separations occur simultaneously, but at 70-90% methanol the swelled state of the particles (size 250-375 nm) is noticed. For 50 vol % methanol by varying polymer concentration (0.07-0.2% w/v) we have drawn a quasibinary phase diagram that indicates an approximate inverted hourglass phase diagram where a swelled state exists between two single phase boundary produced from LCST- and UCST-type phase transitions. An attempt is made to understand the phase separation process by temperature-dependent (1)H NMR spectroscopy along with transmission electron microscopy.

  2. Cononsolvency-induced micellization of pyrene end-labeled diblock copolymers of N-isopropylacrylamide and oligo(ethylene glycol) methyl ether methacrylate.

    PubMed

    Rao, Jingyi; Xu, Jian; Luo, Shizhong; Liu, Shiyong

    2007-11-06

    Pyrene end-labeled double hydrophilic diblock copolymers, poly(N-isopropylacrylamide)-b-poly(oligo(ethylene glycol) methyl ether methacrylate) (Py-PNIPAM-b-POEGMA), were synthesized via consecutive reversible addition-fragmentation chain transfer polymerization using a pyrene-containing dithioester as the chain transfer agent. These diblock copolymers molecularly dissolve in pure methanol and water, but form well-defined and nearly monodisperse PNIPAM-core micelles in an appropriate mixture of them due to the cononsolvency of PNIPAM block. 1H NMR, laser light scattering, fluorescence spectroscopy, and transmission electron microscopy were employed to characterize the cononsolvency-induced PNIPAM-core micelles. When the volume fraction of water, phi water, in the methanol/water mixture is in the range of 0.5-0.8, the sizes of micelles are in the range of 20-30 nm in radius for Py-PNIPAM50-b- POEGMA18. At phi water = 0.5, the formed micelles possess the highest overall micelle density and the largest molar mass. The effects of varying the block lengths of Py-PNIPAM-b-POEGMA diblock copolymers on the structural parameters of PNIPAM-core micelles have also been explored. Although we can observe the immediate appearance of bluish tinge upon mixing the diblock copolymer solution in methanol with equal volume of water (phi water = 0.5), which is characteristic of the formation of micellar aggregates, the whole micellization process apparently takes a relatively long time to complete, as revealed by monitoring the time dependence of fluorescence emission spectra. The excimer/monomer fluorescence intensity ratios, IE/IM, continuously decrease with time and then reach a plateau value after approximately 20 min. The decrease of IE/IM after the initial formation of pseudo-equilibrium micelles should be ascribed to the structural rearrangement and further packing of PNIPAM segments within the micelle core, restricting the mobility of pyrene end groups and decreasing the

  3. Reduced hydrophobic interaction of polystyrene surfaces by spontaneous segregation of block copolymers with oligo (ethylene glycol) methyl ether methacrylate blocks: force measurements in water using atomic force microscope with hydrophobic probes.

    PubMed

    Zhang, Rui; Seki, Akiko; Ishizone, Takashi; Yokoyama, Hideaki

    2008-05-20

    Reduction of hydrophobic interaction in water is important in biological interfaces. In our previous work, we have found that poly(styrene- b-triethylene glycol methyl ether methacrylate) (PS-PME3MA) segregates the PME3MA block to the surface in hydrophobic environment, such as in air or in a vacuum, and shows remarkable resistance against adsorption or adhesion of proteins, platelets, and cells in water. In this paper, we report that atomic force microscopy (AFM) with hydrophobic probes can directly monitor the reduced hydrophobic interaction of the PS surfaces modified by poly(styrene- b-origoethylene glycol methyl ether methacrylate) (PS-PME NMA), where N is the number of ethylene glycol units. The pull-off forces between the hydrophobic probes that are coated with octyltrichlorosilane (OLTS) and the PS-PME NMA modified polystyrene (PS) surfaces in water were measured. The absolute spring constants and tip-curvatures of the AFM cantilevers were measured to compute the work of adhesion by the Johnson, Kendall, and Roberts (JKR) theory, which relates the pull-off force at which the separation occurs between a hemisphere and a plane to the work of adhesion. The hydrophobic interactions between the hydrophobic tip and polymer surfaces in water were greatly reduced with the segregated PME NMA blocks. The hydrophobic interactions decrease with increasing N of the series of PS-PME NMA and show a correlation with the amount of protein adsorbed.

  4. Biodegradation of poly(2-hydroxyethyl methacrylate) (PHEMA) and poly{(2-hydroxyethyl methacrylate)-co-[poly(ethylene glycol) methyl ether methacrylate]} hydrogels containing peptide-based cross-linking agents.

    PubMed

    Casadio, Ylenia S; Brown, David H; Chirila, Traian V; Kraatz, Heinz-Bernhard; Baker, Murray V

    2010-11-08

    PHEMA-peptide and P[HEMA-co-(MeO-PEGMA)]-peptide conjugate hydrogels [where PHEMA = poly(2-hydroxyethyl methacrylate; PEGMA = poly(ethylene glycol) methacrylate] were readily prepared via photoinitiated free-radical polymerization in water. The PHEMA-peptide hydrogels were opaque and had a heterogeneous morphology of interconnected polymer droplets, characteristic of polymers that separate from the aqueous phase during the polymerization experiment. The P[HEMA-co-(MeO-PEGMA)]-peptide conjugates were transparent gels with a homogeneous morphology when formed in water, but when formed in aqueous NaCl solutions the P[HEMA-co-(MeO-PEGMA)]-peptide conjugates were also opaque and exhibited the heterogeneous morphology of interconnected polymer droplets. When incubated in solutions containing activated papain, P[HEMA-co-(MeO-PEGMA)]-peptide conjugates underwent degradation that was characterized by macroscopic changes to sample shape and size, sample weight, and microscopic structure. PHEMA-peptide conjugates did not undergo any significant degradation when incubated with papain, although ninhydrin-staining experiments suggested that some peptide cross-linker groups were cleaved during the incubation. The difference in degradation behavior of PHEMA-peptide and P[HEMA-co-(MeO-PEGMA)]-peptide conjugates is attributed to differences in aqueous solubility of PHEMA and P[HEMA-co-(MeO-PEGMA)].

  5. Desoxyhemigossypol-6-methyl-ether

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Desoxyhemigossypol-6-methyl ether is an antimicrobial compound produced by the cotton plant in response to attack by pathogens. For the first time, we now report the crystal structure of this compound. This may prove useful in studies on the interaction of the compound with pathogenic fungal cells...

  6. Lacinilene C 7-methyl ether

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Lacinilene C 7-methyl ether is an antimicrobial compound produced by the cotton plant in response to attack by pathogens. For the first time, we now report the crystal structure of this compound. This may prove useful in studies on the interaction of the compound with pathogenic fungal cells....

  7. A pre-formed methyl methacrylate cranioplasty.

    PubMed

    Cooper, P R; Schechter, B; Jacobs, G B; Rubin, R C; Wille, R L

    1977-09-01

    The use of a pre-formed methyl methacrylate cranioplasty prosthesis reinforced with stainless steel wire is described. The prosthesis is non-reactive, virtually unbreakable, and undentable. Pre-forming of the prosthesis in the dental laboratory using a mold of the patient's bony defect as a model saves considerable operating time, and when employed for a large cranial defect the three dimensional cosmetic effect is superior to intra-operatively fashioned prostheses.

  8. 21 CFR 882.5300 - Methyl methacrylate for cranioplasty.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... methacrylate for cranioplasty. (a) Identification. Methyl methacrylate for cranioplasty (skull repair) is a self-curing acrylic that a surgeon uses to repair a skull defect in a patient. At the time of...

  9. 21 CFR 882.5300 - Methyl methacrylate for cranioplasty.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... methacrylate for cranioplasty. (a) Identification. Methyl methacrylate for cranioplasty (skull repair) is a self-curing acrylic that a surgeon uses to repair a skull defect in a patient. At the time of...

  10. 21 CFR 882.5300 - Methyl methacrylate for cranioplasty.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... methacrylate for cranioplasty. (a) Identification. Methyl methacrylate for cranioplasty (skull repair) is a self-curing acrylic that a surgeon uses to repair a skull defect in a patient. At the time of...

  11. 21 CFR 882.5300 - Methyl methacrylate for cranioplasty.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... methacrylate for cranioplasty. (a) Identification. Methyl methacrylate for cranioplasty (skull repair) is a self-curing acrylic that a surgeon uses to repair a skull defect in a patient. At the time of...

  12. 21 CFR 882.5300 - Methyl methacrylate for cranioplasty.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... methacrylate for cranioplasty. (a) Identification. Methyl methacrylate for cranioplasty (skull repair) is a self-curing acrylic that a surgeon uses to repair a skull defect in a patient. At the time of...

  13. Dendrimer/methyl methacrylate co-polymers: residual methyl methacrylate and degree of conversion.

    PubMed

    Viljanen, Eeva K; Skrifvars, Mikael; Vallittu, Pekka K

    2005-01-01

    Dendrimer/methyl methacrylate co-polymers were studied for use in dental composites. The aim was to determine the effects of methyl methacrylate concentration in the resin mixture and polymerization method on the degree of conversion and residual monomer content of the copolymers. Two dendrimers were studied, D12 with 12 reactive methacrylate groups and D24 with 24 reactive groups. The concentration of methyl methacrylate varied from 20 wt% to 50 wt% of monomers. Camphorquinone (CQ) was used as the light-activation initiator and 2-(N,N-dimethylamino)ethyl methacrylate (DMAEMA) as the activator, both in the quantity of 3.0 wt%. Three polymerization methods were used: photo-polymerization, photo-polymerized immediately followed by post-polymerization at 120 degrees C for 15 min, and photo-polymerization followed by postpolymerization after 7 days. The degree of conversion was determined using FT-IR. Residual monomers were extracted with tetrahydrofuran and methanol and analyzed with HPLC. The highest degrees of conversion were 65 and 62%, and the lowest residual monomer contents 1.0 and 1.5% for D12 and D24, respectively. These were measured after heat-induced post-polymerization. For D12, increasing the proportion of methyl methacrylate decreased the degree of conversion and increased the residual monomer content after photo-polymerization. Post-polymerization enhanced the polymerization of the dendrimer co-polymers in respect of degree of conversion and residual monomer content. The present study suggested that the tested dendrimer/methyl methacrylate copolymers require heat-induced polymerization to reach the generally accepted levels of degree of conversion and residual monomers.

  14. Cononsolvency-induced micellization kinetics of pyrene end-labeled diblock copolymer of N-isopropylacrylamide and oligo(ethylene glycol) methyl ether methacrylate studied by stopped-flow light-scattering and fluorescence.

    PubMed

    Rao, Jingyi; Zhang, Jingyan; Xu, Jian; Liu, Shiyong

    2008-12-01

    Cononsolvency-induced micellization kinetics of a pyrene end-labeled diblock copolymer of N-isopropylacrylamide and oligo(ethylene glycol) methyl ether methacrylate, Py-PNIPAM-b-POEGMA, was investigated in detail via a combination of stopped-flow light-scattering and fluorescence techniques. Upon a stopped-flow jump from pure methanol to proper methanol/water mixtures, scattered light intensity exhibited an initial increase and then stabilized out; whereas the time-dependence of monomer to excimer fluorescence intensity ratios (I E/I M) revealed an abrupt increase followed by a gradual decrease to plateau values. The dynamic traces of scattered intensity can be well fitted by double exponential functions, the obtained tau 1, scat and tau 2, scat can be ascribed to processes of forming quasi-equilibrium micelles and their relaxation into final equilibrium states, respectively. On the other hand, a triple exponential function was needed to fit the dynamic traces of I E/I M, leading to three characteristic relaxation times (tau 1, fluo, tau 2, fluo, and tau 3, fluo). It was found that the time scales of tau 1, scat and tau 2, scat obtained from stopped-flow light scattering were in general agreement with tau 2, fluo and tau 3, fluo obtained from stopped-flow fluorescence. Considering that excimer fluorescence is extremely sensitive to small aggregates, the newly detected fast process (tau 1, fluo) approximately 10 ms) by stopped-flow fluorescence should be ascribed to the early stage of micellization, i.e., the burst formation of small transient micelles, in which light scattering detection was still not sensitive enough. These small transient micelles fused and grew into quasi-equilibrium micelles, which then slowly relaxed into the final equilibrium state.

  15. 21 CFR 177.2000 - Vinylidene chloride/methyl acrylate/methyl methacrylate polymers.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... methacrylate polymers. 177.2000 Section 177.2000 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) INDIRECT FOOD ADDITIVES: POLYMERS Substances for Use as Basic.../methyl methacrylate polymers. The vinylidene chloride/methyl acrylate/methyl methacrylate polymers...

  16. pH-sensitive micelles self-assembled from multi-arm star triblock co-polymers poly(ε-caprolactone)-b-poly(2-(diethylamino)ethyl methacrylate)-b-poly(poly(ethylene glycol) methyl ether methacrylate) for controlled anticancer drug delivery.

    PubMed

    Yang, You Qiang; Zhao, Bin; Li, Zhen Dong; Lin, Wen Jing; Zhang, Can Yang; Guo, Xin Dong; Wang, Ju Fang; Zhang, Li Juan

    2013-08-01

    A series of amphiphilic 4- and 6-armed star triblock co-polymers poly(ε-caprolactone)-b-poly(2-(diethylamino)ethyl methacrylate)-b-poly(poly(ethylene glycol) methyl ether methacrylate) (4/6AS-PCL-b-PDEAEMA-b-PPEGMA) were developed by a combination of ring opening polymerization and continuous activators regenerated by electron transfer atom transfer radical polymerization. The critical micelle concentration values of the star co-polymers in aqueous solution were extremely low (2.2-4.0mgl(-1)), depending on the architecture of the co-polymers. The self-assembled blank and doxorubicin (DOX)-loaded three layer micelles were spherical in shape with an average size of 60-220nm determined by scanning electron microscopy and dynamic light scattering. The in vitro release behavior of DOX from the three layer micelles exhibited pH-dependent properties. The DOX release rate was significantly accelerated by decreasing the pH from 7.4 to 5.0, due to swelling of the micelles at lower pH values caused by the protonation of tertiary amine groups in DEAEMA in the middle layer of the micelles. The in vitro cytotoxicity of DOX-loaded micelles to HepG2 cells suggested that the 4/6AS-PCL-b-PDEAEMA-b-PPEGMA micelles could provide equivalent or even enhanced anticancer activity and bioavailability of DOX and thus a lower dosage is sufficient for the same therapeutic efficacy. The results demonstrate that the pH-sensitive multilayer micelles could have great potential application in delivering hydrophobic anticancer drugs for improved cancer therapy.

  17. DEGRADATION OF POLY(METHYL METHACRYLATE) IN SOLUTION

    EPA Science Inventory

    The rate of degradation of poly(methyl methacrylate) (PMMA) to methyl methacrylate (MMA) was investigated in the liquid phase with toluene as the solvent. The degradation experiments were carried out in a tubular flow reactor at 1000 psig (6.8 MPa) and at four different temperat...

  18. Toughening epoxy resin with poly(methyl methacrylate)-grafted natural rubber

    SciTech Connect

    Rezaifard, A.H.; Hodd, K.A.; Barton, J.M.

    1993-12-31

    A novel rubber, poly(methyl methacrylate)-g-natural rubber (Hevea-plus MG), has been studied as a toughening agent for bisphenol A diglycidyl ether (Shell 828 epoxy resin) cured with piperidine. Effective dispersions of the rubber, in concentrations of 2-10 parts per hundred parts resin, were achieved by adjusting the solubility parameter of the epoxy to approximate that of poly(methyl methacrylate) by adding bisphenol A. The fracture energy of the rubber-modified resin was determined by compact tension tests (in the temperature range -60 to +40{degrees}C) and by Charpy impact tests. The poly(methyl methacrylate)-g-natural rubber was found to be an effective toughening agent for the epoxy resin at both low and high rates of strain. Possible fracture mechanisms are discussed. 22 refs., 16 figs., 5 tabs.

  19. Conformations and Barriers to Methyl Group Internal Rotation in Two Asymmetric Ethers: Propyl Methyl Ether and Butyl Methyl Ether

    NASA Astrophysics Data System (ADS)

    Long, B. E.; Dechirico, F.; Cooke, S. A.

    2012-06-01

    The conformational preferences of the O-C-C-C unit are important in many biological systems with the unit generally preferring a gauche configuration compared to an anti configuration. Butyl methyl ether and propyl methyl ether provide very simple systems for this phenomenom to manifest. Pure rotational spectra of the title molecules have been recorded using chirped pulse Fourier transform microwave spectroscopy (CP-FTMW). In the case of butyl methyl ether, only one conformer has been observed. This conformer has torsional angles of COCC = 180°, OCCC = 62° and CCCC = 180° (anti-gauche-anti) and rotational constants of A = 10259.4591(33) MHz, B = 1445.6470(13) MHz, and C = 1356.2944(14) MHz. The rotational spectrum was doubled and has been analyzed to produce an effective barrier to methyl group internal rotation of 780(35) cm-1. A prior rotational spectroscopic study on propyl methyl ether had focused only on the high energy anti-anti conformer. We have analyzed spectra from the lowest energy anti-gauche conformer and the spectroscopic constants will be presented. A summary of the differences in conformational energies and methyl group internal rotation barriers for the class of aliphatic asymmetric ethers will be presented. K. N. Houk, J. E. Eksterowicz, Y.-D. Wu, C. D. Fuglesang, D. B. Mitchell. J. Am. Chem. Soc. 115 (4170), 1993. Hiroshi Kato, Jun Nakagawa, Michiro Hayashi. J. Mol. Spectrosc. 80 (272), 1980.

  20. 40 CFR 721.6920 - Butyl acrylate, polymer with substituted methyl styrene, methyl methacrylate, and substituted...

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 32 2013-07-01 2013-07-01 false Butyl acrylate, polymer with... acrylate, polymer with substituted methyl styrene, methyl methacrylate, and substituted silane. (a... butyl acrylate, polymer with substituted methyl styrene, methyl methacrylate, and substituted...

  1. 40 CFR 721.6920 - Butyl acrylate, polymer with substituted methyl styrene, methyl methacrylate, and substituted...

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 31 2011-07-01 2011-07-01 false Butyl acrylate, polymer with... acrylate, polymer with substituted methyl styrene, methyl methacrylate, and substituted silane. (a... butyl acrylate, polymer with substituted methyl styrene, methyl methacrylate, and substituted...

  2. 40 CFR 721.6920 - Butyl acrylate, polymer with substituted methyl styrene, methyl methacrylate, and substituted...

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Butyl acrylate, polymer with... acrylate, polymer with substituted methyl styrene, methyl methacrylate, and substituted silane. (a... butyl acrylate, polymer with substituted methyl styrene, methyl methacrylate, and substituted...

  3. 40 CFR 721.6920 - Butyl acrylate, polymer with substituted methyl styrene, methyl methacrylate, and substituted...

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 31 2014-07-01 2014-07-01 false Butyl acrylate, polymer with... acrylate, polymer with substituted methyl styrene, methyl methacrylate, and substituted silane. (a... butyl acrylate, polymer with substituted methyl styrene, methyl methacrylate, and substituted...

  4. 40 CFR 721.6920 - Butyl acrylate, polymer with substituted methyl styrene, methyl methacrylate, and substituted...

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 32 2012-07-01 2012-07-01 false Butyl acrylate, polymer with... acrylate, polymer with substituted methyl styrene, methyl methacrylate, and substituted silane. (a... butyl acrylate, polymer with substituted methyl styrene, methyl methacrylate, and substituted...

  5. 21 CFR 177.2000 - Vinylidene chloride/methyl acrylate/methyl methacrylate polymers.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... methacrylate polymers. 177.2000 Section 177.2000 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF...: POLYMERS Substances for Use as Basic Components of Single and Repeated Use Food Contact Surfaces § 177.2000 Vinylidene chloride/methyl acrylate/methyl methacrylate polymers. The vinylidene chloride/methyl...

  6. 21 CFR 177.2000 - Vinylidene chloride/methyl acrylate/methyl methacrylate polymers.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... methacrylate polymers. 177.2000 Section 177.2000 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF...: POLYMERS Substances for Use as Basic Components of Single and Repeated Use Food Contact Surfaces § 177.2000 Vinylidene chloride/methyl acrylate/methyl methacrylate polymers. The vinylidene chloride/methyl...

  7. 21 CFR 177.2000 - Vinylidene chloride/methyl acrylate/methyl methacrylate polymers.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... methacrylate polymers. 177.2000 Section 177.2000 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF...: POLYMERS Substances for Use as Basic Components of Single and Repeated Use Food Contact Surfaces § 177.2000 Vinylidene chloride/methyl acrylate/methyl methacrylate polymers. The vinylidene chloride/methyl...

  8. 21 CFR 177.2000 - Vinylidene chloride/methyl acrylate/methyl methacrylate polymers.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... methacrylate polymers. 177.2000 Section 177.2000 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF...: POLYMERS Substances for Use as Basic Components of Single and Repeated Use Food Contact Surfaces § 177.2000 Vinylidene chloride/methyl acrylate/methyl methacrylate polymers. The vinylidene chloride/methyl...

  9. SYNTHESIS OF METHYL METHACRYLATE FROM COAL-DERIVED SYNGAS

    SciTech Connect

    BEN W.-L. JANG; GERALD N. CHOI; JAMES J. SPIVEY; JOSPEH R. ZOELLER; RICHARD D. COLBERG.

    1999-01-20

    Research Triangle Institute (RTI), Eastman Chemical Company, and Bechtel collectively are developing a novel three-step process for the synthesis of methyl methacrylate (MMA) from coal-derived syngas that consists of the steps of synthesis of a propionate, its condensation with formaldehyde to form methacrylic acid (MAA), and esterification of MAA with methanol to produce MMA. The research team has completed the research on the three-step methanol-based route to MMA. Under an extension to the original contract, we are currently evaluating a new DME-based process for MMA. The key research need for DME route is to develop catalysts for DME partial oxidation reactions and DME condensation reactions. Over the last quarter(Oct.-Dec./98), we have investigated the condensation between methyl propionate and formaldehyde (MP/HCHO=4.5/1) at various reaction temperatures(280-360EC) over 5%, 10%, and 20% Nb O /SiO catalysts. The conversion of HCHO increases with reaction 2 5 2 temperature and niobium loading. MMA+MAA selectivity goes through a maximum with the temperature over both 10% and 20% Nb O /SiO . The selectivities to MMA+MAA are 67.2%, 2 5 2 72.3%and 58.1% at 320EC over 5%, 10%, 20% Nb O /SiO , respectively. However, the 2 5 2 conversion of formaldehyde decreases rapidly with time on stream. The results suggest that silica supported niobium catalysts are active and selective for condensation of MP with HCHO, but deactivation needs to be minimized for the consideration of commercial application. We have preliminarily investigated the partial oxidation of dimethyl ether(DME) over 5% Nb O /SiO catalyst. Reactant gas mixture of 0.1% DME, 0.1% O and balance nitrogen is 2 5 2 2 studied with temperature ranging from 200C to 500C. The conversion of DME first increases with temperature reaching an maximum at 400C then decreases. The selectivity to HCHO also increases with reaction temperature first. But the selectivity to HCHO decreases at temperature above 350C accompanied by

  10. SYNTHESIS OF METHYL METHACRYLATE FROM COAL-DERIVED SYNGAS

    SciTech Connect

    BEN W.-L. JANG; GERALD N. CHOI; JAMES J. SPIVEY; JOSPEH R. ZOELLER; RICHARD D. COLBERG

    1999-01-20

    Research Triangle Institute (RTI), Eastman Chemical Company, and Bechtel collectively are developing a novel three-step process for the synthesis of methyl methacrylate (MMA) from coal-derived syngas that consists of the steps of synthesis of a propionate, its condensation with formaldehyde to form methacrylic acid (MAA), and esterification of MAA with methanol to produce MMA. The research team has completed the research on the three-step methanol-based route to MMA. Under an extension to the original contract, we are currently evaluating a new DME-based process for MMA. The key research need for DME route is to develop catalysts for DME partial oxidation reactions and DME condensation reactions. Over the last quarter(Oct.-Dec./98), we have investigated the condensation between methyl propionate and formaldehyde (MP/HCHO=4.5/1) at various reaction temperatures(280-360EC) over 5%, 10%, and 20% Nb O /SiO catalysts. The conversion of HCHO increases with reaction 2 5 2 temperature and niobium loading. MMA+MAA selectivity goes through a maximum with the temperature over both 10% and 20% Nb O /SiO . The selectivities to MMA+MAA are 67.2%, 2 5 2 72.3%and 58.1% at 320EC over 5%, 10%, 20% Nb O /SiO , respectively. However, the 2 5 2 conversion of formaldehyde decreases rapidly with time on stream. The results suggest that silica supported niobium catalysts are active and selective for condensation of MP with HCHO, but deactivation needs to be minimized for the consideration of commercial application. We have preliminarily investigated the partial oxidation of dimethyl ether(DME) over 5% Nb O /SiO catalyst. Reactant gas mixture of 0.1% DME, 0.1% O and balance nitrogen is 2 5 2 2 studied with temperature ranging from 200°C to 500°C. The conversion of DME first increases with temperature reaching an maximum at 400°C then decreases. The selectivity to HCHO also increases with reaction temperature first. But the selectivity to HCHO decreases at temperature above 350

  11. Methyl tert-butyl ether (MTBE)

    Integrated Risk Information System (IRIS)

    Methyl tert - butyl ether ( MTBE ) ; CASRN 1634 - 04 - 4 Human health assessment information on a chemical substance is included in the IRIS database only after a comprehensive review of toxicity data , as outlined in the IRIS assessment development process . Sections I ( Health Hazard Assessments f

  12. Solute solvent interaction in methyl methacrylate and 2-hydroxyethyl methacrylate monomers solutions

    NASA Astrophysics Data System (ADS)

    Al-ghamdi, Attieh A.; Bahattab, M. A.; Farhoud, M.; Al-Dossary, Mishal; Al-Enizi, Abdullah; Al-Deyab, S. S.

    2006-11-01

    Solute-solvent interactions are studied using induced birefringence measurements in monomers solutions of methyl methacrylate (MMA) and 2-hydroxyethyl methacrylate (HEMA), dissolved in ethanol, acetone, ethyl acetate, tetrahydrofuran and dimethyl sulfoxide, over a broad range of concentrations. The data are combined with refractive index and density to calculate the electric, optical and molar Kerr constants. All related microscopic parameters concerning the molecular structure such as nonlinear Kerr constants, anisotropic factors, and optical anisotropy have been calculated.

  13. Poly(methyl methacrylate)-cellulose nitrate copolymers. I. Preparation

    SciTech Connect

    Badran, B.M.; Sherif, S.; Abu-Sedira, A.A.

    1981-03-01

    Poly(methyl methacrylate)-cellulose nitrate copolymers were prepared in the form of rods and sheets by bulk polymerization using benzoyl peroxide as initiator. Suspension polymerization did not succeed in preparing poly(methyl methacrylate)-cellulose nitrate copolymers, especially when cellulose nitrate of 11.4% nitrogen content was used. The parameters such as cellulose nitrate concentration, nitrogen content of cellulose nitrate, the amount of initiator and the reaction time, and the temperature are discussed. The prepared copolymers were irradiated for specified periods of up to 11.83 Mrad. It was found that poly(methyl methacrylate)-cellulose nitrate copolymers did not dissolve in any conventional solvent, but they swelled. Swelling decreases with increasing cellulose nitrate concentrations, nitrogen content of cellulose nitrate, and irradiation dose, indicating the crosslinked structure of the prepared copolymers.

  14. Crosslinked superhydrophobic films fabricated by simply casting poly(methyl methacrylate-butyl acrylate-hydroxyethyl methacrylate)-b-poly(perfluorohexylethyl methacrylate) solution

    NASA Astrophysics Data System (ADS)

    Wen, Xiufang; Ye, Chao; Cai, Zhiqi; Xu, Shouping; Pi, Pihui; Cheng, Jiang; Zhang, Lijuan; Qian, Yu

    2015-06-01

    This study focuses on the preparation of superhydrophobic films by crosslinkable polymer material-Poly(methyl methacrylate-butyl acrylate-hydroxyethyl methacrylate)-b-Poly(perfluorohexylethyl methacrylate) (P (MMA-BA-HEMA)-b-PFMA) with a simple one-step casting process. Nanoscale micelle particles with core-shell structure was obtained by dissolving the polymer and curing agent in the mixture of acetone and 1H, 1H, 5H octafluoropentyl-1,1,2,2 tetrafluoroethyl ether (FHT). Superhydrophobic films were fabricated by casting the micelle solution on the glass slides. By controlling the polymer concentration and acetone/FHT volume ratio, superhydrophobic polymer film with water contact angle of 153.2 ± 2.1° and sliding angle of 4° was obtained. By introducing a curing agent into the micelle solution, mechanical properties of the films can be improved. The adhension grade and hardness of the crosslinked superhydrophobic films reached 2 grade and 3H, respectively. The hydrophobicity is attributed to the synergistic effect of micro-submicro-nano-meter scale roughness by nanoscale micelle particles and low surface energy of fluoropolymer. This procedure makes it possible for widespread applications of superhydrophobic film due to its simplicity and practicability.

  15. 21 CFR 73.3127 - Vinyl alcohol/methyl methacrylate-dye reaction products.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 1 2013-04-01 2013-04-01 false Vinyl alcohol/methyl methacrylate-dye reaction... Vinyl alcohol/methyl methacrylate-dye reaction products. (a) Identity. The color additives are formed by reacting the dyes, either alone or in combination, with a vinyl alcohol/methyl methacrylate copolymer,...

  16. 21 CFR 73.3127 - Vinyl alcohol/methyl methacrylate-dye reaction products.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 1 2012-04-01 2012-04-01 false Vinyl alcohol/methyl methacrylate-dye reaction... Vinyl alcohol/methyl methacrylate-dye reaction products. (a) Identity. The color additives are formed by reacting the dyes, either alone or in combination, with a vinyl alcohol/methyl methacrylate copolymer,...

  17. 21 CFR 73.3127 - Vinyl alcohol/methyl methacrylate-dye reaction products.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 1 2014-04-01 2014-04-01 false Vinyl alcohol/methyl methacrylate-dye reaction... Vinyl alcohol/methyl methacrylate-dye reaction products. (a) Identity. The color additives are formed by reacting the dyes, either alone or in combination, with a vinyl alcohol/methyl methacrylate copolymer,...

  18. Occupational asthma due to methyl methacrylate and cyanoacrylates.

    PubMed Central

    Lozewicz, S; Davison, A G; Hopkirk, A; Burge, P S; Boldy, D A; Riordan, J F; McGivern, D V; Platts, B W; Davies, D; Newman Taylor, A J

    1985-01-01

    Five patients had asthma provoked by cyanoacrylates and one by methyl methacrylate, possibly because of the development of a specific hypersensitivity response. Acrylates have wide domestic as well as industrial uses, and inhalation of vapour emitted during their use can cause asthma. PMID:4071461

  19. 21 CFR 73.3127 - Vinyl alcohol/methyl methacrylate-dye reaction products.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 1 2011-04-01 2011-04-01 false Vinyl alcohol/methyl methacrylate-dye reaction... Vinyl alcohol/methyl methacrylate-dye reaction products. (a) Identity. The color additives are formed by... methacrylate-dye reaction product listed under this section into commerce shall submit to the Food and...

  20. 21 CFR 73.3127 - Vinyl alcohol/methyl methacrylate-dye reaction products.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 1 2010-04-01 2010-04-01 false Vinyl alcohol/methyl methacrylate-dye reaction... Vinyl alcohol/methyl methacrylate-dye reaction products. (a) Identity. The color additives are formed by... methacrylate-dye reaction product listed under this section into commerce shall submit to the Food and...

  1. Solid coatings deposited from liquid methyl methacrylate via Plasma Polymerization

    NASA Astrophysics Data System (ADS)

    Wurlitzer, Lisa; Maus-Friedrichs, Wolfgang; Dahle, Sebastian

    2016-09-01

    The polymerization of methyl methacrylate via plasma discharges is well known today. Usually, plasma-enhanced chemical vapor deposition (PECVD) is used to deposit polymer coatings. Solid coatings are formed out of the liquid phase from methyl methacrylate via dielectric barrier discharge. The formation of the coating proceeds in the gas and the liquid phase. To learn more about the reactions in the two phases, the coatings from MMA monomer will be compared to those from MMA resin. Finally, attenuated total reflection infrared spectroscopy, confocal laser scanning microscopy and X-ray photoelectron spectroscopy are employed to characterize the solid coatings. In conclusion, the plasma enhanced chemical solution deposition is compared to the classical thermal polymerization of MMA.

  2. [Chest granuloma secondary to methyl methacrylate. Case report].

    PubMed

    Martínez-Bistrain, Ricardo; Robles García, Verónica; Cornejo-Morales, Ivonne

    2010-01-01

    We present the case of a patient with a history of a massive left hemithorax crushing injury in 1985; the exact management of the lesion is unknown. Twenty years later he had a thoracic fistula with a culture that was reported as positive for Enteroccocus faecalis and Staphyloccocus epidermidis. The patient was referred by the chest surgery service with the diagnosis of rib osteomyelitis once complementary imaging tests were performed (plain X-rays, CAT scan and MRI). The patient underwent surgery at our service; a granulomatous reaction secondary to a foreign body (methyl methacrylate and Ethibon) was reported. Chest reconstruction for massive lesions is possible with methyl methacrylate. Imaging studies involve the well-known difficulty to identify this material, given that it may produce signals and densities that are difficult to interpret by specialized physicians.

  3. SYNTHESIS OF METHYL METHACRYLATE FROM COAL-DERIVED SYNGAS

    SciTech Connect

    Makarand R. Gogate; James J. Spivey; Joseph R. Zoeller; Richard D. Colberg; Gerald N. Choi; Samuel S. Tam

    1999-04-21

    Research Triangle Institute (RTI), Eastman Chemical Company, and Bechtel collectively are developing a novel three-step process for the synthesis of methyl methacrylate (MMA) from coal-derived syngas that consists of the steps of synthesis of a propionate, its condensation with formaldehyde to form methacrylic acid (MAA), and esterification of MAA with methanol to produce MMA. The research team has completed the research on the three-step methanol-based route to MMA. Under an extension to the original contract, we are currently evaluating a new DME-based process for MMA. The key research need for DME route is to develop catalysts for DME partial oxidation reactions and DME condensation reactions. Over the last quarter (January-March/99), in-situ formaldehyde generation and condensation with methyl propionate were tested over various catalysts and reaction conditions. The patent application is in preparation and the results are retained for future reports.

  4. Positron annihilation investigations on poly(methyl methacrylate)

    NASA Astrophysics Data System (ADS)

    Mohamed, Hamdy F. M.; Abd-Elsadek, Gomaa G.

    2000-06-01

    Positron lifetime and Doppler broadened annihilation radiation were measured for seven different samples of poly(methyl methacrylate) at room temperature in vacuum. The polymerisation of methyl methacrylate was carried out as a bulk polymerisation in the presence of benzoyl peroxide as an initiator. The effect of the amount of the initiator on the viscosity-average molecular weight was studied. It was found that the viscosity-average molecular weight decreased with increasing amount of the initiator. The average lifetime and intensity of ortho-positronium ( o-Ps) increased with increasing viscosity-average molecular weight up to 6.85 × 10 4 and remained constant after that. The S-parameter showed a similar behaviour as that of the o-Ps intensity.

  5. Mechanism of plasma polymerization of methyl methacrylate

    SciTech Connect

    Denes, F.; Sarmadi, A.M.; Hop, C.E.C.A.; Young, R.A.

    1993-12-31

    Molecular fragments from radio-frequency plasma polymerization of methylmethacrylate (MMA) were cold-trapped and characterized by gas chromatography-mass spectroscopy (GC/MS). The gas phase and the liquid phase products from the cold trap were analyzed separately. The gas phase contained a predominance of the saturated aliphatic compounds butane, pentane, and isopentane and unsaturated l-butene, in addition to saturated MMA monomer (methyl isobutyrate); the liquid phase contained mainly isopropenyl alcohol, saturated MMA and a methylated form of the saturated MMA. Calculations of the predominant plasma-generated molecular clusters using the CG/MS data for both the gas and liquid phases indicated that saturated and unsaturated propyl radicals (molecular weight 41-43) were by far the predominant radical species in the plasma reactions and would lead to a hydrocarbon-type polymer with considerable unsaturation and crosslinking. The occurrence of other radical species containing methyl ester and hydroxyl groups accounts for the presence of these functional groups in the final polymer. Infrared and ultraviolet spectra confirmed the participation of the predominant aliphatic radicals in the formation of PPMMA. Clearly PPMA is a distinctly different polymer when compared to conventional PMMA.

  6. Improvement of holographic thermal stability in phenanthrenequinone-doped poly(methyl methacrylate-co-methacrylic acid) photopolymer

    NASA Astrophysics Data System (ADS)

    Yu, Dan; Liu, Hongpeng; Wang, Heng; Wang, Jian; Jiang, Yongyuan; Sun, Xiudong

    2011-08-01

    Experimental studies of holographic thermal stability in phenanthrenequinone (PQ)-doped poly(methyl methacrylate-co-methacrylic acid) [P(MMA-co-MAA)] photopolymers are presented. A possibility to improve the thermal stability of holograms is demonstrated by doping methacrylic acid (MAA) into the poly(methyl methacrylate) (PMMA) polymer matrix. MAA as a copolymerization monomer can form a more stable polymer matrix with methyl methacrylate (MMA) monomer and increase average molecular weight of photoproducts, which finally depress the diffusion of photoproduct. The optimized MAA concentration copolymerized into P(MMA-co-MAA) polymer matrix can bring nearly a month's lifetime of gratings, which is obviously an improvement over the usual PQ-PMMA material under thermal treatment.

  7. On permeability of methyl methacrylate, 2-hydroxyethyl methacrylate and triethyleneglycol dimethacrylate through protective gloves in dentistry.

    PubMed

    Andreasson, Harriet; Boman, Anders; Johnsson, Stina; Karlsson, Stig; Barregård, Lars

    2003-12-01

    Continuous glove use is more common in dentistry than in most other occupations, and the glove should offer protection against blood-borne infections, skin irritants and contact allergens. Methacrylate monomers are potent contact allergens, and it is known that these substances may penetrate the glove materials commonly used. The aim of this study was to assess the permeability of various types of gloves to methyl methacrylate (MMA), 2-hydroxyethyl methacrylate (HEMA) and triethyleneglycol dimethacrylate (TEGDMA) with special reference to combinations with ethanol or acetone. The permeation rate and time lag breakthrough (lag-BT) for MMA (neat, or diluted to 30% in ethanol or acetone), HEMA (30% in water, ethanol, or acetone) and TEGDMA (30% in ethanol or acetone) were investigated for different protective gloves. Nine different types of gloves were tested for one or several of these methacrylates. The lag-BT for neat MMA was

  8. Uptake of isoprene, methacrylic acid and methyl methacrylate into aqueous solutions of sulfuric acid and hydrogen peroxide.

    PubMed

    Liu, Ze; Ge, Maofa; Wang, Weigang

    2012-01-01

    Multiphase acid-catalyzed oxidation by hydrogen peroxide has been suggested to be a potential route to secondary organic aerosol formation from isoprene and its gas-phase oxidation products, but the lack of kinetics data significantly limited the evaluation of this process in the atmosphere. Here we report the first measurement of the uptake of isoprene, methacrylic acid and methyl methacrylate into aqueous solutions of sulfuric acid and hydrogen peroxide. Isoprene cannot readily partition into the solution because of its high volatility and low solubility, which hinders its further liquid-phase oxidation. Both methacrylic acid and methyl methacrylate can enter the solutions and be oxidized by hydrogen peroxide, and steady-state uptake was observed with the acidity of solution above 30 wt.% and 70 wt.%, respectively. The steady-state uptake coefficient of methacrylic acid is much larger than that of methyl methacrylate for a solution with same acidity. These observations can be explained by the different reactivity of these two compounds caused by the different electron-withdrawing conjugation between carboxyl and ester groups. The atmospheric lifetimes were estimated based on the calculated steady-state uptake coefficients. These results demonstrate that the multiphase acid-catalyzed oxidation of methacrylic acid plays a role in secondary organic aerosol formation, but for isoprene and methyl methacrylate, this process is not important in the troposphere.

  9. Preparation of hydroxyapatite/poly(methyl methacrylate) and calcium silicate/poly(methyl methacrylate) interpenetrating hybrid composites.

    PubMed

    Monvisade, Pathavuth; Siriphannon, Punnama; Jermsungnern, Rapee; Rattanabodee, Sirirat

    2007-10-01

    Hydroxyapatite/poly(methyl methacrylate) (HAp/PMMA) and calcium silicate/poly(methyl methacrylate) (CS/PMMA) composites were prepared by interpenetrating bulk polymerization of methyl methacrylate (MMA) monomer in porous structures of HAp and CS. The porous HAp and CS templates were prepared by mixing their calcined powders with poly(vinyl alcohol) (PVA) solution, shaping by uniaxial pressing and then firing at 1,100 degrees C for HAp and 900 degrees C for CS. The templates were soaked in the solution mixture of MMA monomer and 0.1 mol% of benzoyl peroxide (BPO) for 24 h. The pre-composites were then bulk polymerized at 85 degrees C for 24 h under nitrogen atmosphere. The microstructures of the composites showed the interpenetrating of PMMA into the porous HAp and CS structures. Thermogravimetric analysis indicated that the PMMA content in the HAp/PMMA and CS/PMMA composites were 13 and 26 wt%, respectively. Weight average molecular weights (M(w)) of PMMA were about 491,000 for HAp/PMMA composites and about 348,000 for CS/PMMA composites. Compressive strengths of these composites were about 90-131 MPa in which they were significantly higher than their starting porous templates.

  10. Studies on novel radiopaque methyl methacrylate: glycidyl methacrylate based polymer for biomedical applications.

    PubMed

    Dawlee, S; Jayakrishnan, A; Jayabalan, M

    2009-12-01

    A new class of radiopaque copolymer using methyl methacrylate (MMA) and glycidyl methacrylate (GMA) monomers was synthesized and characterized. The copolymer was made radiopaque by the epoxide ring opening of GMA using the catalyst o-phenylenediamine and the subsequent covalent attachment of elemental iodine. The copolymer was characterized by Fourier transform infrared (FTIR) spectra, energy dispersive X-ray analysis using environmental scanning electron microscope (EDAX), thermogravimetric analysis (TGA), and differential scanning calorimetry (DSC). X-ray visibility of the copolymer was checked by X-radiography. Blood compatibility and cytotoxicity of the newly synthesized copolymer were also evaluated. The iodinated copolymer was thermally stable, blood compatible, non-cytotoxic, and highly radiopaque. The presence of bulky iodine group created a new copolymer with modified properties for potential use in biomedical applications.

  11. Solid state dye lasers based on 2-hydroxyethyl methacrylate and methyl methacrylate co-polymers

    NASA Astrophysics Data System (ADS)

    Giffin, Shirin M.; McKinnie, Iain T.; Wadsworth, William J.; Woolhouse, Anthony D.; Smith, Gerald J.; Haskell, Tim G.

    1999-03-01

    The laser performance of a range of solid state dye lasers based on rhodamine 590-doped co-polymers of 2-hydroxyethyl methacrylate (HEMA) and methyl methacrylate (MMA) has been investigated. The optimisation of preparation conditions, including polymerisation initiator and solvent for dye delivery is discussed in detail. Laser efficiency is compared for different polymeric hosts and dye concentrations with a range of output couplers, cavity lengths and repetition rates. Passive and dynamic loss have been determined for each host medium. Laser efficiencies of optimised polymers are among the highest reported for rhodamine 590-doped solid state dye lasers under these operating conditions. Highest slope efficiency of 35% and lowest threshold fluence of 0.06 J cm -2 were obtained with dimethyl sulphoxide (DMSO) additive in MPMMA at 10 Hz repetition rate.

  12. Evaluation of alternate routes for the synthesis of methyl methacrylate

    SciTech Connect

    Spivey, J.J.; Gogate, M.R.; Zoeller, J.R.; Colberg, R.D.; Choi, G.N.

    1998-12-31

    The use of coal-derived syngas to produce high value chemicals is an important means of upgrading this resource. One example of a chemical that can be produced from coal-derived syngas is methyl methacrylate (MMA). Poly-methyl methacrylate is widely used in coatings and in various industrial molded products. The most widely practiced commercial technology for the synthesis of MMA is the acetone cyanohydrin (ACH) process. This process requires handling of large quantities of toxic hydrogen cyanide and generates one mole of ammonium bisulfate waste per mole of MMA. This bisulfate must either be regenerated or discarded, either of which substantially increases the cost. The ACH technology is thus environmentally and economically untenable for any new MMA plant expansions that would be needed to meet increasing demand. The RTI-Eastman-Bechtel research team is developing an alternative, environmentally benign route to MMA consisting of three steps; (step 1) synthesis of a propionate from ethylene, carbon monoxide, and steam, (step 2) condensation of this propionate with formaldehyde, and (step 3) esterification of resulting methacrylic acid with methanol to form MMA. This paper describes the preliminary economics of the overall process compared to other emerging processes, and focuses on step 2, including long term testing of catalysts for the condensation of propionic acid with formaldehyde to form MAA.

  13. Effect of methacrylic acid:methyl methacrylate monomer ratios on polymerization rates and properties of polymethyl methacrylates.

    PubMed

    Chen, T; Kusy, R P

    1997-08-01

    Five binary formulations were prepared from methyl methacrylate (MMA) and methacrylic acid (MAA) monomers, and six ternary formulations were prepared from polysols of 30% wt polymethyl methacrylate (PMMA)/MMA and MAA. Using thermal analyses (DSC and TGA) the polymerization kinetics, condition of postcuring, relative amount of residual monomers, and glass transition temperature (Tg) were determined. From bar-shaped samples, 25 x 5 x 0.9 mm in dimensions, mechanical properties [flexural moduli (E) and maximum strengths (sigma)] were measured in three-point bending. Polymerization kinetics of binary formulations improved over pure PMMA (from 15 to 4 min) as a result of over a 60-fold increase in propagation-to-termination constants (Kp/Kt) of MAA/MMA. The further addition of PMMA increased the viscosity, slowed down termination, and, consequently, improved the polymerization kinetics twofold. These enhancements occurred without a substantive change in the Tg of the ternary system (ca. 107 degrees C) over pure PMMA (ca. 112 degrees C). Moreover, the Es of the four ternary formulations averaged 2.94 GPa, which was comparable with many values reported in the literature. In contrast the sigma s of these same formulations averaged 97 MPa, which was about 25% better than earlier investigations of pure acrylic. When a thermoplastic material is required for pultruding profiles that cure fast and have good thermal-mechanical properties, ternaries of PMMA/MMA/MAA should be considered.

  14. Molecular Dynamics Simulations of Hugoniot Relations for Poly[methyl methacrylate

    DTIC Science & Technology

    2011-11-01

    Molecular Dynamics Simulations of Hugoniot Relations for Poly[ methyl methacrylate ] by Tanya L. Chantawansri, Edward F. C. Byrd, Betsy M. Rice...Ground, MD 21005-5066 ARL-TR-5819 November 2011 Molecular Dynamics Simulations of Hugoniot Relations for Poly[ methyl methacrylate ...4. TITLE AND SUBTITLE Molecular Dynamics Simulations of Hugoniot Relations for Poly[ methyl methacrylate ] 5a. CONTRACT NUMBER 5b. GRANT NUMBER

  15. Methyl substituted polyimides containing carbonyl and ether connecting groups

    NASA Technical Reports Server (NTRS)

    Hergenrother, Paul M. (Inventor); Havens, Stephen J. (Inventor)

    1992-01-01

    Polyimides were prepared from the reaction of aromatic dianhydrides with novel aromatic diamines having carbonyl and ether groups connecting aromatic rings containing pendant methyl groups. The methyl substituent polyimides exhibit good solubility and form tough, strong films. Upon exposure to ultraviolet irradiation and/or heat, the methyl substituted polyimides crosslink to become insoluble.

  16. Hardness of irradiated poly(methyl methacrylate) at elevated temperatures

    SciTech Connect

    Lu, K.-P.; Lee, Sanboh; Cheng, Cheu Pyeng

    2001-08-15

    The decrease in hardness induced by gamma irradiation in poly(methyl methacrylate) (PMMA) has been investigated. The hardness is assumed to decrease linearly with the concentration of radiation-induced defects. Annealing at high temperatures induces defect annihilation as tracked by an increase in hardness. The annihilation follows first-order kinetics during isothermal annealing. The dependence of hardness on the reciprocal of the time constant satisfies the Arrhenius equation, and the corresponding activation energy of the kinetic process decreases with increasing dose. The hardness of postannealed PMMA decreases linearly with increasing dose. {copyright} 2001 American Institute of Physics.

  17. Methyl methacrylate permeability of dental and industrial gloves.

    PubMed

    Thomas, Sebastian; Padmanabhan, T V

    2009-01-01

    Our study was undertaken to measure the amount and time it took for methyl methacrylate monomer (MMA) to permeate latex, vinyl and industrial neoprene gloves and to compare the results to obtain a rating of the permeability of each of the gloves studied to MMA. The monomer, permeated under static conditions, was measured using a spectrophotometer. Latex and vinyl clinical gloves became permeable to MMA in a very short amount of time. Neoprene industrial gloves remained impervious for 25 minutes. Dentists and dental technicians should be aware of the toxic effects of MMA and understand that clinical gloves do not afford protection from MMA.

  18. Ab initio study of acrylate polymerization reactions: methyl methacrylate and methyl acrylate propagation.

    PubMed

    Yu, Xinrui; Pfaendtner, Jim; Broadbelt, Linda J

    2008-07-24

    The kinetic parameters of the free radical propagation of methyl methacrylate and methyl acrylate have been calculated using quantum chemistry and transition state theory. Multiple density functional theory (DFT) methods were used to calculate the activation energy, and it was found that MPWB1K/6-31G(d,p) yields results that are in very good agreement with experimental data. To obtain values of the kinetic parameters that were in the best agreement with experimental data, low frequencies were treated using a one-dimensional internal rotor model. Chain length effects were also explored by examining addition reactions of monomeric, dimeric, and trimeric radicals to monomer for both methyl methacrylate and methyl acrylate. The results show that the values for the addition of the trimeric radical to monomer are closest to experimental data. The kinetic parameters that were calculated using a continuum description of the monomer as a solvent were not significantly different from the vacuum results.

  19. Inhibition of the polymerization of methyl methacrylate and methyl acrylate by mixtures of chloranil with phenothiazine

    SciTech Connect

    Ivanov, A.A; Lysenko, G.M.; Zholina, I.N.

    1985-09-01

    This paper investigates the kinetic peculiarities of inhibited polymerization of methyl methacrylate and methyl acrylate in the presence of mixtures of chloranil with phenothiazine. It is shown that depending on the structure of the monomer and the concentrations of the electron donor and electron acceptor, the radicals of propagation may form complexes with chloranil or with phenothiazine at the first step of the inhibition reaction or may interact with the complex (phenothiazine to chloranil).

  20. Degradation of poly(methyl methacrylate) in solution

    SciTech Connect

    Madras, G.; Smith, J.M.; McCoy, B.J.

    1996-06-01

    The rate of degradation of poly(methyl methacrylate) (PMMA) to methyl methacrylate (MMA) was investigated in the liquid phase with toluene as the solvent. The degradation experiments were carried out in a tubular flow reactor at 1,000 psig (6.8 MPa) and at four different temperatures (200, 225, 275, and 300 C). The polymer concentration was varied by 1 to 4 g/L. A discrete model for the first-order rate of polymer degradation was derived and compared to the continuous kinetics approach. Both models lead to the same expression for monomer concentration increasing linearly with time. Rate constants were evaluated using the moments of the molecular weight distributions of the reacted and unreacted polymer. The rate was first order in polymer concentration, and the activation energy was 8.4 kcal/mol (34 kJ/mol). This activation energy suggests that the rate controlling step for the thermal degradation of PMMA is the depropagation process.

  1. Photoinitiated polymerization of new hybrid monomer containing vinyl ether and (methyl) acryloyl groups

    NASA Astrophysics Data System (ADS)

    Diao, Cuimei; Zou, Yingquan

    2011-04-01

    The photopolymerization kinetics of 4-(vinyloxy)butyl methacrylate containing cationic and free radical polymerizable vinyl groups was studied by real-time Fourier transform infrared spectra (RT-FTIR) .The cationic polymerizable vinyl ether moieties(Vc) of the hybrid monomer in solution polymerized rapidly by exposure to UV light in presence of a cationic photoinitiator such as an iodonium salt or suflonium salt .High conversions, of 90%, were obtained for most of the systems investigated. The efficiency of the cationic photoinitiators in initiating the polymerization of the vinyl ether moieties (Vc) of the hybrid monomer was in the order: suflonium salt > iodonium salt . The free radical polymerizable methacrylate groups (Vr) of the hybrid monomer in solution polymerized by exposure to UV light in presence of a radical photoinitiator such as 2,4,6-trimethyl benzoyl diphenylphoshine oxide (TPO), 2-isopropyl thioxanthone (ITX) , Phenylbis(2,4,6-trimethylbenzoyl)phosphine oxide (Irgaure 819), 2-Methyl-4'-(methylthio)-2-morpholinopropiophenone (Irgaure 907). Among the photoinitiators , the best effect in initiating the polymerization of methacrylate groups (Vr) of the hybrid monomer is initiator Irgaure 907.

  2. Characterization of new acrylic bone cement based on methyl methacrylate/1-hydroxypropyl methacrylate monomer.

    PubMed

    Pascual, B; Goñi, I; Gurruchaga, M

    1999-01-01

    New formulations of acrylic bone cement based on methyl methacrylate/1-hydroxypropyl methacrylate (MMA/HPMA) monomers were developed with the purpose of obtaining more ductile materials with reduced polymerization shrinkage. In this way, the ductility of such materials increased, but the introduction of high percentages of the hydrophilic component produced an important decrease in Young's modulus and strength. To ascertain the reason for the deterioration of the tensile parameters, an analysis by scanning electron microscopy of these formulations was carried out; it revealed poor adhesion between the matrix and poly(MMA) beads. We also observed that the polymerization shrinkage increased as the amount of hydrophilic monomer in the formulation decreased, and the 50% (v/v) HPMA modified bone cement compensated for this volume reduction with its water uptake swelling. Measurements taken on the setting time and polymerization exotherm showed a decrease in the former and an increase in the latter, because of the introduction of a more reactive monomer in the bone cement formulation.

  3. Synthesis of Methyl Methacrylate from Coal-Derived Syngas

    SciTech Connect

    Gerald N. Choi; James J. Spivey; Jospeh R. Zoeller; Makarand R. Gogate; Richard D. Colberg; Samuel S. Tam

    1998-04-17

    Research Triangle Institute (RTI), Eastman Chemical Company, and Bechtel collectively are developing a novel three-step process for the synthesis of methyl methacrylate (MMA) from coal-derived syngas that consists of the steps of synthesis of a propionate, its condensation with formaldehyde to form methacrylic acid (MAA), and esterification of MAA with methanol to produce MMA. RTI has completed the research on the three-step methanol-based route to MMA. Under an extension to the original contract, RTI is currently evaluating a new DME-based process for MMA. The key research need for DME route is to develop catalysts for DME partial oxidation reactions and DME condensation reactions. Over the last month, RTI has finalized the design of a fixed-bed microreactor system for DME partial oxidation reactions. RTI incorporated some design changes to the feed blending system, so as to be able to blend varying proportions of DME and oxygen. RTI has also examined the flammability limits of DME-air mixtures. Since the lower flammability limit of DME in air is 3.6 volume percent, RTI will use a nominal feed composition of 1.6 percent in air, which is less than half the lower explosion limit for DME-air mixtures. This nominal feed composition is thus considered operationally safe, for DME partial oxidation reactions. RTI is also currently developing an analytical system for DME partial oxidation reaction system.

  4. Novel syngas-based process for methyl methacrylate

    SciTech Connect

    Gogate, M.R.; Spivey, J.J.; Zoeller, J.R.; Choi, G.N.; Tam, S.S.; Tischer, R.E.; Srivastava, R.D.

    1996-12-31

    Research Triangle Institute (RTI), Eastman Chemical Company, and Bechtel are developing a novel process for synthesis of methyl methacrylate (MMA) from coal-derived syngas, under a contract from the U.S. Department of Energy, Pittsburgh Energy Technology Center. This three-step process consists of synthesis of a propionate, its condensation with formaldehyde, and esterification of resulting methacrylic acid (MAA) with methanol to produce MMA. Eastman has focused on the research on propionate synthesis step. The resultant Mo catalysts work efficiently at much less severe conditions (170{degrees}C and 30 atm) than the conventional Ni catalysts (270{degrees}C and 180 atm). Bechtel has performed an extensive cost analysis, which shows that Eastman`s propionate synthesis process is competitive with other technologies to produce the anhydride. In the second step, RTI and Eastman have developed active and stable V-SI-P and Ta metal oxide catalysts for condensation reactions of propionates with formaldehyde. RTI has demonstrated a novel correlation among the catalyst acid-base properties, condensation reaction yield, and long-term catalyst activity. Current research focuses on enhancing the condensation reaction yields, acid-base properties, in situ condensation in a high- temperature, high-pressure (HTHP) slurry reactor, and alternate formaldehyde feedstocks. Based on Eastman and RTI laboratory reactor operating data, a cost estimate is also being developed for the integrated process.

  5. Synthesis of methyl methacrylate from coal-derived syngas: Quarterly report,, October 1-December 31, 1997

    SciTech Connect

    1998-09-01

    Research Triangle Institute (RTI), Eastman Chemical Company, and Bechtel collectively are developing a novel process for the synthesis of methyl methacrylate (MMA) from coal-derived syngas that consists of three steps of synthesis of a propionate, its condensation with formaldehyde, and esterification of resulting methacrylic acid (MAA) with methanol to produce MMA. Over the last quarter, Eastman developed two new processes which have resulted in two new invention reports. One process deals with carbonylation of benzyl ether which represents a model for coal liquefaction and the second focuses on the acceleration of carbonylation rates for propionic acid synthesis, via use of polar aprotic solvents. These two inventions are major improvements in the novel Mo-catalyzed homogeneous process for propionic acid synthesis technology, developed by Eastman. Over the last quarter, RTI completed three reaction cycles and two regeneration cycles as a part of long-term reaction regeneration cycle study on a 10% Nb{sub 2}O{sub 5}/Si0{sub 2} catalyst, for vapor phase condensation reaction of formaldehyde with propionic acid.

  6. Methyl Methacrylate Polymerization in Nanoporous Matrix: Reactivity and Molecular Weight

    NASA Astrophysics Data System (ADS)

    Zhao, Haoyu; Simon, Sindee

    2011-03-01

    The influence of nanoconfinement on the free radical polymerization of methyl methacrylate is investigated. Nanoporous controlled pore glass (CPG) is used as a nanoconfining matrix for the polymerization. The reaction is followed by measuring heat flow as a function of reaction time during isothermal polymerization using differential scanning calorimetry (DSC). Preliminary results indicate several interesting effects for polymerization in 110 nm diameter pores: the induction time increases under nanoconfinement, the effective reaction rate constant increases, the effective activation energy is unchanged, and the gel effect or autoaccleration occurs at earlier times after induction. The latter result concerning the gel effect is presumably due to the decrease in diffusivity under nanoconfinement which results in a decrease in the termination rate of free radicals. The cause of the longer induction times and accelerated reaction rates just after induction are under investigation. The influence of nanoconfinement on molecular weight will also be examined.

  7. Interaction between N-vinylpyrrolidone and methyl methacrylate

    NASA Astrophysics Data System (ADS)

    Zaitseva, V. V.; Shtonda, A. V.; Tyurina, T. G.; Bagdasarova, A. R.; Zaitsev, S. Yu.

    2014-04-01

    It is established that the interaction of the isomers of N-vinylpyrrolidone (NVP) and methyl methacrylate (MMA) leads to the formation of molecular π-H- and H-complexes with energies within the limits of 10.2-13.6 (AM1) or 18.2-24.0 (B3LYP/6-311++G( d)) kJ/mol. The structures of complex-bound molecules are examined with respect to changes in the charges on terminal -C1=C2- groups, the distance between them and atoms in an H-bond, and the presence of combined overlapping molecular orbitals (MOs). The presence of an averaged complex that includes presumably all possible structures and allows us to perform the copolymerization of specified monomers in the absence of an initiator is confirmed by means of UV and NMR spectroscopy.

  8. Porous conductive polyblends of polyaniline in poly(methyl methacrylate)

    NASA Astrophysics Data System (ADS)

    Price, Aaron D.; Naguib, Hani E.

    2008-03-01

    The conductive polymer polyaniline is typically blended with conventional industrial thermoplastics in order to obtain an electrically conductive polymer blend with adequate mechanical properties. Processing these polyblends into foams yields a porous conductive material that exhibits immense application potential such as dynamic separation media and low-density electrostatic discharge protection. In the current study, the morphology of a thermally-processable blend consisting of an electrically conductive polyaniline-dodecylbenzene sulfonic acid complex and poly(methyl methacrylate) is explored using a two-phase batch foaming setup. The effect of blend composition and processing parameters on the resulting cellular morphology is investigated. Finally, the impact of the underlying microstructure on the frequency dependent electrical conductivity is elucidated.

  9. 40 CFR 721.10153 - Modified methyl methacrylate, 2-hydroxyethyl methacrylate polymer (generic).

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ...-hydroxyethyl methacrylate polymer (generic). 721.10153 Section 721.10153 Protection of Environment...-hydroxyethyl methacrylate polymer (generic). (a) Chemical substance and significant new uses subject to... methacrylate polymer (PMN P-08-6) is subject to reporting under this section for the significant new...

  10. 40 CFR 721.10153 - Modified methyl methacrylate, 2-hydroxyethyl methacrylate polymer (generic).

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ...-hydroxyethyl methacrylate polymer (generic). 721.10153 Section 721.10153 Protection of Environment...-hydroxyethyl methacrylate polymer (generic). (a) Chemical substance and significant new uses subject to... methacrylate polymer (PMN P-08-6) is subject to reporting under this section for the significant new...

  11. 40 CFR 721.10153 - Modified methyl methacrylate, 2-hydroxyethyl methacrylate polymer (generic).

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ...-hydroxyethyl methacrylate polymer (generic). 721.10153 Section 721.10153 Protection of Environment...-hydroxyethyl methacrylate polymer (generic). (a) Chemical substance and significant new uses subject to... methacrylate polymer (PMN P-08-6) is subject to reporting under this section for the significant new...

  12. 40 CFR 721.10153 - Modified methyl methacrylate, 2-hydroxyethyl methacrylate polymer (generic).

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ...-hydroxyethyl methacrylate polymer (generic). 721.10153 Section 721.10153 Protection of Environment...-hydroxyethyl methacrylate polymer (generic). (a) Chemical substance and significant new uses subject to... methacrylate polymer (PMN P-08-6) is subject to reporting under this section for the significant new...

  13. 40 CFR 721.10153 - Modified methyl methacrylate, 2-hydroxyethyl methacrylate polymer (generic).

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ...-hydroxyethyl methacrylate polymer (generic). 721.10153 Section 721.10153 Protection of Environment...-hydroxyethyl methacrylate polymer (generic). (a) Chemical substance and significant new uses subject to... methacrylate polymer (PMN P-08-6) is subject to reporting under this section for the significant new...

  14. Synthesis of Methyl Methacrylate From Coal-Derived Syngas

    SciTech Connect

    Ben W.-L. Jang; Gerald N. Choi; James J. Spivey; Jospeh R. Zoeller; Richard D. Colberg; Samuel S. Tam

    1998-07-27

    Research Triangle Institute (RTI), Eastman Chemical Company, and Bechtel collectively are developing a novel three-step process for the synthesis of methyl methacrylate (MMA) from coal-derived syngas that consists of the steps of synthesis of a propionate, its condensation with formaldehyde to form methacrylic acid (MAA), and esterification of MAA with methanol to produce MMA. RTI has completed the research on the three-step methanol-based route to MMA. Under an extension to the original contract, RTI is currently evaluating a new DME-based process for MMA. The key research need for DME route is to develop catalysts for DME partial oxidation reactions and DME condensation reactions. Over the last quarter(April-June, 1998), RTI has modified the reactor system including a new preheater and new temperature settings for the preheater. Continuous condensation of formaldehyde with propionic acid were carried out over 10% Nb O /SiO at 300°C without 2 5 2 interruption. Five activity and four regeneration cycles have been completed without plugging or material balance problems. The results show that 10% Nb O /SiO deactivates slowly with time 2 5 2 but can be regenerated, at least four times, to 100% of its original activity with 2% O in nitrogen 2 at 400°C. The cycles continue with consistent 90-95% of carbon balance. The reaction is scheduled to complete with 6 activity cycles and 5 regenerations. Used catalysts will be analyzed with TGA and XPS to determine bulk and surface coke content and coke properties. RTI will start the investigation of effects of propionic acid/formaldehyde ratio on reaction activity and product selectivity over 20% Nb O /SiO catalysts.

  15. Nano-imprint lithography using poly (methyl methacrylate) (PMMA) and polystyrene (PS) polymers

    NASA Astrophysics Data System (ADS)

    Ting, Yung-Chiang; Shy, Shyi-Long

    2016-04-01

    Nano-imprinting lithography (NIL) technology, as one of the most promising fabrication technologies, has been demonstrated to be a powerful tool for large-area replication up to wafer-level, with features down to nanometer scale. The cost of resists used for NIL is important for wafer-level large-area replication. This study aims to develop capabilities in patterning larger area structure using thermal NIL. The commercial available Poly (Methyl Methacrylate) (PMMA) and Polystyrene (PS) polymers possess a variety of characteristics desirable for NIL, such as low material cost, low bulkvolumetric shrinkage, high spin coating thickness uniformity, high process stability, and acceptable dry-etch resistance. PMMA materials have been utilized for positive electron beam lithography for many years, offering high resolution capability and wide process latitude. In addition, it is preferable to have a negative resist like PMMA, which is a simple polymer with low cost and practically unlimited shelf life, and can be dissolved easily using commercial available Propylene glycol methyl ether acetate (PGMEA) safer solvent to give the preferred film thickness. PS is such a resist, as it undergoes crosslinking when exposed to deep UV light or an electron beam and can be used for NIL. The result is a cost effective patterning larger area structure using thermal nano-imprint lithography (NIL) by using commercial available PMMA and PS ploymers as NIL resists.

  16. SYNTHESIS OF METHYL METHACRYLATE FROM COAL-DERIVED SYNGAS

    SciTech Connect

    Makarand R. Gogate; James J. Spivey; Joseph R. Zoeller; Richard D. Colberg; Gerald N. Choi

    1999-07-19

    Research Triangle Institute (RTI), Eastman Chemical Company, and Bechtel collectively are developing a novel three-step process for the synthesis of methyl methacrylate (MMA) from coal-derived syngas that consists of the steps of synthesis of a propionate, its condensation with formaldehyde to form methacrylic acid (MAA), and esterification of MAA with methanol to produce MMA. The research team has completed the research on the three-step methanol-based route to MMA. Under an extension to the original contract, we are currently evaluating a new DME-based process for MMA. The key research need for DME route is to develop catalysts for DME partial oxidation reactions and DME condensation reactions. During the April-June quarter(04-06/99) the first in-situ formaldehyde generation from DME and condensation with methyl propionate is demonstrated and the results are summarized. The supported niobium catalyst shows better condensation activity, but supported tungsten catalyst has higher formaldehyde selectivity. The project team has also completed a 200-hour long term test of PA-HCHO condensation over 30% Nb{sub 2}O{sub 5}/SiO{sub 2}. Three activity cycles and two regeneration cycles were carried out. 30% Nb{sub 2}O{sub 5}/SiO{sub 2} showed similar MAA yields as 10% Nb{sub 2}O{sub 5}/SiO{sub 2} at 300 C. However, the deactivation appears to be slower with 30% Nb{sub 2}O{sub 5}/SiO{sub 2} than 10% Nb{sub 2}O{sub 5}/SiO{sub 2}. An detailed economic analysis of PA-HCHO condensation process for a 250 million lb/yr MMA plant is currently studied by Bechtel. Using the Amoco data-based azeotropic distillation model as the basis, an ASPEN flow sheet model was constructed to simulate the formaldehyde and propionic acid condensation processing section based on RTI's design data. The RTI MAA effluent azeotropic distillation column was found to be much more difficult to converge. The presence of non-condensible gases along with the byproduct DEK (both of which were not presented in

  17. Radical Polymerization of Vinyl Acetate and Methyl Methacrylate Using Organochromium Initiators Complexed with Macrocyclic Polyamines

    DTIC Science & Technology

    1994-06-30

    METHYL METHACRYLATE USING ORGANOCHROMIUM REA NTS COMPLEXED WITH MACROCYCLIC A• by Daniela Mardare, Scott Gaynor, Krzysztof Matyjaszewski DTIC Published... Daniela Mardare, Scott Gaynor, Krzysztof Matyjaszewski 7. PERFORMING ORGANIZATION NAME(S) AND ADORESS(ES) a. PERFORMING ORGANIZATION Carnegie Mellon

  18. 29 CFR 1915.1006 - Methyl chloromethyl ether.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 29 Labor 7 2010-07-01 2010-07-01 false Methyl chloromethyl ether. 1915.1006 Section 1915.1006 Labor Regulations Relating to Labor (Continued) OCCUPATIONAL SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR (CONTINUED) OCCUPATIONAL SAFETY AND HEALTH STANDARDS FOR SHIPYARD EMPLOYMENT Toxic...

  19. Mössbauer studies of solid state decomposition of methyl methacrylate-ethyl methacrylate copolymers containing ferric chloride

    NASA Astrophysics Data System (ADS)

    Kapur, G. S.; Brar, A. S.

    1990-07-01

    Methyl methacrylate (MMA)-ethyl methacrylate (EMA) copolymers of different monomer concentrations containing anhydrous ferric chloride were prepared by bulk polymerization at 70°C. TGA studies showed that inclusion of iron salt increases the thermal stability of copolymers by 50°C. Mössbauer spectra of copolymers heated at different temperatures showed the presence of Fe3+ species only, in different environments. The mechanism of thermal stabilization of copolymer has been proposed on the basis of IR, TGA and Mössbauer spectroscopy studies.

  20. Solid-state dye lasers based on copolymers of 2-hydroxyethyl methacrylate and methyl methacrylate doped with rhodamine 6G

    NASA Astrophysics Data System (ADS)

    Costela, A.; Florido, F.; Garcia-Moreno, I.; Duchowicz, R.; Amat-Guerri, F.; Figuera, J. M.; Sastre, R.

    1995-04-01

    Rhodamine 6G has been dissolved in copolymers of 2-HydroxyEthyl MethAcrylate (HEMA) and Methyl MethAcrylate (MMA) and the resulting solid-state solutions have been pumped at 337 nm and 532 nm. Lasing efficiencies similar to those found in ethanol solution have been obtained with a 1:1 vol/vol HEMA: MMA copolymer matrix, and lifetimes of ca. 10 000 (337 nm pumping) and ca. 75 000 (532 nm pumping) pulses at repetition rates up to 15 Hz and 10 Hz, respectively, have been demonstrated.

  1. Methyl methacrylate and respiratory sensitization: A Critical review

    PubMed Central

    Borak, Jonathan; Fields, Cheryl; Andrews, Larry S; Pemberton, Mark A

    2011-01-01

    Methyl methacrylate (MMA) is a respiratory irritant and dermal sensitizer that has been associated with occupational asthma in a small number of case reports. Those reports have raised concern that it might be a respiratory sensitizer. To better understand that possibility, we reviewed the in silico, in chemico, in vitro, and in vivo toxicology literature, and also epidemiologic and occupational medicine reports related to the respiratory effects of MMA. Numerous in silico and in chemico studies indicate that MMA is unlikely to be a respiratory sensitizer. The few in vitro studies suggest that MMA has generally weak effects. In vivo studies have documented contact skin sensitization, nonspecific cytotoxicity, and weakly positive responses on local lymph node assay; guinea pig and mouse inhalation sensitization tests have not been performed. Cohort and cross-sectional worker studies reported irritation of eyes, nose, and upper respiratory tract associated with short-term peaks exposures, but little evidence for respiratory sensitization or asthma. Nineteen case reports described asthma, laryngitis, or hypersensitivity pneumonitis in MMA-exposed workers; however, exposures were either not well described or involved mixtures containing more reactive respiratory sensitizers and irritants.The weight of evidence, both experimental and observational, argues that MMA is not a respiratory sensitizer. PMID:21401327

  2. Methyl Methacrylate Polymerization in Nanoporous Matrix: Reactivity and Resulting Properties

    NASA Astrophysics Data System (ADS)

    Zhao, Haoyu; Begum, Fatema; Simon, Sindee

    2012-02-01

    Nanoconfinement is well known to affect the properties of polymers, including changes in the glass transition temperature (Tg). In this work, the focus is on the influence of nanoconfinement on free radical polymerization reaction kinetics and the properties of the polymer produced. Controlled pore glass (CPG) is used as a nanoconfining matrix for methyl methacrylate (MMA) polymerization with pore diameters of 13 nm, 50 nm, and 110 nm. The reaction is followed by measuring heat flow as a function of reaction time during isothermal polymerization at temperatures ranging from 60 C to 95 C using differential scanning calorimetry (DSC). After reaction, the properties of the polymer are measured, including Tg, molecular weight, and tacticity. Nanoconfiment is found to result in earlier onset of autoacceleration, presumablely due to a decrease in the rate of termination arising from decreases in chain diffusivity in the confined state. In addition, Tg and molecular weight of the resulting PMMA are found to increase. A model of the nanoconfined reaction is able to quantitatively capture these effects by accounting for changes in chain diffusivity, and in native pores, also accounting for changes in intrinsic reaction rates.

  3. Wettability interpretation of oxygen plasma modified poly(methyl methacrylate).

    PubMed

    Chai, Jinan; Lu, Fuzhi; Li, Baoming; Kwok, Daniel Y

    2004-12-07

    Poly(methyl methacrylate) (PMMA) has been modified via a dc pulsed oxygen plasma for different treatment times. The modified surfaces were characterized by X-ray photoelectron spectroscopy (XPS), optical profilometer, zeta potential, and advancing contact angle measurements. The measured advancing contact angles of water decreased considerably as a function of discharge. Several oxygen-based functionalities (carbonyl, carboxyl, carbonate, etc.) were detected by XPS, while zeta potential measurements confirmed an increase in negative charge for the treated PMMA surface. Evaluating the correlation between the concentration of polar chemical species and zeta potential, we found that increase in surface hydrophilicity results from the coeffect due to incorporation of oxygen functional groups and creation of charge states. The electrical double layer (EDL) effect was also considered in contact angle interpretation by introducing an additional surface tension term into Young's equation. We also found that EDL contribution to the solid-liquid interfacial tension is negligible and can be safely ignored for the systems considered here.

  4. Reactive compatibilization of PBT/ABS blends by methyl methacrylate, glycidyl methacrylate, ethyl acrylate terpolymers

    NASA Astrophysics Data System (ADS)

    Hale, Wesley Raymond

    The impact resistance of poly(butylene terephthalate), PBT, has been improved by blending with acrylonitrile-butadiene-styrene terpolymers, ABS, as a minor dispersed phase; however, extensive coarsening of the dispersed phase in the blends occurs under certain heat fabrication conditions. The incorporation of certain reactive polymers (compatibilizers) that are miscible with the styrene/acrylonitrile (SAN) matrix of ABS should result in more stable morphologies. Terpolymers of methyl methacrylate, glycidyl methacrylate (GMA), ethyl acrylate, MGE, are effective as reactive compatibilizers for blends of PBT with SAN and ABS materials. The epoxide groups of MGE react with the carboxyl endgroups of PBT to form a MGE-g-PBT graft copolymer at the PBT/SAN interface to provide improved SAN or ABS dispersion, morphological stability, and a broadening of the melt processing window. Additionally, compatibilization produces large improvements in the low temperature fracture toughness of PBT/ABS blends; however, the toughness depends on the order of mixing blend components due to crosslinking reactions involving the epoxide groups of MGE catalyzed by residual acids present in some emulsion-made ABS materials. The PBT, ABS, and MGE type, content, and composition have been examined to evaluate their effects on the mechanical and morphological properties of PBT/ABS blends. Additionally, the effects of different processing conditions have been examined. High PBT melt viscosity is desirable for improving ABS dispersion and low temperature toughness of the blends. Generally, ABS materials with a high rubber content and low melt viscosity are desirable for toughening PBT. Moderate amounts of GMA in the blend were found to significantly improve blend properties. Melt blending can be performed using a variety of equipment; however, a co-rotating intermeshing twin screw extruder is the most effective for producing blends with excellent properties. The fracture properties of PBT

  5. Synthesis of methyl acetate from syngas via dimethyl ether

    SciTech Connect

    Tartamella, T.; Sardesai, A.; Lanterman, H.B.; Lee, S.

    1999-07-01

    Dimethyl ether (DME) can be used as a building block for a variety of specialty chemicals in the petrochemical industry. Its utilization stems mainly from its efficient production from synthesis gas in a single stage. This Liquid Phase Dimethyl Ether (LP-DME) process, based on dual catalysts slurried in inert oil, can alleviate the chemical equilibrium limitation governing the methanol synthesis reaction and concurrently improve once-through syngas conversion and reactor productivity. Studies in the past have focused on using DME as a feedstock for gasoline range hydrocarbons as well as lower olefins. The focus of this investigation is to study the synthesis of methyl acetate, an important intermediate for acetic acid, from dimethyl ether. In particular, conversion of DME to methyl acetate is investigated over a variety of Group VIII metal substituted phosphotungstic acid salts. Key aspects of the process such as the effect of active metal, support types, multiple metal loading, and feed conditions are examined. Thus, this paper introduces a novel process route for synthesis of methyl acetate from natural gas-based syngas via dimethyl ether as an intermediate.

  6. SYNTHESIS OF METHYL METHACRYLATE FROM COAL-DERIVED SYNGAS

    SciTech Connect

    BEN W.-L. JANG; GERALD N. CHOI; JAMES J. SPIVEY; JOSPEH R. ZOELLER; RICHARD D. COLBERG

    1998-10-20

    Research Triangle Institute (RTI), Eastman Chemical Company, and Bechtel collectively are developing a novel three-step process for the synthesis of methyl methacrylate (MMA) from coal-derived syngas that consists of the steps of synthesis of a propionate, its condensation with formaldehyde to form methacrylic acid (MAA), and esterification of MAA with methanol to produce MMA. RTI has completed the research on the three-step methanol-based route to MMA. Under an extension to the original contract, RTI is currently evaluating a new DME-based process for MMA. The key research need for DME route is to develop catalysts for DME partial oxidation reactions and DME condensation reactions. Over the last quarter (July-September, 1998), the project team has completed the continuous condensation of formaldehyde with propionic acid over 10% Nb{sub 2}O{sub 5}/SiO{sub 2} at 300 C. Six activity and five regeneration cycles have been completed. The results show that 10% Nb{sub 2}O{sub 5}/SiO{sub 2} deactivates slowly with time but can be regenerated to its original activity with 2% O{sub 2} in nitrogen over night at 400 C. We have investigated the effects of regeneration, propionic acid/formaldehyde ratio (PA/HCHO = 4.5/1 to 1.5/1) and reaction temperature(280-300 C) on reaction activity and product selectivity over 20% Nb{sub 2}O{sub 5}/SiO{sub 2} catalysts. The regeneration effect on 20% Nb{sub 2}O{sub 5}/SiO{sub 2} is similar to the effect on 10% Nb{sub 2}O{sub 5}/SiO{sub 2}. The regeneration can bring the deactivated catalyst to its original activity. However, the selectivity to MAA decreases with regeneration while the selectivity to DEK and CO{sub 2} increases. When PA/HCHO ratio is decreased from 4.5/1 to 2.25/1 then to 1.5/1 at 300 C the MAA yield decreases but the MAA selectivity first increases then decreases. Decreasing the reaction temperature from 300 C to 280 C decreases the MAA yield from 39.5% to 30.7% but increases the MAA selectivity from 73.7% to 82.2%. The

  7. Novel catalysts for the environmentally friendly synthesis of methyl methacrylate

    SciTech Connect

    Spivey, J.J.; Gogate, M.R.; Zoeller, J.R.; Colberg, R.D.

    1997-11-01

    The development of a process for the synthesis of methyl methacrylate (MMA) from coal-derived syngas can alleviate the environmental hazards associated with the current commercial MMA technology, the acetone cyanohydrin (ACH) process. A three-step syngas-based process consisted of synthesis of a propionic acid, its condensation with formaldehyde, and esterification of resulting methacrylic acid (MAA) to form MMA. The first two steps, propionic acid synthesis and condensation, are discussed here. The low-temperature, low-pressure process for single-step hydrocarbonylation of ethylene to propionic acid is carried out using a homogeneous iodine-promoted Mo(CO){sub 6} catalyst at pressures (30--70 atm) and temperatures (150--200 C) lower than those reported for other catalysts. Mechanistic investigations suggest that catalysis is initiated by a rate-limiting CO dissociation from Mo(CO){sub 6}. This dissociation appears to be followed by an inner electron-transfer process of an I atom from EtI to the coordinately unsaturated Mo(CO){sub 5}. This homogeneous catalyst for propionate synthesis represents the first case of an efficient carbonylation process based on Cr group metals. The condensation of formaldehyde with propionic acid is carried out by acid-base bifunctional catalysts. As a result of screening over 80 catalytic materials, group V metals supported on an amorphous silica are found to be most effective. A 20% Nb/SiO{sub 2} catalyst appears to be the most active and stable catalyst thus far. Preliminary relations among the reaction yield and catalyst properties indicate that a high surface area and a low overall surface acidity (<50 = mol of NH{sub 3}/g), with a high proportion of the acidity being weak (<350 C desorption of NH{sub 3}), are desirable. Long-term deactivation of V-Si-P, Nb-Si, and Ta-Si catalysts suggests that carbon deposition is the primary cause for activity decay, and the catalyst activity is partially restorable by oxidative regeneration.

  8. Poly(methacrylic acid-co-methyl methacrylate) beads promote vascularization and wound repair in diabetic mice.

    PubMed

    Martin, Daniel C; Semple, John L; Sefton, Michael V

    2010-05-01

    Topical application of beads made from poly(methacrylic acid-co-methyl methacrylate) (45 mol % methacrylic acid, MAA) increased the number of blood vessels and improved 1.5 x 1.5 cm full thickness wound closure in a diabetic mouse (db/db) model. Three groups were compared: MAA beads, control poly(methyl methacrylate) beads (PMMA), and no bead blanks. MAA bead treatment significantly increased percent wound closure at all timepoints (7, 14, and 21 days) with MAA bead-treated wounds almost closed at day 21 (91 +/- 5.4% MAA vs. 79 +/- 3.2% PMMA or 76 +/- 4.8% no beads; p < 0.05). This was consistent with the expected significant increase in vascularity in the MAA group at days 7 and 14. For example at day 14, MAA bead-treated wounds had a vascular density of 22.7 +/- 2.6 vessels/hpf compared with 17.0 +/- 2.0 vessels/hpf in the PMMA bead group (p < 0.05). Epithelial gap and migration measurements suggested that the increased vascularity leads to enhanced epithelial cell migration as a principal means of wound closure. Although studies are underway to elucidate the mechanism of this angiogenic response, the results presented here support the notion that such materials, perhaps in other forms, may be useful in wound care or in other situations where vascularity is to be enhanced without the use of exogenous growth factors.

  9. Molecularly imprinted films of acrylonitrile/methyl methacrylate/acrylic acid terpolymers: influence of methyl methacrylate in the binding performance of L-ephedrine imprinted films.

    PubMed

    Brisbane, Carrie; McCluskey, Adam; Bowyer, Michael; Holdsworth, Clovia I

    2013-05-07

    Molecularly imprinted polymeric films (MIPFs) highly selective to 1R,2S(-)ephedrine (L-ephedrine, EPD) were produced by phase inversion post-polymerization imprinting on poly(acrylonitrile-co-methyl methacrylate-co-acrylic acid) (PAMA) terpolymers. The inclusion of methyl methacrylate (MMA) to the polymer formulation resulted in enhanced EPD selectivity which appears to be dictated by polymer composition to achieve the necessary balance between polymer rigidity and porosity. Substitution of MMA with methyl acrylate, ethyl acrylate and n-butyl acrylate resulted in a loss of EPD selectivity and EPD entrapment within the polymer matrix not observed in PAMA MIPFs. MMA, by virtue of its methyl group, is able to provide the scaffolding and rigidity necessary for stability and preservation of imprinted cavities within the PAMA MIPF leading to high EPD selectivity.

  10. Thermally Switchable Thin Films of an ABC Triblock Copolymer of Poly(n-butyl methacrylate)-poly(methyl methacrylate)-poly(2-fluoroethyl methacrylate)

    SciTech Connect

    Zhang, Shanju; Liu, Zhan; Bucknall, David G.; He, Lihong; Hong, Kunlun; Mays, Jimmy; Allen, Mark

    2011-01-01

    The thermo-responsive behavior of polymer films consisting of novel linear triblock copolymers of poly(n-butyl methacrylate)-poly(methyl methacrylate)-poly(2-fluoroethyl methacrylate) (PnBuMA-PMMA-P2FEMA) are reported using differential scanning calorimetry (DSC), atomic forcing microscopy (AFM), X-ray photoelectron spectroscopy (XPS) and contacting angle (CA) measurements. The surface morphology, wettability and chemical structure of thin films of these triblock copolymers on silicon wafers as a function of temperature have been investigated. It has been shown that the wettability of the films is thermally switchable. Detailed structural analysis shows that thermo-responsive surface composition changes are produced. The underlying mechanism of the thermoresponsive behavior is discussed.

  11. Thermally switchable thin films of an ABC triblock copolymer of poly( n -butyl methacrylate)-poly(methyl methacrylate)-poly(2-fluoroethyl methacrylate)

    NASA Astrophysics Data System (ADS)

    Zhang, Shanju; Liu, Zhan; Bucknall, David G.; He, Lihong; Hong, Kunlun; Mays, Jimmy W.; Allen, Mark G.

    2011-09-01

    The thermo-responsive behavior of polymer films consisting of novel linear triblock copolymers of poly( n-butyl methacrylate)-poly(methyl methacrylate)-poly(2-fluoroethyl methacrylate) (PnBuMA-PMMA-P2FEMA) are reported using differential scanning calorimetry (DSC), atomic forcing microscopy (AFM), X-ray photoelectron spectroscopy (XPS) and contacting angle (CA) measurements. The surface morphology, wettability and chemical structure of thin films of these triblock copolymers on silicon wafers as a function of temperature have been investigated. It has been shown that the wettability of the films is thermally switchable. Detailed structural analysis shows that thermo-responsive surface composition changes are produced. The underlying mechanism of the thermoresponsive behavior is discussed.

  12. Horseradish peroxidase mediated free radical polymerization of methyl methacrylate.

    PubMed

    Kalra, B; Gross, R A

    2000-01-01

    This paper reports the free radical polymerization of methyl methacrylate (MMA) catalyzed by horseradish peroxidase (HRP). A novel method was developed whereby MMA polymerization can be carried out at ambient temperatures in the presence of low concentrations of hydrogen peroxide and 2,4-pentanedione in a mixture of water and a water-miscible solvent. Polymers of MMA formed were highly stereoregular with predominantly syndiotactic sequences (syn-dyad fractions from 0.82 to 0.87). Analyses of the chloroform-soluble fraction of syndio-PMMA products by GPC showed that they have number-average molecular weights, Mn, that range from 7500 to 75,000. By using 25% v/v of the cosolvents dioxane, tetrahydrofuran, acetone, and dimethylformamide, 85, 45, 7 and 2% product yields, respectively, resulted after 24 h. Increasing the proportion of dioxane to water from 1:3 to 1:1 and 3:1 resulted in a decrease in polymer yield from 45 to 38 and 7%, respectively. Increase in the enzyme concentration from 70 to 80 and 90 mg/mL resulted in increased reaction kinetics. By adjustment of the molar ratio of 2,4-pentanedione to hydrogen peroxide between 1.30:1.0 and 1.45:1.0, the product yields and Mn values were increased. On the basis of the catalytic properties of HRP and studies herein, we believe that the keto-enoxy radicals from 2,4-pentanedione are the first radical species generated. Then, initiation may take place through this radical or by the radical transfer to another molecule.

  13. Assessment of methyl methacrylate genotoxicity by the micronucleus test.

    PubMed

    Araújo, Amarildo Mariano de; Alves, Guilherme Rodrigues; Avanço, Guilherme Trevisan; Parizi, José Luiz Santos; Nai, Gisele Alborghetti

    2013-01-01

    The aim of this study was to evaluate the genotoxic potential of methyl methacrylate (MMA) vapor by simulating standard occupational exposure of 8 hours per day and using the micronucleus test. We used 32 adult male Wistar rats divided into three groups: A - 16 rats exposed to MMA for 8 hours a day, B - Eight rats receiving single subcutaneous doses of cyclophosphamide on the first day of the experiment (positive control), C - Eight rats receiving only water and food ad libitum (negative control). Eight rats from group A and all of the rats from groups B and C were sacrificed 24 hours after beginning the experiment (acute exposure in group A). The remaining animals in group A were sacrificed 5 days after the experiment began (repeated exposure assessment in group A, simulating occupational exposure 40 hours/week). Femoral bone marrow was collected from each rat at the time of sacrifice for use in the micronucleus test. Two slides were completed per animal and were stained with Giemsa staining. Two thousand polychromatic erythrocytes were counted per animal. The Kruskal-Wallis test followed by a multiple comparisons test (Dunn test) was used for statistical analysis. The median number of micronuclei was 7.00 in the group exposed to MMA for 1 day, 2.00 in the group exposed to MMA for 5 days, 9.00 in the group exposed to cyclophosphamide (positive control) and 0.756 in the negative control group (p < 0.0001). MMA was genotoxic when measured after 1 day of exposure but was not evidently genotoxic after 5 days.

  14. Alternariol 9-O-methyl ether.

    PubMed

    Dasari, Sreekanth; Bhadbhade, Mohan; Neilan, Brett A

    2012-05-01

    The title compound (AME; systematic name: 3,7-dihy-droxy-9-meth-oxy-1-methyl-6H-benzo[c]chromen-6-one), C(15)H(12)O(5), was isolated from an endophytic fungi Alternaria sp., from Catharanthus roseus (common name: Madagascar periwinkle). There is an intramolecular O-H⋯O hydrogen bond in the essentially planar mol-ecule (r.m.s. deviation 0.02 Å). In the crystal, the molecule forms an O-H⋯O hydrogen bond with its centrosymmetric counterpart with four bridging inter-actions (two O-H⋯O and two C-H⋯O). The almost planar sheets of the dimeric units thus formed are stacked along b axis via C-H⋯π and π-π contacts [with C⋯C short contacts between aromatic moieties of 3.324 (3), 3.296 (3) and 3.374 (3) Å].

  15. Preparation of Optically Transparent Films of Poly(methyl methacrylate) (PMMA) and Montmorillonite

    DTIC Science & Technology

    2001-11-01

    methacrylate] [PMMA] and Montmorillonite DISTRIBUTION: Approved for public release, distribution unlimited This paper is part of the following report...Society V6.4 Preparation of Optically Transparent Films of Poly(methyl methacrylate) (PMMA) and Montmorillonite Elena Vasiliul, Chyi-Shan Wang"’ 2...exchanged with 1.40 meq/g of dimethyl dehydrogenated tallow ammonium from a sodium montmorillonite , Cloisite Na+ (CNa). Since the cation-exchange

  16. Analytical strategy for the molecular weight determination of random copolymers of poly(methyl methacrylate) and poly(methacrylic acid).

    PubMed

    Giordanengo, Rémi; Viel, Stéphane; Hidalgo, Manuel; Allard-Breton, Béatrice; Thévand, André; Charles, Laurence

    2010-06-01

    Molecular weight characterization of random amphiphilic copolymers currently represents an analytical challenge. In particular, molecules composed of methacrylic acid (MAA) and methyl methacrylate (MMA) as the repeat units raise issues in commonly used techniques. The present study shows that when random copolymers cannot be properly ionized by MALDI, and hence detected and measured in MS, one possible analytical strategy is to transform them into homopolymers, which are more amenable to this ionization technique. Then, by combining the molecular weight of the so-obtained homopolymers, as measured by MS, with the relative molar proportion of the MMA and MMA units, as given by (1)H NMR spectrum, one can straightforwardly estimate the molecular weight of the initial copolymer. A methylation reaction was performed to transform MAA-MMA copolymer samples into PMMA homopolymers, using trimethylsilyldiazomethane as a derivatization agent. Weight average molecular weight (M(w)) parameters of the MAA-MMA copolymers could then be derived from M(w) values obtained for the methylated MAA-MMA molecules by MALDI, which were also validated by pulsed gradient spin echo (PGSE) NMR. An alkene function in one of the studied copolymer end-groups was also shown to react with the methylation agent, giving rise to MMA-like polymeric by-products characterized by tandem mass spectrometry and which could be avoided by adjusting the amount of the trimethylsilyldiazomethane in the reaction medium.

  17. Synthesis of branched poly(methyl methacrylate)s via controlled/living polymerisations exploiting ethylene glycol dimethacrylate as branching agent.

    PubMed

    Isaure, Francoise; Cormack, Peter A G; Graham, Susan; Sherrington, David C; Armes, Steven P; Bütun, Vural

    2004-05-07

    With appropriate choice of reaction composition and conditions, copolymerisation of methyl methacrylate and ethylene glycol dimethacrylate using Cu-based ATRP or GTP methodologies yields soluble branched polymers in facile one-pot reactions.

  18. Novel poly(methyl methacrylate)-based semi-interpenetrating polyelectrolyte gels for rechargeable lithium batteries

    NASA Astrophysics Data System (ADS)

    Kalapala, Saibabu; Easteal, Allan J.

    Novel semi-interpenetrating polymer gel electrolytes designed for use in rechargeable lithium polymer batteries are synthesised from methyl methacrylate and the lithium salt of 2-acrylamido-2-methylpropanesulfonic acid (LiAMPS). The gels are made by first synthesising linear chains of poly(LiAMPS) by free radical polymerisation of LiAMPS dissolved in dimethyl acetamide (DMA) or DMA/ethylene carbonate mixtures, then co-polymerisation of methyl methacrylate and a cross-linking monomer (tetraethyleneglycol diacrylate) to form the semi-interpenetrating network. The electrical conductivity of the gels is determined as a function of LiAMPS and methyl methacrylate (MMA) concentrations, cross-link density, and solvent composition. The conductivity ( σ) is found to be in the range 0.2 ≤ σ ≤ 0.8 mS cm -1 at ambient temperature (20 ± 1 °C).

  19. Ether Cleavage Re-Investigated: Elucidating the Mechanism of BBr3-Facilitated Demethylation of Aryl Methyl Ethers

    PubMed Central

    Kosak, Talon M; Conrad, Heidi A; Korich, Andrew L; Lord, Richard L

    2015-01-01

    One of the most well-known, highly utilized reagents for ether cleavage is boron tribromide (BBr3), and this reagent is frequently employed in a 1:1 stoichiometric ratio with ethers. Density functional theory calculations predict a new mechanistic pathway involving charged intermediates for ether cleavage in aryl methyl ethers. Moreover, these calculations predict that one equivalent of BBr3 can cleave up to three equivalents of anisole, producing triphenoxyborane [B(OPh)3] prior to hydrolysis. These predictions were validated by gas chromatography analysis of reactions where the BBr3:anisole ratio was varied. Not only do we confirm that sub-stoichiometric equivalents may be used for ether demethylation, but the findings also support our newly proposed three cycle mechanism for cleavage of aryl methyl ethers. PMID:26693209

  20. The Mark-Houwink-Sakurada Relation for Poly(Methyl Methacrylate)

    NASA Astrophysics Data System (ADS)

    Wagner, Herman L.

    1987-04-01

    In this third review of a series, the literature values for the viscosity-molecular weight relationship (Mark-Houwink-Sakurada) for poly(methyl methacrylate) have been critically evaluated. Although most of the studies have been concerned with conventionally produced poly(methyl methacrylate), some work has also been done with the isotactic polymer. The Mark-Houwink relations for the following solvents are discussed: benzene, toluene, acetone, chloroform, 2-butanone, and tetrahydrofuran, as well as for several other infrequently used solvents. The values of the coefficient K in the relation [η]=KM0.5 for several theta solvents are also reported.

  1. Photo-Physical Behavior and Fluorescence of Thermo Switchable Nanocomposite Based on Methyl Methacrylate -Spirobenzopyran.

    PubMed

    Rouhani, Shohre; Pishvaei, Malihe

    2017-03-01

    Nanocomposites with thermo and photo-switchable fluorescent properties were synthesized via mini-emulsion polymerization based on spiropyran and methyl methacrylate monomer. The photophysical behavior of fluorescence nanocomposites was investigated by fluorescence spectrophotometry in different temperature, UV-light and time of exposure. It was found that methyl methacrylate polymer is capable of acting as a protective layer and play a critical role in improving the photostability of colorants. The nanocomposites exhibited excellent fluorescent thermo-switching action with respect to the free spiro molecule. Graphical Abstract ᅟ.

  2. Disabling disturbance of olfaction in a dental technician following exposure to methyl methacrylate.

    PubMed

    Braun, D; Wagner, W; Zenner, H-P; Schmahl, F W

    2002-10-01

    It is often difficult to diagnose dysosmia due to occupational olfactotoxic substances. The authors present a case of disabling disturbance of olfaction in a dental technician. This is very likely to have been caused by exposure to methyl methacrylate. From 1988-1992, the dental technician had very extensive and sustained contact with a self-polymerizing acrylic resin based on methyl methacrylate. Her perception of smell was still normal in 1988, but it deteriorated up to 1992. The olfactory disorders have persisted and impede social life and occupational rehabilitation.

  3. Evaluation of alternariol and alternariol methyl ether for mutagenic activity in Salmonella typhimurium

    SciTech Connect

    Davis, V.M.; Stack, M.E. )

    1994-10-01

    Alternariol and alternariol methyl ether were tested in the Ames Salmonella typhimurium assay, and both were shown, with and without metabolic activation, to be nonmutagenic to strains TA98 and TA100. The finding of other investigators that alternariol methyl ether is weakly mutagenic to Ta98 without metabolic activation could have resulted from the presence of a small amount of one of the highly mutagenic altertoxins in the alternariol methyl ether originally tested. 9 refs., 3 figs., 1 tab.

  4. 21 CFR 177.1830 - Styrene-methyl methacrylate copolymers.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... methacrylate copolymers identified in this section may be safely used as components of plastic articles... weight percent of polymer units derived from styrene. (b) The finished plastic food-contact article, when... not to exceed an absorbance of 0.15. (3) Ultraviolet-absorbing distilled water and 8 and 50...

  5. Affinity chromatography of proteins on non-porous copolymerized particles of styrene, methyl methacrylate and glycidyl methacrylate.

    PubMed

    Chen, C H; Lee, W C

    2001-06-29

    Non-porous particles having an average diameter of 2.1 microm were prepared by co-polymerization of styrene, methyl methacrylate and glycidyl methacrylate, which was abbreviated as P(S-MMA-GMA). The particles were mechanically stable due to the presence of benzene rings in the backbone of polymer chains, and could withstand high pressures when a column packed with these particles was operated in the HPLC mode. The polymer particles were advantaged by immobilization of ligands via the epoxy groups on the particle surface that were introduced by one of the monomers, glycidyl methacrylate. As a model system, Cibacron Blue 3G-A was covalently immobilized onto the non-porous copolymer beads. The dye-immobilized P(S-MMA-GMA) particles were slurry packed into a 1.0 cm x 0.46 cm I.D. column. This affinity column was effective for the separation of turkey egg white lysozyme from a protein mixture. The bound lysozyme could be eluted to yield a sharp peak by using a phosphate buffer containing 1 M NaCl. For a sample containing up to 8 microg of lysozyme, the retained portion of proteins could be completely eluted without any slit peak. Due to the use of a shorter column, the analysis time was shorter in comparison with other affinity systems reported in the literature. The retention time could be reduced significantly by increasing the flow-rate, while the capacity factor remained at the same level.

  6. Biodegradation of ethyl t-butyl ether (ETBE), methyl t-butyl ether (MTBE) and t-amyl methyl ether (TAME) by Gordonia terrae.

    PubMed

    Hernandez-Perez, G; Fayolle, F; Vandecasteele, J P

    2001-01-01

    Gordonia terrae strain IFP 2001 was selected from activated sludge for its capacity to grow on ethyl t-butyl ether (ETBE) as sole carbon and energy source. ETBE was stoichiometrically degraded to t-butyl alcohol (TBA) and the activity was inducible. A constitutive strain, G. terrae IFP 2007, derived from strain IFP 2001, was also selected. Methyl t-butyl ether (MTBE) and t-amyl methyl ether (TAME) were not used as carbon and energy sources by the two strains, but cometabolic degradation of MTBE and TAME was demonstrated, to TBA and t-amyl alcohol (TAA) respectively, in the presence of a carbon source such as ethanol. No two-carbon compound was detected during growth on ETBE, but formate was produced during cometabolic degradation of MTBE or TAME. A monooxygenase was involved in the degradation of ethers, because no degradation of ETBE was observed under anaerobic conditions and the presence of a cytochrome P-450 was demonstrated in G. terrae IFP 2001 after induction by cultivation on ETBE.

  7. Optical Properties of Nanocellulose Dispersions in Water, Dimethylformamide and Poly(Methyl Methacrylate)

    DTIC Science & Technology

    2013-10-01

    measurements for cellulose and PMMA thin- films . ..13  v List of Tables Table 1. Recorded optical data for nanocellulose in water...applications beyond thin films . In particular, the effects of nanocellulose fibers in higher concentrations, processed in different solvents, and...Optical Properties of Nanocellulose Dispersions in Water, Dimethylformamide and Poly(Methyl Methacrylate) by James F. Snyder, Joshua Steele

  8. Controlled Degradation of Poly(Ethyl Cyanoacrylate-Co-Methyl Methacrylate)(PECA-Co-PMMA) Copolymers

    Technology Transfer Automated Retrieval System (TEKTRAN)

    This paper describes a method for modifying poly(ethyl cyanoacrylate) in order to control the degradation and the stability as well as the glass transition temperatures. Copolymers of poly(ethyl cyanoacrylate-co-methyl methacrylate) (PECA-co-PMMA) with various compositions were synthesized by free ...

  9. Chest Wall Reconstruction Using a Methyl Methacrylate Neo-Rib and Mesh.

    PubMed

    Suzuki, Kei; Park, Bernard J; Adusumilli, Prasad S; Rizk, Nabil P; Huang, James; Jones, David R; Bains, Manjit S

    2015-08-01

    Prosthetic reconstruction of the chest wall after oncologic resection is performed by means of various techniques using different materials. We describe a new technique of chest wall reconstruction that includes the use of Marlex mesh and the creation of a neo-rib from a Steinmann pin and methyl methacrylate.

  10. Characterization of methyl methacrylate grafting onto preirradiated biodegradable lignocellulose fiber by gamma-radiation.

    PubMed

    Khan, Ferdous

    2005-01-14

    Gamma-radiation-induced graft copolymerization of methyl methacrylate onto natural lignocellulose (jute) fiber was carried out by the preirradiation method in an aqueous medium by using octylphenoxy-polyethoxyethanol as an emulsifier. The different factors that influenced the graft copolymer reaction process were investigated. In the case of radiation-dose-dependent grafting, samples irradiated in the presence of air produced up to 73% graft weight compared to 53% obtained in the case of irradiation in a nitrogen environment. By assuming Arrhenius reaction kinetics, the activation energy (E(a)) of the grafting reaction process was evaluated for different reaction temperatures. Moreover, the graft copolymer reaction was controlled by incorporating a homopolymer-inhibiting agent and three different chain-transfer agents in the reaction medium. The mechanical and thermal properties of jute fiber 'as received' and jute-graft-poly(methyl methacrylate) were also investigated. The results showed that the percentage of grafting with jute fiber has a significant effect on the properties. The kinetic parameters were evaluated from TGA thermograms by using Broido's method in the temperature range 240-350 degrees C. Scanning electron micrographs show that the structural changes on the surface of jute fibers were induced by graft copolymerization of methyl methacrylate monomer. Fiber-fiber surface friction was measured in terms of the average maximum load and the kinetic friction. SEM of jute-graft-poly(methyl methacrylate).

  11. 21 CFR 177.1030 - Acrylonitrile/butadiene/styrene/methyl methacrylate copolymer.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    .../styrene/methyl methacrylate copolymer consists of: (1) 73 to 79 parts by weight of a matrix polymer... composition range as the matrix polymer. (b) Adjuvants. The copolymer identified in paragraph (a) of this...: POLYMERS Substances for Use as Basic Components of Single and Repeated Use Food Contact Surfaces §...

  12. 21 CFR 177.1030 - Acrylonitrile/butadiene/styrene/methyl methacrylate copolymer.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    .../styrene/methyl methacrylate copolymer consists of: (1) 73 to 79 parts by weight of a matrix polymer... composition range as the matrix polymer. (b) Adjuvants. The copolymer identified in paragraph (a) of this... HUMAN SERVICES (CONTINUED) FOOD FOR HUMAN CONSUMPTION (CONTINUED) INDIRECT FOOD ADDITIVES:...

  13. 21 CFR 177.1030 - Acrylonitrile/butadiene/styrene/methyl methacrylate copolymer.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    .../styrene/methyl methacrylate copolymer consists of: (1) 73 to 79 parts by weight of a matrix polymer... composition range as the matrix polymer. (b) Adjuvants. The copolymer identified in paragraph (a) of this...: POLYMERS Substances for Use as Basic Components of Single and Repeated Use Food Contact Surfaces §...

  14. 21 CFR 177.1030 - Acrylonitrile/butadiene/styrene/methyl methacrylate copolymer.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    .../styrene/methyl methacrylate copolymer consists of: (1) 73 to 79 parts by weight of a matrix polymer... composition range as the matrix polymer. (b) Adjuvants. The copolymer identified in paragraph (a) of this...: POLYMERS Substances for Use as Basic Components of Single and Repeated Use Food Contact Surfaces §...

  15. Flexural properties of ethyl or methyl methacrylate-UDMA blend polymers.

    PubMed

    Kanie, Takahito; Kadokawa, Akihiko; Arikawa, Hiroyuki; Fujii, Koichi; Ban, Seiji

    2010-10-01

    Light-curing polyethyl methacrylate (PEMA)-urethane dimethacrylate (UDMA) resins and polymethyl methacrylate (PMMA)-UDMA resins were prepared by two processes. For first step, PEMA or PMMA powders were fully dissolved in ethyl methacrylate (EMA) or methyl methacrylate (MMA) and then the PEMA-EMA/PMMA-MMA mixtures were mixed with UDMA. The flexural properties of cured PEMA-UDMA and PMMA-UDMA polymers were measured using two PEMA (Mw: 300,000-400,000 and 650,000-1,000,000) and three PMMA (Mw: 30,000-60,000, 350,000 and 650,000-1,000,000) powders with different molecular weight, four mixing ratios of PMMA-MMA, and three mixing ratios of PMMA-MMA mixture and UDMA oligomer. Polymers with PMMA(Mw: 350,000) MMA=25/50, and with PMMA(Mw: 350,000)-MMA/UDMA=1/2 and =1/1, showed no-fracture in a flexural test at 1 mm/min and flexural strength and flexural modulus showed no significant difference compared with those of commercially available heat- and self-curing acrylic resins (p>0.01). Within limitation of this investigation, methyl methacrylate-UDMA blend polymer of this composition is available for denture base resin.

  16. Enhanced surface segregation of poly(methyl methacrylate) end-capped with 2-perfluorooctylethyl methacrylate by introduction of a second block.

    PubMed

    Ni, Huagang; Gao, Jie; Li, Xuehua; Hu, Yanyan; Yan, Donghuan; Ye, XiuYun; Wang, Xinping

    2012-01-01

    New fluorinated copolymers of poly(methyl methacrylate)-b-poly(butyl methacrylate) or poly(n-octadecyl methacrylate) end-capped with 2-perfluorooctylethyl methacrylate (PMMA(x)-b-PBMA(y)-ec-PFMA(z) or PMMA(x)-b-PODMA(y)-ec-PFMA(z)) were synthesized by living atom transfer radical polymerization. Thin films made of PMMA(230)-b-PODMA(y)-ec-PFMA(1) were characterized by differential scanning calorimetry, angle-resolved X-ray photoelectron spectroscopy and X-ray diffraction. These films were found to exhibit robust surface segregation of the end groups. Furthermore, the fluorine enrichment factor at the film surface was found to increase linearly with increasing degree of polymerization of poly(n-octadecyl methacrylate) and its increasing fusion enthalpy in the second block, which enhances the segregation of the fluorinated moieties.

  17. [Gas chromatographic analysis of methyl methacrylate and methanol in its esterification mixture].

    PubMed

    Wu, C; Zeng, C

    1997-09-01

    A fast, simple and accurate gas chromatographic method is established for determining the content of methyl methacrylate (MMA) and methanol in the esterification mixture of methacrylic acid with methanol in the presence of sulfuric acid. In the measurement, polyethylene glycol-20M/sodium hydroxide was adopted as liquid phase, coated on the acid-washed 201 pink support. n-Heptane was used as the internal standard and the correction factors of MMA and methanol obtained were 1.65 and 4.10, respectively. It is significant for this method to be used to control MMA production by acetone cyanohydrin method and to improve the production technology.

  18. Biodegradation of the gasoline oxygenates methyl tert-butyl ether, ethyl tert-butyl ether, and tert-amyl methyl ether by propane-oxidizing bacteria.

    PubMed

    Steffan, R J; McClay, K; Vainberg, S; Condee, C W; Zhang, D

    1997-11-01

    Several propane-oxidizing bacteria were tested for their ability to degrade gasoline oxygenates, including methyl tert-butyl ether (MTBE), ethyl tert-butyl ether (ETBE), and tert-amyl methyl ether (TAME). Both a laboratory strain and natural isolates were able to degrade each compound after growth on propane. When propane-grown strain ENV425 was incubated with 20 mg of uniformly labeled [14C]MTBE per liter, the strain converted > 60% of the added MTBE to 14CO2 in < 30 h. The initial oxidation of MTBE and ETBE resulted in the production of nearly stoichiometric amounts of tert-butyl alcohol (TBA), while the initial oxidation of TAME resulted in the production of tert-amyl alcohol. The methoxy methyl group of MTBE was oxidized to formaldehyde and ultimately to CO2. TBA was further oxidized to 2-methyl-2-hydroxy-1-propanol and then 2-hydroxy isobutyric acid; however, neither of these degradation products was an effective growth substrate for the propane oxidizers. Analysis of cell extracts of ENV425 and experiments with enzyme inhibitors implicated a soluble P-450 enzyme in the oxidation of both MTBE and TBA. MTBE was oxidized to TBA by camphor-grown Pseudomonas putida CAM, which produces the well-characterized P-450cam, but not by Rhodococcus rhodochrous 116, which produces two P-450 enzymes. Rates of MTBE degradation by propane-oxidizing strains ranged from 3.9 to 9.2 nmol/min/mg of cell protein at 28 degrees C, whereas TBA was oxidized at a rate of only 1.8 to 2.4 nmol/min/mg of cell protein at the same temperature.

  19. Selection and identification of bacterial strains with methyl-tert-butyl ether, ethyl-tert-butyl ether, and tert-amyl methyl ether degrading capacities.

    PubMed

    Purswani, Jessica; Pozo, Clementina; Rodríguez-Díaz, Marina; González-López, Jesús

    2008-11-01

    Nine bacterial strains isolated from two hydrocarbon-contaminated soils were selected because of their capacity for growth in culture media amended with 200 mg/L of one of the following gasoline oxygenates: Methyl-tert-butyl ether (MTBE), ethyl-tert-butyl ether (ETBE), and tert-amyl methyl ether (TAME). These strains were identified by amplification of their 16S rRNA gene, using fDl and rD1 primers, and were tested for their capacity to grow and biotransform these oxygenates in both mineral and cometabolic media. The isolates were classified as Bacillus simplex, Bacillus drentensis, Arthrobacter sp., Acinetobacter calcoaceticus, Acinetobacter sp., Gordonia amicalis (two strains), Nocardioides sp., and Rhodococcus ruber. Arthrobacter sp. (strain MG) and A. calcoaceticus (strain M10) consumed 100 (cometabolic medium) and 82 mg/L (mineral medium) of oxygenate TAME in 21 d, respectively, under aerobic conditions. Rhodococcus ruber (strain E10) was observed to use MTBE and ETBE as the sole carbon and energy source, whereas G. amicalis (strain T3) used TAME as the sole carbon and energy source for growth. All the bacterial strains transformed oxygenates better in the presence of an alternative carbon source (ethanol) with the exception of A. calcoaceticus (strain M10). The capacity of the selected strains to remove MTBE, ETBE, and TAME looks promising for application in bioremediation technologies.

  20. Poly[tri(ethylene glycol) ethyl ether methacrylate]-coated surfaces for controlled fibroblasts culturing.

    PubMed

    Dworak, Andrzej; Utrata-Wesołek, Alicja; Szweda, Dawid; Kowalczuk, Agnieszka; Trzebicka, Barbara; Anioł, Jacek; Sieroń, Aleksander L; Klama-Baryła, Agnieszka; Kawecki, Marek

    2013-03-01

    Well-defined thermosensitive poly[tri(ethylene glycol) monoethyl ether methacrylate] (P(TEGMA-EE)) brushes were synthesized on a solid substrate by the surface-initiated atom transfer radical polymerization of TEGMA-EE. The polymerization reaction was initiated by 2-bromo-2-methylpropionate groups immobilized on the surface of the wafers. The changes in the surface composition, morphology, philicity, and thickness that occurred at each step of wafer functionalization confirmed that all surface modification procedures were successful. Both the successful modification of the surface and bonding of the P(TEGMA-EE) layer were confirmed by X-ray photoelectron spectroscopy (XPS) measurements. The thickness of the obtained P(TEGMA-EE) layers increased with increasing polymerization time. The increase of environmental temperature above the cloud point temperature of P(TEGMA-EE) caused the changes of surface philicity. A simultaneous decrease in the polymer layer thickness confirmed the thermosensitive properties of these P(TEGMA-EE) layers. The thermosensitive polymer surfaces obtained were evaluated for the growth and harvesting of human fibroblasts (basic skin cells). At 37 °C, seeded cells adhered to and spread well onto the P(TEGMA-EE)-coated surfaces. A confluent cell sheet was formed within 24 h of cell culture. Lowering the temperature to an optimal value of 17.5 °C (below the cloud point temperature of the polymer, TCP, in cell culture medium) led to the separation of the fibroblast sheet from the polymer layer. These promising results indicate that the surfaces produced may successfully be used as substrate for engineering of skin tissue, especially for delivering cell sheets in the treatment of burns and slow-healing wounds.

  1. Methylation of acidic moieties in poly(methyl methacrylate-co-methacrylic acid) copolymers for end-group characterization by tandem mass spectrometry.

    PubMed

    Giordanengo, Rémi; Viel, Stéphane; Hidalgo, Manuel; Allard-Breton, Béatrice; Thévand, André; Charles, Laurence

    2010-07-30

    The complete structural characterization of a copolymer composed of methacrylic acid (MAA) and methyl methacrylate (MMA) units was achieved using tandem mass spectrometry. In a first step, collision-induced dissociation (CID) of sodiated MAA-MMA co-oligomers allowed us to determine the co-monomeric composition, the random nature of the copolymer and the sum of the end-group masses. However, dissociation reactions of MAA-based molecules mainly involve the acidic pendant groups, precluding individual characterization of the end groups. Therefore, methylation of all the acrylic acid moieties was performed to transform the MAA-MMA copolymer into a PMMA homopolymer, for which CID mainly proceeds via backbone cleavages. Using trimethylsilyldiazomethane as a derivatization agent, this methylation reaction was shown to be complete without affecting the end groups. Using fragmentation rules established for PMMA polymers together with accurate mass measurements of the product ions and knowledge of reagents used for the studied copolymer synthesis, a structure could be proposed for both end groups and it was found to be consistent with signals obtained in nuclear magnetic resonance spectra.

  2. Structural characterization of a poly(methacrylic acid)-poly(methyl methacrylate) copolymer by nuclear magnetic resonance and mass spectrometry.

    PubMed

    Giordanengo, Rémi; Viel, Stéphane; Hidalgo, Manuel; Allard-Breton, Béatrice; Thévand, André; Charles, Laurence

    2009-11-03

    Mass spectrometry (MS) and nuclear magnetic resonance (NMR) have been combined to achieve the complete microstructural characterization of a poly(methacrylic acid)-poly(methyl methacrylate) (PMAA-PMMA) copolymer synthesized by nitroxide-mediated polymerization. Various PMAA-PMMA species could be identified which mainly differ in terms of terminaisons. 1H and 13C NMR experiments revealed the structure of the end-groups as well as the proportion of each co-monomer in the copolymers. These end-group masses were further confirmed from m/z values of doubly charged copolymer anions detected in the single stage mass spectrum. In contrast, copolymer composition derived from MS data was not consistent with NMR results, obviously due to strong mass bias well known to occur during electrospray ionization of these polymeric species. Tandem mass spectrometry could reveal the random nature of the copolymer based on typical dissociation reactions, i.e., water elimination occurred from any two contiguous MAA units while MAA-MMA pairs gave rise to the loss of a methanol molecule. Polymer backbone cleavages were also observed to occur and gave low abundance fragment ions which allowed the structure of the initiating end-group to be confirmed.

  3. Vapor intrusion risk of fuel ether oxygenates methyl tert-butyl ether (MTBE), tert-amyl methyl ether (TAME) and ethyl tert-butyl ether (ETBE): A modeling study.

    PubMed

    Ma, Jie; Xiong, Desen; Li, Haiyan; Ding, Yi; Xia, Xiangcheng; Yang, Yongqi

    2017-06-15

    Vapor intrusion of synthetic fuel additives represents a critical yet still neglected problem at sites contaminated by petroleum fuel releases. This study used an advanced numerical model to investigate the vapor intrusion potential of fuel ether oxygenates methyl tert-butyl ether (MTBE), tert-amyl methyl ether (TAME), and ethyl tert-butyl ether (ETBE). Simulated indoor air concentration of these compounds can exceed USEPA indoor air screening level for MTBE (110μg/m(3)). Our results also reveal that MTBE has much higher chance to cause vapor intrusion problems than TAME and ETBE. This study supports the statements made by USEPA in the Petroleum Vapor Intrusion (PVI) Guidance that the vertical screening criteria for petroleum hydrocarbons may not provide sufficient protectiveness for fuel additives, and ether oxygenates in particular. In addition to adverse impacts on human health, ether oxygenate vapor intrusion may also cause aesthetic problems (i.e., odour and flavour). Overall, this study points out that ether oxygenates can cause vapor intrusion problems. We recommend that USEPA consider including the field measurement data of synthetic fuel additives in the existing PVI database and possibly revising the PVI Guidance as necessary.

  4. Searching for trans ethyl methyl ether in Orion KL(.)

    PubMed

    Tercero, B; Cernicharo, J; López, A; Brouillet, N; Kolesniková, L; Motiyenko, R A; Margulès, L; Alonso, J L; Guillemin, J-C

    2015-10-01

    We report on the tentative detection of trans ethyl methyl ether (tEME), t-CH3CH2OCH3, through the identification of a large number of rotational lines from each one of the spin states of the molecule towards Orion KL. We also search for gauche-trans-n-propanol, Gt-n-CH3CH2CH2OH, an isomer of tEME in the same source. We have identified lines of both species in the IRAM 30 m line survey and in the ALMA Science Verification data. We have obtained ALMA maps to establish the spatial distribution of these species. Whereas tEME mainly arises from the compact ridge component of Orion, Gt-n-propanol appears at the emission peak of ethanol (south hot core). The derived column densities of these species at the location of their emission peaks are ≤(4.0 ± 0.8) × 10(15) cm(-2) and ≤(1.0 ± 0.2)× 10(15) cm(-2) for tEME and Gt-n-propanol, respectively. The rotational temperature is ~100 K for both molecules. We also provide maps of CH3OCOH, CH3CH2OCOH, CH3OCH3, CH3OH, and CH3CH2OH to compare the distribution of these organic saturated O-bearing species containing methyl and ethyl groups in this region. Abundance ratios of related species and upper limits to the abundances of non-detected ethers are provided. We derive an abundance ratio N(CH3OCH3)/N(tEME) ≥ 150 in the compact ridge of Orion.

  5. A rare case of pseudotumor formation associated with methyl methacrylate hypersensitivity in a patient following cemented total knee arthroplasty.

    PubMed

    Kenan, Shachar; Kahn, Leonard; Haramati, Noga; Kenan, Samuel

    2016-08-01

    Hypersensitivity to orthopedic implant materials has been well documented with potential catastrophic consequences if not addressed pre-operatively. The spectrum of reactions is wide, from mild non-specific pain with localized erythema to severe periprosthetic inflammatory destruction and pseudotumor formation. It is therefore essential to identify patients who have or are at risk for implant-associated hypersensitivity. Although metal sensitivity is commonly cited as the cause of these reactions, methyl methacrylate (MMA) has rarely been implicated. To the best of our knowledge, methyl methacrylate-associated pseudotumor formation has not yet been described. The following is a case report of a 68-year-old female who, after undergoing a routine cemented right total knee arthroplasty, developed a painless, enlarging mass during a 13-year period. This mass was found to be a pseudotumor in association with methyl methacrylate hypersensitivity. A review of pseudotumor pathogenesis, methyl methacrylate hypersensitivity, and preoperative preventative care is discussed.

  6. Alternariol 9-methyl ether from the endophytic fungus Alternaria sp. Samif01 and its bioactivities

    PubMed Central

    Lou, Jingfeng; Yu, Ruiting; Wang, Xiaohan; Mao, Ziling; Fu, Linyun; Liu, Yang; Zhou, Ligang

    2016-01-01

    One bioactive compound, identified as alternariol 9-methyl ether, was isolated from the crude extract of the endophytic fungus Alternaria sp. Samif01 residing in the roots of Salvia miltiorrhiza Bunge. Alternariol 9-methyl ether was active against bacteria with minimum inhibitory concentration values ranging from 25 to 75 μg/mL and median inhibitory concentration (IC50) values ranging from 16.00 to 38.27 μg/mL. The IC50 value of alternariol 9-methyl ether against spore germination of Magnaporthe oryzae was 87.18 μg/mL. Alternariol 9-methyl ether also showed antinematodal activity against Bursaphelenchus xylophilus and Caenorhabditis elegans with IC50 values of 98.17 μg/mL and 74.62 μg/mL, respectively. This work is the first report on alternariol 9-methyl ether and its biological activities from the endophytic fungus Alternaria sp. Samif01 derived from S. miltiorrhiza Bunge. The results indicate the potential of Alternaria sp. Samif01 as a source of alternariol 9-methyl ether and also support that alternariol 9-methyl ether is a natural compound with high potential bioactivity against microorganisms. PMID:26887231

  7. Alternariol 9-methyl ether from the endophytic fungus Alternaria sp. Samif01 and its bioactivities.

    PubMed

    Lou, Jingfeng; Yu, Ruiting; Wang, Xiaohan; Mao, Ziling; Fu, Linyun; Liu, Yang; Zhou, Ligang

    2016-01-01

    One bioactive compound, identified as alternariol 9-methyl ether, was isolated from the crude extract of the endophytic fungus Alternaria sp. Samif01 residing in the roots of Salvia miltiorrhiza Bunge. Alternariol 9-methyl ether was active against bacteria with minimum inhibitory concentration values ranging from 25 to 75μg/mL and median inhibitory concentration (IC50) values ranging from 16.00 to 38.27μg/mL. The IC50 value of alternariol 9-methyl ether against spore germination of Magnaporthe oryzae was 87.18μg/mL. Alternariol 9-methyl ether also showed antinematodal activity against Bursaphelenchus xylophilus and Caenorhabditis elegans with IC50 values of 98.17μg/mL and 74.62μg/mL, respectively. This work is the first report on alternariol 9-methyl ether and its biological activities from the endophytic fungus Alternaria sp. Samif01 derived from S. miltiorrhiza Bunge. The results indicate the potential of Alternaria sp. Samif01 as a source of alternariol 9-methyl ether and also support that alternariol 9-methyl ether is a natural compound with high potential bioactivity against microorganisms.

  8. Effect of epoxidation on 30% poly(methyl methacrylate)-grafted natural rubber polymer electrolytes

    NASA Astrophysics Data System (ADS)

    Nazir, Khuzaimah; Aziz, Ahmad Fairoz; Adam, Nurul Ilham; Yahya, Muhd Zu Azhan; Ali, Ab Malik Marwan

    2015-08-01

    Epoxidized 30% poly(methyl methacrylate)-grafted natural rubber (EMG 30) as a polymer host in solid polymer electrolytes (SPEs) has been investigated. EMG30 was synthesized via performicepoxidation method onto 30% poly(methyl methacrylate)-grafted natural rubber (MG30) and the formations of epoxy group were discussed. The EMG30 were characterized by proton nuclear magnetic resonance (1HNMR) to investigate their chemical structure and differential scanning calorimeter to determine their crystallinity. A new peak in 1HNMR spectra (2.71 ppm) confirmed the appearance of epoxy group. SPE based on EMG30 doped with 40 wt% LiCF3SO3 show the highest conductivity. The complexation between EMG30 and LiCF3SO3 were confirmed by attenuated total reflection Fourier transform infrared (ATR-FTIR).

  9. Effect of epoxidation on 30% poly(methyl methacrylate)-grafted natural rubber polymer electrolytes

    SciTech Connect

    Nazir, Khuzaimah; Aziz, Ahmad Fairoz; Adam, Nurul Ilham; Yahya, Muhd Zu Azhan; Ali, Ab Malik Marwan

    2015-08-28

    Epoxidized 30% poly(methyl methacrylate)-grafted natural rubber (EMG 30) as a polymer host in solid polymer electrolytes (SPEs) has been investigated. EMG30 was synthesized via performicepoxidation method onto 30% poly(methyl methacrylate)-grafted natural rubber (MG30) and the formations of epoxy group were discussed. The EMG30 were characterized by proton nuclear magnetic resonance ({sup 1}HNMR) to investigate their chemical structure and differential scanning calorimeter to determine their crystallinity. A new peak in {sup 1}HNMR spectra (2.71 ppm) confirmed the appearance of epoxy group. SPE based on EMG30 doped with 40 wt% LiCF{sub 3}SO{sub 3} show the highest conductivity. The complexation between EMG30 and LiCF{sub 3}SO{sub 3} were confirmed by attenuated total reflection Fourier transform infrared (ATR-FTIR)

  10. Preparation of poly(methyl methacrylate) grafted hydroxyapatite nanoparticles via reverse ATRP.

    PubMed

    Wang, Yan; Xiao, Yan; Huang, Xiujuan; Lang, Meidong

    2011-08-15

    Surface-initiated reverse atom transfer radical polymerization (reverse ATRP) technical was successfully employed to modify hydroxyapatite (HAP) nanoparticles with poly(methyl methacrylate) (PMMA). The peroxide initiator moiety for reverse ATRP was covalently attached to the HAP surface through the surface hydroxyl groups. Reverse ATRP of methyl methacrylate (MMA) from the initiator-functionalized HAP was carried out, and the end bromide groups of grafted PMMA initiated ATRP of MMA subsequently. Fourier transformation infrared (FTIR) spectroscopy, thermal gravimetric analysis (TGA) and transmission electron microscopy (TEM) were employed to confirm the grafting and to characterize the nanoparticle structure. The grafted PMMA gave HAP nanoparticles excellent dispersibility in MMA monomer. As the amount of grafted PMMA increased, the dispersibility of surface-grafted HAP and the compressive strength of HAP/PMMA composites were improved.

  11. Preparation and Characterization of Poly(methyl methacrylate)-functionalized Carboxyl Multi-walled Carbon Nanotubes

    NASA Astrophysics Data System (ADS)

    Meng, Qing-jie; Zhang, Xing-xiang; Bai, Shi-he; Wang, Xue-chen

    2007-12-01

    An in situ polymerization process was used to prepare poly (methyl methacrylate) (PMMA)-functionalized carboxyl multi-walled carbon nanotubes using carboxylate carbon nanotubes and methyl methacrylate as reactants and benzoyl peroxide as an initiator agent. The functionalized multi-walled carbon nanotubes were characterized using transmission electron microscope, scanning electron microscope, nuclear magnetic resonance, Fourier transform infrared spectroscopy, thermogravimetric analysis and Raman. The results indicate that the PMMA chains are covalently linked with the surface of carboxylate carbon nanotubes. The surface morphology is controlled by the content of carboxylate carbon nanotubes in the reactants. The PMMA functionalized multi-walled carbon nanotubes are soluble in deuterated chloroform. The storage modulus and tanδ magnitude increase as the content of CCNTs increases up to 0.3%.

  12. Poly(methyl methacrylate)-cellulose nitrate copolymers. II. Physical and mechanical properties

    SciTech Connect

    Badran, B.M.; Sherif, S.; El-Sheltawi, S.T.; Abu-Sedira, A.A.

    1981-03-01

    Poly(methyl methacrylate)-cellulose nitrate copolymers were prepared by bulk polymerization using benzoyl peroxide as initiator. Cellulose nitrates of two different nitrogen contents (11.4 and 12.2%) were used. The prepared copolymers were ..gamma..-irradiated for specified periods of up to 11.83 Mrad. Their physical and mechanical properties were measured before and after irradiation. The title copolymers showed lower modulus, tensile strength, and elongation at break than poly(methyl methacrylate) itself, but they showed better hardness and abrasian. Irradiation of up to 6.57 Mrad improved the modulus of the copolymers. Hardness and abrasion were improved by increasing cellulose nitrate content. The prepared copolymers that contained cellulose nitrate of 11.4% nitrogen showed secondary transition points. The increase of cellulose nitrate concentration shifted both first and second transition points to relatively higher values.

  13. Fabrication of Poly(methyl Methacrylate) microfluidic chips by redox-initiated polymerization

    SciTech Connect

    Chen, Jiang; Lin, Yuehe; Chen, Gang

    2007-08-16

    In this report, a method based on the redox-initiated polymerization of methyl methacrylate (MMA) has been developed for the rapid fabrication of PMMA microfluidic chips.The new fabrication approach obviates the need for special equipment and significantly simplifies the process of fabricating microdevices. The attractive performance of the novel PMMA microchips has been demonstrated in connection with contactless conductivity detection for the separation and detection of ionic species.

  14. Durability of Poly(Methyl Methacrylate) Lenses Used in Concentrating Photovoltaic Technology (Revised) (Presentation)

    SciTech Connect

    Miller, D. C.; Carloni, J. D.; Pankow, J. W.; Gjersing, E. L.; To, B.; Packard, C. E.; Kennedy, C. E.; Kurtz, S. R.

    2012-01-01

    Concentrating photovoltaic (CPV) technology recently gained interest based on its expected low levelized cost of electricity, high efficiency, and scalability. Many CPV systems employ Fresnel lenses composed of poly(methyl methacrylate) (PMMA) to obtain a high optical flux density on the cell. The optical and mechanical durability of these lenses, however, is not well established relative to the desired surface life of 30 years. Our research aims to quantify the expected lifetime of PMMA in key market locations (FL, AZ, and CO).

  15. Organophosphazenes.22 Copolymerization of (Alpha-Methylethenylphenyl) Penta-fluorocyclotriphosphazenes with Styrene and Methyl Methacrylate.

    DTIC Science & Technology

    1988-03-15

    pennultimate effects , 19. BSTRACT (Continue on reverse it necessary and identify by block number) i ., i. Both 3- and 4- (l-Methylethenylphenyl...parameters for theA, styrene system show that the major perturbation produced by the phosphazene is a polar6 electron withdrawing effect . The methyl...methacrylate system was found to exhibit significant penultimate effects in its reactivity behavior. The copolymers were characteri-zed using elemental

  16. Photoluminescence of Electrospun Poly-Methyl-Methacrylate:Alq3 Composite Fibres

    NASA Astrophysics Data System (ADS)

    Tong, Ke-Qin; Xu, Chun-Xian; Wang, Qiong; Gu, Bao-Xiang; Zheng, Ke; Ye, Li-Hua; Li, Xin-Song

    2008-12-01

    Tris(8-hydroxyquinoline) aluminium doped poly-methyl-methacrylate (PMMA:Alq3) composite nanofibres are fabricated by electrospinning. The morphology of fibres is characterized by scanning electron microscopy. The photoluminescence of a series of the nanofibres with various contents of Alqs to PMMA is investigated. UV-visible absorption and the PL spectra analysis are employed to analyse the interaction between the polymer and the luminescent molecule.

  17. Occupational exposure to methyl methacrylate monomer induces generalised neuropathy in a dental technician.

    PubMed

    Sadoh, D R; Sharief, M K; Howard, R S

    1999-04-24

    A 36-year-old dental technician for 14 years developed paraesthesia and numbness in her legs. Neurophysiological studies revealed absent sensory nerve action potentials (SNAPs) from her lower limbs and normal upper limb SNAPs on presentation. Motor nerve studies were normal. Repeat studies 2 months after leaving her job showed some improvement in the lower limb SNAPs. It is suggested that her symptoms were caused by occupational exposure to methyl methacrylate monomer.

  18. The electrochemical detection of Ru(II) in a methyl methacrylate solution.

    PubMed

    De Wael, Karolien; Adriaens, Annemie; Temmerman, Eduard

    2006-02-15

    This article describes the voltammetric behaviour of RuCl(2)(PPh(3))(3) in a methyl methacrylate (MMA) solution. Acquiring this type of information is only possible when the ohmic resistance can be kept sufficiently low. Therefore, the conductivity study of pure methyl methacrylate and a tetrabutylammonium tetrafluoroborate (TBABF(4)) methyl methacrylate solution has been described as well. Impedance measurements show an increase in conductivity by adding TBABF(4), while a conductometric curve illustrates the presence of ion pairs, triple ions and quadrupoles depending on the TBABF(4) concentration. The conductivity of a 0.1molL(-1) TBABF(4)-MMA solution (formation of charged triple ions) was high enough to perform electrochemical experiments and a calibration curve could be obtained. The ability of obtaining relevant electrochemical data in low conducting media opens up new perspectives, especially for electroanalytical purposes used to monitor polymer reactions, more specific atom transfer radical polymerization (ATRP) reactions. This method employs a redox process with transition metal complexes in which a halogen ion is transferred reversibly between the transition metal and the polymer chain end. The dynamic equilibrium can be monitored by measuring the ruthenium concentration.

  19. The thickening additives for mineral and synthetic oils based on the copolymers of alkyl acrylates or methacrylates and butyl vinyl ether

    NASA Astrophysics Data System (ADS)

    Geraskina, Evgeniya V.; Moikin, Alexey A.; Semenycheva, Ludmila L.

    2014-05-01

    A new method for synthesizing of the copolymers of acrylic and methacrylic acid esters with butyl vinyl ether in an excess of low-boiling monomer, which has proven effective for a number of alkyl methacrylates was proposed. Tests of thickening efficiency of the obtained copolymers were carried out. The resistance to mechanical degradation of the mineral, semi synthetic and synthetic base oils doped with the copolymers was evaluated.

  20. Vibrational overtone enhancement of methyl methacrylate polymerization initiated by benzoyl peroxide decomposition

    NASA Astrophysics Data System (ADS)

    Grinevich, Oleg; Snavely, D. L.

    1997-03-01

    Vibrational overtone initiated polymerization has been demonstrated using intracavity photolysis of a benzoyl peroxide/methyl methacrylate mixture. Excitation of the 6 νCH overtone transition of the ground electronic state of benzoyl peroxide creates radicals which subsequently begin the polymerization process. Polymer yield was monitored by comparison of the 2 νCH overtone absorptions for the methyl, methylenic and olefinic CH stretches at 5946 and 6170 cm -1, respectively. Plots of polymer yield versus time demonstrate an autoacceleration of the polymerization rate commencing many hours after the photolysis period. The delay before autoacceleration depends on the duration of the photolysis.

  1. 75 FR 4288 - Oxirane, 2-Methyl-, Polymer with Oxirane, Dimethyl Ether; Tolerance Exemption

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-01-27

    ... AGENCY 40 CFR Part 180 Oxirane, 2-Methyl-, Polymer with Oxirane, Dimethyl Ether; Tolerance Exemption... an exemption from the requirement of a tolerance for residues of oxirane, 2-methyl-,polymer with... eliminates the need to establish a maximum permissible level for residues of oxirane, 2-methyl-, polymer...

  2. Separation of methyl t-butyl ether from close boiling C[sub 5] hydrocarbons by extractive distillation

    SciTech Connect

    Berg, L.

    1993-07-20

    A method for recovering methyl t-butyl ether from a mixture of methyl t-butyl ether and 1-pentene which comprises distilling a mixture of methyl t-butyl ether and 1-pentene in the presence of about one part of an extractive agent per part of methyl t-butyl ether -- 1-pentene mixture, recovering the 1-pentene as overhead product and obtaining the methyl t-butyl ether and the extractive agent from the still pot, wherein said extractive agent consists of one material selected from the group consisting of sulfolane, nitroethane, t-butanol, ethylene glycol diacetate, 1-methoxy-2-propanol acetate, methyl isoamyl ketone, ethylene glycol methyl ether, propylene glycol phenyl ether and diethyl malonate.

  3. Manufacture of poly(2-hydroxyethyl methacrylate-co-methyl methacrylate) hydrogel tubes for use as nerve guidance channels.

    PubMed

    Dalton, Paul D; Flynn, Lauren; Shoichet, Molly S

    2002-09-01

    Hydrogel tubes of poly(2-hydroxyethyl methacrylate-co-methyl methacrylate) (p(HEMA-co-MMA)) made by liquid-liquid centrifugal casting are being investigated as potential nerve guidance channels in the central nervous system. An important criterion for the nerve guidance channel is that its mechanical properties are similar to those of the spinal cord, where it will be implanted. The formulated p(HEMA-co-MMA) tubes are soft and flexible, consisting of a gel-like outer layer, and an interconnected macroporous, inner layer. The relative thickness of the gel phase to macroporous phase is controlled by the formulation chemistry, and specifically by the ratio of co-monomers, HEMA and MMA. By varying the surface chemistry of the mold within which the tubes are synthesized, tubes were prepared with either a "cracked" or a smooth outer morphology. Tubes with the cracked outer morphology had periodic channels that traversed the wall of the tube, which resulted in a lower modulus than smooth outer morphology tubes, yet likely greater diffusive permeability. For tubes (and not rods) to be formed, phase separation must precede gelation as is detailed in a formulation phase diagram for HEMA, MMA and water. The tensile elastic modulus of p(HEMA-co-MMA) tubes reflected the formulation chemistry, with greater moduli (up to 400 kPa) recorded for tubes having 10 wt% MMA. The p(HEMA-co-MMA) tubes therefore had similar mechanical properties to those of the spinal cord, which has a reported elastic modulus range between 200 and 600 kPa.

  4. Monitoring of acid-base status of workers at a methyl methacrylate and polymethyl methacrylate production plant in Bulgaria.

    PubMed

    Prakova, Gospodinka R

    2003-01-01

    This study was carried out on 104 workers at three work operations and a control (nonproduction) area, within a methyl methacrylate (MMA)/polymethyl methacrylate (PMMA) production facility in Bulgaria. Airborne monitoring was conducted over a 10-year period for MMA and the reactant chemicals methanol and acetone cyanhydrine at the MMA operation, and MMA was monitored at the PMMA operation. Acid-base status of the workers was evaluated using traditional criteria (pH, pCO(2), pO(2), and HCO(3) in plasma). Data from retrospective monitoring of air levels of the chemicals were compared with the acid-base status of workers at the plant. In some cases air concentrations exceeded the threshold limit value, with the highest percentage of overexposure occurring with airborne MMA in the PMMA production operation. Acid-base disruption indicated by reductions in plasma pH and HCO(3) was found for all groups except the control population. The highest percentage reduction was associated with PMMA production workers. Additionally, respiratory acidosis, indicated by increased pCO(2), was noted in the MMA production and maintenance groups, implying that the response to MMA exposure may involve both the metabolic and respiratory acidosis component. This study was unique in that the combined exposure to MMA and the precursor chemical (methanol) were shown to produce the same effects in workers. It is suggested that when combined exposure occurs, disruption of acid-base status may occur. Enforcement of PPM requirements for coveralls and gloves should prevent skin contamination. Additionally, improvement of equipment in MMA and PMMA production areas is recommended: (1) automation of some manual operations; (2) use of respiratory protection during equipment cleaning; and (3) installation of local ventilation when applicable.

  5. Searching for trans ethyl methyl ether in Orion KL⋆

    NASA Astrophysics Data System (ADS)

    Tercero, B.; Cernicharo, J.; López, A.; Brouillet, N.; Kolesniková, L.; Motiyenko, R. A.; Margulès, L.; Alonso, J. L.; Guillemin, J.-C.

    2015-10-01

    We report on the tentative detection of trans ethyl methyl ether (tEME), t-CH3CH2OCH3, through the identification of a large number of rotational lines from each one of the spin states of the molecule towards Orion KL. We also search for gauche-trans-n-propanol, Gt-n-CH3CH2CH2OH, an isomer of tEME in the same source. We have identified lines of both species in the IRAM 30 m line survey and in the ALMA Science Verification data. We have obtained ALMA maps to establish the spatial distribution of these species. Whereas tEME mainly arises from the compact ridge component of Orion, Gt-n-propanol appears at the emission peak of ethanol (south hot core). The derived column densities of these species at the location of their emission peaks are ≤(4.0 ± 0.8) × 1015 cm-2 and ≤(1.0 ± 0.2) × 1015 cm-2 for tEME and Gt-n-propanol, respectively. The rotational temperature is ~100 K for both molecules. We also provide maps of CH3OCOH, CH3CH2OCOH, CH3OCH3, CH3OH, and CH3CH2OH to compare the distribution of these organic saturated O-bearing species containing methyl and ethyl groups in this region. Abundance ratios of related species and upper limits to the abundances of non-detected ethers are provided. We derive an abundance ratio N(CH3OCH3)/N(tEME) ≥ 150 in the compact ridge of Orion. This paper makes use of the following ALMA data: ADS/JAO.ALMA#2011.0.00009.SV. ALMA is a partnership of ESO (representing its member states), NSF (USA), and NINS (Japan) with NRC (Canada), NSC, and ASIAA (Taiwan), and KASI (Republic of Korea), in cooperation with the Republic of Chile. The Joint ALMA Observatory is operated by ESO, AUI/NRAO, and NAOJ. This work was also based on observations carried out with the IRAM 30-m telescope. IRAM is supported by INSU/CNRS (France), MPG (Germany), and IGN (Spain).Appendix A is available in electronic form at http://www.aanda.org

  6. Preparation of poly(methyl methacrylate) grafted titanate nanotubes by in situ atom transfer radical polymerization

    NASA Astrophysics Data System (ADS)

    Gao, Yuan; Gao, Xueping; Zhou, Yongfeng; Yan, Deyue

    2008-12-01

    This paper reports the successful preparation of core-shell hybrid nanocomposites by a 'grafting from' approach based on in situ atom transfer radical polymerization (ATRP) of methyl methacrylate (MMA) from titanate nanotubes (TNTs). Transmission electron microscope (TEM) images of the products provide direct evidence for the formation of a core-shell structure, possessing a hard core of TNTs and a soft shell of poly-MMA (PMMA). Fourier-transform infrared spectroscopy (FT-IR), hydrogen nuclear magnetic resonance (1H NMR), scanning electron microscopy (SEM), and thermal gravimetric analysis (TGA) were used to determine the chemical structure, morphology, and the grafted PMMA quantities of the resulting products. The grafted PMMA content was well controlled and increased with increasing monomer/initiator ratio. Further copolymerization of hydroxyethyl methacrylate (HEMA) with PMMA-coated TNTs as initiators was realized, illustrating the 'living' characteristics of the ATRP method used in this paper.

  7. Laboratory Method for Analysis of Small Concentrations of Methyl tert-Butyl Ether and Other Ether Gasoline Oxygenates in Water

    USGS Publications Warehouse

    Rose, Donna L.; Connor, Brooke F.; Abney, Sonja R.; Raese, Jon W.

    1998-01-01

    This Fact Sheet presents data for analysis of nanogram-per-liter concentrations of methyl tert-butyl ether (MTBE) and three other ether gasoline oxygenates, including methyl tert-pentyl ether (TAME), diisopropyl ether (DIPE), and ethyl tert-butyl ether (ETBE), by purge- and-trap capillary-column gas chromatography. Long-term method detection levels (LT-MDLs) for MTBE, TAME, DIPE, and ETBE ranged from 15 to 83 nanograms per liter (0.015 to 0.083 microgram per liter). Nanogram-per-liter-concentration detections are reported if all of the identification criteria are met, whereas previous methods censored detections at a pre-determined method reporting level. The reporting level for this method is defined as two times the LT-MDL, does not censor detections at less than this concentration, and is referred to as the nondetection value (NDV). Bias and variability data from multiple analyses, analysts, and instruments over a 60-day period show the oxygenate recoveries ranging from 100 to 109 percent, with 6 to 8 percent relative standard deviation. MTBE, TAME, DIPE, and ETBE were not detected in the analysis of 225 laboratory reagent blanks from January to December 1997. A preservation study in ground water and surface water indicates that all the oxygenates are stable at pH 2 for up to 216 days, with recoveries ranging from 94 to 115 percent on day 216, and relative standard deviations ranging from 5 to 9 percent for the duration of the study.

  8. Computational evidence for self-initiation in spontaneous high-temperature polymerization of methyl methacrylate.

    PubMed

    Srinivasan, Sriraj; Lee, Myung Won; Grady, Michael C; Soroush, Masoud; Rappe, Andrew M

    2011-02-17

    This paper presents computational evidence for the occurrence of diradical mechanism of self-initiation in thermal polymerization of methyl methacrylate. Two self-initiation mechanisms of interest were explored with first-principles density functional theory calculations. Singlet and triplet potential energy surfaces were constructed. The formation of two Diels-Alder adducts, cis- and trans-dimethyl 1,2-dimethylcyclobutane-1,2-dicarboxylate and dimethyl 2-methyl-5-methylidene-hexanedioate, on the singlet surface was identified. Transition states were calculated using B3LYP/6-31G* and assessed using MP2/6-31G*. The calculated energy barriers and rate constants with different levels of theory were found to show good agreement to corresponding data obtained from laboratory experiments. The presence of a diradical intermediate on the triplet surface was identified. When MCSCF/6-31G* was used, the spin-orbit coupling constant for the singlet to triplet crossover was calculated to be 2.5 cm(-1). The mechanism of monoradical generation via a hydrogen abstraction by both triplet and singlet diradicals from a third monomer was identified to be the most likely mechanism of initiation in spontaneous polymerization of methyl methacrylate.

  9. Effect of curing environment on mechanical properties and polymerizing behaviour of methyl-methacrylate autopolymerizing resin.

    PubMed

    Ogawa, T; Hasegawa, A

    2005-03-01

    Methyl-methacrylate autopolymerizing resin is used for multiple applications. Therefore, the mechanical properties of autopolymerizing resin should be assessed comprehensively including strength, stiffness and hardness. Any methods that effectively improve these mechanical properties are desirable. The objective of this study is to examine the effects of the curing environment: air or water with/without pressure, and air or water temperature during polymerization, on the strength, stiffness and hardness of autopolymerizing resin. In addition, we examined the polymerizing behaviour associated with the mechanical properties. Autopolymerizing methyl-methacrylate resin (Unifast II) was polymerized under the following conditions: in air and water with/without pressure at 10, 23, 30, 40, 60 and 80 degrees C. The resin specimens were subjected to a transverse test (three-point flexural test) and micro-Brinell surface hardness test. Fractured surfaces of the specimens after the transverse test were examined using a scanning electron microscope (SEM). The transverse strength and transverse modulus increased with increasing curing temperature in both wet and dry conditions. Pressured wet conditions increased transverse strength and transverse modulus over non-pressured wet and dry conditions. The resin polymerized in dry conditions showed higher surface hardness than the one polymerized in wet conditions at matching temperature. The SEM images of fractured surfaces cured at lower temperature exhibited porosity within the polymer base and cracks between the base and poly-methyl-methacrylate (PMMA) particulates. Surfaces of the resin polymerized in wet conditions were characterized with PMMA particulates having rougher surfaces suggestive of water incorporation. Raising temperature and pressuring during polymerization increase strength and stiffness of autopolymerizing resin. However, wet condition reduces surface hardness of resin compared with dry condition. These altered

  10. Far infrared-assisted encapsulation of filter paper strips in poly(methyl methacrylate) for proteolysis.

    PubMed

    Chen, Qiwen; Bao, Huimin; Zhang, Luyan; Chen, Gang

    2016-02-01

    Filter paper strips were enclosed between two poly(methyl methacrylate) plates to fabricate paper-packed channel microchips under pressure in the presence of far infrared irradiation. After the enclosed paper strip was oxidized by periodate, trypsin was covalently immobilized in them to fabricate microfluidic proteolysis bioreactor. The feasibility and performance of the unique bioreactor were demonstrated by digesting BSA and lysozyme. The results were comparable to those of conventional in-solution proteolysis while the digestion time was significantly reduced to ∼18 s. The suitability of the microfluidic paper-based bioreactors to complex proteins was demonstrated by digesting human serum.

  11. Controlling of optical energy gap of Co-ferrite quantum dots in poly (methyl methacrylate) matrix

    NASA Astrophysics Data System (ADS)

    El-Sayed, H. M.; Agami, W. R.

    2015-07-01

    Different crystallite sizes of Co-ferrite nanoparticles were prepared and dispersed in the matrix of poly (methyl methacrylate) (PMMA) polymer. The effect of crystallite size on the structure and optical energy gap of Co-nanoferrite/PMMA composite has been studied. The optical energy gap of Co-ferrite was greatly affected by the crystallite size. This result was discussed in terms of the formation of electron-hole exciton using particle in a box model. The effective mass and the Bohr radius of the formed exciton have been calculated from the spectroscopic measurements.

  12. Generalized peripheral neuropathy in a dental technician exposed to methyl methacrylate monomer

    SciTech Connect

    Donaghy, M.; Rushworth, G.; Jacobs, J.M. )

    1991-07-01

    A 58-year-old dental prosthetic technician developed generalized sensorimotor peripheral neuropathy. Neurophysiologic studies showed a generalized sensorimotor neuropathy of axonal degeneration type. Examination of a sural nerve biopsy showed a moderately severe axonal neuropathy with loss of large myelinated fibers and unmyelinated axons. There was evidence of slow ongoing degeneration and considerable fiber regeneration. Electron microscopy showed increased numbers of filaments in a few fibers. These findings show resemblances to the nerve changes caused by another acrylic resin, acrylamide. They suggest that the neuropathy may have been caused by 30 years of occupational cutaneous and inhalational exposure to methyl methacrylate monomer since they excluded other recognized causes of neuropathy.

  13. Thermal response of polystyrene/poly methyl methacrylate (PS/PMMA) polymeric blends

    NASA Astrophysics Data System (ADS)

    Mathur, Vishal; Sharma, Kananbala

    2016-12-01

    The present paper reports the investigationsto evaluate thermal behavior of polystyrene/poly methyl methacrylate (PS/PMMA) polymeric blends, prepared at different compositions through solution casting method. The glass transition temperatures have been obtained using dynamic mechanical analyzer. Simultaneous measurements of temperature dependentthermal transport properties (thermal conductivity and thermal diffusivity) have been made using Hot Disk Thermal Constants Analyzer based on transient plane source. The study reveals that blending of PS with PMMA leads to different phase morphologies corresponding to different composition range which further affects the thermal performance of respective blends.

  14. Turning electrospun poly(methyl methacrylate) nanofibers into graphitic nanostructures by in situ electron beam irradiation

    SciTech Connect

    Duan, H. G.; Xie, E. Q.; Han, L.

    2008-02-15

    Using ultrathin electrospun poly(methyl methacrylate) (PMMA) nanofibers as precursor, graphitic nanofibers, nanobridges, nanocones, and fullerenelike onions could be prepared by electron beam irradiation in a controlled manner. With the help of the high resolution transmission electron microscopy, the real time processing of the carbonization and graphitization of the PMMA nanofibers could be investigated. This way to obtain graphitic nanostructures has promising applications in graphitic carbon nanostructure electronics and devices. Because PMMA is a widely used standard high resolution electron resist, this graphitization could be combined with electron beam lithography to obtain high resolution patterned graphitic circuits.

  15. Femtosecond laser fabrication of tubular waveguides in poly(methyl methacrylate).

    PubMed

    Zoubir, Arnaud; Lopez, Cedric; Richardson, Martin; Richardson, Kathleen

    2004-08-15

    Femtosecond laser direct writing is employed for the fabrication of buried tubular waveguides in bulk poly(methyl methacrylate). A novel technique using selective chemical etching is presented to resolve the two-dimensional refractive-index profile of the fabrication structures. End-to-end coupling in the waveguides reveals a near-field intensity distribution that results from the superimposition of several propagating modes with different azimuthal symmetries. Mode analysis of the tubular waveguides is performed using the finite-difference method, and the possible propagating mode profiles are compared with the experimental data.

  16. Photoinitiated polymerization of methyl methacrylate using Q-sized ZnO colloids

    SciTech Connect

    Hoffman, A.J.; Yee, H.; Mills, G.; Hoffmann, M.R.

    1992-06-25

    Q-sized ZnO particles are determined to be efficient photoinitiators of methyl methacrylate polymerization. The effects of semiconductor particle size, solvent, initiator concentration, monomer concentration, and light intensity on reaction rates are examined. The reaction path is initiated anionically, followed by free-radical propogation steps. Polymerization increases with increased photoinitiator and monomer concentration and particle size; it also has a dependence upon the square root of the light intensity. Illumination-induced holes are scavenged by the solvent. 29 refs., 8 figs., 2 tabs.

  17. Antibacterial properties of novel poly(methyl methacrylate) nanofiber containing silver nanoparticles.

    PubMed

    Kong, Hyeyoung; Jang, Jyongsik

    2008-03-04

    Poly(methyl methacrylate) (PMMA) nanofiber containing silver nanoparticles was synthesized by radical-mediated dispersion polymerization and applied to an antibacterial agent. UV-vis spectroscopic analysis indicated that the silver nanoparticles were continually released from the polymer nanofiber in aqueous solution. The antibacterial properties of silver/PMMA nanofiber against both Gram-negative (Escherichia coli) and Gram-positive (Staphylococcus aureus) bacteria were evaluated using minimum inhibitory concentration (MIC), the modified Kirby-Bauer method, and a kinetic test. The MIC test demonstrated that the silver/PMMA nanofiber had enhanced antimicrobial efficacy compared to that of silver sulfadiazine and silver nitrate at the same silver concentration.

  18. Properties of cellulase as template molecule on chitosan—methyl methacrylate membrane

    NASA Astrophysics Data System (ADS)

    Lian, Qi; Zheng, Xuefang; Wu, Haixia; Song, Shitao; Wang, Dongjun

    2015-12-01

    In this study, a novel molecular imprinting membrane made of chitosan and methyl methacrylate (MMA) was fabricated with cellulase as template molecule and the thermal response to cellulase was characterized. The film was characterized by infrared spectroscopy (IR), X-ray diffraction (XRD), scanning electron microscopy (SEM) and the permeation experiment. The results showed that the space structure of the film was as similar as the cellulase. Moreover, the membrane had advanced molecular imprinting capability to cellulase comparing to pepsin and pectinase at any temperature and the film had excellent ability to identify specific template molecule (cellulase) at the synthesis temperature compared to other temperatures.

  19. Poly (methyl methacrylate) Formation and Patterning Initiated by Synchrotron X-ray Illumination

    SciTech Connect

    Xiao, J.; Je, J. H.; Wang, C. H.; Yang, T. Y.; Hwu, Y.

    2007-01-19

    A facile radiation method was developed to obtain micro-sized poly (methyl methacrylate) (PMMA) particles and create patterned coating on different substrates by a synchrotron x-ray induced dispersion polymerization. The polymerization of MMA monomer and well defined patterning was successfully realized. The produced PMMA particles and patterning were characterized by Fourier transformation infrared (FTIR), 1H-Nuclear Magnetic Resonance (NMR), and Scanning Electron Microscope (SEM). The observed patterning contrast essentially derived from a variation of size, density and morphology of particles and the type of substrate materials used.

  20. Fracture resistance of Kevlar-reinforced poly(methyl methacrylate) resin: a preliminary study.

    PubMed

    Berrong, J M; Weed, R M; Young, J M

    1990-01-01

    The reinforcing effect of Kevlar fibers incorporated in processed poly(methyl methacrylate) resin samples was studied using 0% (controls), 0.5%, 1%, and 2% by weight of the added fibers. The samples were subjected to impact testing to determine fracture resistance, and sample groups were statistically compared using an ANOVA. Each reinforced sample had significantly greater fracture resistance (P less than 0.05) than the control, and no difference was found either within or between control groups. The use of reinforcing Kevlar fibers appears to enhance the fracture resistance of acrylic resin denture base materials.

  1. Thermo-reversible gelation of atactic poly(methyl methacrylate) in poly(ethylene glycol) oligomers.

    PubMed

    Gao, Yun; Yu, Chunhong; Chen, Minzhi; Wang, Xiaoliang; Zhou, Dongshan; Xue, Gi

    2013-04-01

    The temperature-concentration behavior of physical gel by atactic poly(methyl methacrylate) (aPMMA) in poly(ethylene glycol) oligomer (PEG400) was investigated. A liquid-liquid demixing interferes with a glass transition during cooling. The combination of demixing and T g leads to the formation of amorphous gels at low temperature. We suggest that the gelation of aPMMA/PEG400 is a glassy gel, in which short-range attractive depletion interaction in the polymer/oligomer system was the driving force at molecular level.

  2. Carcinogenicity of methyl-tertiary butyl ether in gasoline.

    PubMed

    Mehlman, Myron A

    2002-12-01

    Methyl tertiary butyl ether (MTBE) was added to gasoline on a nationwide scale in 1992 without prior testing of adverse, toxic, or carcinogenic effects. Since that time, numerous reports have appeared describing adverse health effects of individuals exposed to MTBE, both from inhalation of fumes in the workplace and while pumping gasoline. Leakage of MTBE, a highly water-soluble compound, from underground storage tanks has led to contamination of the water supply in many areas of the United States. Legislation has been passed by many states to prohibit the addition of MTBE to gasoline. The addition of MTBE to gasoline has not accomplished its stated goal of decreasing air pollution, and it has posed serious health risks to a large portion of the population, particularly the elderly and those with respiratory problems, asthma, and skin sensitivity. Reports of animal studies of carcinogenicity of MTBE began to appear in the 1990s, prior to the widespread introduction of MTBE into gasoline. These reports were largely ignored. In ensuing years, further studies have shown that MTBE causes various types of malignant tumors in mice and rats. The National Toxicology Program (NTP) Board of Scientific Counselors' Report on Carcinogens Subcommittee met in December 1998 to consider listing MTBE as "reasonably anticipated to be a human carcinogen." In spite of recommendations from Dr. Bailer, the primary reviewer, and other scientists on the committee, the motion to list MTBE in the report was defeated by a six to five vote, with one abstention. On the basis of animal studies, it is widely accepted that if a chemical is carcinogenic in appropriate laboratory animal test systems, it must be treated as though it were carcinogenic in humans. In the face of compelling evidence, NTP Committee members who voted not to list MTBE as "reasonably anticipated to be a human carcinogen" did a disservice to the general public; this action may cause needless exposure of many to health risks

  3. Synthesis and Characterization of Amphiphilic Graft Copolymers of Poly (1,3dioxolane) Macromonomers with Styrene and Methyl Methacrylate

    NASA Astrophysics Data System (ADS)

    Bendaikha, H.; Clisson, G.; Khoukh, A.; François, J.; Kada, S. Ould; Krallafa, A.

    2008-08-01

    Methacrylate-terminated Poly (1,3dioxolane) (PDXL) macromonomers were synthesized by cationic ring-opening polymerization in the presence of 2-hydroxypropyl methacrylate (2-HPMA) as transfer agent. Molecular weights and polydispersity index of the PDXL macromonomers were evaluated by size exclusion chromatography (SEC) and 1H-NMR. Copolymerizations of PDXL macromonomers with styrene (St) and methyl methacrylate (MMA) were carried out using various feed molar ratios. Monomer reactivity ratios between the macromonomers and the comonomers were estimated from the copolymerization results. Glass transition temperatures of the copolymers were found to decrease with an increase in the amount of PDXL in the copolymers.

  4. Aliphatic polycarbonates based on carbon dioxide, furfuryl glycidyl ether, and glycidyl methyl ether: reversible functionalization and cross-linking.

    PubMed

    Hilf, Jeannette; Scharfenberg, Markus; Poon, Jeffrey; Moers, Christian; Frey, Holger

    2015-01-01

    Well-defined poly((furfuryl glycidyl ether)-co-(glycidyl methyl ether) carbonate) (P((FGE-co-GME)C)) copolymers with varying furfuryl glycidyl ether (FGE) content in the range of 26% to 100% are prepared directly from CO2 and the respective epoxides in a solvent-free synthesis. All materials are characterized by size-exclusion chromatography (SEC), (1)H NMR spectroscopy, and differential scanning calorimetry (DSC). The furfuryl-functional samples exhibit monomodal molecular weight distributions with Mw/Mn in the range of 1.16 to 1.43 and molecular weights (Mn) between 2300 and 4300 g mol(-1). Thermal properties reflect the amorphous structure of the polymers. Both post-functionalization and cross-linking are performed via Diels-Alder chemistry using maleimide derivatives, leading to reversible network formation. This transformation is shown to be thermally reversible at 110 °C.

  5. Terminal-Selective Transesterification of Chlorine-Capped Poly(Methyl Methacrylate)s: A Modular Approach to Telechelic and Pinpoint-Functionalized Polymers.

    PubMed

    Ogura, Yusuke; Terashima, Takaya; Sawamoto, Mitsuo

    2016-04-20

    Terminal-selective transesterification of chlorine-capped poly(methyl methacrylate)s (PMMA-Cl) with alcohols was developed as a modular approach to create telechelic and pinpoint-functionalized polymers. Being sterically less hindered and electronically activated, both the α-end ethyl ester and ω-end methyl ester of PMMA-Cl were efficiently and selectively transesterified with diverse alcohols in the presence of a titanium alkoxide catalyst, while retaining the pendent esters intact, to almost quantitatively give various chlorine-capped telechelic PMMAs. In sharp contrast to conventional telechelic counterparts, the telechelic polymers obtained herein yet carry a chlorine atom at the ω-terminal to further work as a macroinitiator in living radical polymerization. The iterative process of living radical polymerization and terminal-selective transesterification successfully afforded unique pinpoint-functionalized polymers where a single functional monomer unit was introduced into the desired site of the polymer chains.

  6. Proton nuclear magnetic resonance spectroscopic detection and determination of ethylene glycol dimethacrylate as a contaminant of methyl methacrylate raw material.

    PubMed

    Hanna, G M; Lau-Cam, C A

    1995-01-01

    A simple, specific, and accurate proton nuclear magnetic resonance (1H NMR) spectroscopic method is presented for detection and assay of ethylene glycol dimethacrylate dimer as a contaminant of methyl methacrylate monomer. In addition to minimizing exposure of the analyst to the irritant and toxic methacrylic acid esters, the proposed method requires no sample preparation. Quantitations are based on integrals for signals of methylene protons of ethylene glycol dimethacrylate at 4.37 ppm and methyl protons of methyl methacrylate at 3.70 ppm. Analysis of 10 synthetic mixtures of the monomer with 1-11% of dimer yielded a dimer recovery of 100.5 +/- 2.05% (mean +/- standard deviation). Correspondence (correlation coefficient, r = 0.9999) between the amount of dimer added and the amount found was excellent. The proposed method measures as little as 1% of dimer.

  7. Iron-catalyzed AGET ATRP of methyl methacrylate using an alcohol as a reducing agent in a polar solvent.

    PubMed

    Xue, Zhigang; Zhou, Jun; He, Dan; Wu, Fan; Yang, Danfeng; Ye, Yun Sheng; Liao, Yonggui; Zhou, Xingping; Xie, Xiaolin

    2014-11-21

    The alcohols, methanol, ethanol, ethylene glycol (EG), and glycerol, were used as reducing agents for iron(III)-catalyzed activators generated by electron transfer atom transfer radical polymerizations (AGET ATRPs) of methyl methacrylate in polar solvents (N,N-dimethylformamide, N-methylpyrrolidone, or acetonitrile). The effects of the iron catalyst, initiator and alcohol on polymerization were investigated, and most of the systems showed the typical features of controlled radical polymerization. In studies of the ATRP behavior, polymerizations were well controlled with a linear increase in the molecular weight (Mn) versus conversion in agreement with the theoretical one, and low molecular weight distributions (Mw/Mn) were observed throughout the reactions. To gain a deeper understanding of the iron(III)/polar solvent-mediated ATRP, the polymerizations of various monomers (methyl acrylate, methyl methacrylate, n-butyl acrylate, and n-butyl methacrylate) were also investigated.

  8. Biodegradation of methyl tert-butyl ether by cold-adapted mixed and pure bacterial cultures.

    PubMed

    Zaitsev, G M; Uotila, J S; Häggblom, M M

    2007-04-01

    An aerobic mixed bacterial culture (CL-EMC-1) capable of utilizing methyl tert-butyl ether (MTBE) as the sole source of carbon and energy with a growth temperature range of 3 to 30 degrees C and optimum of 18 to 22 degrees C was enriched from activated sludge. Transient accumulation of tert-butanol (TBA) occurred during utilization of MTBE at temperatures from 3 degrees C to 14 degrees C, but TBA did not accumulate above 18 degrees C. The culture utilized MTBE at a concentration of up to 1.5 g l(-1) and TBA of up to 7 g l(-1). The culture grew on MTBE at a pH range of 5 to 9, with an optimum pH of 6.5 to 7.1. The specific growth rate of the CL-EMC-1 culture on 0.1 g l(-1) of MTBE at 22 degrees C and pH 7.1 was 0.012 h(-1), and the growth yield was 0.64 g (dry weight) g(-1). A new MTBE-utilizing bacterium, Variovorax paradoxus strain CL-8, isolated from the mixed culture utilized MTBE, TBA, 2-hydroxy isobutyrate, lactate, methacrylate, and acetate as sole sources of carbon and energy but not 2-propanol, acetone, methanol, formaldehyde, or formate. Two other isolates, Hyphomicrobium facilis strain CL-2 and Methylobacterium extorquens strain CL-4, isolated from the mixed culture were able to grow on C(1) compounds. The combined consortium could thus utilize all of the carbon of MTBE.

  9. Computational investigation of intermolecular interactions in polymer mixtures: Polycarbonate and poly(methyl methacrylate)

    SciTech Connect

    Fitzwater, S.

    1993-12-31

    Molecular modeling and semiempirical quantum mechanical calculations on model compounds can give us detailed information about specific interactions in polymer mixtures. This study examines interactions between a poly(methyl methacrylate) (PMMA) tetramer and the polycarbonate (PC) repeat unit. The results suggested that PC-PMMA mixtures are stabilizing by hydrogen bonds between a carbonyl oxygen on one polymer and a proton or protons on the other. Multiple hydrogen bonds occur; stabilized generally increases with the number of hydrogen bonds. Several configurations had a PMMA carbonyl O H-bonded to a PC ring H, and the adjacent PC carbyonyl O H-bonded to PMMA methyl and methylene H`s. This suggests that the reduced PC mobility observed in PC-PMMA mixtures arises from suppression of both ring flips and carbonate group motion.

  10. Poly(methyl methacrylate)-titania hybrid materials by sol-gel processing

    SciTech Connect

    Zhang, J.; Luo, S.; Gui, L.; Tang, Y.

    1996-12-31

    Sol-gel derived Poly(methyl methacrylate)-titania hybrid materials were synthesized by using acrylic acid or allyl acetylacetone (3-allyl-2,4-pentanedione) as coupling agents. Titanium butoxide modified with acrylic acid (or titanium isopropoxide modified with allyl acetylacetone) was hydrolyzed to produce a titania network, and then poly (methyl methacrylate) (PMMA) chains formed in situ through a radical polymerization were chemically bonded to the forming titania network to synthesize a hybrid material. Transparent hybrid materials with different contents of titania were achieved. With the increase of the titania content, the colors of the products changed form yellow to dark red. The synthesis process was investigated step by step by using FTIR spectroscopy, and the experimental results demonstrated that acrylate or acetylacetonato groups bound to titanium remain in the final hybrid materials. The thermal stability of the hybrid materials was considerably improved relative to pure PMMA. Field emission scanning electron microscopy (FE-SEM) analyses showed the hybrid materials are porous and pore diameters vary from 10nm to 100nm. The hybrid materials using allyl acetylacetone as the coupling agent exhibited thermochromic effects that both pure PMMA and titania do not have.

  11. Low-cost fabrication of poly(methyl methacrylate) microchips using disposable gelatin gel templates.

    PubMed

    Chen, Zhi; Yu, Zhengyin; Chen, Gang

    2010-06-15

    A simple method based on disposable gelatin gel templates has been developed for the low-cost fabrication of poly(methyl methacrylate) (PMMA) microfluidic chips. Gelatin was dissolved in glycerol aqueous solution under heat to prepare a thermally reversible impression material. The molten gel was then sandwiched between a glass plate and a SU-8 template bearing negative relief of microstructure. After cooling, the negative SU-8 template could be easily separated from the solidified gelatin gel and a layer of gelatin template bearing positive relief of the microstructure was left on the glass plate. Subsequently, prepolymerized methyl methacrylate molding solution containing a UV-initiator was sandwiched between the gel template and a PMMA plate and was allowed to polymerize under UV light to fabricate PMMA channel plate at room temperature. Complete microchips could be obtained by bonding the channel plates with covers using plasticizer-assisted thermal bonding at 90 degrees C. Gelatin gel template can be mass-produced and will find application in the mass production of PMMA microchips at low cost. The prepared microfluidic microchips have been successfully employed in the capillary electrophoresis analysis of several ions in connection with contactless conductivity detection.

  12. Formation of poly(methyl methacrylate) thin films onto wool fiber surfaces by vapor deposition polymerization.

    PubMed

    Hassan, M Mahbubul; McLaughlin, J Robert

    2013-03-13

    Chemical vapor deposition (CVD) polymerization is a useful technique because of the possibility of forming very thin film of pure polymers on substrates with any geometric shape. In this work, thin films of poly(methyl methacrylate) or PMMA were formed on the surfaces of wool fabrics by a CVD polymerization process. Various polymerization initiators including dicumyl peroxide, tert-butyl peroxide, and potassium peroxydisulfate have been investigated to polymerize methyl methacrylate onto the surfaces of wool by the CVD polymerization. The wool fabrics were impregnated with initiators and were then exposed to MMA monomer vapor under vacuum at the boiling temperature of the monomer. Wool fabrics with vapor-deposited PMMA surfaces were characterized by elemental analysis, TGA, FTIR, disperse dye absorption, contact angles measurement, AFM, and SEM. PMMA-coated wool fabrics showed higher contact angle and absorbed more dyes than that of the control wool. It was evident from the results obtained by various characterization techniques that MMA was successfully polymerized and formed thin films on the surfaces of wool fabrics by all initiators investigated but the best results were achieved with tert-butyl peroxide.

  13. Chalcogenide amorphous nanoparticles doped poly (methyl methacrylate) with high nonlinearity for optical waveguide

    NASA Astrophysics Data System (ADS)

    Xue, Xiaojie; Nagasaka, Kenshiro; Cheng, Tonglei; Deng, Dinghuan; Zhang, Lei; Liu, Lai; Suzuki, Takenobu; Ohishi, Yasutake

    2015-03-01

    Nonlinear optical polymers show promising potential applications in photonics, for example, electro-optical devices. Poly (methyl methacrylate) (PMMA) is widely used in optical waveguides, integrated optics and optical fibers. However, PMMA has not been used for nonlinear optical waveguides since it has a low nonlinear refractive index. We successfully prepared chalcogenide amorphous nanoparticles doped PMMA that had a high nonlinearity. The As3S7 bulk glass was dissolved in propylamine to form a cluster solution. Then the As3S7/propylamine solution was added into methyl methacrylate (MMA) containing photoinitiator Irgacure 184 about 0.5 wt%. After well mixing the As3S7 nanoparticle doped MMA was transparent. Under the irradiation by a 365 nm UV lamp, As3S7 nanoparticles doped PMMA was obtained with yellow color. The third-order nonlinear optical susceptibility of As3S7 nanoparticles doped PMMA was investigated. An optical waveguide array based on the As3S7 nanoparticles doped PMMA composite of high nonlinearity was fabricated.

  14. 75 FR 770 - Acrylic acid-benzyl methacrylate-1-propanesulfonic acid, 2-methyl-2-[(1-oxo-2-propenyl)amino...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-01-06

    ... AGENCY 40 CFR Part 180 Acrylic acid-benzyl methacrylate-1-propanesulfonic acid, 2- methyl-2... residues of acrylic acid-benzyl methacrylate-1- propanesulfonic acid, 2-methyl-2- -, monosodium salt... to establish a maximum permissible level for residues of acrylic acid-benzyl...

  15. 9(10 leads to 19)abeo steriods. Total synthesis of abeo-estradiol, abeo-estradiol 3-methyl ether, and 17 alpha-ethynyl abeo-estradiol 3-methyl ether.

    PubMed

    Abushanab, E; Lee, D Y; Meresak, W A; Duax, W L

    1976-04-30

    Total synthesis of abeo-estradiol, abeo-estradiol 3-methyl ether, and 17alpha-ethynyl abeo-estradiol 3-methyl ether is described. Stereochemical assignments in 9(10 through 19) abeo-estradiol and its 3-methyl ether were made by X-ray analysis of the 17-keytone. Single crystals were grown by evaporation of a petroleum ether-ethanol solution and the intensities of 2619 diffraction spectra were measured, of which 1036 had intensity greater than twice the background. The structure was refined by full-matrix least-squares techniques and all hydrogen atoms were located in the Fourier difference syntheses.

  16. Surface modification of silk fibroin fibers with poly(methyl methacrylate) and poly(tributylsilyl methacrylate) via RAFT polymerization for marine antifouling applications.

    PubMed

    Buga, Mihaela-Ramona; Zaharia, Cătălin; Bălan, Mihai; Bressy, Christine; Ziarelli, Fabio; Margaillan, André

    2015-06-01

    In this study, silk fibroin surface containing hydroxyl and aminogroups was firstly modified using a polymerizable coupling agent 3-(trimethoxysilyl) propyl methacrylate (MPS), in order to induce vinyl groups onto the fiber surface. The reversible addition-fragmentation chain transfer (RAFT)-mediated polymerization of methyl methacrylate (MMA) and tributylsilyl methacrylate (TBSiMA) through the immobilized vinyl bond on the silk fibroin surface in the presence of 2-cyanoprop-2-yl dithiobenzoate (CPDB) as chain-transfer agent and 2,2'-azobis(isobutyronitrile) (AIBN) as initiator was conducted in toluene solution at 70°C for 24h. The structure and properties of the modified fiber were characterized by Fourier Transform Infrared Spectroscopy, (13)C, (29)Si Nuclear Magnetic Resonance (NMR) spectroscopy, thermogravimetric analysis (TGA), scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS), confirming the presence of the coupling molecule and the methacrylate groups onto the silk fibroin fiber surface. Molecular weight distributions were assessed by triple detection size exclusion chromatography (TD-SEC) in order to verify the livingness of the polymerization.

  17. Evaluation of different nonspecific binding blocking agents deposited inside poly(methyl methacrylate) microfluidic flow-cells.

    PubMed

    Le, Nam Cao Hoai; Gubala, Vladimir; Gandhiraman, Ram P; Daniels, Stephen; Williams, David E

    2011-07-19

    Poly(methyl methacrylate) (PMMA) flow-cells containing microwells were deposited with different nonspecific binding blocking agents, namely, bovine serum albumin (BSA), cationic lipid (DOTAP:DOPE) and diethylene glycol dimethyl ether (DEGDME). Water contact angle (WCA) and atomic force microscope (AFM) measurements were carried out to confirm the successful depositions of BSA, DOTAP, and DEGDME onto the PMMA surfaces. Fluorescent intensity measurements were performed to evaluate the degree of nonspecific adsorption of Cy5-labeled anti-IgG proteins onto plain and oxygen plasma-treated (PT) PMMA flow-cells as well as PMMA flow-cells deposited with different above-mentioned blocking agents. We then employed a label-free detection method called total internal reflection ellipsometry (TIRE) to evaluate the stability of the deposited blocking agents inside the PMMA flow-cells. It was found that, while DOTAP:DOPE was the best agent for blocking the nonspecific adsorption, it could be removed from the PMMA surfaces of the flow-cells upon rinsing with phosphate buffered saline (PBS) and later deposited back onto the Au-coated glass sensing substrate of the TIRE. The removal of the blocking agents from PMMA surfaces and their deposition onto the sensing substrate were further manifested by measuring the kinetics and the amount of adsorbed anti-α-hCG proteins. Overall, the dry DEGDME coating by plasma-enhanced chemical vapor deposition (PECVD) showed very good blocking and excellent stability for subsequent assay inside the microwells. Our results could be useful when one considers what blocking agents should be used for PMMA-based microfluidic immunosensor or biosensor devices by looking at both the blocking efficiency and the stability of the blocking agent.

  18. On the degelation of networks - Case of the radiochemical degradation of methyl methacrylate - ethylene glycol dimethacrylate copolymers

    NASA Astrophysics Data System (ADS)

    Richaud, Emmanuel; Gilormini, Pierre; Verdu, Jacques

    2016-05-01

    Methyl methacrylate networks were synthetized and submitted to radiochemical degradation. Ageing was monitored by means of sol-gel analysis and glass transition temperature measurements. Networks were shown to undergo exclusively chain scission process leading to the degelation of network. The critical conversion degree corresponding to degelation (loss of all elastically active chains) is discussed regarding a statistical theory.

  19. Radiation induced graft copolymerization of methyl methacrylate onto chrome-tanned pig skins

    NASA Astrophysics Data System (ADS)

    Pietrucha, K.; Pȩkala, W.; Kroh, J.

    Graft copolymerization of methyl methacrylate (MMA) onto chrome-tanned pig skins was carried out by the irradiation with 60Co ?-rays. The grafted polymethyl methacrylate (PMMA) chains were isolated by acid hydrolysis of the collagen backbone in order to characterize the graft copolymers. Proof of grafting was obtained through the detection of amino acid endgroups in the isolated grafts by reaction with ninhydrin. The grafting yield of MMA in aqueous emulsion was found to be higher than that for pure MMA and MMA in acetone. The degree of grafting increases with increasing monomer concentration in emulsion and reaches maximum at radiation dose ca 15 kGy. The yield of grafting is very high - ca 90% of monomer converts into copolymer and only 10% is converted into homopolymer. The present paper reports the physical properties of chrome-tanned pig skins after graft polymerization with MMA in emulsion. Modified leathers are more resistant against water absorption and abrasion in comparison with unmodified ones. They have more uniform structure over the whole surface, greater thickness and stiffness. The results reported seem to indicate that MMA may be used in the production of shoe upper and sole leathers. The mechanism of some of the processes occuring during radiation grafting of MMA in water emulsion on tanned leathers has been also suggested and discussed.

  20. ETBE (ethyl tert butyl ether) and TAME (tert amyl methyl ether) affect microbial community structure and function in soils.

    PubMed

    Bartling, Johanna; Esperschütz, Jürgen; Wilke, Berndt-Michael; Schloter, Michael

    2011-03-15

    Ethyl tert butyl ether (ETBE) and tert amyl methyl ether (TAME) are oxygenates used in gasoline in order to reduce emissions from vehicles. The present study investigated their impact on a soil microflora that never was exposed to any contamination before. Therefore, soil was artificially contaminated and incubated over 6 weeks. Substrate induced respiration (SIR) measurements and phospholipid fatty acid (PLFA) analysis indicated shifts in both, microbial function and structure during incubation. The results showed an activation of microbial respiration in the presence of ETBE and TAME, suggesting biodegradation by the microflora. Furthermore, PLFA concentrations decreased in the presence of ETBE and TAME and Gram-positive bacteria became more dominant in the microbial community.

  1. Robust isocratic liquid chromatographic separation of functional poly(methyl methacrylate).

    PubMed

    Jiang, Xulin; Lima, Vincent; Schoenmakers, Peter J

    2003-11-07

    The separation of telechelic poly(methyl methacrylate) (PMMA) prepolymers based on the number of end-groups under critical liquid chromatography (LC) conditions has been studied using a bare-silica column, which can interact with polar functional groups. The critical solvent compositions for non-functional, mono-functional and bi-functional PMMAs were determined in normal-phase LC using mixtures of acetonitrile and dichloromethane (DCM) of varying composition as the mobile phase. The telechelic prepolymers were successfully separated according to hydroxyl (OH) functionality (with zero, one, or two OH groups, respectively) under the critical conditions, in which fast (5 min), base-line separations were obtained independent of molecular weight. Changing the column temperature, flow rate, and mobile-phase composition within a certain range did not affect the functionality separation. Therefore this isocratic LC separation method is quite robust. Evaporative light-scattering detector (ELSD) calibration curves were used for the quantitative analysis of functional PMMA prepolymers.

  2. Facile Soap-Free Miniemulsion Polymerization of Methyl Methacrylate via Reverse Atom Transfer Radical Polymerization.

    PubMed

    Zhu, Gaohua; Zhang, Lifen; Pan, Xiangqiang; Zhang, Wei; Cheng, Zhenping; Zhu, Xiulin

    2012-12-21

    A facile soap-free miniemulsion polymerization of methyl methacrylate (MMA) was successfully carried out via a reverse ATRP technique, using a water-soluble potassium persulfate (KPS) or 2,2'-azobis(2-methylpropionamidine) dihydrochloride (V-50) both as the initiator and the stabilizer, and using an oil-soluble N,N-n-butyldithiocarbamate copper (Cu(S2CN(C4H9)2)2) as the catalyst without adding any additional ligand. Polymerization results demonstrated the "living"/controlled characteristics of ATRP and the resultant latexes showed good colloidal stability with average particle size around 300-700 nm in diameter. The monomer droplet nucleation mechanism was proposed. NMR spectroscopy and chain-extension experiments under UV light irradiation confirmed the attachment and livingness of UV light sensitive -S-C(=S)-N(C4H9)2 group in the chain end.

  3. Facile fabrication of superhydrophobic poly(methyl methacrylate) substrates using ultrasonic imprinting

    NASA Astrophysics Data System (ADS)

    Cho, Young Hak; Seo, Young Soo; Moon, In Yong; Kim, Bo Hyun; Park, Keun

    2013-05-01

    Superhydrophobic surfaces (SHSs) have received increasing attention in the last decade, and have been generally developed from hydrophobic materials. In this study, a facile fabrication method based on ultrasonic imprinting is proposed to develop SHSs from a hydrophilic polymer, poly(methyl methacrylate) (PMMA). To fabricate SHSs on PMMA substrates, micro electrical discharge machining, micromachining and ultrasonic imprinting were sequentially used. The ultrasonic imprinting was performed for various channel designs and imprinting conditions, and the resulting water contact angles were measured for the replicated samples. As a result, superhydrophobic characteristics could be obtained on a hydrophilic PMMA replica without any chemical treatments. The effects of nanoscale roughness on the replicated channel as well as composition change are discussed with respect to the analyses using an atomic force microscope, x-ray photoelectron spectroscopy and Fourier transform infrared spectroscopy.

  4. Dry-adhesives based on hierarchical poly(methyl methacrylate) electrospun fibers

    NASA Astrophysics Data System (ADS)

    Sahay, Rahul; Baji, Avinash; Parveen, Hashina; Ranganath, Anupama Sargur

    2017-03-01

    Here, we combine electrospinning and replica-molding to produce hierarchical poly(methyl methacrylate) structures and investigate its adhesion behavior. Normal and shear adhesion of these biomimetic hierarchical structures was measured using nanoindentaton and a custom-built apparatus attached to Zwick tensile testing machine, respectively. Shear adhesion was measured by sliding the samples along the glass slide under a predefined normal preload. Normal adhesion was measured by indenting the surface of the sample with the help of a diamond indenter tip and retracting it back to determine the pull-off force needed to detach it from the sample. These experiments were also conducted on neat PMMA fibers to investigate the effect of hierarchy on the adhesion performance of the samples. Our results show that the shear adhesion strength and pull-off forces recorded for the hierarchical samples are higher than those recorded for neat fibers.

  5. Tensile behaviour of blends of poly(vinylidene fluoride) with poly(methyl methacrylate)

    NASA Technical Reports Server (NTRS)

    Cebe, Peggy; Chung, Shirley Y.

    1990-01-01

    Blends of poly(vinylidene fluoride) (PVF2) and poly(methyl methacrylate) (PMMA) were prepared over a wide concentration range and tested in tension at the same relative temperature below the glass transition. In nearly all blends, under conditions favoring disentanglement, (decrease in strain rate, or increase in test temperature), the yield stress and drawing stress decreased while the breaking strain increased. For materials with about the same degree of crystallinity, those with a higher proportion of amorphous PVF2 exhibited brittle-like behavior as a result of interlamellar tie molecules. In the semicrystalline blends, yield stress remains high as the test temperature approaches Tg, whereas in the amorphous blends the yield stress falls to zero near Tg. Results of physical aging support the role of interlamellar ties which cause semicrystalline blends to exhibit aging at temperatures above Tg.

  6. Raman spectra of bilayer graphene covered with Poly(methyl methacrylate) thin film

    SciTech Connect

    Xia Minggang; Su Zhidan; Zhang Shengli

    2012-09-15

    The Raman spectra of bilayer graphene covered with poly(methyl methacrylate) (PMMA) were investigated. Both the G and 2D peaks of PMMA-coated graphene were stiff and broad compared with those of uncovered graphene. This could be attributed to the residual strain induced by high-temperature baking during fabrication of the nanodevice. Furthermore, the two 2D peaks stiffened and broadened with increasing laser power, which is just the reverse to uncovered graphene. The stiffness is likely caused by graphene compression induced by the circular bubble of the thin PMMA film generated by laser irradiation. Our findings may contribute to the application of PMMA in the strain engineering of graphene nanodevices.

  7. Free Radical Polymerization of Styrene and Methyl Methacrylate in Various Room Temperature Ionic Liquids

    SciTech Connect

    Zhang, Hongwei; Hong, Kunlun; Mays, Jimmy

    2005-01-01

    Conventional free radical polymerization of styrene and methyl methacrylate was carried out in various room temperature ionic liquids (RTILs). The RTILs used in this research encompass a wide range of cations and anions. Typical cations include imidazolium, phosphonium, pyridinium, and pyrrolidinium; typical anions include amide, borate, chloride, imide, phosphate, and phosphinate. Reactions are faster and polymers obtained usually have higher molecular weights when compared to polymerizations carried out in volatile organic solvents under the same conditions. This shows that rapid rates of polymerization and high molecular weights are general features of conventional radical polymerizations in RTILs. Attempts to correlate the polarities and viscosities of the RTILs with the polymerization behavior fail to yield discernible trends.

  8. Tuning of cross-linking and mechanical properties of laser-deposited poly (methyl methacrylate) films

    SciTech Connect

    Sueske, Erik; Scharf, Thorsten; Krebs, Hans-Ulrich; Panchenko, Elena; Junkers, Thomas; Egorov, Mark; Buback, Michael; Kijewski, Harald

    2005-03-15

    The chemical composition, amount of cross-linking and its influence on the mechanical properties of poly(methyl methacrylate) (PMMA) thin films produced by pulsed laser deposition (PLD) at a wavelength of 248 nm under ultrahigh vacuum were investigated by infrared spectroscopy, scanning electron microscopy, size-exclusion chromatography, thermogravimetric analysis, and nanoindentation experiments. The films consist of two components, one fraction with a molecular weight well below that of the target material and a second fraction, which is cross-linked. Compared to bulk material, the Young's modulus of the film is increased. The amount of cross-linking in the film can be tuned by the applied laser fluence leading to changes of the mechanical properties.

  9. Tuning of cross-linking and mechanical properties of laser-deposited poly (methyl methacrylate) films

    NASA Astrophysics Data System (ADS)

    Süske, Erik; Scharf, Thorsten; Krebs, Hans-Ulrich; Panchenko, Elena; Junkers, Thomas; Egorov, Mark; Buback, Michael; Kijewski, Harald

    2005-03-01

    The chemical composition, amount of cross-linking and its influence on the mechanical properties of poly(methyl methacrylate) (PMMA) thin films produced by pulsed laser deposition (PLD) at a wavelength of 248nm under ultrahigh vacuum were investigated by infrared spectroscopy, scanning electron microscopy, size-exclusion chromatography, thermogravimetric analysis, and nanoindentation experiments. The films consist of two components, one fraction with a molecular weight well below that of the target material and a second fraction, which is cross-linked. Compared to bulk material, the Young's modulus of the film is increased. The amount of cross-linking in the film can be tuned by the applied laser fluence leading to changes of the mechanical properties.

  10. [Study on photoluminescence of 8-hydroxyquinaldine gallium acrylate and methyl methacrylate copolymer].

    PubMed

    Xiao, Zun-hong

    2006-03-01

    A new copolymer of 8-hydroxyquinaldine gallium acrylate and methyl methacrylate was prepared. The composition and properties of the copolymer were characterized by FTIR, UV-Vis, DSC, TG and fluorescence spectra. A strong blue-green photoluminescence, with the peak at 496 nm, was observed for the copolymer/CHCl3 solution. Effect of monomer ratio and concentration on the photoluminescence property of the copolymer was investigated. The results showed that the maximum fluorescence intensity was attained when Ga(Mq)2A: MMA was 1:20, the maximum excitation wavelength is approximately 263 nm when the concentration of the copolymer is under 2 g x L(-1), but the maximum excitation wavelength exceeds 365 nm when the concentration is above 4 g x L(-1). The copolymer was soluble in chloroform, acetone, and DMF at 25 degrees C, so it could be easier to prepare electroluminescent device by spin-coat technology.

  11. [Formation of stereocomplexes in atactic poly(methyl methacrylate) studied by FTIR].

    PubMed

    Gu, Q; Shen, D

    2000-10-01

    The stereocomplexation of atactic poly(methyl methacrylate) (a-PMMA) films after isolated from acetone, benzene, and chloroform solution, respectively, was studied by Fourier transformation infrared (FTIR). The results of spectra showed that the stereocomplex was formed for the films cast from acetone and benzene solutions with the appearance of the characteristic bands for the stereocomplex. The population of trans-trans conformers for the i- and s-sequences increased and the side chain preferred to its energetically optimized conformation during the formation of stereocomplex. The stereocomplexes may be formed by the interactions between the i- and s-sequences in the same molecular chain. During the annealing process the self-aggregation of s-sequences played a role in the aggregation process of stereocomplex, which was a function of annealing temperature and annealing time.

  12. Methyl methacrylate from iso-butylene via a vapor phase catalytic oxidation

    SciTech Connect

    Shimizu, N.; Yoshida, H.; Matsumoto, G.; Abe, T.

    1987-01-01

    Methyl methacrylate (MMA) is a useful chemical intermediate having many applications, particularly in polymers, by virtue of their excellent properties with regard to transparency and weatherability. The main current production route to MMA is the acetone cyanohydrin (ACn) process in which acetone and hydrogen cyanide are used as raw materials. This is the only process that was used for commercial production until recently. The annual production capacity in the world is estimated to be about one million metric tons. Annual growth rate will be expected to be more or less 4% in the near future. MMA is used in various products among which are acrylic sheets (casting and extrusion), acrylic moldings (molding and extrusion), surface coatings etc. The further application to high-technology products such as optical fiber and optical memory disk is being developed. The conventional ACH process has several drawbacks, in particular, (1) insufficient supply of by-product hydrogen cyanide, and (2) troublesome treatment of waste ammonium bisulfate.

  13. Gradient structure-induced temperature responsiveness in styrene/methyl methacrylate gradient copolymers micelles.

    PubMed

    Zheng, Chao; Huang, Haiying; He, Tianbai

    2014-02-01

    In this work, micelles are formed by gradient copolymer of styrene and methyl methacrylate in acetone-water mixture and their temperature responsiveness is investigated in a narrow range near room temperature. Three different kinds of structural transitions could be induced by temperature: unimers to micelle transition, shrinkage/stretching of micelles, and morphological transition from spherical micelles to vesicles. In addition, a model analysis on the interface of gradient copolymer micelle is made to better understand these phenomena. It is found that both position and composition of the interface could alter in response to the change in temperature. According to the experiments and model analysis, it is proposed that temperature responsiveness might be an intrinsic and universal property of gradient copolymer micelles, which only originates from the gradient structure.

  14. Floating-Gate Type Organic Memory with Organic Insulator Thin Film of Plasma Polymerized Methyl Methacrylate

    NASA Astrophysics Data System (ADS)

    Kim, Hee-sung; Lee, Boong-Joo; Kim, Gun-Su; Shin, Paik-Kyun

    2013-02-01

    To fabricate organic memory device by entirely dry process, plasma polymerized methyl methacrylate (ppMMA) thin films were prepared and they were used as both tunneling layer and gate insulator layer in a floating-gate type organic memory device. The ppMMA thin films were prepared with inductively coupled plasma (ICP) source combined with stabilized monomer vapor control. The ppMMA gate insulator thin film revealed dielectric constant of 3.75 and low leakage current of smaller than 10-9 A/cm. The floating-gate type organic memory device showed promising memory characteristics such as memory window value of 12 V and retention time of over 2 h, where 60 V of writing voltage and -30 V of erasing voltage were applied, respectively.

  15. Review of methyl methacrylate (MMA)/tributylborane (TBB)-initiated resin adhesive to dentin.

    PubMed

    Taira, Yohsuke; Imai, Yohji

    2014-01-01

    This review, focusing mainly on research related to methyl methacrylate/tributylborane (MMA/TBB) resin, presents the early history of dentin bonding and MMA/TBB adhesive resin, followed by characteristics of resin bonding to dentin. Bond strengths of MMA/TBB adhesive resin to different adherends were discussed and compared with other bonding systems. Factors affecting bond strength (such as conditioners, primers, and medicaments used for dental treatment), bonding mechanism, and polymerization characteristics of MMA/TBB resin were also discussed. This review further reveals the unique adhesion features between MMA/TBB resin and dentin: in addition to monomer diffusion into the demineralized dentin surface, graft polymerization of MMA onto dentin collagen and interfacial initiation of polymerization at the resin-dentin interface provide the key bonding mechanisms.

  16. Evaluation of methyl methacrylate monomer cytotoxicity in dental lab technicians using buccal micronucleus cytome assay.

    PubMed

    Azhar, Dawasaz Ali; Syed, Sadatullah; Luqman, Master; Ali, Assiry A

    2013-01-01

    Methyl methacrylate (MMA) monomer, a primary component of dental resins, is known to induce cytotoxicity, dermatitis, and neuropathy. The objective of this study was to assess the incidence of micronuclei (MN) in buccal mucosal cells of dental technicians exposed to MMA using Buccal Micronucleus Cytome (BMCyt) assay. The Risk Group (RG=13) consisted of all the technicians working in the prosthetic production laboratory of KKU-College of Dentistry. The Control Group (CG=14) consisted of healthy students and doctors matching the age of RG subjects. Buccal mucosa scrapes obtained from all the 27 RG and CG subjects were stained with Papanicolaou stain and observed under oil immersion lens (100×) for the presence of MN. There were no significant differences in the incidence of MN between RG and CG (p>0.05).

  17. Styrene and methyl methacrylate copolymer synthesized by RF inductively coupled plasma

    NASA Astrophysics Data System (ADS)

    Li, Z.; Gillon, X.; Diallo, M.; Houssiau, L.; Pireaux, J.-J.

    2011-01-01

    A series of random copolymers of styrene and methyl methacrylate was prepared on a silicon substrate by RF pulsed inductively coupled plasma. The plasma gas phase was investigated by optical emission spectroscopy (OES). The physico-chemical characteristics of the deposited copolymer films were analyzed by several surface techniques: X-ray photoelectron spectroscopy (XPS), Fourier-Transform infrared absorption (FT-IR), Time-of-flight secondary ion mass spectrometry (ToF-SIMS), etc. OES of the plasma and FT-IR spectra of the films are predictive: plasma emitting a higher relative benzyl radical signal results in the deposition of a more aromatic plasma polymer. The functional thin films can be deposited by selection of the co-monomers.

  18. Miscibility and Thermophysical Properties of Blend of Poly methyl methacrylate with Polyvinylchloride

    NASA Astrophysics Data System (ADS)

    Dixit, Manasvi; Mathur, Vishal; Baboo, Mahesh; Sharma, Kananbala; Saxena, N. S.

    2010-06-01

    The present paper reports the investigations on miscibility and thermophysical properties of blend of Poly methyl methacrylate with Polyvinylchloride, prepared by solution casting method. The miscibility of the samples is examined by dynamic mechanical analyzer (DMA) and the thermophysical properties (thermal conductivity (λ) and thermal diffusivity (χ)) have been measured using the transient plane source (TPS) technique from room temperature to 100 °C. The results of thermal transport properties of PMMA/PVC blend show an increasing trend of λ and χ upto Tg, beyond which they show a decreasing trend. The variation of thermal conductivity and diffusivity of PMMA, PVC and PMMA/PVC blend with temperature is explained on the basis of structural changes of the sample and mean free path of the phonons.

  19. Synthesis, characterization and stability of chitosan and poly(methyl methacrylate) grafted carbon nanotubes.

    PubMed

    Carson, Laura; Hibbert, Kemar; Akindoju, Feyisayo; Johnson, Chevaun; Stewart, Melisa; Kelly-Brown, Cordella; Beharie, Gavannie; Fisher, Tavis; Stone, Julia; Stoddart, Dahlia; Oki, Aderemi; Neelgund, Gururaj M; Regisford, Gloria; Traisawatwong, Pasakorn; Zhou, Jianren; Luo, Zhiping

    2012-10-01

    The single walled carbon nanotubes (CNTs) were effectively functionalized through grafting with chitosan (CTS) and poly(methyl methacrylate) (PMMA). Prior to grafting reaction, the carboxylated SWNCTs (SWNCTs-COOH) were obtained by treating pristine CNTs with a mixture of 3:1 (v/v) H(2)SO(4) and HNO(3), and the successive treatment of SWNCTs-COOH with SOCl(2) yielded the acylated CNTs (CNTs-COCl). The functionalized derivatives of CNTs were characterized using Fourier transform infrared spectroscopy, thermogravimetric analysis, atomic force microscopy, scanning electron microscopy and transmission electron microscopy. Both CTS and PMMA grafted CNTs showed better dispersability in acetic acid and tetrahydrofuran, in addition to higher stability in solution.

  20. Synthesis, characterization and stability of chitosan and poly(methyl methacrylate) grafted carbon nanotubes

    NASA Astrophysics Data System (ADS)

    Carson, Laura; Hibbert, Kemar; Akindoju, Feyisayo; Johnson, Chevaun; Stewart, Melisa; Kelly-Brown, Cordella; Beharie, Gavannie; Fisher, Tavis; Stone, Julia; Stoddart, Dahlia; Oki, Aderemi; Neelgund, Gururaj M.; Regisford, Gloria; Traisawatwong, Pasakorn; Zhou, Jianren; Luo, Zhiping

    2012-10-01

    The single walled carbon nanotubes (CNTs) were effectively functionalized through grafting with chitosan (CTS) and poly(methyl methacrylate) (PMMA). Prior to grafting reaction, the carboxylated SWNCTs (SWNCTs-COOH) were obtained by treating pristine CNTs with a mixture of 3:1 (v/v) H2SO4 and HNO3, and the successive treatment of SWNCTs-COOH with SOCl2 yielded the acylated CNTs (CNTs-COCl). The functionalized derivatives of CNTs were characterized using Fourier transform infrared spectroscopy, thermogravimetric analysis, atomic force microscopy, scanning electron microscopy and transmission electron microscopy. Both CTS and PMMA grafted CNTs showed better dispersability in acetic acid and tetrahydrofuran, in addition to higher stability in solution.

  1. Electron capture of dopants in two-photonic ionization in a poly(methyl methacrylate) solid

    SciTech Connect

    Tsuchida, Akira; Sakai, Wataru; Nakano, Mitsuru; Yamamoto, Masahide

    1992-10-29

    Behavior of the electron produced by two-photonic excitation of an aromatic donor in a poly(methyl methacrylate) solid was studied by the addition of the electron scavengers to the system. According to the Perrin type analysis for the two-photonically ejected electron, the capture radii (R{sub c}) of the scavengers examined were estimated to be from 8 to 40 {Angstrom}. For the two-photonically ejected electrons, R{sub c} is a capture radius for thermalized electrons. In this case the parent electron donor is not necessarily within this radius. On the other hand, for the fluorescence quenching, the distance between the donor and acceptor is within the static quenching radius (R{sub q}) of the donor. 13 refs., 4 figs., 2 tabs.

  2. Synthesis, characterization, and antimicrobial activity of poly(acrylonitrile-co-methyl methacrylate) with silver nanoparticles.

    PubMed

    El-Aassar, M R; Hafez, Elsayed E; Fouda, Moustafa M G; Al-Deyab, Salem S

    2013-10-01

    Nanotechnology is expected to open some new aspects to fight and prevent diseases using atomic-scale tailoring of materials. The main aim of this study is to biosynthesize silver nanoparticles (AgNPs) using Trichoderma viride (HQ438699); the metabolite of this fungus will help either in reduction of the silver nitrate-adding active materials which will be loaded on the surface of the produced AgNPs. Poly(acrylonitrile-co-methyl methacrylate) copolymer (poly (AN-co-MMA)) was grafted with the prepared AgNPs. The poly(AN-co-MMA)/AgNPs were examined against ten different pathogenic bacterial strains, and the result was compared with another four different generic antibiotics. The produced poly(AN-co-MMA)/AgNPs showed high antibacterial activity compared with the four standard antibiotics. Moreover, the grafting of these AgNPs into the copolymer has potential application in the biomedical field.

  3. Methyl methacrylate as a healing agent for self-healing cementitious materials

    NASA Astrophysics Data System (ADS)

    Van Tittelboom, K.; Adesanya, K.; Dubruel, P.; Van Puyvelde, P.; De Belie, N.

    2011-12-01

    Different types of healing agents have already been tested on their efficiency for use in self-healing cementitious materials. Generally, commercial healing agents are used while their properties are adjusted for manual crack repair and not for autonomous crack healing. Consequently, the amount of regain in properties due to self-healing of cracks is limited. In this research, a methyl methacrylate (MMA)-based healing agent was developed specifically for use in self-healing cementitious materials. Various parameters were optimized including the viscosity, curing time, strength, etc. After the desired properties were obtained, the healing agent was encapsulated and screened for its self-healing efficiency. The decrease in water permeability due to autonomous crack healing using MMA as a healing agent was similar to the results obtained for manually healed cracks. First results seem promising: however, further research needs to be undertaken in order to obtain an optimal healing agent ready for use in practice.

  4. Radiation graft copolymerization of 2-hydroxyethyl methacrylate onto poly (γ-methyl L-glutamate) membrane

    NASA Astrophysics Data System (ADS)

    Yue-E, Fang; Xia, Zhao; Wu, Ge Xue

    1997-11-01

    Radiation-induced grafting Copolymerization of 2-hydroxyethyl methacrylate (HEMA) onto poly(γ-methyl L-glutamate)(PMLG) membrane was researched in aqueous solution in the absence of oxygen. The grafted weight increases with increasing water content in the grafting system. According to the values of the contact angles, the surface free energy, the interfacial free energy, and the adhesive work of the membranes with deionized water were calculated. Photoacoustic fourier transform infrared spectroscopy and electron spectroscopy were used for chemical analysis for the study of the surface composition of grafted membrane. From scanning electron micrographs and wide-angle X-ray diffraction profiles we found that the radiation-induced graft copolymerization of HEMA onto PMLG membrane in water as solvent was carried out to be a graft in bulk.

  5. Fabrication of Poly (methyl methacrylate) and Poly(vinyl alcohol) Thin Film Capacitors on Flexible Substrates

    NASA Astrophysics Data System (ADS)

    Salim, Bindu; Meenaa Pria KNJ, Jaisree; Alagappan, M.; Kandaswamy, A.

    2015-11-01

    Flexible electronics is becoming more popular with introduction of more and more organic conducting materials and processes for making thin films. The use of polymers as gate dielectric has over ruled the usage of conventional inorganic oxides in Organic Thin Film Transistors (OTFTs) on account of its solution process ability and ease of making highly insulating thin film. In this work Capacitance is fabricated with polymeric dielectrics namely poly (methyl methacrylate) - PMMA and poly (vinyl alcohol) - PVA. The electrodes used for these capacitors are Indium Tin Oxide (ITO) and Aluminium. Capacitance value of 9.5nF/cm2 and 33.12nF/cm2 is achieved for thickness of 510 nm of PMMA and 80 nm of PVA respectively. This study on capacitance can be used for assessing the suitability of these polymers as gate insulators in OTFTs.

  6. Air plasma processing of poly(methyl methacrylate) micro-beads: Surface characterisations

    NASA Astrophysics Data System (ADS)

    Liu, Chaozong; Cui, Nai-Yi; Osbeck, Susan; Liang, He

    2012-10-01

    This paper reports the surface processing of poly(methyl methacrylate) (PMMA) micro-beads by using a rotary air plasma reactor, and its effects on surface properties. The surface properties, including surface wettability, surface chemistry and textures of the PMMA beads, were characterised. It was observed that the air plasma processing can improve the surface wettability of the PMMA microbeads significantly. A 15 min plasma processing can reduce the surface water contact angle of PMMA beads to about 50° from its original value of 80.3°. This was accompanied by about 8% increase in surface oxygen concentration as confirmed by XPS analysis. The optical profilometry examination revealed the air plasma processing resulted in a rougher surface that has a “delicate” surface texture. It is concluded that the surface chemistry and texture, induced by air plasma processing, co-contributed to the surface wettability improvement of PMMA micro-beads.

  7. Thermal assisted ultrasonic bonding method for poly(methyl methacrylate) (PMMA) microfluidic devices.

    PubMed

    Zhang, Zongbo; Wang, Xiaodong; Luo, Yi; He, Shengqiang; Wang, Liding

    2010-06-15

    A thermal assisted ultrasonic bonding method for poly(methyl methacrylate) (PMMA) microfluidic devices has been presented. The substrates were preheated to 20-30 degrees C lower than glass transition temperature (T(g)) of the polymer. Then low amplitude ultrasonic vibration was employed to generate facial heat at the interface of PMMA substrates. PMMA microfluidic chips were successfully bonded with bulk temperature well below T(g) of the material and with pressure two orders lower than conventional thermal bonding, which was of great benefit to reduce the deformation of microstructures. The bonding process was optimized by Taguchi method. This bonding technique showed numerous superiorities including high bonding strength (0.95MPa), low dimension loss (0.3-0.8%) and short bonding time. Finally, a micromixer was successfully bonded by this method and its performance was demonstrated.

  8. Hydrophobic modification of cellulose isolated from Agave angustifolia fibre by graft copolymerisation using methyl methacrylate.

    PubMed

    Rosli, Noor Afizah; Ahmad, Ishak; Abdullah, Ibrahim; Anuar, Farah Hannan; Mohamed, Faizal

    2015-07-10

    Graft copolymerisation of methyl methacrylate (MMA) onto Agave angustifolia was conducted with ceric ammonium nitrate (CAN) as the redox initiator. The maximum grafting efficiency was observed at CAN and MMA concentrations of 0.91 × 10(-3) and 5.63 × 10(-2)M, respectively, at 45°C for 3h reaction time. Four characteristic peaks at 2995, 1738, 1440, and 845 cm(-1), attributed to PMMA, were found in the IR spectrum of grafted cellulose. The crystallinity index dropped from 0.74 to 0.46, while the thermal stability improved upon grafting. The water contact angle increased with grafting yield, indicating increased hydrophobicity of cellulose. SEM images showed the grafted cellulose to be enlarged and rougher. The changes in the physical nature of PMMA-grafted cellulose can be attributed to the PMMA grafting in the amorphous regions of cellulose, causing it to expand at the expense of the crystalline component.

  9. CH stretch excitation causes conformational interconversion in ground state methyl vinyl ether but not in methyl nitrite

    NASA Astrophysics Data System (ADS)

    Ruoff, Rodney S.; Kulp, Thomas J.; McDonald, J. D.

    1984-11-01

    Molecules exhibiting conformational isomerism have been studied by spectrally resolving the infrared laser induced fluorescence from CH stretch fundamental excitation of methyl vinyl ether and from CH stretch fundamental and N=O overtone excitation of methyl nitrite. By comparison of the resolved fluorescence spectra of methyl vinyl ether with its absorbance spectrum, we have observed the first case of state selected ground electronic state intramolecular conformational interconversion in an isolated molecule. The distribution of conformers is altered drastically by the deposition of energy. The cis/trans ratio of the laser excited molecules may also be sensitive to the laser excitation frequency. Excitation of the N=O overtones of both cis methyl nitrite and trans methyl nitrite, which are well separated in frequency, gives resolved fluorescence spectra which mimic the absorbance spectra for cis methyl nitrite and trans methyl nitrite, respectively, thereby placing a lower bound for the conformational interconversion energy barrier from trans to cis of 3325 cm-1. The experiments were performed by exciting either molecule cooled in a pulsed nozzle expansion with light from an infrared optical parametric oscillator. The fluorescence spectra were recorded with a cryogenic Michelson interferometer.

  10. Microwave Spectroscopy of Trans-Ethyl Methyl Ether in the Torsionally Excited State 3

    NASA Astrophysics Data System (ADS)

    Kobayashi, Kaori; Murata, Keigo; Tsunekawa, Shozo; Ohashi, Nobukimi

    2010-06-01

    The trans-ethyl methyl ether molecule (CH_3CH_2OCH_3) has two methyl group internal rotors which are equivalent to the two vibrational motions, ν28 and ν29. There is another low-lying torsional motion which is a skeltal torsion (ν30) and does not cause splitting. The microwave spectra of the trans-ethyl methyl ether molecule in the ν28 = 1, ν29 = 1, and ν30 = 1 have been studied and interactions between these states were discussed. In this paper we report results on the ν30 = 2, and 3 state. The analysis based on Hougen's tunneling matrix formulation considering two methyl groups are used. We try to interpret tunneling parameters obtained in the present analysis quantitatively from the viewpoint of torsion-torsion interaction.

  11. [Analysis of the character of film decomposition of methyl methacrylate (MMA) coated urea by infrared spectrum].

    PubMed

    Li, Dong-po; Wu, Zhi-jie; Liang, Cheng-hua; Chen, Li-jun; Zhang, Yu-lan; Nie, Yan-xi

    2012-03-01

    The degradability characteristics of film with 4 kinds of methyl methacrylate coated urea amended with inhibitors were analyzed by FITR, which was purposed to supply theoretical basis for applying the FITR analysis method to film decomposition and methyl methacrylate coated urea fertilizers on farming. The result showed that the chemical component, molecule structure and material form of the membrane were not changed because of adding different inhibitors to urea. the main peaks of expressing film degradation process were brought by the -C-H of CH3 & CH2, -OH, C-O, C-C, C-O-C, C=O, C=C flexing vibrancy in asymmetry and symmetry in 3 479-3 195, 2 993--2 873, 1 741-1 564, 1 461-925 and 850-650 cm(-1). The peak value changed from smooth to tip, and from width to narrow caused by chemical structural transform of film The infrared spectrum of 4 kinds of fertilizers was not different remarkably before 60 days, and the film was slowly degraded. But degradation of the film was expedited after 60 days, it was most quickened at 120 day, and the decomposition rate of film was decreased at 310 day. The substantiality change of film in main molecule structure of 4 kinds of fertilizers didn't happen in 310 days. The main component of film materials was degraded most slowly in brown soil. The speed of film degradation wasn't heavily impacted by different inhibitors. The characteristic of film degradation may be monitored entirely by infrared spectrum. The degradation dynamic, chemical structure change, degradation speed difference of the film could be represented through infrared spectrum.

  12. Methyl methacrylate levels in orthopedic surgery: comparison of two conventional vacuum mixing systems.

    PubMed

    Jelecevic, Jasmin; Maidanjuk, Stanislaw; Leithner, Andreas; Loewe, Kai; Kuehn, Klaus-Dieter

    2014-05-01

    Poly-methyl methacrylate bone cements contain methyl methacrylate (MMA), which is known for its sensitizing and toxic properties. Therefore, in most European countries and in the USA, guidelines or regulations exist for occupational exposures. The use of vacuum mixing systems can significantly reduce airborne MMA concentrations during bone setting. Our goal was to test two commonly used vacuum mixing systems (Palamix(®) and Optivac(®)) using Palacos(®) R bone cement for their effectiveness at preventing MMA vapor release in a series of standardized trials in a laboratory as well as in an operating theatre. MMA was quantified every second over a period of 3 min using a photoionization detector (MiniRAE(®) 3000) device positioned in the breathing area of the user. Significant differences in MMA mean vapor concentrations over 180 s were observed in the two experimental spaces, with the highest mean concentrations (7.61 and 7.98 ppm for Palamix(®) and Optivac(®), respectively) observed in a laboratory with nine air changes per hour and the lowest average concentrations (1.06 and 1.12 ppm for Palamix(®) and Optivac(®), respectively) in an operating theatre with laminar flow ventilation and 22 air changes per hour. No significant differences in overall MMA concentrations were found between the two vacuum mixing systems in either location. Though, differences were found between both systems during single mixing phases. Thus, typical handling of MMA in orthopedic procedures must be seen as not harmful as concentrations do not reach the short-term exposure limit of 100 ppm. Additionally, laminar airflow seems to have an influence on lowering MMA concentrations in operation theatres.

  13. Kinetics and mechanisms of flash pyrolysis of poly(methyl methacrylate) (PMMA)

    SciTech Connect

    Arisawa, H.; Brill, T.B.

    1997-05-01

    Flash pyrolysis (600--1,000 C/s) of a film of anionically polymerized poly(methyl methacrylate) (PMMA) was conducted at controlled temperatures in the 380--600 C range by T-jump/FTIR spectroscopy. In the endothermic decomposition process, the methyl methacrylate monomer (MMA {ge} 90%) and CO{sub 2} ({le} 10%) are the only pyrolysis products detected. Arrhenius parameters for evolution of MMA and CO{sub 2} were determined under a pressure of 2 and 11 atm Ar for PMMA with MW = 2,000 and 131,000. A zeroth-order rate model was used. A slope break occurs at 460--500 C in the Arrhenius plots. Below this range for MMA, E{sub a} = 43--66 kcal/mol and In(A/s) = 26--44, which are comparable to previous reports for random C-C scission kinetics. For CO{sub 2}, E{sub a} = 39--46 kcal/mol and In(A/s) = 23--27, which are comparable to the decarboxylation rates of other organic compounds. Above 460--500 C, increased control of the rates by desorption/diffusion of MMA and CO{sub 2} is suggested by the lower values of E{sub a} in the 12--30 kcal/mol range and In(A/s) in the 5.7--17 range. Thus, the limiting temperature of pyrolysis of PMMA is about 500 C before the deconsolidation rate of the pyrolysis products begins to take control from the bulk decomposition rate in determining the rate of product evolution.

  14. Identification and Quantitation of Volatile Organic Compounds in Poly(methyl methacrylate) Kitchen Utensils by Headspace Gas Chromatography/Mass Spectrometry.

    PubMed

    Ohno, Hiroyuki; Mutsuga, Motoh; Kawamura, Yoko

    2014-01-01

    A headspace GC/MS method was developed for identification and quantitation of residual volatile organic compounds in poly(methyl methacrylate) (PMMA) kitchen utensils. A sample was cut into small pieces, then N,N-dimethylacetamide was added in a headspace vial and sealed. After storing for more than 1 day at room temperature, the vial was incubated for 1 h at 90°C, and the headspace gas was analyzed by GC/MS. In 24 PMMA kitchen utensils, 16 volatile organic compounds including methyl methacrylate, methyl acrylate, toluene, 2-methyl-1-butene, 2-methyl-2-butene, 2-methylpropanal, methyl propionate, methyl isobutyrate, trans-3-heptene, heptane, cis-3-heptene, trans-2-heptene, cis-2-heptene, 2,4,4-trimethyl-1-pentene, 2,4,4-trimethyl-2-pentene, and 1-octene were identified and quantitated. These 15 volatile compounds except methyl methacrylate were found for the first time in PMMA kitchen utensils. Recovery rates from spiked samples were 97.4-104.0% with CV values of 2.8-9.6%. Samples contained 190-7900 μg/g of methyl methacrylate, 26-810 μg/g of methyl acrylate, and 2-1300 μg/g of toluene; other compounds were at levels less than 100 μg/g. Methyl methacrylate was the main monomer of PMMA and methyl acrylate was a comonomer; toluene should be used as a solvent.

  15. Method for determination of methyl tert-butyl ether and its degradation products in water

    USGS Publications Warehouse

    Church, C.D.; Isabelle, L.M.; Pankow, J.F.; Rose, D.L.; Tratnyek, P.G.

    1997-01-01

    An analytical method is described that can detect the major alkyl ether compounds that are used as gasoline oxygenates (methyl tert-butyl ether, MTBE; ethyl tert-butyl ether, ETBE; and tert-amyl methyl ether, TAME) and their most characteristic degradation products (tert-butyl alcohol, TBA; tert-butyl formate, TBF; and tert-amyl alcohol, TAA) in water at sub-ppb concentrations. The new method involves gas chromatography (GC) with direct aqueous injection (DAI) onto a polar column via a splitless injector, coupled with detection by mass spectrometry (MS). DAI-GC/MS gives excellent agreement with conventional purge-and-trap methods for MTBE over a wide range of environmentally relevant concentrations. The new method can also give simultaneous identification of polar compounds that might occur as degradation products of gasoline oxygenates, such as TBA, TBF, TAA, methyl acetate, and acetone. When the method was applied to effluent from a column microcosm prepared with core material from an urban site in New Jersey, conversion of MTBE to TBA was observed after a lag period of 35 days. However, to date, analyses of water samples from six field sites using the DAI-GC/MS method have not produced evidence for the expected products of in situ degradation of MTBE.An analytical method is described that can detect the major alkyl ether compounds that are used as gasoline oxygenates (methyl tert-butyl ether, MTBE; ethyl tert-butyl ether, ETBE; and tert-amyl methyl ether, TAME) and their most characteristic degradation products (tert-butyl alcohol, TBA; tert-butyl formate, TBF; and tert-amyl alcohol, TAA) in water at sub-ppb concentrations. The new method involves gas chromatography (GC) with direct aqueous injection (DAI) onto a polar column via a splitless injector, coupled with detection by mass spectrometry (MS). DAI-GC/MS gives excellent agreement with conventional purge-and-trap methods for MTBE over a wide range of environmentally relevant concentrations. The new method

  16. BIODEGRADATION OF METHYL TERT-BUTYL ETHER AND BTEX AT VARYING HYDRAULIC RETENTION TIMES

    EPA Science Inventory

    The feasibility of biologically degrading methyl tert-butyl ether (MTBE) contaminated groundwater is dependent on the ability to degrade MTBE and its byproducts in the presence of other gasoline contaminants. This study investigates a mixed culture degrading both MTBE and benzene...

  17. Enhanced diisobutene production in the presence of methyl tertiary butyl ether

    DOEpatents

    Smith, L.A. Jr.

    1983-03-01

    In the liquid phase reaction of isobutene in the presence of resin cation exchange resins with itself in a C[sub 4] hydrocarbon stream to form dimers, the formation of higher polymers, oligomers, and co-dimer by-products is suppressed by the presence of 0.0001 to 1 mole per mole of isobutene of methyl tertiary butyl ether. 1 fig.

  18. INFLUENCE OF METHYL TERT-BUTYL ETHER (MTBE) ON LAKE WATER ALGAE

    EPA Science Inventory

    Methyl tert-butyl ether (MTBE) has been used as an octane booster in gasoline in the United States since the 1970s. MTBE use increased greatly in the 1990s with the implementation of the Clean Air Act Amendments of 1990. The MTBE enhanced a more complete combustion of fuel hydroc...

  19. REFINED PBPK MODEL OF AGGREGATE EXPOSURE TO METHYL TERTIARY-BUTYL ETHER

    EPA Science Inventory

    Aggregate (multiple pathway) exposures to methyl tertiary-butyl ether (MTBE) in air and water occur via dermal, inhalation, and oral routes. Previously, physiologically-based pharmacokinetic (PBPK) models have been used to quantify the kinetic behavior of MTBE and its primary met...

  20. STRUCTURES AND BINDING ENERGIES OF METHYL TERT-BUTYL ETHER-WATER COMPLEXES

    EPA Science Inventory

    Methyl tert-butyl ether (MTBE) is a well-known environmental contaminant owing to its high solubility in water. Since the early 1990s, MTBE has been added to gasoline to improve air quality in some metropolitan areas of the United States. Improved air quality was, however, achiev...

  1. INHALATION EXPOSURE TO METHYL TERT-BUTYL ETHER (MTBE) AND DIBROMOCHLOROMETHANE (DBCM) USING CONTINUOUS BREATH ANALYSIS

    EPA Science Inventory

    The oxygenate methyl tert-butyl ether (MTBE) has been added to gasoline to help meet national ambient air quality standards in those parts of the U.S. that are non-compliant for carbon monoxide. Although MTBE has provided important health benefits in terms of reduced haza...

  2. ATTENUATION OF METHYL TERT-BUTYL ETHER IN WATER USING SUNLIGHT AND A PHOTOCATALYST

    EPA Science Inventory

    The use of methyl tert-butyl ether (MTBE) as a gasoline additive has resulted in increasing pollution of ground water. Most of the conventional treatment technologies are inefficient or costly when the initial concentration of MTBE is low (<200 ug/L). In order to find an eco-frie...

  3. TREATMENT OF METHYL TERT-BUTYL ETHER CONTAMINATED WATER USING PHOTOCATALYSIS

    EPA Science Inventory

    The feasibility of photo-oxidation treatment of methyl tert-butyl ether (MTBE) in water was investigated in three ways, 1) using a slurry falling film photo-reactor, 2) a batch solar reactor system, and 3) a combination of air-stripping and gas phase photooxidation system. MTBE-c...

  4. PHOTOCATALYTIC OXIDATION OF METHYL-TERT-BUTYL ETHER FOR DRINKING WATER TREATMENT

    EPA Science Inventory

    The photo-oxidation of methyl tert-butyl ether (MTBE) in water was investigated to determine the feasibility of using photocatalysis for the treatment of MTBE-contaminated drinking water. The feasibility assessment was conducted using slurries of titanium dioxide in both a photo-...

  5. PHYSIOLOGICALLY BASED PHARMACOKINETIC MODEL FOR HUMAN EXPOSURES TO METHYL TERTIARY-BUTYL ETHER

    EPA Science Inventory

    Humans can be exposed by inhalation, ingestion, or dermal absorption to methyl tertiary-butyl ether (MTBE), an oxygenated fuel additive, from contaminated water sources. The purpose of this research was to develop a physiologically based pharmacokinetic model describing in human...

  6. DERMAL, ORAL, AND INHALATION PHARMACOKINETICS OF METHYL TERTIARY BUTYL ETHER (MTBE) IN HUMAN VOLUNTEERS

    EPA Science Inventory

    Methyl tertiary butyl ether (MTBE), a gasoline additive, used to increase octane and reduce carbon monoxide emissions and ozone precursors has contaminated drinking water leading to exposure by oral, inhalation, and dermal routes. To determine its dermal, oral, and inhalation ki...

  7. DERMAL, ORAL AND INHALATION PHARMACOKINETICS OF METHYL TERTIARY-BUTYL ETHER (MTBE) IN HUMAN VOLUNTEERS

    EPA Science Inventory


    Methyl tertiary butyl ether (MTBE), a gasoline additive used to increase octane and reduce carbon monoxide emissions and ozone precursors, has contaminated drinking water and can lead to exposure by oral, inhalation, and dermal routes. To determine its dermal, oral, and inhal...

  8. Comparison of human mesenchymal stem cells proliferation and differentiation on poly(methyl methacrylate) bone cements with and without mineralized collagen incorporation.

    PubMed

    Wu, Jingjing; Xu, Suju; Qiu, Zhiye; Liu, Peng; Liu, Huiying; Yu, Xiang; Cui, Fu-Zhai; Chunhua, Zhao Robert

    2016-01-01

    Poly(methyl methacrylate) bone cement is widely used in vertebroplasty, joint replacement surgery, and other orthopaedic surgeries, while it also exposed many problems on mechanical property and biocompatibility. Better performance in mechanical match and bone integration is highly desirable. Recently, there reported that incorporation of mineralized collagen into poly(methyl methacrylate) showed positive results in mechanical property and osteointegration ability in vivo. In the present study, we focused on the comparison of osteogenic behavior between mineralized collagen incorporated in poly(methyl methacrylate) and poly(methyl methacrylate). Human marrow mesenchymal stem cells are used in this experiment. Adhesion and proliferation were used to characterize biocompatibility. Activity of alkaline phosphatase was used to assess the differentiation of human marrow mesenchymal stem cells into osteoblasts. Real-time PCR was performed to detect the expression of osteoblast-related markers at messenger RNA level. The results show that osteogenic differentiation on mineralized collagen incorporated in poly(methyl methacrylate) bone cement is more than two times higher than that of poly(methyl methacrylate) after culturing for 21 days. Thus, important mechanism on mineralized collagen incorporation increasing the osteogenetic ability of poly(methyl methacrylate) bone cement may be understood in this concern.

  9. 1D and 2D NMR studies of isobornyl acrylate - Methyl methacrylate copolymers

    NASA Astrophysics Data System (ADS)

    Khandelwal, Deepika; Hooda, Sunita; Brar, A. S.; Shankar, Ravi

    2011-10-01

    Isobornyl acrylate - methyl methacrylate (B/M) copolymers of different compositions were synthesized by atom transfer radical polymerization (ATRP) using methyl-2-bromopropionate as an initiator and PMDETA copper complex as catalyst under nitrogen atmosphere at 70 °C. 1H NMR spectrum was used to determine the compositions of copolymer. The copolymer compositions were then used to determine the reactivity ratios of monomers. Reactivity ratios of co-monomers in B/M copolymer, determined from linear Kelen-Tudos method (KT) and non linear Error-in-Variable Method (EVM), are rB = 0.41 ± 0.11, rM = 1.11 ± 0.33 and rB = 0.52, rM = 1.31 respectively. The complete resonance assignments of 1H and 13C{ 1H} NMR spectra were carried out with the help of Distortion less Enhancement by Polarization Transfer (DEPT), two-dimensional Heteronuclear Single Quantum Coherence (HSQC). 2D HSQC assignments were further confirmed by 2D Total Correlation Spectroscopy (TOCSY). The carbonyl carbon of B and M units and methyl carbon of M unit were assigned up to triad compositional and configurational sequences whereas β-methylene carbons were assigned up to tetrad compositional and configurational sequences. Similarly the methine carbon of B unit was assigned up to pentad level. 1,3 and 1,4 bond order couplings of carbonyl carbon and quaternary carbon resonances with methine, methylene and methyl protons were studied in detail using 2D Hetero Nuclear Multiple Bond Correlation (HMBC) spectra.

  10. Dynamic mechanical thermal analysis of dental polymers. I. Heat-cured poly(methyl methacrylate)-based materials.

    PubMed

    Clarke, R L

    1989-09-01

    The visco-elastic characteristics of homogeneous, heterogeneous and fibre-reinforced poly(methyl methacrylate) for use as denture base resins were measured by a dynamic mechanical thermal analyser in the frequency range 0.033-90 Hz. Dynamic Young's modulus of both polyethylene woven yarn and the polyaramid plain fabric-reinforced acrylics showed considerable improvement over the conventional denture base, whereas the carbon fibre-reinforced acrylic produced results lower than expected. From the loss tangent curves of the homogeneous and heterogeneous methacrylates their transition temperatures were recorded and the reciprocals of both the alpha and beta absorption temperatures were plotted against frequency to obtain their respective activation energies.

  11. Effects of metal ions on entero-soluble poly(methacrylic acid-methyl methacrylate) coating: a combined analysis by ATR-FTIR spectroscopy and computational approaches.

    PubMed

    Cilurzo, Francesco; Gennari, Chiara G M; Selmin, Francesca; Vistoli, Giulio

    2010-04-05

    Poly(methacrylic acid-methyl methacrylate)s (HPMMs) are pH-dependent polymers which ionize and form salts (PMMs) in neutral conditions. Despite their wide use in tablet coating, the interactions of PMMs with electrolytes present in biorelevant media and luminal fluids have been scantly investigated. The data generated in the current work provide the basic information on the effect of bivalent cations, namely, Ca2+, Zn2+ and Mn2+, on the HPMMs' solubility and, consequently, on the performances (disintegration and drug dissolution) of acetaminophen gastroresistant tablets when exposed to fluid containing such salts. The interactions between polymers and metal ions were analyzed by ATR-FTIR spectroscopy and in silico combining molecular dynamics simulations to explore the conformational profiles of several oligomers with different M(w), taken as model of the polymers, with ab initio and semiempirical calculations in the gas phase. The computational results agree with the experimental data in terms of spatial disposition of the bications with respect to PMMs (Ca2+ and Mn2+ as bidentate form and Zn2+ as monodentate ligand) and interaction strength (Zn2+ > Mn(2+) > Ca2+). The tablet disintegration and dissolution rate of acetaminophen were strongly affected by the interactions of the dissolving copolymer with the metal ions which led to coating insolubilization. These preliminary results underline that the ingestion of metal ions at high concentrations could affect the drug liberation from gastroresistant dosage forms.

  12. Single-walled carbon nanotubes as an effective adsorbent in solid-phase microextraction of low level methyl tert-butyl ether, ethyl tert-butyl ether and methyl tert-amyl ether from human urine.

    PubMed

    Rastkari, Noushin; Ahmadkhaniha, Reza; Yunesian, Masud

    2009-05-15

    Carbon nanotubes (CNTs) are a kind of new carbon-based nano-materials which have drawn great attention in many application fields. The potential single-walled carbon nanotubes (SWCNTs) as solid-phase microextraction (SPME) adsorbents for the preconcentration of environmental pollutants have been investigated in recent years. The goal of this work was to investigate the feasibility of SWCNTs used as adsorbents for solid-phase microextraction of methyl tert-butyl ether (MTBE), ethyl tert-butyl ether (ETBE) and tert-amyl methyl ether (TAME) in human urine. SWCNTs were attached onto a stainless steel wire through organic binder. Potential factors affecting the extraction efficiency were optimized, including extraction time, extraction temperature, desorption time, desorption temperature, and salinity. The developed method showed good performance according to the ICH performance criteria for bioanalytical methods. The calibration curves of the ethers were linear (r(2)>or=0.992) in the range from 10 to 5000 ng L(-1). The limits of detection at a signal-to-noise (S/N) ratio of 3 were 10 ng L(-1) for all the analytes. In addition, compared with the commercial carboxen/polydimethylsiloxane (CAR/PDMS) fiber, the SWCNT fiber showed better thermal stability (over 350 degrees C) and longer life span (over 150 times). The developed method was applied successfully to determine trace level of the ethers in urine of 10 healthy male volunteers.

  13. Thermo-Mechanical Properties of Semi-Degradable Poly(β-amino ester)-co-Methyl Methacrylate Networks under Simulated Physiological Conditions

    PubMed Central

    Safranski, David L.; Crabtree, Jacob C.; Huq, Yameen R.; Gall, Ken

    2011-01-01

    Poly(β-amino ester) networks are being explored for biomedical applications, but they may lack the mechanical properties necessary for long term implantation. The objective of this study is to evaluate the effect of adding methyl methacrylate on networks' mechanical properties under simulated physiological conditions. The networks were synthesized in two parts: (1) a biodegradable crosslinker was formed from a diacrylate and amine, (2) and then varying concentrations of methyl methacrylate were added prior to photopolymerizing the network. Degradation rate, mechanical properties, and glass transition temperature were studied as a function of methyl methacrylate composition. The crosslinking density played a limited role on mechanical properties for these networks, but increasing methyl methacrylate concentration improved the toughness by several orders of magnitude. Under simulated physiological conditions, networks showed increasing toughness or sustained toughness as degradation occurred. This work establishes a method of creating degradable networks with tailorable toughness while undergoing partial degradation. PMID:21966028

  14. A simple sonochemical method for fabricating poly(methyl methacrylate)/stearic acid phase change energy storage nanocapsules.

    PubMed

    Wang, Guxia; Xu, Weibing; Hou, Qian; Guo, Shengwei

    2015-11-01

    In this study, stearic acid suitable for thermal energy storage applications was nanoencapsulated in a poly(methyl methacrylate) shell. The nanocapsules were prepared using a simple ultrasonically initiated in situ polymerization method. The morphology and particle size of the poly(methyl methacrylate)/stearic acid phase change energy storage nanocapsules (PMS-PCESNs) were analyzed using transmission electron microscopy, scanning electron microscopy, atomic force microscopy and dynamic light scattering. The latent heat storage capacities of stearic acid and the PMS-PCESNs were determined using differential scanning calorimetry. The chemical composition of the nanocapsules was characterized using Fourier transform infrared spectroscopy. All of the results show that the PMS-PCESNs were synthesized successfully and that the latent heat storage capacity and encapsulation efficiency were 155.6 J/g and 83.0%, respectively, and the diameter of each nanocapsule was 80-90 nm.

  15. Morphological study and thermal analysis of surface modified {alpha}-FeOOH via in situ polymerization of methyl methacrylate

    SciTech Connect

    Han Yaoxing; Ma Xinsheng; Cao Hongming; Zhang Haiying; Wu Qiufang

    2004-06-08

    Considering the interfacial characteristics of goethite ({alpha}-FeOOH, iron oxide yellow), the in situ polymerization of methyl methacrylate was employed to modify the surfaces of {alpha}-FeOOH pigments in aqueous slurry. The scanning electron micrographs indicated that the poly(methyl methacrylate) anchored on the surfaces of the particle homogeneously. From this study, it was found that one of the key requirements in the synthesis of the {alpha}-FeOOH-PMMA composite was to enhance interfacial compatibility between inorganic particles and organic monomer. Moreover, polymer-treated {alpha}-FeOOH particles were easily dispersed in organic medium to form a stable colloid and the heat resistance of {alpha}-FeOOH particles was improved.

  16. Synthesis and properties of poly(methyl methacrylate-2-acrylamido-2-methylpropane sulfonic acid)/PbS hybrid composite

    SciTech Connect

    Preda, N.; Rusen, E.; Musuc, A.; Enculescu, M.; Matei, E.; Marculescu, B.; Fruth, V.; Enculescu, I.

    2010-08-15

    The synthesis of a new hybrid composite based on PbS nanoparticles and poly(methyl methacrylate-2-acrylamido-2-methylpropane sulfonic acid) [P(MMA-AMPSA)] copolymer is reported. The chemical synthesis consists in two steps: (i) a surfactant-free emulsion copolymerization between methyl methacrylate and 2-acrylamido-2-methylpropane sulfonic acid and (ii) the generation of PbS particles in the presence of the P(MMA-AMPSA) latex, from the reaction between lead nitrate and thiourea. The composite was studied by scanning electron microscopy (SEM), X-ray diffraction, FTIR spectroscopy, thermogravimetric analysis and differential scanning calorimetry. The microstructure observed using SEM proves that the PbS nanoparticles are well dispersed in the copolymer matrix. The X-ray diffraction measurements demonstrate that the PbS nanoparticles have a cubic rock salt structure. It was also found that the inorganic semiconductor nanoparticles improve the thermal stability of the copolymer matrix.

  17. Investigation of an accident in a resins manufacturing site: the role of accelerator on polymerisation of methyl methacrylate.

    PubMed

    Casson, Valeria; Snee, Tim; Maschio, Giuseppe

    2014-04-15

    This paper analyzes the effect of an accelerator on the polymerisation of methyl methacrylate (MMA). This study is based on the results of an investigation of an accident in a manufacturing site for resins located in the United Kingdom. As sequence of event to cause the accident the following was assumed: during an unattended batch process a runaway undesired polymerisation of methyl methacrylate occurred, generating rapid vaporisation of monomer, which in contact with an ignition source, led to an explosion followed by a fire. Since no initiator for the polymerisation reaction had been jet added to the blend, it was supposed that the accelerator contributed to the onset of the undesired polymerisation. The accelerator involved in the accident t has therefore been tested by differential scanning calorimetry and adiabatic calorimetry. The experimental data allowed the authors to prove the hypothesis made and to define safety ranges for the polymerisation reaction.

  18. Reduce the cost of producing TAME. [Tertiary Amyl Methyl Ethers

    SciTech Connect

    Rock, K.L.; Gildert, G.R. )

    1994-01-01

    The high atmospheric reactivity and resulting high ozone formation have been previously documented for C5 olefins. Other features such as low octane number and high vapor pressure limit their usefulness as gasoline blendstocks. Conversion of C[sub 5] olefins to TAME is a good way to upgrade these components into high value gasoline blendstocks. The TAME product has high octane and low vapor pressure as well as contained oxygen. The other option is to alkylate the C[sub 5] olefins. This route produces greater volume but with higher vapor pressure and lower octane value. The TAME route also achieves lower capital and operating cost than alkylation. The paper describes a process in which reactive Isoamylenes can be converted to TAME by etherification with methanol. The reactive isoamylenes include 2-methyl butene-1 and 2-methyl butene-2.

  19. ESR study of the radiolysis of cellobiose, cellulose-containing materials, and their mixtures with methyl methacrylate

    SciTech Connect

    Kozlova, E.Y.; Shostenko, A.G.; Ermolaev, S.V.

    1995-01-01

    The ESR spectra of {gamma}-irradiated cellobiose, paper waste, and cellulose extracted from paper waste and waste pulp sludge were analyzed. The kinetics of formation and decay of cellobiose radicals were investigated, and the radiation-chemical yields of the radicals formed in cellulose-containing materials were calculated. The ESR spectra of cellobiose irradiated in the presence of methyl methacrylate (MMA) were obtained. A probable mechanism of MMA grafting onto cellulose-containing matrices is considered.

  20. Bioinspired Hydroxyapatite/Poly(methyl methacrylate) Composite with a Nacre-Mimetic Architecture by a Bidirectional Freezing Method.

    PubMed

    Bai, Hao; Walsh, Flynn; Gludovatz, Bernd; Delattre, Benjamin; Huang, Caili; Chen, Yuan; Tomsia, Antoni P; Ritchie, Robert O

    2016-01-06

    Using a bidirectional freezing technique, combined with uniaxial pressing and in situ polymerization, "nacre-mimetic" hydroxyapatite/poly(methyl methacrylate) (PMMA) composites are developed by processing large-scale aligned lamellar ceramic scaffolds. Structural and mechanical characterization shows "brick-and-mortar" structures, akin to nacre, with interesting combinations of strength, stiffness, and work of fracture, which provide a pathway to making strong and tough lightweight materials.

  1. Microgel formation in the free radical crosslinking copolymerization of methyl methacrylate (MMA) and ethylene glycol dimethcrylate (EGDMA)

    SciTech Connect

    Xiudong Sung; Yuen-Yuen Chiu; Lee, L.J.

    1996-12-31

    The formation of heterogeneous structure through intramolecular reaction is an important feature in the free radical crosslinking copolymerization of methyl methacrylate (MMA) and ethylene glycol dimethacrylate (EGDMA). Such structure formation affects not only the curing behavior but also the rheological changes of the resin. In this work, the effect of co-monomer composition on the reaction kinetics, rheological changes and microgel formation of MMA-EGDMA copolymerization was studied. A percolation model was adopted to simulate such monovinyl-divinyl reactions.

  2. Synthesis of [.sup.13C] and [.sup.2H] substituted methacrylic acid, [.sup.13C] and [.sup.2H] substituted methyl methacrylate and/or related compounds

    DOEpatents

    Alvarez, Marc A.; Martinez, Rodolfo A.; Unkefer, Clifford J.

    2008-01-22

    The present invention is directed to labeled compounds of the formulae ##STR00001## wherein Q is selected from the group consisting of --S--, --S(.dbd.O)--, and --S(.dbd.O).sub.2--, Z is selected from the group consisting of 1-naphthyl, substituted 1-naphthyl, 2-naphthyl, substituted 2-naphthyl, and phenyl groups with the structure ##STR00002## wherein R.sub.1, R.sub.2, R.sub.3, R.sub.4 and R.sub.5 are each independently selected from the group consisting of hydrogen, a C.sub.1-C.sub.4 lower alkyl, a halogen, and an amino group selected from the group consisting of NH.sub.2, NHR and NRR' where R and R' are each independently selected from the group consisting of a C.sub.1-C.sub.4 lower alkyl, an aryl, and an alkoxy group, and X is selected from the group consisting of hydrogen, a C.sub.1-C.sub.4 lower alkyl group, and a fully-deuterated C.sub.1-C.sub.4 lower alkyl group. The present invention is also directed to a process of preparing labeled compounds, e.g., process of preparing [.sup.13C]methacrylic acid by reacting a (CH.sub.3CH.sub.2O--.sup.13C(O)--.sup.13CH.sub.2)-- aryl sulfone precursor with .sup.13CHI to form a (CH.sub.3CH.sub.2O--.sup.13C(O)--.sup.13C(.sup.13CH.sub.3).sub.2)-- aryl sulfone intermediate, and, reacting the (CH.sub.3CH.sub.2O--.sup.13C(O)--.sup.13C(.sup.13CH.sub.3).sub.2)-- aryl sulfone intermediate with sodium hydroxide, followed by acid to form [.sup.13C]methacrylic acid. The present invention is further directed to a process of preparing [.sup.2H.sub.8]methyl methacrylate by reacting a (HOOC--C(C.sup.2H.sub.3).sub.2-- aryl sulfinyl intermediate with CD.sub.3I to form a (.sup.2H.sub.3COOC--C(C.sup.2H.sub.3).sub.2)-- aryl sulfinyl intermediate, and heating the(.sup.2H.sub.3COOC--C(C.sup.2H.sub.3).sub.2)-- aryl sulfinyl intermediate at temperatures and for time sufficient to form [.sup.2H.sub.8]methyl methacrylate.

  3. A comparative study of the decomposition of pig carcasses in a methyl methacrylate box and open air conditions.

    PubMed

    Li, Liangliang; Wang, Jiangfeng; Wang, Yu

    2016-08-01

    Analysis of the process of decomposition is essential in establishing the postmortem interval. However, despite the fact that insects are important players in body decomposition, their exact function within the decay process is still unclear. There is also limited knowledge as to how the decomposition process occurs in the absence of insects. In the present study, we compared the decomposition of a pig carcass in open air with that of one placed in a methyl methacrylate box to prevent insect contact. The pig carcass in the methyl methacrylate box was in the fresh stage for 1 day, the bloated stage from 2 d to 11 d, and underwent deflated decay from 12 d. In contrast, the pig carcass in open air went through the fresh, bloated, active decay and post-decay stages; and 22.3 h (0.93 d), 62.47 h (2.60 d), 123.63 h (5.15 d) and 246.5 h (10.27 d) following the start of the experiment respectively, prior to entering the skeletonization stage. A large amount of soft tissue were remained on the pig carcass in the methyl methacrylate box on 26 d, while only scattered bones remained on the pig carcass in open air. The results indicate that insects greatly accelerate the decomposition process.

  4. Dynamics of Methyl Methacrylate Nanoconfined in Silica Sol Glasses Studied by Optical Kerr Effect Spectroscopy

    NASA Astrophysics Data System (ADS)

    Meng, Dujuan; Xue, Lianjie; Tamas, George; Quitevis, Edward; Simon, Sindee

    2014-03-01

    Nanoconfinement has been found to have an effect on polymerization processes [1,2] and on the glass transition temperature Tg [3]. Here we report studies of the nanoconfinement effect on the dynamics of monomers in the pores of silica sol-gel glass. The samples were prepared under a vacuum and studied by using optical Kerr effect (OKE) spectroscopy. The reorientational dynamics of methyl methacrylate (MMA) confined in silica sol-gel glasses with pore diameters of 32, 41, and 82 Å was studied. The decays of the reorientational correlation function C(t) became longer as the pore size decreased. Based on the analysis of the reorientational correlation functions using a two-state model [4], the nanoconfinement effect is due to the interaction of molecules with the surface of the silica-gel glass. In a study of the effect of nanoconfinement in modified silica sol-gel glasses, which were obtained by refluxing the sol-gel glasses in methanol to give hydrophobic pore surfaces, the decay is faster in the modified silica gel glass than in the unmodified sol-gel glass. This work is supported by NSF Grant CMMI-1235346.

  5. Durability of Poly(Methyl Methacrylate) Lenses Used in Concentrating Photovoltaic Modules: Preprint

    SciTech Connect

    Miller, D. C.; Gedvilas, L. M.; To, B.; Kennedy, C. E.; Kurtz, S. R.

    2010-08-01

    Concentrating photovoltaic (CPV) technology has recently gained interest based on their expected low levelized cost of electricity, high efficiency, and scalability. Many CPV systems use Fresnel lenses made of poly(methyl methacrylate)(PMMA) to obtain a high optical flux density. The optical and mechanical durability of such components, however, are not well established relative to the desired service life of 30 years. Specific reliability issues may include: reduced optical transmittance, discoloration, hazing, surface erosion, embrittlement, crack growth, physical aging, shape setting (warpage), and soiling. The initial results for contemporary lens- and material-specimens aged cumulatively to 6 months are presented. The study here uses an environmental chamber equipped with a xenon-arc lamp to age specimens at least 8x the nominal field rate. A broad range in the affected characteristics (including optical transmittance, yellowness index, mass loss, and contact angle) has been observed to date, depending on the formulation of PMMA used. The most affected specimens are further examined in terms of their visual appearance, surface roughness (examined via atomic force microscopy), and molecular structure (via Fourier transform infrared spectroscopy).

  6. Poly(methyl methacrylate)-supported polydiacetylene films: unique chromatic transitions and molecular sensing.

    PubMed

    Parambath Kootery, Kaviya; Jiang, Hao; Kolusheva, Sofiya; Vinod, T P; Ritenberg, Margarita; Zeiri, Leila; Volinsky, Roman; Malferrari, Danilo; Galletti, Paola; Tagliavini, Emilio; Jelinek, Raz

    2014-06-11

    Polydiacetylenes (PDAs) constitute a family of conjugated polymers exhibiting unique colorimetric and fluorescence transitions, and have attracted significant interest as chemo- and biosensing materials. We spin-coated PDA films upon poly(methyl methacrylate) (PMMA), and investigated the photophysical properties and sensing applications of the new PDA configuration. Specifically, the as-polymerized blue PDA layer underwent distinct transformations to purple, red, and yellow phases, which could be quantified through conventional color scanning combined with application of image analysis algorithms. Furthermore, we recorded a reversible red-purple PDA transition that was induced by ultraviolet irradiation, a phenomenon that had not been reported previously in PDA film systems. We show that distinct color and fluorescence transitions were induced in the PMMA-supported PDA films by amphiphilic substances-surfactants and ionic liquids-and that the chromatic transformations were correlated to the analyte structures and properties. Overall, this study presents a new chromatic PDA film system in which noncovalent interactions between the PMMA substrate and spin-coated PDA give rise to distinct chromatic properties and molecular sensing capabilities.

  7. Nonlinear optical properties of poly(methyl methacrylate) thin films doped with Bixa Orellana dye

    NASA Astrophysics Data System (ADS)

    Zongo, S.; Kerasidou, A. P.; Sone, B. T.; Diallo, A.; Mthunzi, P.; Iliopoulos, K.; Nkosi, M.; Maaza, M.; Sahraoui, B.

    2015-06-01

    Natural dyes with highly delocalized π-electron systems are considered as promising organic materials for nonlinear optical applications. Among these dyes, Bixa Orellana dye with extended π-electron delocalization is one of the most attractive dyes. Bixa Orellana dye-doped Poly(methyl methacrylate) (PMMA) thin films were prepared through spin coating process for linear and nonlinear optical properties investigation. Atomic force microscopy (AFM) was used to evaluate the roughness of the thin films. The optical constants n and k were evaluated by ellipsometric spectroscopy. The refractive index had a maximum of about 1.456 at 508.5, 523.79 and 511.9 nm, while the maximum of k varies from 0.070 to 0.080 with the thickness. The third order nonlinear optical properties of the hybrid Bixa Orellana dye-PMMA polymer were investigated under 30 ps laser irradiation at 1064 nm with a repetition rate of 10 Hz. In particular the third-order nonlinear susceptibility has been determined by means of the Maker Fringes technique. The nonlinear third order susceptibility was found to be 1.00 × 10-21 m2 V-2 or 0.72 × 10-13 esu. Our studies provide concrete evidence that the hybrid-PMMA composites of Bixa dye are prospective candidates for nonlinear material applications.

  8. Poly(methyl methacrylate)-graft-oligoamines as low cytotoxic and efficient nonviral gene vectors.

    PubMed

    Wang, Yong-Qiang; Sun, Yun-Xia; Hong, Xin-Lin; Zhang, Xian-Zheng; Zhang, Gao-Yong

    2010-01-01

    A series of poly(methyl methacrylate)-graft-oligoamines (PMMA-g-oligoamines), including PMMA-g-DETA, PMMA-g-TETA and PMMA-g-TEPA, were synthesized through aminolysis of the PMMA with diethylenetriamine, triethylenetetramine and tetraethylenepentamine. Agarose gel retardation assay indicated that PMMA-g-oligoamines had good binding capability with plasmid DNA, and the binding capability increased with increasing length of oligoamines and content of nitrogen (N%). The results of particle size, zeta potential and morphology observation further showed that the PMMA-g-oligoamines could condense DNA efficiently and the PMMA-g-oligoamine/DNA complexes were uniform nanospheres. The in vitro cell viability indicated that PMMA-g-oligoamines were less toxic than 25 kDa PEI, though the cytotoxicity of PMMA-g-oligoamines increased slightly with increasing length of oligoamines as well as the N% of PMMA-g-oligoamines. The transfection efficiency of PMMA-g-oligoamines/DNA complexes in 293 T and HeLa cells demonstrated that PMMA-g-oligoamines could transfect cells efficiently with increasing the length of oligoamines, especially PMMA-g-TEPA with highest N%, and showed similar transfection capability as 25 kDa PEI. The cellular uptake study showed that the distribution of YOYO-1 labeled DNA in the cytoplasm and nuclei increased gradually with increasing length of oligoamines.

  9. Transient gratings in thin films and bulk azo-dye-containing poly(methyl methacrylate) matrix

    NASA Astrophysics Data System (ADS)

    Luo, Duanbin; Lu, Wei; Wu, Shuizhu

    2005-02-01

    Using holographic recording technology, two kinds of transient diffraction gratings were demonstrated in azo-dye doped Poly(methyl methacrylate) (PMMA) films and bulk matrices respectively. In PMMA films containing azo-dye Disperse Red 13 (DR13), the refractive index gratings came from the reorientation of azo-dye molecules in different areas with different polarization distribution of recording beams. The characteristics of the transient gratings in films samples which were recorded by two mutually parallel polarization beams (PP and SS) as well as orthogonal linear polarization beams (PS and +/-45°) from an Ar ion laser (514nm) were investigated by monitoring the first order diffraction intensity of the readout He-Ne laser beam (632.8nm). With the interaction of bi-photonic lights at 514nm and 632.8nm, the transient gratings in azo-dye DR13 doped PMMA bulk matrices was a kind of population gratings of Trans and Cis isomers, which was attributed to the weak absorption of Cis isomers at 632.8nm and the positive dichroism of Trans isomers at 514nm. Furthermore, the all-optical switching behavior of the two kinds of transient holographic gratings were observed repeatedly by turning on and off the writing beams, and a response time at the magnitude of ten milliseconds order could be obtained.

  10. Rapid Prototyping of Poly(methyl methacrylate) Microfluidic Systems Using Solvent Imprinting and Bonding

    PubMed Central

    Sun, Xiuhua; Peeni, Bridget A.; Yang, Weichun; Becerril, Hector A.

    2011-01-01

    We have developed a method for rapid prototyping of hard polymer microfluidic systems using solvent imprinting and bonding. We investigated the applicability of patterned SU-8 photoresist on glass as an easily fabricated template for solvent imprinting. Poly(methyl methacrylate) (PMMA) exposed to acetonitrile for 2 min then had an SU-8 template pressed into the surface for 10 min, which provided appropriately imprinted channels and a suitable surface for bonding. After a PMMA cover plate had also been exposed to acetonitrile for 2 min, the imprinted and top PMMA pieces could be bonded together at room temperature with appropriate pressure. The total fabrication time was less than 15 min. Under the optimized fabrication conditions, nearly 30 PMMA chips could be replicated using a single patterned SU-8 master with high chip-to-chip reproducibility. Relative standard deviations were 2.3% and 5.4% for the widths and depths of the replicated channels, respectively. Fluorescently labeled amino acid and peptide mixtures were baseline separated using these PMMA microchips in <15 s. Theoretical plate numbers in excess of 5000 were obtained for a ~3 cm separation distance, and the migration time relative standard deviation for an amino acid peak was 1.5% for intra-day and 2.2% for inter-day analysis. This new solvent imprinting and bonding approach significantly simplifies the process for fabricating microfluidic structures in hard polymers such as PMMA. PMID:17466320

  11. Multi-color fluorescence in rare earth acetylacetonate hydrate doped poly methyl methacrylate

    NASA Astrophysics Data System (ADS)

    Zhang, Y. Y.; Shen, L. F.; Pun, E. Y. B.; Chen, B. J.; Lin, H.

    2013-01-01

    Europium and terbium acetylacetonate hydrates were doped into poly methyl methacrylate (PMMA). Efficient purplish-red and green fluorescence was obtained from europium acetylacetonate hydrates (EAH) and terbium acetylacetonate hydrates (TAH) doped PMMA respectively. Judd-Ofelt parameters Ω2 (19.73×10-20 cm2) and Ω4 (2.19×10-20 cm2) indicate a high inversion asymmetric and strong covalent environment in PMMA. The maximum stimulated emission cross-sections for the 5D0→7FJ (J=1, 2 and 4) transitions in EAH doped PMMA were calculated to be 0.38×10-21, 4.90×10-21 and 0.36×10-21 cm2, respectively. Variable fluorescence color can be efficiently achieved from the cooperation of three fluorescence colors offered by red (Eu3+), green (Tb3+) and blue (ligand) in EAH/TAH codoped PMMA by adjusting the excitation wavelength. These results indicate that PMMA is an effective photoluminescence co-sensitizer and PMMA doped with rare earth acetylacetonate hydrates is a promising candidate for a series of optoelectronic functional devices.

  12. A methyl methacrylate-HEMA-CL(n) copolymerization investigation: from kinetics to bioapplications.

    PubMed

    Ferrari, Raffaele; Rooney, Thomas R; Lupi, Monica; Ubezio, Paolo; Hutchinson, Robin A; Moscatelli, Davide

    2013-10-01

    The radical copolymerization kinetics of methyl methacrylate (MMA) and poly-ϵ-caprolactone macromonomer functionalized with a vinyl end group (HEMA-CL(n)) is studied using a pulsed-laser technique. The reactivity ratios for this system are near unity, while a linear relationship between k(p,cop), the copolymer-averaged propagation rate coefficient, and the composition of macromonomer in the feed (0-80 wt% range) is determined. At 50 wt% macromonomer in the feed, a 1.67 ± 0.02 and 1.64 ± 0.06 increase in k(p,cop)/k(p,MMA) is determined for HEMA-CL3 and HEMA-CL2, respectively. These macromonomers are adopted to synthesize nanoparticles (NPs) in the range of 100-150 nm through batch emulsion free radical polymerization (BEP) to produce partially degradable drug delivery carriers. The produced NPs are tested in 4T1 cell line and show excellent characteristics as carriers: they do not affect cell proliferation, and a relevant number of NPs, thousands per cell, are internalized.

  13. Fabrication of superhydrophilic and antireflective silica coatings on poly(methyl methacrylate) substrates

    SciTech Connect

    Geng, Zhi; He, Junhui; Xu, Ligang

    2012-06-15

    Graphical abstract: Self-cleaning and antireflection properties were successfully achieved by assembling (PDDA/S-20){sub n} coatings on PMMA substrates followed by oxygen plasma treatment. Highlights: ► Porous silica coatings were created by layer-by-layer assembly on PMMA substrates. ► Silica coatings were treated by oxygen plasma. ► Porous silica coatings were highly antireflective and superhydrophilic on PMMA substrates. -- Abstract: Silica nanoparticles of ca. 20 nm in size were synthesized, from which hierarchically porous silica coatings were fabricated on poly(methyl methacrylate) (PMMA) substrates via layer-by-layer (LbL) assembly followed by oxygen plasma treatment. These porous silica coatings were highly transparent and superhydrophilic. The maximum transmittance reached as high as 99%, whereas that of the PMMA substrate is only 92%. After oxygen plasma treatment, the time for a water droplet to spread to a contact angle of lower than 5° decreased to as short as 0.5 s. Scanning and transmission electron microscopy were used to observe the morphology and structure of nanoparticles and coating surfaces. Transmission and reflection spectra were recorded on UV–vis spectrophotometer. Surface wettability was studied by a contact angle/interface system. The influence of mesopores on the transmittance and wetting properties of coatings was discussed on the basis of experimental observations.

  14. Adsorption and electron-induced polymerization of methyl methacrylate on Ru(1010)

    SciTech Connect

    Hedhili, M. N.; Yakshinskiy, B. V.; Wasielewski, R.; Ciszewski, A.; Madey, T. E.

    2008-05-07

    The adsorption and electron irradiation of methyl methacrylate (MMA) on a Ru(1010) surface have been studied using x-ray photoelectron spectroscopy (XPS), temperature programmed desorption (TPD), and low energy ion scattering. TPD analysis indicates that a monolayer of MMA chemisorbs and dissociates on the Ru(1010) surface. The reaction products observed upon heating include H{sub 2}, CO, CO{sub 2}, and a small amount of MMA. Physisorbed multilayers of MMA desorb at temperatures around 170 K. Electron irradiation of physisorbed MMA at 140 K leads to a modification of the MMA film: The XPS spectra show an increase in thermal stability of the film with retention of the MMA structure, and indicate that electron irradiation induces polymerization. An increase in the electron bombardment fluence induces a degradation of the formed polymerized species and leads to the accumulation of carbon on the Ru surface. These results are relevant to the accumulation of carbon on surfaces of Ru films that serve as capping layers on Mo/Si multilayer mirrors used in extreme ultraviolet lithography.

  15. On the role of chemical reactions in initiating ultraviolet laser ablation in poly(methyl methacrylate)

    SciTech Connect

    Prasad, Manish; Conforti, Patrick F.; Garrison, Barbara J.

    2007-05-15

    The role of chemical reactions is investigated versus the thermal and mechanical processes occurring in a polymer substrate during irradiation by a laser pulse and subsequent ablation. Molecular dynamics simulations with an embedded Monte Carlo based reaction scheme were used to study ultraviolet ablation of poly(methyl methacrylate) at 157 nm. We discuss the onset of ablation, the mechanisms leading to ablation, and the role of stress relaxation of the polymer matrix during ablation. Laser induced heating and chemical decomposition of the polymer substrate are considered as ablation pathways. It is shown that heating the substrate can set off ablation via mechanical failure of the material only for very short laser pulses. For longer pulses, the mechanism of ejection is thermally driven limited by the critical number of bonds broken in the substrate. Alternatively, if the photon energy goes towards direct bond breaking, it initiates chemical reactions, polymer unzipping, and formation of gaseous products, leading to a nearly complete decomposition of the top layers of substrates. The ejection of small molecules has a hollowing out effect on the weakly connected substrates which can lead to lift-off of larger chunks. Excessive pressure buildup upon the creation of gaseous molecules does not lead to enhanced yield. The larger clusters are thermally ejected, and an entrainment of larger polymer fragments in gaseous molecules is not observed.

  16. Effect of physical aging on stress relaxation of poly/methyl methacrylate/

    NASA Technical Reports Server (NTRS)

    Cizmecioglu, M.; Fedors, R. F.; Hong, S. D.; Moacanin, J.

    1981-01-01

    A study was made on the stress relaxation behavior at 25 C of poly(methyl methacrylate) in uniaxial tension as a function of physical aging at both room temperature and 60 C. Test specimens were compression molded at 165 C, then quenched to room temperature and allowed to age for up to 30 days prior to testing. Stress relaxation curves measured after different aging times could be superposed to a single master curve for each aging temperature. Superposition was achieved by applying vertical and horizontal shifts. Hence, the shape of the response curves was not changed by aging. This is in accordance with observations made by Struik for tensile creep curves. Volume changes as a function of physical aging were also determined. Simple exponential relationships were observed between volume and both horizontal and vertical shifts. The horizontal shift implies a shift in the effective time scale caused by a change in free volume. The vertical shifts could be correlated with changes in Young's modulus caused by a change in density. For the range of aging studied, the response time scale varied over nearly two decades of log-time. For the same conditions modulus varied by 30 percent.

  17. Influence of Ionic Complexes on Phase Behavior of Polystyrene-b-poly(methyl methacrylate) Copolymers

    SciTech Connect

    Wang,J.; Chen, W.; Roy, C.; Sievert, J.; Russell, T.

    2008-01-01

    The influence of ionic complexes on phase behavior of PS-b-PMMA copolymers over a wide range of molecular weights and PS volume fractions was investigated by small-angle X-ray scattering (SAXS), grazing incidence small-angle X-ray scattering (GISAXS), transmission electron microscopy (TEM), and neutron reflectivity (NR). The disorder-to-order transition (DOT) in both symmetric and asymmetric copolymers indicates that the overall Flory-Huggins segmental interaction parameter, eff, between polystyrene (PS) and poly(methyl methacrylate) (PMMA) blocks with lithium-PMMA complexes is increased compared to that of the neat copolymers. This enhanced eff further results in an order-to-order transition (OOT), from spheres to cylinders, and an increase in the ordering and spacing of microdomains. Moreover, transitional metal ionic complexes, such as copper-PMMA complexes, are found to have the similar influence on phase behavior of PS-b-PMMA copolymers. The formation of ionic complexes in the copolymers not only offers a parameter to tune the degree of microphase separation of PS-b-PMMA copolymers but also provides a way to fabricate multifunctional materials.

  18. Molecular dynamics of poly(methyl methacrylate) determined by dielectric relaxation spectroscopy

    NASA Astrophysics Data System (ADS)

    Seki, Yuki; Kita, Rio; Shinyashiki, Naoki; Yagihara, Shin; Yoneyama, Masaru

    2013-02-01

    We performed broadband dielectric measurements for poly(methyl methacrylate) [PMMA], poly(vinyl alcohol) [PVA], and PVA-fibroin blend films in the temperature range of -50 °C to 200 °C, -120 °C to 200 °C, and -120 °C to 25 °C, respectively, in the frequency range of 10 mHz to 10 MHz. For PMMA, three relaxation processes were observed: process α at low frequency, the secondary process β at intermediate frequency, and the last process γ at high frequency. The symmetrically shaped three relaxation processes (α, β, γ) are described by the Cole-Cole equation. Near room temperature, process γ merges with process β. Similarly, at higher temperatures which close to Tg (103 °C for PMMA), process α merges with processes β and γ. For PVA-fibroin blend film, we observe the three relaxation processes (β, γ, δ), and the contribution of dc conductivity is larger than that of PMMA and PVA films.

  19. Superparamagnetic poly(methyl methacrylate) beads for nattokinase purification from fermentation broth.

    PubMed

    Yang, Chengli; Xing, Jianmin; Guan, Yueping; Liu, Huizhou

    2006-09-01

    An effective method for purification of nattokinase from fermentation broth using magnetic poly(methyl methacrylate) (PMMA) beads immobilized with p-aminobenzamidine was proposed in this study. Firstly, magnetic PMMA beads with a narrow size distribution were prepared by spraying suspension polymerization. Then, they were highly functionalized via transesterification reaction with polyethylene glycol. The surface hydroxyl-modified magnetic beads obtained were further modified with chloroethylamine to transfer the surface amino-modified magnetic functional beads. The morphology and surface functionality of the magnetic beads were examined by scanning electron microscopy and Fourier transform infrared. An affinity ligand, p-aminobenzamidine was covalently immobilized to the amino-modified magnetic beads by the glutaraldehyde method for nattokinase purification directly from the fermentation broth. The purification factor and the recovery of the enzyme activity were found to be 8.7 and 85%, respectively. The purification of nattokinase from fermentation broth by magnetic beads only took 40 min, which shows a very fast purification of nattokinase compared to traditional purification methods.

  20. Invivo absorption behaviour of theophylline from starch-methyl methacrylate matrix tablets in beagle dogs.

    PubMed

    Fernández-Campos, F; Ferrero, C; Colom, H; Jiménez-Castellanos, M R

    2015-01-30

    This study evaluates in vivo the drug absorption profiles from potato starch-methyl methacrylate matrices(*) using theophylline as a model drug. Healthy beagle dogs under fasting conditions were used for in vivo studies and plasma samples were analyzed by a fluorescence polarization immunoassay analysis (FPIA method). Non-compartmental and compartmental (population approach) analysis was performed to determine the pharmacokinetic parameters. The principle of superposition was applied to predict multiple dose plasma concentrations from experimental single dose data. An in vitro-in vivo correlation (IVIVC) was also assessed. The sustained absorption kinetics of theophylline from these formulations was demonstrated by comparison with two commercially available oral sustained-release theophylline products (Theo-Dur(®) and Theolair(®)). A one-compartment model with first order kinetics without lag-time best describes the absorption/disposition of theophylline from the formulations. Results revealed a theophylline absorption rate in the order FD-HSMMA≥Theo-Dur(®)≥OD-CSMMA>Theolair(®)≥FD-CSMMA. On the basis of simulated plasma theophylline levels, a twice daily dosage (every 12h) with the FD-CSMMA tablets should be recommended. A Level C IVIVC was found between the in vitrot50% and the in vivo AUC/D, although further optimization of the in vitro dissolution test would be needed to adequately correlate with in vivo data.

  1. The Effect of Nanoconfinemnt on Methyl Methacrylate Polymerization: Reactivity and Resulting Properties

    NASA Astrophysics Data System (ADS)

    Zhao, Haoyu; Yu, Ziniu; Hedden, Ronald; Simon, Sindee

    2014-03-01

    The effect of nanoconfinement is well known to affect the properties of polymers. In this work, free radical polymerization of methyl methacrylate (MMA) is performed in hydrophilic or hydrophobic 13 nm diameter controlled pore glass (CPG). Changes in polymerization kinetics and the properties of the synthesized polymer are quantified. Reaction kinetics and glass transition temperatures are followed by differential scanning calorimetry (DSC). After polymerization, the changes in the molecular weights and tacticity are measured using gel permeation chromatography (GPC) and 1H nuclear magnetic resonance (1H NMR). Nanoconfinement is found to result in earlier onset of autoacceleration leading to the increase in both number-average and weight-average molecular weights, whereas the polydispersity index at full conversion decreases relative to the bulk value. Moreover, for both pore surfaces, the glass transition temperature increases compared with the bulk, but the increase in hydrophilic pores is more pronounced at 20 °C. In addition to the changes in molecular weight and Tg, the tacticity changes from syndiotactic-rich triads for the bulk PMMA to a higher percentage of isotacticity under nanoconfinement. Funding from the National Science Foundation CMMI 0826437 and CRIF MU grant CHE-1048553 is gratefully acknowledged.

  2. Adsorption of doxorubicin on poly(methyl methacrylate)-chitosan-heparin-coated activated carbon beads.

    PubMed

    Miao, Jianjun; Zhang, Fuming; Takieddin, Majde; Mousa, Shaker; Linhardt, Robert J

    2012-03-06

    Extracorporeal filter cartridges, filled with an activated carbon bead (ACB) adsorbent, have been used for removal of overdosed cancer drugs from the blood. Coatings on adsorbent matrices, poly(methyl methacrylate) (PMMA)/activated carbon bead and PMMA/chitosan/heparin/ACB composites, were tested to improve their biocompatibility and blood compatibility. PMMA coating on ACBs was accomplished in a straightforward manner using a PMMA solution in ethyl acetate. A one-step hybrid coating of ACBs with PMMA-anticoagulant heparin required the use of acetone and water co-solvents. Multilayer coatings with three components, PMMA, chitosan, and heparin, involved three steps: PMMA was first coated on ACBs; chitosan was then coated on the PMMA-coated surface; and finally, heparin was covalently attached to the chitosan coating. Surface morphologies were studied by scanning electron microscopy. X-ray photoelectron spectroscopy confirmed the -SO(3)(-) group. Adsorption, of a chemotherapy drug (doxorubicin) from both water and phosphate-buffered saline, by the coated ACBs was examined. The adsorption isotherm curves were fitted using the Freundlich model. The current adsorption system might find potential applications in the removal of high-dose regional chemotherapy drugs while maintaining high efficiency, biocompatibility, and blood compatibility.

  3. Histochemistry and immunohistochemistry on bone marrow biopsies. A rapid procedure for methyl methacrylate embedding.

    PubMed

    Lebeau, A; Muthmann, H; Sendelhofert, A; Diebold, J; Löhrs, U

    1995-03-01

    Starting from previous methodical approaches a procedure for low temperature methyl methacrylate (MMA) embedding of bone marrow biopsies is introduced, which allows routine application of enzyme and immunohistochemistry without loss of morphological quality by retaining fixation in Schaffer's solution. Survival of enzyme activity and antigen determinants is achieved by washing the fixed specimens in 70% methanol and dehydration in acetone in ascending concentrations at 4 degrees C. Modifications of the plastic embedding technique used in this study simplify and shorten the procedure, so that embedding according to this routine method is complete after two days of preparation. Additionally, a rapid embedding variant is introduced, which enables tissue preparation within one day if necessary. Results are demonstrated using markers for myeloid, lymphoid and epithelial cells as well as immunoglobulins and the proliferation associated antigen Ki-67. The investigation of a panel of monoclonal and polyspecific antibodies in 31 cases shows the eventually reduced immunoreactivity of a few markers after prolonged fixation. As a consequence it seems essential to ensure short fixation periods, especially when the specimens are sent by mail.

  4. Effect of moisture on the physical and durability properties of methyl methacrylate polymer concrete

    SciTech Connect

    Fontana, J.J.; Reams, W.

    1983-01-01

    The compressive strength of methyl methacrylate PC composites decays very rapidly as the moisture content of the coarse aggregate is increased from 0 to 1 wt %. The durability of the PC also shows evidence of decay. Addition of silane coupling agent, such as A-1120, to the monomer component of a PC composite increases the compressive strength of such composites made with moist coarse aggregates. The compressive strengths of such PC composites are as high as a normal PCC used in highway applications. The durability of PC composites made with a silane additive seems to increase as the composite undergoes freeze-thaw cycling which reinforces the justification that such materials can be used for PCC repairs without a sacrifice in use lifespans. However, for the convenience of using moist aggregates, one must endure the additional cost of the silane coupling agent. If it costs more than $0.02/lb to dry the aggregate, and one is willing to accept the reduced strengths associated with moist aggregates, then the use of a silane coupling agent can be cost effective. 3 figures, 4 tables.

  5. Highly active ppm level organic copper catalyzed photo-induced ICAR ATRP of methyl methacrylate.

    PubMed

    Jiang, Xiaowu; Wu, Jian; Zhang, Lifen; Cheng, Zhenping; Zhu, Xiulin

    2014-11-01

    A novel photo-induced homogeneous atom transfer radical polymerization (ATRP) system is constructed using an organic copper salt (Cu(SC(S)N(C2 H5 )2 )2 ) as a photo-induced catalyst at 30 °C. Herein, N,N,N',N'',N''-pentamethyldiethylenetriamine (PMDETA) is used as a ligand, ethyl 2-bromophenylacetate (EBPA) as an ATRP initiator, and (2,4,6-trimethylbenzoyl) diphenylphosphine oxide (TPO) as a photo-induced radical initiator to establish an ICAR (initiators for continuous activator regeneration) ATRP using methyl methacrylate (MMA) as a modal monomer. The effect of the concentration of the organic copper on the polymerization is investigated in detail. It is found that well-controlled polymerization can be obtained even with the amount of (Cu(SC(S)N(C2 H5 )2 )2 decreasing to a 1.56 ppm level, with the molecular weight of the resultant polymers increasing linearly with monomer conversion while maintaining a narrow molecular weight distribution (M¯w/M¯n < 1.3).

  6. Water absorption of poly(methyl methacrylate) containing 4-methacryloxyethyl trimellitic anhydride.

    PubMed

    Unemori, Masako; Matsuya, Yoko; Matsuya, Shigeki; Akashi, Akane; Akamine, Akifumi

    2003-04-01

    The amount of water absorption of poly(methyl methacrylate) (PMMA) containing 0, 1, 3 and 5 wt% of an adhesive monomer, 4-methacryloxyethyl trimellitic anhydride (4-META), was measured at 7 degrees C, 37 degrees C and 60 degrees C. After the water uptake reached equilibrium in specimens, they were desorbed to obtain a constant value and the absorption process was repeated. Mass changes in the second desorption were recorded for the storage temperatures of 37 degrees C and 60 degrees C. Multiple regression analyses were conducted on three independent variables, 4-META concentration, storage temperature and absorption-desorption cycle. A statistically significant relationship was found between the maximum water uptake and 4-META concentration, while there was no relationship between the maximum water uptake and diffusion coefficient obtained using the Fick's law. The negative relationship in the latter did not support the free space theory. The significant and positive relationship between the maximum water uptake and 4-META concentration demonstrates that water molecules diffuse through the formation of a hydrogen bond at polar sites. The maximum water uptake was not influenced by temperature, while the diffusion coefficient increased with the rise in temperature. The activation energy was 41-47 and 50-53 kJ/mol in the first and second absorption tests, respectively.

  7. A cross-industry assessment of personal exposures to methyl methacrylate.

    PubMed

    Vos, Gordon A; Stephens, John Paul

    2008-01-01

    This study investigated personal exposures to methyl methacrylate (MMA) monomer during monomer production and use within the chemical manufacturing industry. The aim was to include multiple companies and sites to provide information regarding differences and similarities among exposure subgroups within the industry during the time period of 1998-2000. To this end, personal exposure data for MMA monomer from three chemical corporations was combined into a single data set. The data was stratified by sample type (full shift or short term), job classification (monomer production, monomer use, maintenance, distribution, and laboratory operations), company, and facility. Only classifications with three samples or more were included in the final data set, yielding 376 samples for analysis (334 full-shift and 42 short-term samples). Results compare well with previously published data on MMA monomer exposures. Although there was significant variability in several exposure subgroups (particularly among companies and facilities), MMA monomer use in the manufacture of other products resulted in the highest exposure distributions, with lower exposures associated with monomer production, maintenance, and distribution operations. The usefulness of these findings is related to the provision of information for discussion of current needs in the industry regarding data sampling, exposure assessment, and standards development.

  8. The effect of processing conditions on the properties of poly(methyl methacrylate) fibers.

    PubMed

    Wright, Debra D; Lautenschlager, Eugene P; Gilbert, Jeremy L

    2002-01-01

    Brittle failure of bone cement remains a problem for the long-term stability of hip prostheses. Fibers have been developed from poly(methyl methacrylate) (PMMA) that retain the chemistry of bone cement, but improve the mechanical properties greatly. To fabricate the fibers, a polymer melt is extruded out of a small die (spinneret) and pulled onto a take-up wheel. Varying the speed of extrusion and temperature of the melt can control the viscosity of the molten polymer. This study examines the effect of melt viscosity on the resultant properties of fibers fabricated from PMMA. The goals are to optimize fiber processing and determine processing-structure--property relationships. Resultant fibers had moderate to high levels of retained molecular orientation, and ultimate tensile strengths (UTS) ranging from 60 to 225 MPa, moduli from 1.5 to 3.5 GPa, and strain to failure from 10 to 40%. Fibers fabricated at a constant viscosity and draw velocity had identical properties, whereas decreasing the viscosity generally increased the mechanical properties and retained orientation. Linear regression models were constructed to predict how the processing variables affect the structure (orientation) of the fiber and how the structure affects the UTS. This can be used to design efficient processing methods for PMMA fibers.

  9. Chitosan-functionalized poly(methyl methacrylate) particles by spinning disk processing for lipase immobilization.

    PubMed

    Jenjob, Somkieath; Sunintaboon, Panya; Inprakhon, Pranee; Anantachoke, Natthinee; Reutrakul, Vichai

    2012-07-01

    Chitosan-functionalized poly(methyl methacrylate) (PMMA-CH) particles were prepared by complexation between the negatively charged PMMA particles and the positively charged chitosan via a spinning disk processing. Processing parameters; feed rate and spinning speed, were optimized, which were traced by size distribution profiles of the formed PMMA-CH particles. Their sizes and net surface charges were found to be affected by MWs of chitosan (45, 100, and 230 kDa) used. Microscopic evidences were used to confirm their core-shell morphology. Chemical characteristics and thermal stability of such particles were determined by FTIR and TGA, respectively. Then, their ability to immobilize lipase (EC 3.1.1.3) was conducted and followed through zeta potential measurement. The percentage of lipase adsorption capacity increased with increasing lipase content, but the value decreased when the size of PMMA-CH particles increased. Also, the activity of lipase attached on PMMA-CH particles' surface was preserved and increased with lipase loading.

  10. Preparation, characterization, and oral delivery of insulin loaded carboxylated chitosan grafted poly(methyl methacrylate) nanoparticles.

    PubMed

    Cui, Fuying; Qian, Feng; Zhao, Ziming; Yin, Lichen; Tang, Cui; Yin, Chunhua

    2009-05-11

    To improve the efficiency of insulin via oral administration, pH-sensitive carboxylated chitosan grafted poly(methyl methacrylate) nanoparticles (CCGN) were prepared. CCGN were characterized by (1)H NMR, dynamic light scattering, zeta potential, and transmission electron microscopy, and the hypoglycemic effect of insulin loaded CCGN via the oral route was evaluated in normal and diabetic rats. CCGN exhibited a homogeneous morphology and a spherical shape with core-shell structure. They were aggregated in simulated gastric fluid while separated in simulated intestinal fluid. Insulin was mainly located in the shell of the CCGN via hydrogen bonding, electrostatic interaction, and Van der Waals force. Insulin release from the CCGN exhibited a pH-sensitive property in that it had a slow release rate at pH 2.0 and a fast release rate at pH 6.8 and 7.4. The pharmacological bioavailability after oral administration of insulin loaded CCGN at a dose of 25 IU/kg was found to be 9.7%. Besides, CCGN showed desirable tissue and blood compatibility. Therefore, the CCGN would be a promising delivery carrier for protein drugs via the oral route.

  11. Hot-Press Molded Poly(Methyl Methacrylate) Matrix for Solid-State Dye Lasers

    NASA Astrophysics Data System (ADS)

    Yee, Kwong-Cheong; Tou, Teck-Yong; Ng, Seik-Weng

    1998-09-01

    A hot-press molding method was used to fabricate dye-doped poly(methyl methacrylate) (PMMA) slabs. Three rhodamine dyes, Rh640 (ClO 4 ), Rh6G(ClO 4 ), and Rh6G (Cl), were impregnated into the PMMA matrix first by dissolving the dye and granular PMMA in a solvent mixture of chloroform and methanol and then heating the mixture in vacuo at 175 C to obtain a spongy preform. The powdered preform was molded into slabs at 175 C and at 1 mbar, to eliminate the formation of bubbles in the slabs. We annealed the slabs for several hours to improve its optical homogeneity and hence its lasing efficiency. When pumped by a 1.5-mJ nitrogen laser, we obtained peak lasing efficiencies of 8% and 7.8%, respectively, for Rh6G (ClO 4 ) and Rh640 (ClO 4 ) in PMMA matrices. The lasing efficiency of Rh6G (ClO 4 )-doped PMMA suffered a reduction rate of 0.012% shot compared with 0.15% shot for Rh640 (ClO 4 )-doped PMMA. In contrast, Rh6G (Cl) in a hot-press molded PMMA slab suffered thermal bleaching that resulted in a low lasing efficiency of 1%; this can be explained by its absorption and fluorescence characteristics.

  12. Hydrogen peroxide filled poly(methyl methacrylate) microcapsules: potential oxygen delivery materials.

    PubMed

    Mallepally, Rajendar R; Parrish, Chance C; Mc Hugh, Mark A M; Ward, Kevin R

    2014-11-20

    This paper describes the synthesis of H₂O₂-H₂O filled poly(methyl methacrylate) (PMMA) microcapsules as potential candidates for controlled O₂ delivery. The microcapsules are prepared by a water-in-oil solvent emulsion and evaporation method. The results of this study describe the effect of process parameters on the characteristics of the microcapsules and on their in vitro performance. The size of the microcapsules, as determined from scanning electron microscopy, ranges from ∼5 to 30 μm and the size distribution is narrow. The microcapsules exhibit an internal morphology with entrapped H₂O₂-H₂O droplets randomly distributed in the PMMA continuous phase. In vitro release studies of 4.5 wt% H₂O₂-loaded microcapsules show that ∼70% of the H₂O₂ releases in 24h. This corresponds to a total O₂ production of ∼12 cc/gram of dry microcapsules. Shelf-life studies show that the microcapsules retain ∼84 wt% of the initially loaded H₂O₂ after nine months storage at 2-8 °C, which is an attractive feature for clinical applications.

  13. Biomolecular functionalization for enhanced cell–material interactions of poly(methyl methacrylate) surfaces

    PubMed Central

    Punet, Xavier; Mauchauffé, Rodolphe; Rodríguez-Cabello, José C.; Alonso, Matilde; Engel, Elisabeth; Mateos-Timoneda, Miguel A.

    2015-01-01

    The integration of implants or medical devices into the body tissues requires of good cell–material interactions. However, most polymeric materials used for these applications lack on biological cues, which enhanced mid- and long-term implant failure due to weak integration with the surrounding tissue. Commonly used strategies for tissue–material integration focus on functionalization of the material surface by means of natural proteins or short peptides. However, the use of these biomolecules involves major drawbacks such as immunogenic problems and oversimplification of the constructs. Here, designed elastin-like recombinamers (ELRs) are used to enhance poly(methyl methacrylate) surface properties and compared against the use of short peptides. In this study, cell response has been analysed for different functionalization conditions in the presence and absence of a competing protein, which interferes on surface–cell interaction by unspecific adsorption on the interface. The study has shown that ELRs can induce higher rates of cell attachment and stronger cell anchorages than short peptides, being a better choice for surface functionalization. PMID:26816640

  14. Responses of Vascular Endothelial Cells to Photoembossed Topographies on Poly(Methyl Methacrylate) Films

    PubMed Central

    Qiu, Lin; Hughes-Brittain, Nanayaa F.; Bastiaansen, Cees W. M.; Peijs, Ton; Wang, Wen

    2016-01-01

    Failures of vascular grafts are normally caused by the lack of a durable and adherent endothelium covering the graft which leads to thrombus and neointima formation. A promising approach to overcome these issues is to create a functional, quiescent monolayer of endothelial cells on the surface of implants. The present study reports for the first time on the use of photoembossing as a technique to create polymer films with different topographical features for improved cell interaction in biomedical applications. For this, a photopolymer is created by mixing poly(methyl methacrylate) (PMMA) and trimethylolpropane ethoxylate triacrylate (TPETA) at a 1:1 ratio. This photopolymer demonstrated an improvement in biocompatibility over PMMA which is already known to be biocompatible and has been extensively used in the biomedical field. Additionally, photoembossed films showed significantly improved cell attachment and proliferation compared to their non-embossed counterparts. Surface texturing consisted of grooves of different pitches (6, 10, and 20 µm) and heights (1 µm and 2.5 µm). The 20 µm pitch photoembossed films significantly accelerated cell migration in a wound-healing assay, while films with a 6 µm pitch inhibited cells from detaching. Additionally, the relief structure obtained by photoembossing also changed the surface wettability of the substrates. Photoembossed PMMA-TPETA systems benefited from this change as it improved their water contact angle to around 70°, making it well suited for cell adhesion. PMID:27941669

  15. Absorption behavior of poly(methyl methacrylate)-multiwalled carbon nanotube composites: effects of UV irradiation.

    PubMed

    Hsu, Je-Chuan; Cao, Wenxin; Yang, Fuqian; Yang, Tsong-Jen; Lee, Sanboh

    2017-03-08

    Understanding the effects of carbon nanotubes (CNTs) and ultraviolet (UV) irradiation on solvent transport in polymers is of practical importance for the applications of polymer-CNT composites in electronics and photonics. The transport behavior of methanol in poly(methyl methacrylate)-multiwalled carbon nanotube (PMMA-MWCNT) composites with and without UV light irradiation has been studied. The anomalous transport has been investigated as a function of the weight percentage of MWCNTs and UV dose in the temperature range of 30-50 °C. The anomalous transport consists of Case I (controlled by concentration gradient) and Case II (controlled by stress relaxation) transport; both UV irradiation and the addition of MWCNTs in PMMA enhance the transport of methanol. The activation energies for Case I and Case II transport decrease with the increase of UV dose for the PMMA-MWCNT plates with the same weight percentage of MWCNTs. Without UV irradiation, the activation energy for Case I transport of methanol decreases with the increase of the weight percentage of MWCNTs, and the activation energy for Case II transport increases with the increase of the weight percentage of MWCNTs.

  16. Dielectric properties and fluctuating relaxation processes of poly(methyl methacrylate) based polymeric nanocomposite electrolytes

    NASA Astrophysics Data System (ADS)

    Sengwa, R. J.; Choudhary, Shobhna

    2014-06-01

    Solid polymer nanocomposite electrolytes (SPNEs) consisted of poly(methyl methacrylate) (PMMA) and lithium perchlorate (LiClO4) of molar ratio C=O:Li+=4:1 with varying concentration of montmorillonite (MMT) clay as nanofiller have been prepared by classical solution casting and high intensity ultrasonic assisted solution casting methods. The dielectric/electrical dispersion behaviour of these electrolytes was studied by dielectric relaxation spectroscopy at ambient temperature. The dielectric loss tangent and electric modulus spectra have been analyzed for relaxation processes corresponding to the side groups rotation and the segmental motion of PMMA chain, which confirm their fluctuating behaviour with the sample preparation methods and also with change of MMT concentration. The feasibility of these relaxation fluctuations has been explained using a transient complex structural model based on Lewis acid-base interactions. The low permittivity and moderate dc ionic conductivity at ambient temperature suggest the suitability of these electrolytes in fabrication of ion conducting electrochromic devices and lithium ion batteries. The amorphous behaviour and the exfoliated/intercalated MMT structures of these nanocomposite electrolytes were confirmed by X-ray diffraction measurements.

  17. Segmental and local dynamics of stacked thin films of poly(methyl methacrylate)

    NASA Astrophysics Data System (ADS)

    Hayashi, Tatsuhiko; Fukao, Koji

    2014-02-01

    The glass transition temperature and the dynamics of the α and β processes have been investigated using differential scanning calorimetry and dielectric relaxation spectroscopy during successive annealing processes above the glass transition temperature for stacked thin films of poly(methyl methacrylate) (PMMA) of various thicknesses. The glass transition temperature and the dynamics of the α process (segmental motion) of as-stacked PMMA thin films exhibit thin-film-like behavior, insofar as the glass transition temperature is depressed and the dynamics of the α process are faster than those of the bulk system. Annealing at high temperature causes the glass transition temperature to increase from the reduced value and causes the dynamics of the α process to become slower approaching those of the bulk. Contrary to the segmental motion, the relaxation time of the β process (local motion) of the stacked PMMA thin films is almost equal to that of the bulk PMMA and is unaffected by the annealing process. However, the relaxation strengths of both the α process and β process show a strong correlation between each other. The sum of the relaxation strengths remains almost unchanged, while the individual relaxation strengths change during the annealing process. The fragility index of the stacked PMMA thin films increases with annealing, which suggests that the glassy state of the stacked thin films changes from strong to fragile.

  18. Bioactivity and architecture of Candida albicans biofilms developed on poly(methyl methacrylate) resin surface.

    PubMed

    da Silva, Wander José; Seneviratne, Jayampath; Samaranayake, Lakshman Perera; Del Bel Cury, Altair Antoninha

    2010-07-01

    The aim of this study was to evaluate the bioactivity and architecture of Candida albicans biofilms developed on the surface of poly(methyl methacrylate) (PMMA) resin. To do this, surface roughness (SR) and surface free energy of PMMA specimens were measured. Next, the biofilms of two different C. albicans strains (ATCC 90028 and SC5314) were allowed to develop on the PMMA surface and evaluated at 24, 48, and 72 h after adhesion. The bioactivity of the biofilms was measured by the XTT reduction assay. Biofilm topography was evaluated by scanning electron microscopy. Confocal microscopy was used to evaluate the architectural properties of bio-volume, average thickness, biofilm roughness, surface area/volume ratio and the proportion of live/dead cells in the different biofilm development stages. SR and SFE had no influence on biofilm development. Each strain exhibited a different biofilm activity (P < 0.001). Confocal images showed different architectures for the different biofilm development stages. We conclude that the main differences detected in biofilm bioactivity and architecture were related to the characteristics of each C. albicans strain and to biofilm development time.

  19. Blend miscibility of cellulose propionate with poly(N-vinyl pyrrolidone-co-methyl methacrylate).

    PubMed

    Sugimura, Kazuki; Teramoto, Yoshikuni; Nishio, Yoshiyuki

    2013-10-15

    The blend miscibility of cellulose propionate (CP) with poly(N-vinyl pyrrolidone-co-methyl methacrylate) (P(VP-co-MMA)) was investigated. The degree of substitution (DS) of CP used ranged from 1.6 to >2.9, and samples for the vinyl polymer component were prepared in a full range of VP:MMA compositions. Through DSC analysis and solid-state (13)C NMR and FT-IR measurements, we revealed that CPs of DS<2.7 were miscible with P(VP-co-MMA)s of VP≥~10mol% on a scale within a few nanometers, in virtue of hydrogen-bonding interactions between CP-hydroxyls and VP-carbonyls. When the DS of CP exceeded 2.7, the miscibility was restricted to the polymer pairs using P(VP-co-MMA)s of VP=ca. 10-40 mol%; the scale of mixing in the blends concerned was somewhat larger (ca. 5-20 nm), however. The appearance of such a "miscibility window" was interpretable as an effect of intramolecular repulsion in the copolymer component. Results of DMA and birefringence measurements indicated that the miscible blending of CP with the vinyl polymer invited synergistic improvements in thermomechanical and optical properties of the respective constituent polymers. Additionally, it was found that the VP:MMA composition range corresponding to the miscibility window was expanded by modification of the CP component into cellulose acetate propionate.

  20. Metal-Free Atom Transfer Radical Polymerization of Methyl Methacrylate with ppm Level of Organic Photocatalyst.

    PubMed

    Huang, Zhicheng; Gu, Yu; Liu, Xiaodong; Zhang, Lifen; Cheng, Zhenping; Zhu, Xiulin

    2016-10-28

    It is well known that the recently developed photoinduced metal-free atom transfer radical polymerization (ATRP) has been considered as a promising methodology to completely eliminate transition metal residue in polymers. However, a serious problem needs to be improved, namely, large amount of organic photocatalysts should be used to keep the controllability over molecular weights and molecular weight distributions. In this work, a novel photocatalyst 1,2,3,5-tetrakis(carbazol-9-yl)-4,6-dicyanobenzene (4CzIPN) with strong excited state reduction potential is successfully used to mediate a metal-free ATRP of methyl methacrylate just with parts per million (ppm) level usage under irradiation of blue light emitting diode at room temperature, using ethyl α-bromophenyl-acetate as a typical initiator with high initiator efficiency. The polymerization kinetic study, multiple controlled "on-off" light switching cycle regulation, and chain extension experiment confirm the "living"/controlled features of this promising photoinduced metal-free ATRP system with good molecular weight control in the presence of ppm level photocatalyst 4CzIPN.

  1. Control of methyl methacrylate during the preparation of orthopedic bone cements.

    PubMed

    Ungers, Leslie J; Vendrely, Timothy G; Barnes, C Lowry

    2007-04-01

    The use of methyl methacrylate (MMA) bone cement during orthopedic procedures has been seen as a potential exposure hazard to health care professionals. However, that assessment is based on a number of investigations with problems in experimental design, analysis, and data interpretation. The current investigation quantified differences in MMA vapors produced during the preparation of competing bone cements using various methods of preparation. Unlike previous investigations, this effort employs modern validated sampling and analytical methods, and considers the affect of censored results. Measurements of sufficient quality and number were collected to allow for a statistical treatment of the data. The ability of two controlled preparation techniques to reduce MMA emissions were compared with a traditional open container. The results confirmed that the preparation of bone cement releases MMA vapors into the breathing zone of the preparer. One preparation technique (Stryker Bowl) controlled emissions during mixing and curing and affected a 73% reduction in measured MMA concentrations. In addition to mixing and curing, the second technique (UltraMix System) also controlled the MMA during pouring of the monomer and affected a 90% reduction in MMA concentrations. An ANOVA test of interaction indicates that the reductions are attributable to the preparation technique regardless of the type of cement being used. Both a Fisher's PLSD and Games/Howell post hoc test of the results indicate that the mean differences between the uncontrolled open container and the controlled preparation techniques are significant (p < 0.05).

  2. Facile control of surface wettability in TiO2/poly(methyl methacrylate) composite films.

    PubMed

    Yang, Mengjin; Di, Zengfeng; Lee, Jung-Kun

    2012-02-15

    A facile method to produce very hydrophobic surface was developed simply using the mixture of TiO(2) nanoparticles and poly(methyl methacrylate) (PMMA). When the volume ratio of TiO(2) to PMMA is between 35 vol.% and 50 vol.%, the mixture of two hydrophilic materials became very hydrophobic. Analysis of the molecular structure by infrared spectroscopy shows that the preferential orientation and attachment of a carbonyl group of a polymer molecule to the surface of TiO(2) nanoparticles play a critical role in the appearance of the strong hydrophobicity. When this composite was exposed to UV light, PMMA on the surface of the mixture film was decomposed through a photocatalytic reaction and the very hydrophobic surface turned to the superhydrophilic one. The superhydrophilic property of UV-irradiated composite lasts as long as several months. This long lasting superhydrophilicity is ascribed to the porous structure, which provides high roughness and strong capillary interaction. Easy transition from strong hydrophobicity to superhydrophilicity in TiO(2)/PMMA composites could be applied to designing high contrast hydrophilic/hydrophobic patterns.

  3. Surface characterization of poly(methyl methacrylate) microgrooved for contact guidance of mammalian cells.

    PubMed

    Alaerts, J A; De Cupere, V M; Moser, S; Van den Bosh de Aguilar, P; Rouxhet, P G

    2001-06-01

    High-resolution patterns of grooves have been made in poly(methyl methacrylate) films, PMMA, by an electron-beam microlithographic process. The surface of films processed over a large width was characterized in terms of chemical composition (X-ray photoelectron spectroscopy (XPS). time of flight secondary ion mass spectroscopy), wettability (sessile drop) and topography (atomic force microscopy). Collagen adsorption was also studied (radiocounting, XPS) as such or in competition with Pluronic F68. The chemical alteration of the surface induced by the electron-beam irradiation disappeared after the dissolution involved in the development process. W138 human fibroblasts cultivated on microgrooved substrata (grooves 1 microm deep and 0.5-10 microm wide) showed a strong orientation parallel to the grooves. The contact guidance is induced by the topography of the surface and not by the alternation of zones with different physico-chemical properties. It may be explained in terms of probability of successful substratum contact by cell protrusions.

  4. Effects of nystatin, fluconazole and propolis on poly(methyl methacrylate) resin surface.

    PubMed

    da Silva, Wander José; Rached, Rodrigo Nunes; Rosalen, Pedro Luis; Del bel Cury, Altair Antoninha

    2008-01-01

    The prevalence of candidosis in denture wearers is as well established as its treatment with antifungal agents (AAs). However, little research has been done regarding the effects of AAs on denture base surfaces. Therefore, the aim of this study was to evaluate the effects of fluconazole (FLU), nystatin (NYS) and propolis orabase gel (PRO) on poly (methyl-methacrylate) (PMMA) surfaces. Deionized water and orabase gel without any active component were used as control groups. Conventional heat-polymerized (Clássico) and microwave-polymerized (Onda Cryl) acrylic resins were used. After polymerization, the specimens were polished and had their surfaces evaluated for roughness, free energy and Knoop hardness. Subsequently, specimens were immersed in AAs and controls for 14 days at 35+/-2 degrees C and all variables were measured again. Data were analyzed statistically by 2-way ANOVA followed by Tukey's test (alpha=0.05). Roughness results showed similar behavior for both PMMA resins, with PRO reaching the highest values and differing significantly from the other AAs (p<0.05). No statistically significant differences (p>0.05) were found between the two PMMA resins or between NYS and FLU as regards surface free energy. In conclusion, PRO was able to induce changes in PMMA surface properties, such as roughness, which could be related to microbial adhesion.

  5. Photochemically patterned poly(methyl methacrylate) surfaces used in the fabrication of microanalytical devices.

    PubMed

    Wei, Suying; Vaidya, Bikas; Patel, Ami B; Soper, Steven A; McCarley, Robin L

    2005-09-08

    We report here the photochemical surface modification of poly(methyl methacrylate), PMMA, microfluidic devices by UV light to yield pendant carboxylic acid surface moieties. Patterns of carboxylic acid sites can be formed from the micrometer to millimeter scale by exposure of PMMA through a contact mask, and the chemical patterns allow for further functionalization of PMMA microdevice surfaces to yield arrays or other structured architectures. Demonstrated here is the relationship between UV exposure time and PMMA surface wettability, topography, surface functional group density, and electroosmotic flow (EOF) of aqueous buffer solutions in microchannels made of PMMA. It is found that the water contact angle on PMMA surfaces decreases from 70 degrees to 24 degrees after exposure to UV light as the result of the formation of carboxylic acid sites. However, upon rinsing with 2-propanol, the water contact angle increases to approximately 80 degrees , and this increase is attributed to changes in surface roughness resulting from removal of low molecular weight PMMA formed from scission events. In addition, the surface roughness and surface coverage of carboxylic acid groups exhibit a characteristic trend with UV exposure time. Electroosmotic flow (EOF) in PMMA microchannels increases upon UV modification and is pH dependent. The possible photolysis mechanism for formation of carboxylic acid groups on PMMA surfaces under the conditions outlined in this work is discussed.

  6. Homogeneously aligned liquid crystal molecules on reformed poly(methyl methacrylate) via ion-beam irradiation

    NASA Astrophysics Data System (ADS)

    Jeong, Hae-Chang; Park, Hong-Gyu; Lee, Ju Hwan; Jang, Sang Bok; Oh, Byeong-Yun; Han, Jeong-Min; Seo, Dae-Shik

    2016-04-01

    We demonstrated uniform LC alignment using IB-irradiated poly(methyl methacrylate) (PMMA) as an alignment layer. We confirmed the topographical changes on PMMA caused by IB irradiation. Moreover, the wettability and chemical modification of the PMMA surface were investigated as functions of incidence angle. The results show that PMMA irradiated with IB at an incidence angle of 30° had a higher molecular polarity than PMMA irradiated with IB at other incidence angles, resulting in strong van der Waals interactions between the surface and LC molecules. The LC cells containing PMMA irradiated with IB at an incidence angle of 30° exhibited good thermal stability (180°) compared with LC cells containing conventional rubbing PI (150°). In addition, LC molecules on PMMA irradiated with IB at an incidence angle of 30° were observed to switch faster than those on conventional rubbing PI. Therefore, PMMA irradiated with IB under the optimal conditions may allow for PMMA to be applied in advanced LC devices as an alternative alignment layer.

  7. Gas-to-liquid permeation in silicon-containing, crosslinked, glassy copolymers of methyl methacrylate.

    PubMed

    Yang, W M; Peppas, N A

    1983-10-01

    Copolymers of methyl methacrylate with disiloxane derivatives have been proposed as biomaterials for contact lens applications. Although glassy, these copolymers exhibit high oxygen permeability and adequate wettability so that they can be used for manufacture of hard, extended wear lenses. Crosslinked copolymers of poly(methylmethacrylate-co-1,3-bis(methacryloxymethyl) -1,1,3,3-tetramethyl-disiloxane), P(MMA-co-BMTDS), containing from 0.085 to 0.53 mole fraction of BMTDS were prepared and tested for oxygen permeation using a novel apparatus which simulates the atmosphere/lens/cornea conditions. The gas-to-liquid dissolved oxygen permeability, P gd1 was determined and it was found to increase with BMTDS content. Permeability values for P(MMA-co-BMTDS) at 34 degrees C were significantly higher than for pure homopolymer PMMA, although these copolymers were glassy at this temperature. The increased oxygen permeation was attributed to increased oxygen solubility in the copolymers due to the presence of the -Si-O-bonds.

  8. Nanopillar formation from two-shot femtosecond laser ablation of poly-methyl methacrylate

    NASA Astrophysics Data System (ADS)

    Baset, F.; Popov, K.; Villafranca, A.; Alshehri, A. M.; Guay, J.-M.; Ramunno, L.; Bhardwaj, V. R.

    2015-12-01

    We present experimental and numerical studies on the morphological evolution and dynamics of femtosecond laser ablation of bulk poly-methyl methacrylate (PMMA) irradiated with a pair of pulses. We show that a nanopillar-like structure is formed in the middle of the ablation crater for pulse energies below single-shot ablation threshold. The nanopillar is ∼400 nm long, lies adjacent to a nanopore, and protrudes ∼150 nm above the sample surface. As the pulse energy is increased gradually, the nanopillar disappears and the nanopore inside the ablation crater becomes larger. At higher pulse energies, a volcanic eruption like structure appears in the middle of the crater whose size and height increases with energy. 2D molecular dynamics simulations reveal that a nanojet and other features observed at higher pulse energies can be formed when the reflection of a shockwave, induced by the second laser pulse, causes density pinching in the middle of the interaction region that rapidly pushes out molten material towards the surface. The shockwave is reflected from the cold boundaries of a modified region created by the first laser pulse.

  9. Fabrication and characterization of carbon nanotube reinforced poly(methyl methacrylate) nanocomposites.

    PubMed

    Yu, Suzhu; Juay, Yang Kang; Young, Ming Shyan

    2008-04-01

    Multiwall carbon nanotube (CNT) reinforced poly(methyl methacrylate) (PMMA) nanocomposites have been successfully fabricated with melt blending. Two melt blending approaches of batch mixing and continuous extrusion have been used and the properties of the derived nanocomposites have been compared. The interaction of PMMA and CNTs, which is crucial to greatly improve the polymer properties, has been physically enhanced by adding a third party of poly(vinylidene fluoride) (PVDF) compatibilizer. It is found that the electrical threshold for both PMMA/CNT and PMMA/PVDF/CNT nanocomposites lies between 0.5 to 1 wt% of CNTs. The thermal and mechanical properties of the nanocomposites increase with CNTs and they are further increased by the addition of PVDF For 5 wt% CNT reinforced PMMA/PVDF/CNT nanocomposite, the onset of decomposition temperature is about 17 degrees C higher and elastic modulus is about 19.5% higher than those of neat PMMA. Rheological study also shows that the CNTs incorporated in the PMMA/PVDF/CNT nanocomposites act as physical cross-linkers.

  10. Dispersion characteristics and properties of poly(methyl methacrylate)/multi-walled carbon nanotubes nanocomposites.

    PubMed

    Vaudreuil, Sébastien; Labzour, Asmae; Sinha-Ray, Suprakas; El Mabrouk, Khalil; Bousmina, Mosto

    2007-07-01

    The preparation, characterization, and properties of poly(methyl methacrylate) (PMMA)/multi-walled carbon nanotubes (MWCNTs) nanocomposites are described. Nanocomposites have been prepared by melt-blending in a batch mixer. Both unmodified and surface modified MWCNTs have been used for the nanocomposites preparation. Using both unmodified and modified MWCNTs, the effect of surface modification in nanocomposites is investigated by focusing on three major aspects: dispersion characteristics, mechanical properties, and electrical conductivity measurements. Dispersion of the MWCNTs in the PMMA matrix is examined by scanning and transmission electron microscopy that revealed a homogeneous distribution-dispersion of MWCNTs in the PMMA matrix for both unmodified and modified MWCNTs. Thermomechanical behavior is studied by dynamic mechanical analyzer and results showed a substantial improvement in the mechanical properties of PMMA in conjunction to an increase in the elastic behavior. The tensile properties of neat PMMA moderately improved after nanocomposites preparation with both modified and unmodified MWCNTs, however, electrical conductivity of neat PMMA significantly improved after nanocomposites preparation with 2 wt% unmodified MWCNTs. For example, the through plane conductivity increased from 3.6 x 10(-12) S x cm(-1) for neat PMMA to 3.6 x 10(-9) S x cm(-1) for nanocomposite. The various property measurements have been conducted and results have shown that, in overall, surface modifications have very little or no effect on final properties of neat PMMA.

  11. Cisplatin-incorporated nanoparticles of poly(acrylic acid-co-methyl methacrylate) copolymer

    PubMed Central

    Lee, Kyung Dong; Jeong, Young-Il; Kim, Da Hye; Lim, Gyun-Taek; Choi, Ki-Choon

    2013-01-01

    Background Although cisplatin is extensively used in the clinical field, its intrinsic toxicity limits its clinical use. We investigated nanoparticle formations of poly(acrylic acid-co-methyl methacrylate) (PAA-MMA) incorporating cisplatin and their antitumor activity in vitro and in vivo. Methods Cisplatin-incorporated nanoparticles were prepared through the ion-complex formation between acrylic acid and cisplatin. The anticancer activity of cisplatin-incorporated nanoparticles was assessed with CT26 colorectal carcinoma cells. Results Cisplatin-incorporated nanoparticles have small particle sizes of less than 200 nm with spherical shapes. Drug content was increased according to the increase of the feeding amount of cisplatin and acrylic acid content in the copolymer. The higher acrylic acid content in the copolymer induced increase of particle size and decrease of zeta potential. Cisplatin-incorporated nanoparticles showed a similar growth-inhibitory effect against CT26 tumor cells in vitro. However, cisplatin-incorporated nanoparticles showed improved antitumor activity against an animal tumor xenograft model. Conclusion We suggest that PAA-MMA nanoparticles incorporating cisplatin are promising carriers for an antitumor drug-delivery system. PMID:23966778

  12. A Sol-Gel-Modified Poly(methyl methacrylate) Electrophoresis Microchip with a Hydrophilic Channel Wall

    SciTech Connect

    Chen, Gang; Xu, Xuejiao; Lin, Yuehe; Wang, Joseph

    2007-07-27

    A sol-gel method was employed to fabricate a poly(methyl methacrylate) (PMMA) electrophoresis microchip that contains a hydrophilic channel wall. To fabricate such a device, tetraethoxysilane (TEOS) was injected into the PMMA channel and was allowed to diffuse into the surface layer for 24 h. After removing the excess TEOS, the channel was filled with an acidic solution for 3 h. Subsequently, the channel was flushed with water and was pretreated in an oven to obtain a sol-gel-modified PMMA microchip. The water contact angle for the sol-gel-modified PMMA was 27.4° compared with 66.3° for the pure PMMA. In addition, the electro-osmotic flow increased from 2.13×10-4 cm2 V-1 s-1 for the native-PMMA channel to 4.86×10-4 cm2 V-1 s-1 for the modified one. The analytical performance of the sol-gel-modified PMMA microchip was demonstrated for the electrophoretic separation of several purines, coupled with amperometric detection. The separation efficiency of uric acid increased to 74 882.3 m-1 compared with 14 730.5 m-1 for native-PMMA microchips. The result of this simple modification is a significant improvement in the performance of PMMA for microchip electrophoresis and microfluidic applications.

  13. Effect of ZnO on the Thermal Degradation Behavior of Poly(Methyl Methacrylate) Nanocomposites.

    PubMed

    Japić, Dajana; Marinšek, Marjan; Crnjak Orel, Zorica

    2016-01-01

    The influence of ZnO nanoparticles on the thermal degradation behavior of poly(methyl methacrylate) (PMMA) was tested using thermoanalytical techniques. The studied materials were investigated using TG, DTA, EGA, XRD, SEM and TEM. The ZnO nanoparticles were synthesized via precipitation by adding LiOH into Zn2+ water/ethylene glycol solutions. The ZnO-PMMA nanocomposites were prepared by adding the appropriate amount of ZnO into MMA and subsequent MMA radical polymerization. According to the experimental results and model-free isoconversional activation energy calculations, the addition of ZnO into PMMA played a double role. The ZnO concentrations up to 0.15% stabilized the composite by shifting the degradation interval toward higher temperatures and increasing the apparent activation energy relative to pure PMMA. At higher concentrations, the catalytic effect of ZnO started to prevail and was reflected in the lower temperature intervals of intense PMMA degradation and lower apparent activation energy. The addition of ZnO generally did not change the nature of the PMMA decomposition process.

  14. Surface dilational moduli of poly (ethylene oxide), poly (methyl methacrylate), and their blend films.

    PubMed

    Kato, Satoaki; Kawaguchi, Masami

    2012-10-15

    Surface dilational moduli of poly (ethylene oxide) (PEO), poly (methyl methacrylate) (PMMA), and compatible PEO/PMMA blend films spread at the air-water interface were investigated as a function of surface concentration. The surface dilational modulus of an expanded PEO film increased as the surface concentration increased to 0.4 mg/m(2), which corresponds to the limiting surface area of PEO. After peaking at this value, the surface dilational modulus decreased with an increase in the PEO concentration. Lissajous orbits of PEO films exhibited positive hysteresis loops for all surface concentration ranges. On the other hand, the surface dilational modulus of a condensed PMMA film steeply increased as the surface concentration increased. Lissajous orbits of PMMA films changed from positive hysteresis loops to negative loops at the surface concentration at which the surface pressure reached in the plateau region. The magnitude of the surface dilational modulus of PMMA was larger than that of PEO at a fixed surface concentration. The surface dilational moduli of the PEO/PMMA blend films increased with the total surface concentration and their magnitudes were less than those of the individual PMMA films and larger than those of the individual PEO films at fixed surface concentrations. Lissajous orbits of the PEO/PMMA blend films also changed from positive hysteresis loops to negative loops beyond the surface concentration at which the plateau surface pressure of PEO was attained.

  15. Transesterification of propylene glycol methyl ether in chromatographic reactors using anion exchange resin as a catalyst.

    PubMed

    Oh, Jungmin; Sreedhar, Balamurali; Donaldson, Megan E; Frank, Timothy C; Schultz, Alfred K; Bommarius, Andreas S; Kawajiri, Yoshiaki

    2016-09-30

    Reactive chromatography using an anion exchange resin is proposed for a transesterification reaction of propylene glycol methyl ether (DOWANOL™ PM) with ethyl acetate to produce propylene glycol methyl ether acetate (DOWANOL™ PMA). This reaction is studied in batch and chromatographic reactors catalyzed by an anion exchange resin. Several anion exchange resins are tested and compared based on the performance of resin as an adsorbent and a catalyst. A chromatographic column is packed with a selected catalyst, AMBERLITE™ IRA904, and both reaction and chromatographic elution are studied at different temperatures and feed concentrations. The resulting chromatograms are fitted to a mathematical model to obtain adsorption equilibrium and reaction kinetic parameters by the inverse method. Compared to esterification investigated in a previous study, transesterification has advantages such as a higher conversion at lower temperature and easy removal of the byproduct which may lead to higher productivity. Deactivation of anion exchange resins is observed and potential solutions are suggested.

  16. Determination of low level methyl tert-butyl ether, ethyl tert-butyl ether and methyl tert-amyl ether in human urine by HS-SPME gas chromatography/mass spectrometry.

    PubMed

    Scibetta, Licia; Campo, Laura; Mercadante, Rosa; Foà, Vito; Fustinoni, Silvia

    2007-01-02

    Methyl tert-butyl ether (MTBE), ethyl tert-butyl ether (ETBE) and tert-amyl methyl ether (TAME) are oxygenated compounds added to gasoline to enhance octane rating and to improve combustion. They may be found as pollutants of living and working environments. In this work a robotized method for the quantification of low level MTBE, ETBE and TAME in human urine was developed and validated. The analytes were sampled in the headspace of urine by SPME in the presence of MTBE-d12 as internal standard. Different fibers were compared for their linearity and extraction efficiency: carboxen/polydimethylsiloxane, polydimethylsiloxane/divinylbenzene, and polydimethylsiloxane. The first, although highly efficient, was discarded due to deviation of linearity for competitive displacement, and the polydimethylsiloxane/divinylbenzene fiber was chosen instead. The analysis was performed by GC/MS operating in the electron impact mode. The method is very specific, with range of linearity 30-4600 ng L(-1), within- and between-run precision, as coefficient of variation, <22 and <16%, accuracy within 20% the theoretical level, and limit of detection of 6 ng L(-1) for all the analytes. The influence of the matrix on the quantification of these ethers was evaluated analysing the specimens of seven traffic policemen exposed to autovehicular emissions: using the calibration curve and the method of standard additions comparable levels of MTBE (68-528 ng L(-1)), ETBE (<6 ng L(-1)), and TAME (<6 ng L(-1)) were obtained.

  17. Metabolism of Diethyl Ether and Cometabolism of Methyl tert-Butyl Ether by a Filamentous Fungus, a Graphium sp

    PubMed Central

    Hardison, L. K.; Curry, S. S.; Ciuffetti, L. M.; Hyman, M. R.

    1997-01-01

    In this study, evidence for two novel metabolic processes catalyzed by a filamentous fungus, Graphium sp. strain ATCC 58400, is presented. First, our results indicate that this Graphium sp. can utilize the widely used solvent diethyl ether (DEE) as the sole source of carbon and energy for growth. The kinetics of biomass accumulation and DEE consumption closely followed each other, and the molar growth yield on DEE was indistinguishable from that with n-butane. n-Butane-grown mycelia also immediately oxidized DEE without the extracellular accumulation of organic oxidation products. This suggests a common pathway for the oxidation of both compounds. Acetylene, ethylene, and other unsaturated gaseous hydrocarbons completely inhibited the growth of this Graphium sp. on DEE and DEE oxidation by n-butane-grown mycelia. Second, our results indicate that gaseous n-alkane-grown Graphium mycelia can cometabolically degrade the gasoline oxygenate methyl tert-butyl ether (MTBE). The degradation of MTBE was also completely inhibited by acetylene, ethylene, and other unsaturated hydrocarbons and was strongly influenced by n-butane. Two products of MTBE degradation, tert-butyl formate (TBF) and tert-butyl alcohol (TBA), were detected. The kinetics of product formation suggest that TBF production temporally precedes TBA accumulation and that TBF is hydrolyzed both biotically and abiotically to yield TBA. Extracellular accumulation of TBA accounted for only a maximum of 25% of the total MTBE consumed. Our results suggest that both DEE oxidation and MTBE oxidation are initiated by cytochrome P-450-catalyzed reactions which lead to scission of the ether bonds in these compounds. Our findings also suggest a potential role for gaseous n-alkane-oxidizing fungi in the remediation of MTBE contamination. PMID:16535667

  18. Methyl tert-butyl ether and tert-butyl alcohol degradation by Fusarium solani.

    PubMed

    Magaña-Reyes, Miguel; Morales, Marcia; Revah, Sergio

    2005-11-01

    Fusarium solani degraded methyl tert-butyl ether (MTBE) and other oxygenated compounds from gasoline including tert-butyl alcohol (TBA). The maximum degradation rate of MTBE was 16 mg protein h and 46 mg/g protein h for TBA. The culture transformed 77% of the total carbon to 14CO2. The estimated yield for MTBE was 0.18 g dry wt/g MTBE.

  19. Geissoschizine methyl ether N-oxide, a new alkaloid with antiacetylcholinesterase activity from Uncaria rhynchophylla.

    PubMed

    Jiang, Wei-Wei; Su, Jia; Wu, Xing-De; He, Juan; Peng, Li-Yan; Cheng, Xiao; Zhao, Qin-Shi

    2015-01-01

    Geissoschizine methyl ether N-oxide, a new oxindole alkaloid, along with 14 known alkaloids, was isolated from the aerial part of Uncaria rhynchophylla. Their structures were identified by comprehensive spectral methods, including 2D NMR experiments, and confirmed by comparing with the literature data. In vitro acetylcholinesterase (AChE) inhibitory activity assay showed that the new compound exhibited anti-AChE activity with IC₅₀ value of 23.4 μM.

  20. Methyl t-Butyl Ether Mineralization in Surface-Water Sediment Microcosms under Denitrifying Conditions

    USGS Publications Warehouse

    Bradley, P.M.; Chapelle, F.H.; Landmeyer, J.E.

    2001-01-01

    Mineralization of [U-14C] methyl t-butyl ether (MTBE) to 14CO2 without accumulation of t-butyl alcohol (TBA) was observed in surface-water sediment microcosms under denitrifying conditions. Methanogenic activity and limited transformation of MTBE to TBA were observed in the absence of denitrification. Results indicate that bed sediment microorganisms can effectively degrade MTBE to nontoxic products under denitrifying conditions.

  1. Asbestos-Induced Epithelial Changes in Organ Cultures of Hamster Trachea: Inhibition by Retinyl Methyl Ether

    NASA Astrophysics Data System (ADS)

    Mossman, B. T.; Craighead, J. E.; MacPherson, B. V.

    1980-01-01

    The epithelium of the hamster trachea in organ culture undergoes hyperplasia and squamous metaplasia after exposure to the amphibole types of asbestos, crocidolite and amosite. These changes are inhibited when the synthetic vitamin A analog, retinyl methyl ether, is incorporated into the culture medium. These findings suggest a possible use for retinoids in the prevention and treatment of respiratory tract disease associated with environmental exposure to asbestos.

  2. Relationship between water structure and properties of poly(methyl methacrylate-b-2-hydroxyethyl methacrylate) by solid-state NMR.

    PubMed

    Mochizuki, Akira; Miwa, Yuko; Miyoshi, Riko; Namiki, Takahiro

    2017-03-22

    We previously reported that the platelet compatibility of methyl methacrylate (MMA)-2-hydroxyethyl methacrylate (HEMA) diblock copolymers is related to the characteristic water structure in the copolymer, as the copolymer has an excess amount of nonfreezing water when compared with that estimated from the amounts of water in HEMA and MMA homopolymers. Thus, in this study, the relationship between water structure and polymer structure, including the heterogeneity and mobility of the copolymer, was investigated using differential scanning calorimetry (DSC) and nuclear magnetic resonance (NMR) spectroscopy. The prepared copolymers were classified into two groups: copolymers with a short, constant polyMMA segment length (Mn = ~2900) and copolymers with a constant polyHEMA segment length (Mn = ~9500), whereas the lengths of the counter segments varied. DSC analysis showed that when the polyMMA and polyHEMA segment lengths are similar, the amount of nonfreezing water increases, regardless of the total molecular weight of the copolymer. NMR analysis showed that heterogeneity of the copolymer is enhanced and the mobility of the copolymer decreases when the segment lengths are similar. These findings suggested that the excess amount of nonfreezing water is formed when the properties of water near the HEMA unit change from freezing to nonfreezing owing to interactions with the MMA unit. In addition, it is suggested that the heterogeneity of the copolymer structure or the mobility of the polymer are involved in the generation of excess nonfreezing water.

  3. Effect of mouse VEGF164 on the viability of hydroxyethyl methacrylate-methyl methacrylate-microencapsulated cells in vivo: bioluminescence imaging.

    PubMed

    Cheng, Dangxiao; Lo, Chuen; Sefton, Michael V

    2008-11-01

    Bioluminescent imaging was used to track the viability of luciferase transfected L929 cells in poly(hydroxyethyl methacrylate-co-methyl methacrylate) (HEMA-MMA) microcapsules. Bioluminescence, as determined by Xenogen imaging after addition of luciferin to microcapsules in vitro, increased with time, consistent with an increase in cell number. Capsules were suspended in Matrigel and injected subcutaneously. The bioluminesence in vivo increased over the first 3 weeks and then decreased, both with and without the delivery of mVEGF(164) (1.2 ng/24 h/200 microcapsules in vitro); VEGF delivery was from microencapsulated doubly transfected cells (both luciferase and mVEGF(164)). VEGF delivery was sufficient to generate a greater number of vascular structures, but this did not result in the expected increase in microencapsulated cell viability. Interestingly, the number of vessels at day 28 was less than at day 21, consistent with what would be an expected reduction in VEGF secretion when cell viability is lost. The results presented here do not support the hypothesis that transfection of microencapsulated cells with VEGF is sufficient to correct the oxygen transport limitation, at least with this type of tissue engineering construct. On the other hand, bioluminescent imaging proved to be a useful method of monitoring microencapsulated cell viability over many weeks in vivo.

  4. Surface segregation of fluorinated moieties on poly(methyl methacrylate-ran-2-perfluorooctylethyl methacrylate) films during film formation: Entropic or enthalpic influences.

    PubMed

    Ye, Xiuyun; Zuo, Biao; Deng, Mao; Hei, Yanlin; Ni, Huagang; Lu, Xiaolin; Wang, Xinping

    2010-09-01

    The effects of solvents, fluorinated monomer content and film-formation methods on the surface structures of random copolymers composed of methyl methacrylate (MMA) and 2-perfluorooctylethyl methacrylate (FMA) were investigated by contact angle goniometry, X-ray photoelectron spectroscopy, sum frequency generation (SFG) vibrational spectroscopy and surface tension measurement. It is found that, with cyclohexanone as the solvent, there is a critical FMA content of 9mol%, below which the copolymer films by spin coating have a more surface segregation extent of fluorinated moieties than those by solution casting; above which the copolymer films by solution casting have a more surface segregation extent of fluorinated moieties than those by spin coating. However, with toluene as solvent, the critical FMA content lowers down to 3mol%. We believe that the solvent nature and the content of fluorinated moieties in the random copolymer have the great effect because the combined effect of these two factors can determine the random copolymer chain conformations and their thermodynamic dominating factors in the solution and at the solution-air interface. A thermodynamic analysis combining the entropic and enthalpic effects is suggested to explain the observed phenomenon. This research is believed to obtain an enhanced understanding of the surface formation mechanism of the polymer films and thus demonstrate how to promote the segregation of fluorinated moieties at the polymer film surfaces.

  5. Photophysical, photochemical and laser behavior of some diolefinic laser dyes in sol-gel and methyl methacrylate/2-hydroxyethyl methacrylate copolymer matrices

    NASA Astrophysics Data System (ADS)

    Sakr, Mahmoud A. S.; Abdel Gawad, El-Sayed A.; Abou Kana, Maram T. H.; Ebeid, El-Zeiny M.

    2015-08-01

    The photophysical properties such as singlet absorption, molar absorptivity, fluorescence spectra, dipole moment, fluorescence quantum yields, fluorescence lifetimes and laser activity of 1,4-bis (β-Pyridyl-2-Vinyl) Benzene (P2VB), 2,5-distyryl-pyrazine (DSP) and 1,4-bis(2-methylstyryl)benzene(MSB) diolefineic laser dyes have been measured in different restricted hosts. (P2VB), (DSP) and (MSB) are embedded in transparent sol-gel glass and a copolymer of methyl methacrylate (MMA) and 2-hydroxyethyl methacrylate (HEMA) media. The absorption and fluorescence properties of these laser dyes in sol-gel glass matrices are compared with their respective properties in copolymer host. The photostability of these laser dyes in sol-gel glass and (MMA/HEMA) copolymer samples are measured in terms of half-life method (using nitrogen laser 337.1 nm in pumping), as the number of pulses necessary to reduce the dye laser intensity to 50% of its original value. The gel laser materials show improved photostability upon pumping by nitrogen laser compared with those in organic polymeric host matrix.

  6. Preparation and characterization of pH-sensitive and antifouling poly(vinylidene fluoride) microfiltration membranes blended with poly(methyl methacrylate-2-hydroxyethyl methacrylate-acrylic acid).

    PubMed

    Ju, Junping; Wang, Chao; Wang, Tingmei; Wang, Qihua

    2014-11-15

    Functional terpolymer of poly(methyl methacrylate-2-hydroxyethyl methacrylate-acrylic acid) (P(MMA-HEMA-AA)) was synthesized via a radical polymerization method. The terpolymer could be directly blended with poly(vinylidene fluoride) (PVDF) to prepare the microfiltration (MF) membranes via phase separate process. The synthesized polymers were characterized by Fourier transform infrared (FTIR), the nuclear magnetic resonance proton spectra ((1)H NMR). The membrane had the typical asymmetric structure and the hydrophilic side chains tended to aggregate on the membrane surface. The surface enrichment of amphiphilic copolymer and morphology of MF membranes were characterized by Fourier transform infrared attenuated total reflection spectroscopy (FTIR-ATR) and scanning electron microscopy (SEM). The contact angle (CA) and water uptake were also tested to assess the hydrophilicity and wetting characteristics of the polymer surface. The water filtration properties were measured. It was found the modified membranes showed excellent pH-sensitivity and pH-reversibility behavior. Furthermore, the hydrophilicity of the blended membranes increased, and the membranes showed good protein antifouling property.

  7. Study of the water structure in poly(methyl methacrylate-block-2-hydroxyethyl methacrylate) and its relationship to platelet adhesion on the copolymer surface.

    PubMed

    Mochizuki, Akira; Namiki, Takahiro; Nishimori, Yusuke; Ogawa, Haruki

    2015-01-01

    The water structure and platelet compatibility of poly(methyl methacrylate (MMA)-block-2-hydroxyethyl methacrylate (HEMA)) were investigated. The molecular weight (Mn) of the polyHEMA segment was kept constant (average: 9600), while the Mn of the polyMMA segment was varied from 1340 to 7390. The equilibrium water content of the copolymers was found to be mainly governed by the HEMA content. The water structure in the copolymers was characterized in terms of the amounts of non-freezing and freezing water (abbreviated as Wnf and Wfz, respectively) using differential scanning calorimetry. It was found that the Wnf for the copolymers were higher than those estimated from the Wnf for the HEMA and MMA homopolymers and that the amount of excess non-freezing water depended on the polyMMA segment length. In addition, X-ray diffraction analysis revealed that some of the copolymers had cold-crystallizable water. These facts suggested that the polyMMA segments were involved in determining the water structures in the copolymers. Furthermore, the platelet compatibility of the copolymers was improved as compared to that of the HEMA homopolymer. It was therefore concluded that the platelet compatibility of the copolymer was related to the amount of excess non-freezing water.

  8. Poly(butyl methacrylate-g-methoxypoly(ethylene glycol)) and poly(methyl methacrylate-g-methoxypoly(ethylene glycol)) graft copolymers: preparation and aqueous solution properties.

    PubMed

    Horgan, Adrian; Saunders, Brian; Vincent, Brian; Heenan, Richard K

    2003-06-15

    A series of water-soluble, amphiphilic graft copolymers has been prepared by free-radical copolymerization of methoxypoly(ethylene glycol) macromonomers, with either methyl methacrylate or butyl methacrylate as the comonomers, in water/ethanol solvent mixtures. Lower molecular weight copolymers were obtained by increasing the concentration of the initiator, azobisisobutyronitrile (AIBN), used in the polymerization reaction. However, the route used also led to the formation of significant quantities of tetramethylsuccinodinitrile, a toxic byproduct resulting from the cage reaction of AIBN. Static fluorescence measurements using pyrene as a probe, along with 1H NMR experiments, showed that the graft copolymers form aggregates in water at very low concentrations (approximately 0.01 g l(-1)) with the pendant hydrophilic graft chains forming a stabilizing shell around the hydrophobic backbone. An increase in the hydrophile-lipophile balance of the graft copolymers was found to lead to smaller aggregates with lower aggregation numbers and highly swollen hydrophilic shells, as revealed by small angle neutron scattering (SANS).

  9. Polystyrene nanoparticles based on poly(butyl methacrylate-g-methoxypoly(ethylene glycol)) and poly(methyl methacrylate-g-methoxypoly(ethylene glycol)) graft copolymers.

    PubMed

    Horgan, Adrian; Vincent, Brian

    2003-06-15

    The solubilization of styrene by poly(butyl methacrylate-g-methoxypoly(ethylene glycol)) and poly(methyl methacrylate-g-methoxypoly(ethylene glycol)) graft copolymers has been examined. From turbidity measurements the solubility limit of the monomer in the micelles was obtained and the distribution coefficients were evaluated. Dynamic light scattering revealed that below the solubility limit, solubilization leads to a slight increase in micelle size, while above the solubility limit, there is a dramatic increase in particle size and turbidity as oil-in-water emulsions are formed through coalescence of monomer-swollen micelles. Polymerizations carried out below the solubility limit using the graft copolymer micelles as templates resembled microemulsion polymerizations in nature and led to very fine sterically stabilized polystyrene latex particles. Through careful control of the monomer concentration and the polymerization temperature it was possible to obtain spherical nanosize latex particles with similar size to those of the micelle precursors (10 nm) up to 11% monomer by weight. Polymerizations above the solubility limit, on the other hand, showed similarities with emulsion polymerizations and resulted in larger particles with higher polydispersity.

  10. Development of microporous drug-releasing films cast from artificial nanosized latexes of poly(styrene-co-methyl methacrylate) or poly(styrene-co-ethyl methacrylate).

    PubMed

    Otto, Daniel P; Vosloo, Hermanus C M; Liebenberg, Wilna; de Villiers, Melgardt M

    2008-08-01

    Two sets of copolymers comprising of styrene and either methyl or ethyl methacrylate as comonomer were conveniently synthesized by microemulsion copolymerization. The purified materials were characterized by GPC-MALLS and were shown to form artificial nanolatexes in THF. ATR-FTIR analysis revealed differences in copolymer composition and based on the copolymer properties, a selection of copolymers was chosen to cast drug-loaded, microporous films that exhibit microencapsulation of drug agglomerates. The contact angles of the copolymers suggested potential applications in medical devices to prevent the formation of bacterial biofilms that commonly result in infections. Additionally, the different copolymeric films showed two phases of drug release characterized by a rapid initial drug release followed by a zero-order phase. Depending on the application, one could select the copolymer films that best suited the application i.e. for short-term drug release applications such as urinary catheters or long-term applications such as artificial implants.

  11. Characterization and electrolytic cleaning of poly(methyl methacrylate) residues on transferred chemical vapor deposited graphene

    NASA Astrophysics Data System (ADS)

    Sun, Jianbo; Finklea, Harry O.; Liu, Yuxin

    2017-03-01

    Poly(methyl methacrylate) (PMMA) residue has long been a critical challenge for practical applications of the transferred chemical vapor deposited (CVD) graphene. Thermal annealing is empirically used for the removal of the PMMA residue; however experiments imply that there are still small amounts of residues left after thermal annealing which are hard to remove with conventional methods. In this paper, the thermal degradation of the PMMA residue upon annealing was studied by Raman spectroscopy. The study reveals that post-annealing residues are generated by the elimination of methoxycarbonyl side chains in PMMA and are believed to be absorbed on graphene via the π–π interaction between the conjugated unsaturated carbon segments and graphene. The post-annealing residues are difficult to remove by further annealing in a non-oxidative atmosphere due to their thermal and chemical stability. An electrolytic cleaning method was shown to be effective in removing these post-annealing residues while preserving the underlying graphene lattice based on Raman spectroscopy and atomic force microscopy studies. Additionally, a solution-gated field effect transistor was used to study the transport properties of the transferred CVD graphene before thermal annealing, after thermal annealing, and after electrolytic cleaning, respectively. The results show that the carrier mobility was significantly improved, and that the p-doping was reduced by removing PMMA residues and post-annealing residues. These studies provide a more in-depth understanding on the thermal annealing process for the removal of the PMMA residues from transferred CVD graphene and a new approach to remove the post-annealing residues, resulting in a residue-free graphene.

  12. Characterization and electrolytic cleaning of poly(methyl methacrylate) residues on transferred chemical vapor deposited graphene.

    PubMed

    Sun, Jianbo; Finklea, Harry O; Liu, Yuxin

    2017-03-24

    Poly(methyl methacrylate) (PMMA) residue has long been a critical challenge for practical applications of the transferred chemical vapor deposited (CVD) graphene. Thermal annealing is empirically used for the removal of the PMMA residue; however experiments imply that there are still small amounts of residues left after thermal annealing which are hard to remove with conventional methods. In this paper, the thermal degradation of the PMMA residue upon annealing was studied by Raman spectroscopy. The study reveals that post-annealing residues are generated by the elimination of methoxycarbonyl side chains in PMMA and are believed to be absorbed on graphene via the π-π interaction between the conjugated unsaturated carbon segments and graphene. The post-annealing residues are difficult to remove by further annealing in a non-oxidative atmosphere due to their thermal and chemical stability. An electrolytic cleaning method was shown to be effective in removing these post-annealing residues while preserving the underlying graphene lattice based on Raman spectroscopy and atomic force microscopy studies. Additionally, a solution-gated field effect transistor was used to study the transport properties of the transferred CVD graphene before thermal annealing, after thermal annealing, and after electrolytic cleaning, respectively. The results show that the carrier mobility was significantly improved, and that the p-doping was reduced by removing PMMA residues and post-annealing residues. These studies provide a more in-depth understanding on the thermal annealing process for the removal of the PMMA residues from transferred CVD graphene and a new approach to remove the post-annealing residues, resulting in a residue-free graphene.

  13. Radiation grafting of methyl methacrylate monomer on natural rubber latex. [Gamma radiation

    SciTech Connect

    Sundardi, F.; Kadariah, S.

    1984-05-01

    A method of radiation grafting of methyl methacrylate (MMA) monomer on natural rubber (NR) latex has been studied. The irradiation dose in radiation emulsion polymerization of MMA monomer was lower compared to the irradiation dose for grafting of MMA monomer on NR latex, in order to obtain the same degree of conversion. This is due to the size of the rubber particles which are quite large and, hence, not sufficient to ensure an ideal emulsion polymerization. The irradiation dose for radiation grafting of MMA monomer on latex was around 300 krad to obtain a 75% degree of conversion. However, this irradiation dose was lower compared to the irradiation dose for bulk polymerization of MMA momomer, in order to obtain the same degree of conversion. This is due to the gel effect in the viscous media. Radiation grafting of MMA monomer on NR latex does not influence the pH of the latex, but influences the viscosity significantly. The viscosity of the NR latex increased with an increase in irradiation dose, due to the increase of the total solid content in the latex. The MMA monomer converted to P-MMA in NR latex was largely grafted on the NR, or at least insoluble in a solvent for P-MMA, such as acetone or toluene. The hardness of the pure gum vulcanizate increased with an increase in the degree of grafting or P-MMA content, but the other physical properties, such as tensile strength, modulus, elongation at break, and thermal stability, were not greatly influenced by the degree of grafting. 9 references, 3 figures, 5 tables.

  14. Water absorption of poly(methyl methacrylate) measured by vertical interference microscopy.

    PubMed

    N'Diaye, Mambaye; Pascaretti-Grizon, Florence; Massin, Philippe; Baslé, Michel Felix; Chappard, Daniel

    2012-08-07

    PMMA (poly(methyl methacrylate)) is widely used to prepare orthopedic cements. They are in direct contact with cells and body fluids. PMMA, despite its hydrophobic nature, can absorb ~2% w/w water. We have evaluated by vertical interference microscopy if water absorption can produce a significant swelling in different types of PMMA blocks: pure, with a plasticizer, with a cross-linker, and in two types of commercial bone cements. Graphite rods which do not swell in water were used as internal standard. Hardness, indentation modulus, plastic, and elastic works were determined by nanoindentation under a 25mN fixed force. Vertical interference microscopy was used to image the polymer in the dry state and hydrated states (after 24 h in distilled water). On the surface of the polished polymers (before and after hydration), we measured roughness by the fractal dimension, the swelling in the vertical and the lateral directions. For each polymer block, four images were obtained and values were averaged. Comparison and standardization of the images in the dry and hydrated states were done with Matlab software. The average value measured on the graphite rod between the two images (dried and hydrated) was used for standardization of the images which were visualized in 3D. After grinding, a small retraction was noticeable between the surface of the rod and the polymers. A retraction ring was also visible around the graphite rod. After hydration, only the pure PMMA and bone cements had a significant swelling in the vertical direction. The presence of polymer beads in the cements limited the swelling in the lateral direction. Swelling parameters correlated with the nanoindentation data. PMMA can swell by absorbing a small amount of water and this induces a swelling that varies with the polymer composition and particle inclusions.

  15. Polymer PCF Bragg grating sensors based on poly(methyl methacrylate) and TOPAS cyclic olefin copolymer

    NASA Astrophysics Data System (ADS)

    Johnson, Ian. P.; Webb, David J.; Kalli, Kyriacos; Yuan, Wu; Stefani, Alessio; Nielsen, Kristian; Rasmussen, Henrik K.; Bang, Ole

    2011-05-01

    Fibre Bragg grating (FBG) sensors have been fabricated in polymer photonic crystal fibre (PCF). Results are presented using two different types of polymer optical fibre (POF); first multimode PCF with a core diameter of 50μm based on poly(methyl methacrylate) (PMMA) and second, endlessly single mode PCF with a core diameter of 6μm based on TOPAS cyclic olefin copolymer. Bragg grating inscription was achieved using a 30mW continuous wave 325nm helium cadmium laser. Both TOPAS and PMMA fibre have a large attenuation of around 1dB/cm in the 1550nm spectral region, limiting fibre lengths to no longer than 10cm. However, both have improved attenuation of under 10dB/m in the 800nm spectral region, thus allowing for fibre lengths to be much longer. The focus of current research is to utilise the increased fibre length, widening the range of sensor applications. The Bragg wavelength shift of a grating fabricated in PMMA fibre at 827nm has been monitored whilst the POF is thermally annealed at 80°C for 7 hours. The large length of POF enables real time monitoring of the grating, which demonstrates a permanent negative Bragg wavelength shift of 24nm during the 7 hours. This creates the possibility to manufacture multiplexed Bragg sensors in POF using a single phase mask in the UV inscription manufacturing. TOPAS holds certain advantages over PMMA including a much lower affinity for water, this should allow for the elimination of cross-sensitivity to humidity when monitoring temperature changes or axial strain, which is a significant concern when using PMMA fibre.

  16. Preclinical pharmacokinetic evaluation of praziquantel loaded in poly (methyl methacrylate) nanoparticle using a HPLC-MS/MS.

    PubMed

    Malhado, Mayara; Pinto, Douglas P; Silva, Aline C A; Silveira, Gabriel P E; Pereira, Heliana M; Santos, Jorge G F; Guilarducci-Ferraz, Carla V V; Viçosa, Alessandra L; Nele, Márcio; Fonseca, Laís B; Pinto, José Carlos C S; Calil-Elias, Sabrina

    2016-01-05

    Praziquantel (PZQ) is the drug recommended by the World Health Organization for treatment of schistosomiasis. However, the treatment of children with PZQ tablets is complicated due to difficulties to adapt the dose and the extremely bitter taste of PZQ. For this reason, poly (methyl methacrylate) nanoparticles loaded with Praziquantel (PZQ-NP) were developed for preparation of a new formulation to be used in the suspension form. For this reason, the main aim of the present study was to evaluate the pharmacokinetic (PK) profile of PZQ-NP, through HPLC-MS/MS assays. Analyses were performed with an Omnisphere C18 column (5.0 μm×4.6 mm×150.0 mm), using a mixture of an aqueous solution containing 0.1 wt% of formic acid and methanol (15:85-v/v) as the mobile phase at a flow rate of 0.800mL/min. Detection was performed with a hybrid linear ion-trap triple quadrupole mass spectrometer with multiple reactions monitoring in positive ion mode via electrospray ionization. The monitored transitions were m/z 313.18>203.10 for PZQ and m/z 285.31>193.00 for the Internal Standard. The method was validated with the quantification limit of 1.00 ng/mL, requiring samples of 25 μL for analyses. Analytic responses were calibrated with known concentration data, leading to correlation coefficients (r) higher than 0.99. Validation performed with rat plasma showed that PZQ was stable for at least 10 months when stored below -70 °C (long-term stability), for at least 17 h when stored at room temperature (RT, 22 °C) (short-term stability), for at least 47 h when stored at room temperature in auto-sampler vials (post-preparative stability) and for at least 8 successive freeze/thaw cycles at -70 °C. For PK assays, Wistar rats, weighing between 200 and 300 g were used. Blood samples were collected from 0 to 24 h after oral administration of single doses of 60 mg/kg of PZQ-NP or raw PZQ (for the control group). PZQ was extracted from plasma by liquid-liquid extraction with terc-butyl methyl

  17. Tacticity Effects on the Local Conformation and Interfacial Properties of poly (methyl methacrylate) at the Liquid-Vapor Interface

    NASA Astrophysics Data System (ADS)

    Jha, Kshitij C.; Zhu, He; Dhinojwala, Ali; Tsige, Mesfin

    2013-03-01

    The orientation of functional groups of poly (methyl methacrylate) (PMMA) play a key role in understanding functionalities like wettability, aggregation and solvent interaction. We have studied the orientation of different functional groups such as the α-methyl, ester methyl, methylene and carbonyl groups of the PMMA chain through all atom Molecular Dynamics (MD) simulations for different chain lengths of the polymer. Through orientational correlation, and number density computations we are able to establish the identity and extent of groups coming to the surface. Surface tensions are computed to validate our PMMA model. Analysis has been carried out for all three tacticities-atactic, syndiotactic, and isotactic. Sum Frequency Generation (SFG) spectroscopy also provides insight into the orientation of various groups at the liquidvapor interface. Characterization of the SFG peaks is the point of some debate and MD simulations aim to aid in the understanding of local ordering.

  18. Metabolism of methyl tert-butyl ether and other gasoline ethers in mouse liver microsomes lacking cytochrome P450 2E1.

    PubMed

    Hong, J Y; Wang, Y Y; Bondoc, F Y; Yang, C S; Gonzalez, F J; Pan, Z; Cokonis, C D; Hu, W Y; Bao, Z

    1999-03-08

    To reduce the production of pollutants in motor vehicle exhaust, methyl tert-butyl ether (MTBE) and other ethers such as ethyl tert-butyl ether (ETBE) and tert-amyl methyl ether (TAME) are added to gasoline as oxygenates for more complete combustion. Metabolism of these gasoline ethers is catalyzed by cytochrome P450 (P450) enzymes. P450 2E1, which metabolizes diethyl ether, was suggested to be an enzyme involved. The present study used 2E1 knock-out mice (2E1-/-) to assess the contribution of 2E1 to the metabolism of MTBE, ETBE and TAME. Liver microsomes prepared from the 2E1 knock-out mice lacked 2E1 activity (assayed as N-nitrosodimethylamine demethylation), but were still active in metabolizing all three gasoline ethers. The levels of ether-metabolizing activity (nmol/min per mg) in the liver microsomes from 7 week old female 2E1 knock-out mice were 0.54+/-0.17 for MTBE, 0.51+/-0.24 for ETBE and 1.14+/-0.25 for TAME at a 1 mM substrate concentration. These activity levels were not significantly different from those of the sex- and age-matched C57BL/6N and 129/Sv mice, which are the parental lineage strains of the 2E1 knock-out mice and are both 2E1+/+. Our results clearly demonstrate that 2E1 plays a negligible role in the metabolism of MTBE, ETBE and TAME in mouse livers.

  19. 40 CFR 721.10556 - Poly(oxy-1,2-ethanediyl), .alpha.- (2-methyl-2-propen-1-yl) -.omega.-hydroxy-,C12-15-alkyl ethers.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ...-methyl-2-propen-1-yl) -.omega.-hydroxy-,C12-15-alkyl ethers. 721.10556 Section 721.10556 Protection of...-ethanediyl), .alpha.- (2-methyl-2-propen-1-yl) -.omega.-hydroxy-,C12-15-alkyl ethers. (a) Chemical substance...-ethanediyl), .alpha.- (2-methyl-2-propen-1-yl) -.omega.-hydroxy-,C12-15-alkyl ethers (PMN P-06-450; CAS...

  20. 40 CFR 721.10558 - Poly(oxy-1,2-ethanediyl), .alpha.- (2-methyl-2-propen-1-yl) -.omega.-hydroxy-,C12-16-alkyl ethers.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ...-methyl-2-propen-1-yl) -.omega.-hydroxy-,C12-16-alkyl ethers. 721.10558 Section 721.10558 Protection of...-ethanediyl), .alpha.- (2-methyl-2-propen-1-yl) -.omega.-hydroxy-,C12-16-alkyl ethers. (a) Chemical substance...-ethanediyl), .alpha.- (2-methyl-2-propen-1-yl) -.omega.-hydroxy-,C12-16-alkyl ethers (PMN P-06-452; CAS...

  1. 40 CFR 721.10558 - Poly(oxy-1,2-ethanediyl), .alpha.- (2-methyl-2-propen-1-yl) -.omega.-hydroxy-,C12-16-alkyl ethers.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ...-methyl-2-propen-1-yl) -.omega.-hydroxy-,C12-16-alkyl ethers. 721.10558 Section 721.10558 Protection of...-ethanediyl), .alpha.- (2-methyl-2-propen-1-yl) -.omega.-hydroxy-,C12-16-alkyl ethers. (a) Chemical substance...-ethanediyl), .alpha.- (2-methyl-2-propen-1-yl) -.omega.-hydroxy-,C12-16-alkyl ethers (PMN P-06-452; CAS...

  2. 40 CFR 721.10556 - Poly(oxy-1,2-ethanediyl), .alpha.- (2-methyl-2-propen-1-yl) -.omega.-hydroxy-,C12-15-alkyl ethers.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ...-methyl-2-propen-1-yl) -.omega.-hydroxy-,C12-15-alkyl ethers. 721.10556 Section 721.10556 Protection of...-ethanediyl), .alpha.- (2-methyl-2-propen-1-yl) -.omega.-hydroxy-,C12-15-alkyl ethers. (a) Chemical substance...-ethanediyl), .alpha.- (2-methyl-2-propen-1-yl) -.omega.-hydroxy-,C12-15-alkyl ethers (PMN P-06-450; CAS...

  3. 40 CFR 721.10557 - Poly(oxy-1,2-ethanediyl), .alpha.- (2-methyl-2-propen-1-yl) -.omega.-hydroxy-,C10-16-alkyl ethers.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ...-methyl-2-propen-1-yl) -.omega.-hydroxy-,C10-16-alkyl ethers. 721.10557 Section 721.10557 Protection of...-ethanediyl), .alpha.- (2-methyl-2-propen-1-yl) -.omega.-hydroxy-,C10-16-alkyl ethers. (a) Chemical substance...-ethanediyl), .alpha.- (2-methyl-2-propen-1-yl) -.omega.-hydroxy-,C10-16-alkyl ethers (PMN P-06-451; CAS...

  4. 40 CFR 721.10557 - Poly(oxy-1,2-ethanediyl), .alpha.- (2-methyl-2-propen-1-yl) -.omega.-hydroxy-,C10-16-alkyl ethers.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ...-methyl-2-propen-1-yl) -.omega.-hydroxy-,C10-16-alkyl ethers. 721.10557 Section 721.10557 Protection of...-ethanediyl), .alpha.- (2-methyl-2-propen-1-yl) -.omega.-hydroxy-,C10-16-alkyl ethers. (a) Chemical substance...-ethanediyl), .alpha.- (2-methyl-2-propen-1-yl) -.omega.-hydroxy-,C10-16-alkyl ethers (PMN P-06-451; CAS...

  5. Synthesis, structural features, and methyl methacrylate polymerisation of binuclear zinc(II) complexes with tetradentate pyrazolyl ligands

    NASA Astrophysics Data System (ADS)

    Kim, Sunghoon; Kim, Dongil; Lee, Ha-Jin; Lee, Hyosun

    2014-04-01

    The reaction of ZnCl2 with ancillary ligands, including 1,4-bis-(N,N-di-(1H-pyrazolyl-1-methyl)amine)benzene (L1) and 4,4‧-bis-(N,N-di(1H-pyrazolyl-1-methyl)phenyl)methane (L2), in ethanol yields Zn(II) chloride complexes, i.e., 1,4-bis-(N,N-di-(1H-pyrazolyl-1-methyl)amine)benzene(dichloro)Zn(II) [L1Zn2Cl4] and 4,4‧-bis-(N,N-di-(1H-pyrazolyl-1-methyl)phenyl)methane(dichloro)Zn(II) [L2Zn2Cl4]. The X-ray crystal structures of Zn(II) complexes revealed that they are binuclear, and each zinc atom has a distorted tetrahedral geometry which involves a nitrogen atom from two pyrazole groups and two chloro ligands. The catalytic activity of [L1Zn2Cl4] and [L2Zn2Cl4] for the polymerisation of methyl methacrylate (MMA) in the presence of modified methylaluminoxane (MMAO) increased by twofold compared to the corresponding monomeric Zn(II) complex, N,N-bis(1H-pyrazolyl-1-methyl)aniline(dichloro)Zn(II) [LZnCl2], at 60 °C.

  6. Identification of covalent binding sites of ethyl 2-cyanoacrylate, methyl methacrylate and 2-hydroxyethyl methacrylate in human hemoglobin using LC/MS/MS techniques.

    PubMed

    Jeppsson, Marina C; Mörtstedt, Harriet; Ferrari, Giovanni; Jönsson, Bo A G; Lindh, Christian H

    2010-10-01

    Acrylates are used in vast quantities, for instance in paints, adhesive glues, molding. They are potent contact allergens and known to cause respiratory hypersensitivity and asthma. Here we study ethyl 2-cyanoacrylate (ECA), methyl methacrylate (MMA) and 2-hydroxyethyl methacrylate (HEMA). There are only limited possibilities to measure the exposure to acrylates, especially for biological monitoring. The aim of the present study was to investigate the chemical structures of adducts formed after reaction of hemoglobin (Hb) with ECA, MMA, and HEMA. This information may be used to identify adducted Hb peptides for biological monitoring of exposure to acrylates. Hb-conjugates with ECA, MMA, and HEMA were synthesized in vitro. The conjugates were digested by trypsin and pronase E. Adducted peptides were characterized and analyzed by liquid chromatography and nano electro spray/hybrid quadrupole time-of-flight mass spectrometry (MS) as well as tandem quadrupole MS. The search for the adducted peptides was facilitated by visualizing the MS data by different computer programs. The results showed that ECA binds covalently to cysteines at the 104 position in the α and the position 112 in the β-chains in Hb. MMA and HEMA bound to all the cysteines in both chains, Cys(104) in the α-chain and Cys(93) and 112 in the β-chain. The full-length spectra of in un-digested Hb confirmed this binding pattern. There was no reaction with N-acetyl-L-lysine at physiological pH. The adducted peptides were possible to measure using LC/MS/MS in selected reaction monitoring mode. These peptides may be used for biological monitoring of exposure to ECA, MMA and HEMA.

  7. Simple, green, and clean removal of a poly(methyl methacrylate) film on chemical vapor deposited graphene

    NASA Astrophysics Data System (ADS)

    Park, J.-H.; Jung, W.; Cho, D.; Seo, J.-T.; Moon, Y.; Woo, S. H.; Lee, C.; Park, C.-Y.; Ahn, J. R.

    2013-10-01

    The clean removal of a poly(methyl methacrylate) (PMMA) film on graphene has been an essential part of the process of transferring chemical vapor deposited graphene to a specific substrate, influencing the quality of the transferred graphene. Here we demonstrate that the clean removal of PMMA can be achieved by a single heat-treatment process without the chemical treatment that was adopted in other methods of PMMA removal. The cleanness of the transferred graphene was confirmed by four-point probe measurements, synchrotron radiation x-ray photoemission spectroscopy, optical images, and Raman spectroscopy.

  8. Molecular structure of poly(methyl methacrylate) surface II: Effect of stereoregularity examined through all-atom molecular dynamics.

    PubMed

    Jha, Kshitij C; Zhu, He; Dhinojwala, Ali; Tsige, Mesfin

    2014-11-04

    Utilizing all-atom molecular dynamics (MD), we have analyzed the effect of tacticity and temperature on the surface structure of poly(methyl methacrylate) (PMMA) at the polymer-vacuum interface. We quantify these effects primarily through orientation, measured as the tilt with respect to the surface normal, and the surface number densities of the α-methyl, ester-methyl, carbonyl, and backbone methylene groups. Molecular structure on the surface is a complex interplay between orientation and number densities and is challenging to capture through sum frequency generation (SFG) spectroscopy alone. Independent quantification of the number density and orientation of chemical groups through all-atom MD presents a comprehensive model of stereoregular PMMA on the surface. SFG analysis presented in part I of this joint publication measures the orientation of molecules that are in agreement with MD results. We observe the ester-methyl groups as preferentially oriented, irrespective of tacticity, followed by the α-methyl and carbonyl groups. SFG spectroscopy also points to ester-methyl being dominant on the surface. The backbone methylene groups show a very broad angular distribution, centered along the surface plane. The surface number density ratios of ester-methyl to α-methyl groups show syndiotactic PMMA having the lowest value. Isotactic PMMA has the highest ratios of ester- to α-methyl. These subtle trends in the relative angular orientation and number densities that influence the variation of surface structure with tacticity are highlighted in this article. A more planar conformation of the syndiotactic PMMA along the surface (x-y plane) can be visualized through the trajectories from all-atom MD. Results from conformation tensor calculations for chains with any of their segments contributing to the surface validate the visual observation.

  9. Investigation of dairy cattle ease of movement on new methyl methacrylate resin aggregate floorings.

    PubMed

    Franco-Gendron, N; Bergeron, R; Curilla, W; Conte, S; DeVries, T; Vasseur, E

    2016-10-01

    Freestall dairy farms commonly present issues with cattle slips and falls caused by smooth flooring and manure slurry. This study examined the effect of 4 new methyl methacrylate (MMA) resin aggregate flooring types (1-4) compared with rubber (positive) and concrete (negative control) on dairy cow (n=18) ease of movement when walking on straight and right-angled corridors. Our hypothesis was that cow ease of movement when walking on the MMA surfaces would be better than when walking on traction milled concrete, and at least as good as when walking on rubber. Cattle ease of movement was measured using kinematics, accelerometers, and visual observation of gait and associated behaviors. Stride length, swing time, stance time, and hoof height were obtained from kinematic evaluation. Acceleration and asymmetry of variance were measured with accelerometers. Locomotion score and behaviors associated with lameness, such as arch back, head bob, tracking up, step asymmetry, and reluctance to bear weight were visually observed. Stride length, swing time, stance time, and the number of steps taken were the only variables affected by flooring type. Differences between flooring types for these variables were tested using a generalized linear mixed model with cow as a random effect, week as a random block factor, and flooring type as a fixed effect. Multiple comparisons with a Scheffé adjustment were done to analyze differences among flooring types. Stride length was 0.14 m longer (better) on rubber when compared with concrete, and 0.11 and 0.17 m shorter on MMA 1 and 2 compared with rubber. On MMA 3 and 4, stride length did not differ from either rubber or concrete. Swing time was 0.04 s shorter (worse) on MMA 1 than on rubber, but did not differ from any other flooring. Stance time was 0.18 s longer (worse) on MMA 2 when compared with rubber, but it did not differ from any other treatment. The number of steps was higher on MMA 4 compared with rubber (4.57 vs. 3.95 steps), but

  10. Overview of technologies for removal of methyl tert-butyl ether (MTBE) from water.

    PubMed

    Levchuk, Irina; Bhatnagar, Amit; Sillanpää, Mika

    2014-04-01

    Wide use of methyl tert-butyl ether (MTBE) as fuel oxygenates leads to worldwide environment contamination with this compound basically due to fuel leaks from storage or pipelines. Presence of MTBE in drinking water is of high environmental and social concern. Existing methods for MTBE removal from water have a number of limitations which can be possibly overcome in the future with use of emerging technologies. This work aims to provide an updated overview of recent developments in technologies for MTBE removal from water.

  11. Measurement of methyl-tert-butyl-ether (MTBE) in raw drinking water

    SciTech Connect

    Davisson, M L; Koester, C J; Moran, J E

    1999-10-14

    In order to assess the pathways for human exposure to methyl-tert-butyl-ether (MTBE) and to understand the extent of MTBE contamination in watersheds, a purge and trap gas chromatographic mass spectrometric method to measure part-per-trillion (ppt) concentrations of MTBE in environmental waters was developed. A variety of California's raw drinking waters were analyzed. No detectable MTBE was found in deep groundwater (>1000 feet). However shallow groundwater ({approx}250 feet) contained MTBE concentrations of non-detect to 1300 ppt. MTBE concentrations measured in rivers and lakes ranged from non-detect to 3500 ppt. East (San Francisco) Bay area rain water contained approximately 80 ppt MTBE.

  12. Influence of Temperature on Thermodynamic Properties of Methyl t-Butyl Ether (MTBE) + Gasoline Additives

    NASA Astrophysics Data System (ADS)

    Gonzalez-Olmos, R.; Iglesias, M.; Goenaga, J. M.; Resa, J. M.

    2007-08-01

    The densities and sound speeds of binary mixtures of methyl tert-butyl ether (MTBE) + (benzene, toluene, ethylbenzene, isooctane, tert-butyl alcohol) have been measured at temperatures from 288.15 to 323.15 K and at atmospheric pressure over the complete concentration range. The experimental excess volumes and deviations of isentropic compressibility were calculated. The deviation of isentropic compressibility data have been analyzed in terms of different theoretical models; adequate agreement between the experimental and predicted values is obtained. The data from this study improve the data situation related to gasoline additives and help to understand the MTBE volumetric and acoustic behavior for various chemical systems.

  13. New corrosion inhibitor acrylamide methyl ether for mild steel in 1 M HCl

    NASA Astrophysics Data System (ADS)

    Ma, Xinyu; Jiang, Xiaohui; Xia, Shuwei; Shan, Mingli; Li, Xia; Yu, Liangmin; Tang, Qunwei

    2016-05-01

    Pursuit of good inhibition performance has been a persistent objective for advanced inhibitor industry. Here we demonstrate the experimental realization of a new corrosion inhibitor acrylamide methyl ether (AAME) from N-Methylol acrylamide (N-MAM) for mild steel in 1 M HCl. The resultant adsorption films have inhibition efficiency as high as 96.2%. Moreover, a theoretical investigation is also launched to demonstrate the potential mechanism behind the promising corrosion behaviors. This work represents a significant step forward, as it demonstrates how to make scalable AAME inhibitors as well as to enhance inhibition performances for high-efficiency and cost-effective corrosion inhibition platforms.

  14. The Knock-Limited Performance of Fuel Blends Containing Spiropentane, Methylenecyclobutane, Di-Tert-Butyl Ether, Methyl Tert-Butyl Ether, and Triptane

    NASA Technical Reports Server (NTRS)

    Meyer, Carl L.

    1946-01-01

    Tests show that at inlet-air temperatures of 250 deg F and 100 deg F the knock-limited performance of the base fuel of blends, leaded with 4 ml TEL per gallon and containing 20 percent spiropentane, was reduced at fuel/air ratios below 0.085. The 20 percent methylenecyclobutane reduced the knock-limited power of the base fuel at fuel/air ratios below 0.112. Di-tert-butyl ether, methyl-tert-butyl ether, and triptane increased the knock-limited power of the base fuel at all fuel/air ratios and at both temperatures.

  15. Synergistic effect of ultrasonication and phase transfer catalysts in radical polymerization of methyl methacrylate - A kinetic study.

    PubMed

    Prabha, J; Susan Jemima, W; Jayaprada, M; Umapathy, M J

    2017-03-01

    Methyl methacrylate (MMA) has been polymerized to poly methyl methacrylate (PMMA) by employing three different phase transfer catalysts (PTC) such as 1,4-bis(dimethylhexyl)ethylenediammoniumbromide (DMHEDAB), 1,4bis(dimethylheptyl)ethylenediammoniumbromide (DMH1EDAB) and 1,4-bis(dimethyloctyl)ethylenediammonium bromide (DMOEDAB) under the influence of ultrasound radiation. The radical polymerization was performed under unstirred condition at a temperature of 60±1°C in an oxygen free atmosphere employing water soluble K2S2O8 as initiator. Various parameters such as role of [Monomer], [Initiator], [PTC], solvent and temperature were investigated on rate of polymerization (Rp) and the synergic efficacy of ultrasound wave variation and phase transfer catalysts were also assessed. It was found that the rate of polymerization (Rp) increased drastically for all the three catalyst under the influence of ultrasound and the order of efficiency was found to be [Formula: see text] This increase may be due to the number of carbon chain attached to the polar group which facilitate and accelerate the rate of polymerization.

  16. Surface modification of magnesium aluminum hydroxide nanoparticles with poly(methyl methacrylate) via one-pot in situ polymerization

    NASA Astrophysics Data System (ADS)

    Guo, Xiaojun; Zhao, Leihua; Zhang, Li; Li, Jing

    2012-01-01

    Hydrophobic magnesium aluminum hydroxide composite particles (PMMA-MAH) were obtained by means of grafting poly(methyl methacrylate) (PMMA) onto the surface of magnesium aluminum hydroxide(MAH) nanoparticles after a novel type of phosphate coupling agent (DN-27) modification. The introduction of functional double bonds was firstly conducted on the surface of nanoparticles by DN-27 modification, followed by one-pot in situ polymerization on the particles surface using methyl methacrylate (MMA) as monomer, azoisobutyronitrile (AIBN) as initiator and sodium dodecyl sulfate (SDS) as stabilizer to graft PMMA on the surface of DN-27-modified MAH particles. The obtained composite particles were characterized by field-emission scanning electron microscope (FESEM), Fourier transform infrared spectroscopy (FT-IR), thermogravimetric analysis (TGA), X-ray powder diffraction (XRD). The results show that the organic macromolecule PMMA could be successfully grafted on the surface of DN-27-modified MAH nanoparticles and the thermal stability of the PMMA-MAH composite particles had been improved. Compared with unmodified blank MAH sample, the product obtained with this method possesses better hydrophobic properties such as a higher water contact angle of 108° and a well dispersion.

  17. Plasma-polymerized methyl methacrylate via intense and highly energetic atmospheric pressure micro-plasma for bio-medical applications

    NASA Astrophysics Data System (ADS)

    Park, Choon-Sang; Ballato, John; Kim, Sung-O.; Clemson University Team

    2013-09-01

    Poly (methyl methacrylate), PMMA, has been widely used as a biocompatible material in bone cement, dental fillings, and many other bio-related applications. Vacuum plasmas and radio frequency (RF) atmospheric plasmas are the most common methods for depositing plasma-derived thin films and nanoparticles. However, the necessary equipment is difficult to operate and maintain as well as being large and expensive. Here, we report the use of a novel intense and highly energetic atmospheric pressure plasma jet array using direct plasma jet-to-jet coupling effects to deposit high quality plasma-polymerized MMA (PPMMA) for bio-medical applications. The newly proposed atmospheric pressure micro-plasma jet array device can generate the intense plasma mode with a strong plasma emission and high plasma particle energy. PPMMA was successfully deposited on a variety of substrates and characterized by SEM, AFM, and FT-IR. The micro-plasma jet is obtained at a sinusoidal voltage with a peak value of 30 kV and frequency of 35 kHz. Argon gas was employed as the discharge gas for plasma generation and its flow rate was in the range of 2230 sccm, Methyl methacrylate (MMA) monomer was vaporized by means of a glass bubbler which was supplied by argon gas with flow rates in the range of 268 sccm from room temperature to 400°C. The deposited PPMMA thin films were flexible, transparent, thin, and strong on metal substrates.

  18. Modulating fibroblast cell proliferation with functionalized poly(methyl methacrylate) based copolymers: chemical composition and monomer distribution effect.

    PubMed

    El Khadali, Fatima; Hélary, Gérard; Pavon-Djavid, Graciela; Migonney, Véronique

    2002-01-01

    Poly(methyl methacrylate)-based terpolymers bearing sulfonate and carboxylate groups have been synthesized by radical copolymerization leading to polymers with random distributions of ionic monomer units. Fibroblast cells were seeded on terpolymers of various molar compositions of ionic groups. Kinetics of the cell proliferation were examined and systematically compared to the nonfunctionalized control polymer, poly(methyl methacrylate). Modulation of cell proliferation was observed on 15% ionic monomer content copolymers of various compositions (R = COO(-)/(COO(-) + SO(3)(-)) and varies from 0 to 1). The inhibition percentage of cell proliferation calculated for each polymer by comparison to the cell proliferation on the control was plotted against R and gave a maximum value for R close to 0.55. Copolymers with ionic group contents higher or lower than 15% exhibit inhibition percentages fitting with those previously observed for the same R values, showing that the hydrophilic properties are not sufficient to explain the modulation effect of this material toward cells. Moreover, for each polymer tested, cells, even if inhibited in growth, were shown to be viable, indicating that the synthesized terpolymers exhibit cytostatic properties excluding any cytotoxic effect. Such polymers may be used for the fabrication of biocompatible intraocular lenses and prevent secondary cataract.

  19. Influence of ultrasonic condition on phase transfer catalyzed radical polymerization of methyl methacrylate in two phase system - A kinetic study.

    PubMed

    Marimuthu, Elumalai; Murugesan, Vajjiravel

    2016-08-25

    An ultrasonic condition assisted phase transfer catalyzed radical polymerization of methyl methacrylate was investigated in an ethyl acetate/water two phase system at 60±1°C and 25kHz, 300W under inert atmosphere. The influence of monomer, initiator, catalyst and temperature, volume fraction of aqueous phase on the rate of polymerization was examined in detail. The reaction order was found to be unity for monomer, initiator and catalyst. Generally, the reaction rate was relatively fast in two phase system, when a catalytic amount of phase transfer catalyst was used. The combined approach, use of ultrasonic and PTC condition was significantly enhances the rate of polymerization. An ultrasonic and phase transfer catalyzed radical polymerization of methyl methacrylate has shown about three fold enhancements in the rate compared with silent polymerization of MMA using cetyltrimethylammonium bromide as PTC. The resultant kinetics was evaluated with silent polymerization and an important feature was discussed. The activation energy and other thermodynamic parameters were computed. Based on the obtained results an appropriate radical mechanism has been derived. TGA showed the polymer was stable up to 150°C. The FT-IR and DSC analysis validates the atactic nature of the obtained polymer. The XRD pattern reveals the amorphous nature of polymer was dominated.

  20. Synthesis of (2-amino)ethyl derivatives of quercetin 3-O-methyl ether and their antioxidant and neuroprotective effects.

    PubMed

    Lee, Young Hun; Kim, Hyoung Ja; Yoo, Ho; Jung, Seo Yun; Kwon, Bong Jin; Kim, Nam-Jung; Jin, Changbae; Lee, Yong Sup

    2015-08-01

    Reactive oxygen species have been implicated in several diseases, particularly in ischemia-reperfusion injury. Quercetin 3-O-methyl ether has been reported to show potent antioxidant and neuroprotective activity against neuronal damage induced by reactive oxygen species. Several aminoethyl-substituted derivatives of quercetin 3-O-methyl ether have been synthesized to increase water solubility while retaining antioxidant and neuroprotective activity. Among such derivatives, compound 3a shows potent and well-balanced antioxidant activity in three types of cell-free assay systems and has in vivo neuroprotective effects on transient focal ischemic injury induced by the occlusion of the middle cerebral artery in rats.

  1. I Situ Laser Interferometry and Fluorescence Quenching Measurements of Poly(methyl Methacrylate) Thin Film Dissolution.

    NASA Astrophysics Data System (ADS)

    Wang, Fei

    The dissolution mechanisms of poly(methyl methacrylate) (PMMA) thin films in selected organic solvents was investigated. The dissolution was monitored using an in situ laser interferometry and fluorescence quenching (LIFQ) technique. Phenanthrene -labeled PMMA (Phe-PMMA) was used as a probe. Solutions of PMMA in toluene were spin-coated onto sapphire substrate to form films approximately 1 μm thick. The LIFQ results show that for PMMA film dissolution the transition layer thickness increases until the dissolution reaches its steady state. Then this final transition layer thickness (FTL) does not change until solvent vanguard molecules reach the surface of the substrate. Thermal history effects on PMMA film dissolution were examined. The dissolution rate decreases with increasing baking temperature and reaches a constant value for annealing at 150^circC. The results show that the thermal history has negligible effect on the factor of reduction f obtained from interferometry measurements. Fluorescence quenching measurements, by contrast, suggest that transition layer thickness decreases with increasing baking temperature. This suggests that the fluorescence quenching part of the LIFQ experiment is sensitive to the Fickian precursor portion of the solvent concentration profile in the film. The dissolution of PMMA films in acetone, 2-butanone, and 2-pentanone was studied. The results show that the dissolution rate decreases significantly with increasing solvent molecular size. Significant differences are found for FTL values calculated from LIFQ experiments and those calculated from f obtained by laser interferometry. Values of f are essentially identical in three solvents used. The effect of non-solvent on PMMA dissolution was studied by using 2-propanol and 2-butanone mixtures as solvents. The dissolution rate decreases with increasing non-solvent content. This indicates a strong thermodynamic effect, especially at high concentration of non-solvent. Molecular weight

  2. Fabrication and physical properties of transparent poly (methyl-methacrylate)-layered silicate nanocomposites

    NASA Astrophysics Data System (ADS)

    Vasiliu, Elena

    Transparent polymer nanocomposites have promising potential for protective coating applications with improved surface resistance, higher temperature performance and low gas permeability for containers and films. Extremely thin protective layers are required for improved performance of various electronic devices in aviation, aerospace and medical equipment as well as for lenses and fiber optics in optical communications. This research study developed a method for fabricating optically transparent nanocomposites of poly(methyl-methacrylate)(PMMA) and a commercial organically-modified layered silicate CloisiteRTM 6A (C6A). The nanocomposites were produced by dispersing C6A and PMMA separately in a common solvent xylene followed by mixing the two solutions by mechanical stirring and/or ultrasonic agitation and then removing the solvent by evaporation. Processing conditions such as the mixing methods and times and the rates of solvent removal were investigated in order to achieve a high degree of dispersion and exfoliation of C6A in the polymer matrix and produce a nanocomposite material with high optical transparency. Small-angle x-ray scattering (SAXS) was used to monitor the morphology of the C6A after each processing step. Thin films of PMMA/C6A nanocomposites were produced by casting and spraying. SAXS results suggest that C6A was partially exfoliated in the composite material with an average of 2 to 3 platelets per crystallite. Transmission electron microscopy (TEM) confirmed the existence of both exfoliated and intercalated C6A in PMMA. One mm thick discs were obtained by molding the sprayed films. The optical transmission of the nanocomposite films and discs was measured with an UV/VIS spectrometer. The spectroscopic results served to identify the best process for producing PMMA-C6A films of high optical transparency. Even the nanocomposite films containing up to 20 wt.% C6A prepared by this process exhibited optical transmittance in the range of 80 to 90

  3. Microwave Spectroscopy of Trans-Ethyl Methyl Ether in the Ground State

    NASA Astrophysics Data System (ADS)

    Kobayashi, Kaori; Sakai, Yusuke; Tsunekawa, Shozo; Miyamoto, Taihei; Fujitake, Masaharu; Ohashi, Nobukimi

    2013-06-01

    The trans-ethyl methyl ether molecule (CH_3CH_2OCH_3) has two inequivalent methyl group internal rotors which corresponds to the two vibrational motions, ν_{28} and ν_{29}. Due to these internal rotations, a rotational transition could be split into maximum five components. The skeletal torsion (ν_{30}) is another low-lying state (ν_{30}) that interacts with the ν_{28} and ν_{29} modes. The microwave spectra of the trans-ethyl methyl ether molecule in the ν_{28} = 1, ν_{29} = 1, and ν_{30} = 1, 2 and 3 have been extensively studied by using Hougen's tunneling matrix formalism. The microwave spectroscopy in the ground state was studied by several groups. The splitting due to the ν_{28} mode (C-CH_3 internal rotation) is small in the ground state and was not fully resolved in most of the previous studied rotational transitions. In this paper, we report the results of the pulsed nozzle-jet Fourier transform microwave spectroscopy so as to measure the fully resolved spectra. The submillmeter wave spectroscopy was also carried out. Our analysis including the previously reported transitions would be useful for astronomical observations. K. Kobayashi, T. Matsui, N. Mori, S. Tsunekawa, and N. Ohashi J. Mol. Spectrosc. {269}, 242 2011. K. Kobayashi, T. Matsui, S. Tsunekawa, and N. Ohashi J. Mol. Spectrosc. {255}, 164 2009. K. Kobayashi, T. Matsui, N. Mori, S. Tsunekawa, and N. Ohashi J. Mol. Spectrosc.{251}, 301 2008. K. Kobayashi, K. Murata, S. Tsunekawa, and N. Ohashi Int. Symposium on Mol. Spectrosc., 65th Meeting TH15 2010.} M. Hayashi, and K. Kuwada J. Mol. Structure {28}, 147 1975. M. Hayashi, and M. Adachi J. Mol. Structure {78}, 53 1982. S. Tsunekawa, Y. Kinai, Y. Kondo, H. Odashima, and K. Takagi Molecules {8}, 103 2003. U. Fuchs, G. Winnewisser, P. Groner, F. C. De Lucia, and E. Herbst Astrophys. J. Suppl. {144}, 277 2003.

  4. Effect of Low Pressure Nitrogen DC Plasma on Optical Properties of Biaxial-Oriented Polypropylene (BOPP), Poly Methyl Methacrylate (PMMA) and Poly Vinyl Chloride (PVC) Films

    NASA Astrophysics Data System (ADS)

    Mortazavi, S. H.; Ghoranneviss, M.; Faryadras, S.

    2012-06-01

    In this paper properties of Biaxial-Oriented Polypropylene, Poly Vinyl Chloride and Poly Methyl Methacrylate samples treated by DC glow discharge of N2 plasma have been investigated by UV-Vis_NIR spectrophotometer. It was found that plasma treatment change chemical structure of polymer surfaces. In addition, absorption coefficient, refractive index and extinction coefficient of all treated samples have been slightly changed.

  5. Dependence of ultraviolet nanosecond laser polymer ablation on polymer molecular weight: Poly(methyl methacrylate) at 248 nm

    NASA Astrophysics Data System (ADS)

    Bounos, Giannis; Selimis, Alexandros; Georgiou, Savas; Rebollar, Esther; Castillejo, Marta; Bityurin, Nikita

    2006-12-01

    We rely on a methodology demonstrated previously for assessing the temperature evolution and polymer viscosity changes in the 248nm irradiation of poly(methyl methacrylate)s (PMMAs) with molecular weights (Mw) ranging from 2.5to996kDa. Briefly, this methodology [G. Bounos et al., J. Appl. Phys. 98, 084317 (2005)] relies on monitoring the formation of aryl products in the irradiation of polymer doped with iodonaphthalene or iodophenanthrene. The results demonstrate that higher temperatures are attained with increasing Mw. The surface temperatures at the corresponding ablation thresholds are estimated to be ˜850-900K for Mw⩾120kDa vs ˜600K for 2.5kDa PMMA. In addition, for all Mw's, melting is demonstrated (viscosity values of ≈101Pas), but it lasts longer for high Mw PMMAs. We ascribe these differences to the fact that low Mw PMMAs dissociate efficiently to desorbing monomers/oligomers, thereby resulting in more efficient energy removal. Even so, the ablation threshold of the high Mw PMMAs is attained at higher fluences. This can be ascribed to the higher fraction of bonds that is required to be broken, and also plausibly to the higher gaseous product pressures that must be attained, for material ejection to be effected. The results are overall well accounted by the bulk photothermal model.

  6. Flexible fiber-reinforced composites with improved interfacial adhesion by mussel-inspired polydopamine and poly(methyl methacrylate) coating.

    PubMed

    Yi, Mi; Sun, Hongyang; Zhang, Hongcheng; Deng, Xuliang; Cai, Qing; Yang, Xiaoping

    2016-01-01

    To obtain a kind of light-curable fiber-reinforced composite for dental restoration, an excellent interfacial adhesion between the fiber and the acrylate resin matrix is quite essential. Herein, surface modification on glass fibers were carried out by coating them with poly(methyl methacrylate) (PMMA), polydopamine (PDA), or both. The PMMA or PDA coating was performed by soaking fibers in PMMA/acetone solution or dopamine aqueous solution. PDA/PMMA co-coated glass fibers were obtained by further soaking PDA-coated fibers in PMMA/acetone solution. These modified fibers were impregnated with bisphenol A glycidyl methacrylate (Bis-GMA)/triethylene glycol dimethacrylate (TEGDMA) (5:5, w/w) dental resin at a volume fraction of 75%, using unmodified fibers as reference. Light-cured specimens were submitted to evaluations including flexural properties, morphological observation, dynamic mechanical thermal analysis (DMTA) and pull-out test. In comparison with unmodified glass fibers, all the modified glass fibers showed enhancements in flexural strength and modulus of Bis-GMA/TEGDMA resin composites. Results of DMTA and pull-out tests confirmed that surface modification had significantly improved the interfacial adhesion between the glass fiber and the resin matrix. Particularly, the PDA/PMMA co-coated glass fibers displayed the most efficient reinforcement and the strongest interfacial adhesion due to the synergetic effects of PDA and PMMA. It indicated that co-coating method was a promising approach in modifying the interfacial compatibility between inorganic glass fiber and organic resin matrix.

  7. Dependence of ultraviolet nanosecond laser polymer ablation on polymer molecular weight: Poly(methyl methacrylate) at 248 nm

    SciTech Connect

    Bounos, Giannis; Selimis, Alexandros; Georgiou, Savas; Rebollar, Esther; Castillejo, Marta; Bityurin, Nikita

    2006-12-01

    We rely on a methodology demonstrated previously for assessing the temperature evolution and polymer viscosity changes in the 248 nm irradiation of poly(methyl methacrylate)s (PMMAs) with molecular weights (M{sub w}) ranging from 2.5 to 996 kDa. Briefly, this methodology [G. Bounos et al., J. Appl. Phys. 98, 084317 (2005)] relies on monitoring the formation of aryl products in the irradiation of polymer doped with iodonaphthalene or iodophenanthrene. The results demonstrate that higher temperatures are attained with increasing M{sub w}. The surface temperatures at the corresponding ablation thresholds are estimated to be {approx}850-900 K for M{sub w}{>=}120 kDa vs {approx}600 K for 2.5 kDa PMMA. In addition, for all M{sub w}'s, melting is demonstrated (viscosity values of {approx_equal}10{sup 1} Pa s), but it lasts longer for high M{sub w} PMMAs. We ascribe these differences to the fact that low M{sub w} PMMAs dissociate efficiently to desorbing monomers/oligomers, thereby resulting in more efficient energy removal. Even so, the ablation threshold of the high M{sub w} PMMAs is attained at higher fluences. This can be ascribed to the higher fraction of bonds that is required to be broken, and also plausibly to the higher gaseous product pressures that must be attained, for material ejection to be effected. The results are overall well accounted by the bulk photothermal model.

  8. Influence of the volumes of bis-acryl and poly(methyl methacrylate) resins on their exothermic behavior during polymerization.

    PubMed

    Ha, Jung-Yun; Kim, Sung-Hun; Kim, Kyo-Han; Kwon, Tae-Yub

    2011-01-01

    This study aimed to evaluate the influence of the volumes of a bis-acryl resin (Luxatemp) and a poly(methyl methacrylate) resin (Jet) on their exothermic behaviors during polymerization based on vinyl group conversion. The number of vinyl groups reacted and exotherm were determined based on weight percent of methacrylate groups using FTIR spectroscopy. Temperature changes during polymerization at 23°C were recorded for 20 minutes using a multiple cavity mold overlying a thermocouple. The number of vinyl groups reacted and exotherm of Luxatemp were consistently lower than those of Jet at each resin volume. Mean peak temperature rises of Luxatemp and Jet were in the range of 2.0-6.6°C and 4.2-11.6°C respectively, with Luxatemp and Jet taking 2 and 10 minutes respectively to reach their peak temperatures. As their resin volumes increased, their peak temperatures and total peak areas were also observed to increase significantly (p<0.01).

  9. Surface modification of glycidyl-containing poly(methyl methacrylate) microchips using surface-initiated atom-transfer radical polymerization.

    PubMed

    Sun, Xuefei; Liu, Jikun; Lee, Milton L

    2008-02-01

    Fabrication of microfluidic systems from polymeric materials is attractive because of simplicity and low cost. Unfortunately, the surfaces of many polymeric materials can adsorb biological samples. Therefore, it is necessary to modify their surfaces before these polymeric materials can be used for separation and analysis. Oftentimes it is difficult to modify polymeric surfaces because of their resistance to chemical reaction. Recently, we introduced a surface-reactive acrylic polymer, poly(glycidyl methacrylate-co-methyl methacrylate) (PGMAMMA), which can be modified easily and is suitable for fabrication of microfluidic devices. Epoxy groups on the surface can be activated by air plasma treatment, hydrolysis, or aminolysis. In this work, the resulting hydroxyl or amino groups were reacted with 2-bromoisobutylryl bromide to introduce an initiator for surface-initiated atom-transfer radical polymerization (SI-ATRP). Polyethylene glycol (PEG) layers grown on the surface using this method were uniform, hydrophilic, stable, and resistant to protein adsorption. Contact angle measurement and X-ray photoelectron spectroscopy (XPS) were used to characterize activated polymer surfaces, initiator-bound surfaces, and PEG-grafted surfaces. We obtained excellent capillary electrophoresis (CE) separations of proteins and peptides with the PEG-modified microchips. A separation efficiency of 4.4 x 10(4) plates for a 3.5 cm long separation channel was obtained.

  10. WATER QUALITY AT FIVE MARINAS IN LAKE TEXOMA AS RELATED TO METHYL TERT-BUTYL ETHER (MTBE)

    EPA Science Inventory

    Occurrence of methyl tert-butyl ether (MTBE) in five marinas was monitored between June 1999 and November 2000 in Lake Texoma located on the border of Oklahoma and Texas. MTBE is a commonly used gasoline additive and a suspected carcinogen. Lake water was collected at locations i...

  11. REMOVAL OF METHYL T-BUTYL ETHER (MTBE) FROM WATER BY PERVAPORATION: BENCH-SCALE AND PILOT SCALE EVALUATIONS

    EPA Science Inventory

    The ability of pervaporation to remove methyl t-butyl ether (MTBE) from water was evaluated at bench- and pilot-scales. Process parameters studied included flow rate, temperature, MTBE concentration, membrane module type, and permeate pressure. Pervaporation performance was ass...

  12. DEVELOPMENT OF PHYSIOLOGICAL-BASED PHARMACOKINETIC MODEL FOR DERMAL ABSORPTION NAD PENETRATION OF METHYL TERTIARY BUTYL ETHER IN HUMANS

    EPA Science Inventory

    Background: Methyl tertiary butyl ether (MTBE) is a volatile organic chemical that is added to gasoline as an octane booster and to reduce vehicular emissions of carbon monoxide. MTBE is introduced into the environment through fuel spills, leakage of storage tanks, and evaporat...

  13. CO-OCCURRENCE OF METHYL- TERT-BUTYL ETHER (MTBE) AND BTEX COMPOUNDS AT MARINAS IN A LARGE RESEVOIR

    EPA Science Inventory

    Methyl tert-butyl ether (MTBE) is released into the environment as one of some gasoline components, not as a pure compound. BTEX compounds (benzene, tolune, ethylbenzene, and xylenes) are major volatile constituents found in gasoline and are water soluble and mobile. This study...

  14. DERMAL EXPOSURE TO METHYL TERT-BUTYL ETHER (MTBE) AND DIBROMOCHLOROMETHANE (DBCM) WHILE BATHING WITH CONTAMINATED WATER

    EPA Science Inventory

    The oxygenate methyl tert-butyl ether (MTBE) has been added to gasoline to help meet national ambient air quality standards in those parts of the U.S. that are non-compliant for carbon monoxide. Although MTBE has provided important health benefits in terms of reduced hazardous a...

  15. TOXICITY OF METHYL-TERT BYTYL ETHER (MTBE) TO PLANTS (AVENA SATIVA, ZEA MAYS, TRITICUM AESTIVUM, AND LACTUCA SATIVA)

    EPA Science Inventory

    Effects of Methyl tert-butyl ether (MTBE) on the germination of seeds and growth of the plant were studied in some laboratory experiments. Test plants were wild oat (Avena sative), sweet corn (Zea mays), wheat (Triticum aestivum), and lettuce (Lactuca sativa). Seed germination,...

  16. INTERACTION OF METHYL-TERT BUTYL ETHER AND WATER STRESS ON SEED GERMINATION AND SEEDLING GROWTH IN SOIL MICROCOSMS

    EPA Science Inventory

    Methyl tert-butyl ether (MTBE) is a widespread contaminant in surface and ground water in the United States. Frequently irrigation is used to water fields to germinate planted seeds and sustain plant growth. A likely possibility exists that water used may have some MTBE. Our s...

  17. EVALUATION OF METHYL TERT-BUTYL ETHER (MTBE) AS AN INTERFERENCE ON COMMERCIAL BREATH-ALCOHOL ANALYZERS

    EPA Science Inventory

    Anecdotal reports suggest that high environmental or occupational exposures to the fuel oxygenate methyl tert-butyl ether (MTBE) may result in breath concentrations that are sufficiently elevated to cause a false positive on commercial breath-alcohol analyzers. We evaluated th...

  18. Anaerobic Biodegradation Of Methyl tert-Butyl Ether Under Iron-Reducing Conditions In Batch And Continuous-Flow Cultures

    EPA Science Inventory

    The feasibility of biodegradation of the fuel oxygenate methyl tert-butyl ether (MTBE) under iron-reducing conditions was explored in batch and continuous-flow systems. A porous pot completely-mixed reactor was seeded with diverse cultures and operated under iron-reducing...

  19. Degradation of methyl tert-butyl ether (MTBE) in water by glow discharge plasma.

    PubMed

    Tong, Shaoping; Ni, Yanyan; Shen, Chensi; Wen, Yuezhong; Jiang, Xuanzhen

    2011-01-01

    This study evaluated the ability of the glow discharge plasma (GDP) technique to degrade methyl tert-butyl ether (MTBE) in an aqueous solution. The results showed that a large amount of hydrogen peroxide and highly active *OH free radicals were produced during the treatment. Various experimental parameters including discharge current, initial MTBE concentration and initial pH played significant roles on MTBE degradation. In addition, Fe2+ had a catalytic effect on the degradation of MTBE, which is potentially attributable to the reaction between Fe3+ and the hydrated electron. It was also confirmed that GDP was comparable to electrocatalytic oxidation and high-density plasma and more efficient than photocatalytic degradation techniques. These results suggest that GDP may become a competitive MTBE wastewater treatment technology.

  20. CCSD(T) study of the infrared spectrum of ethyl-methyl-ether isotopic varieties

    NASA Astrophysics Data System (ADS)

    Senent, M. L.; Ruiz, R.; Villa, M.; Domínguez-Gómez, R.

    2010-02-01

    Band positions for the infrared bands of various ethyl-methyl-ether isotopomers (CH 3CH 2OCH 2D, CH 2DCH 2OCH 3, CH 3CH 2OCD 3, CD 3CH 2OCH 3, CH 3CD 2OCH 3, CH 3CH 2O 13CH 3, 13CH 3CH 2OCH 3, and CH 313CH 2OCH 3) are determined using second order perturbation theory. For species showing G18 symmetry, band position are calculated variationally from a CCSD(T)/cc-pVTZ three-dimensional potential energy surface corrected vibrationally. Potential energy barriers, fundamental frequencies, and rotational constants for excited vibrational levels, are also provided. Calculated frequencies for CH 3CH 2OCD 3 confirm experimental assignments and our predictions for the most abundant isotopomer [4].

  1. Evaluation of methyl fluoride and dimethyl ether as inhibitors of aerobic methane oxidation

    USGS Publications Warehouse

    Oremland, R.S.; Culbertson, C.W.

    1992-01-01

    Methyl fluoride (MF) and dimethyl ether (DME) were effective inhibitors of aerobic methanotrophy in a variety of soils. MF and DME blocked consumption of CH4 as well as the oxidation of 14CH4 to 14CO2, but neither MF nor DME affected the oxidation of [14C]methanol or [14C]formate to 14CO2. Cooxidation of ethane and propane by methane-oxidizing soils was also inhibited by MF. Nitrification (ammonia oxidation) in soils was inhibited by both MF and DME. Production of N2O via nitrification was inhibited by MF; however, MF did not affect N2O production associated with denitrification. Methanogenesis was partially inhibited by MF but not by DME. Methane oxidation was ~100-fold more sensitive to MF than was methanogenesis, indicating that an optimum concentration could be employed to selectively block methanotrophy. MF inhibited methane oxidation by cell suspensions of Methylococcus capsulatus; however, DME was a much less effective inhibitor.

  2. Sphaeropsidones, phytotoxic dimedone methyl ethers produced by Diplodia cupressi: a structure-activity relationship study.

    PubMed

    Evidente, Antonio; Maddau, Lucia; Scanu, Bruno; Andolfi, Anna; Masi, Marco; Motta, Andrea; Tuzi, Angela

    2011-04-25

    Sphaeropsidone and episphaeropsidone are two phytotoxic dimedone methyl ethers produced by Diplodia cupressi, the causal agent of a canker disease of cypress in the Mediterranean area. In this study, eight derivatives obtained by chemical modifications and two natural analogues were assayed for phytotoxic and antifungal activities, and a structure-activity relationship was examined. Each compound was tested on nonhost plants and on five fungal pathogenic species belonging to the genus Phytophthora. The results provide insights into structure-activity relationships within these compounds. It was found that the hydroxy group at C-5, the absolute C-5 configuration, the epoxy group, and the C-2 carbonyl group appear to be structural features important in conferring biological activity. The conversion of sphaeropsidone into the corresponding 1,4-dione derivative led to a compound showing greater antifungal activity than its precursor. This finding could be useful in devising new natural fungicides for practical application in agriculture.

  3. Biconvex intraocular lenses and Nd:YAG capsulotomy: Experimental comparison of surface damage with different poly(methyl methacrylate) formulations

    SciTech Connect

    Downing, J.E.; Alberhasky, M.T. )

    1990-11-01

    Biconvex posterior chamber lenses have optical advantages and decrease the risk of capsular opacification, but they are more likely to be pitted during ND:YAG capsulotomy because of apposition of the lens to the capsule. This study reports the likelihood of surface damage to different formulations of poly(methyl methacrylate) at the energy levels required to open posterior capsules. Molded lenses are more easily damaged than higher molecular weight lathe-cut materials (P less than .01), as expected. However, by keeping energy output low, even injection-molded lenses showed minimal damage, with mean pit size 39 +/- 39 microns at 1 mJ. By using a converging contact lens, low power, and keeping the focus behind the capsule, damage to all materials tested should be clinically insignificant.

  4. Pilot-scale synthesis and rheological assessment of poly(methyl methacrylate) polymers: perspectives for medical application.

    PubMed

    Linan, Lamia Zuniga; Nascimento Lima, Nádson M; Filho, Rubens Maciel; Sabino, Marcos A; Kozlowski, Mark T; Manenti, Flavio

    2015-06-01

    This work presents the rheological assessment of poly(methyl methacrylate) (PMMA) polymers synthesized in a dedicated pilot-scale plant. This material is to be used for the construction of scaffolds via Rapid Prototyping (RP). The polymers were prepared to match the physical and biological properties required for medical applications. Differential Scanning Calorimetry (DSC) and Size Exclusion Chromatography (SEC) measurements verified that the synthesized polymers were atactic, amorphous and linear in chains. Rheological properties such as viscosity, storage and loss modulus, beyond the loss factor, and creep and recovery were measured in a plate-plate sensor within the viscoelastic linear region. The results showed the relevant influence of the molecular weight on the viscosity and elasticity of the material, and how, as the molecular weight increases, the viscoelastic properties are getting closer to those of human bone. This article demonstrates that by using the implemented methodology it is possible to synthesize a polymer, with properties comparable to commercially-available PMMA.

  5. Interfacial chemistry of poly(methyl methacrylate) arising from exposure to vacuum-ultraviolet light and atomic oxygen.

    PubMed

    Yuan, Hanqiu; Killelea, Daniel R; Tepavcevic, Sanja; Kelber, Scott I; Sibener, S J

    2011-04-28

    We herein report on the chemical and physical changes that occur in thin films of poly(methyl methacrylate), PMMA, induced by exposure to high-energy vacuum ultraviolet radiation and a supersonic beam of neutral, ground electronic state O((3)P) atomic oxygen. A combination of in situ quartz crystal microbalance and in situ Fourier-transform infrared reflection-absorption spectroscopy were used to determine the photochemical reaction kinetics and mechanisms during irradiation. The surface morphological changes were measured with atomic force microscopy. The results showed there was no enhancement in the mass loss rate during simultaneous exposure of vacuum ultraviolet (VUV) radiation and atomic oxygen. Rather, the rate of mass loss was impeded when the polymer film was exposed to both reagents. This study elucidates the kinetics of photochemical and oxidative reaction for PMMA, and shows that the synergistic effect involving VUV irradiation and exposure to ground state atomic oxygen depends substantially on the relative fluxes of these reagents.

  6. DIELECTRIC PROPERTIES OF POLYVINYL ALCOHOL, POLY(METHYL METHACRYLATE), POLYVINYL BUTYRAL RESIN AND POLYIMIDE AT LOW TEMPERATURES

    SciTech Connect

    Tuncer, Enis; Sauers, Isidor; James, David Randy; Ellis, Alvin R

    2008-01-01

    Performance of materials and their compatibility determine the size of the electrical insulation in power equipment. For this reason dielectric properties of electrical insulation materials are needed for low temperature power applications. In this work we report the dielectric properties of four polymers: polyvinyl alcohol (PVA), poly(methyl methacrylate) (PMMA), polyvinyl butyral resin (PVB), and polyimide (PI--Kapton\\textregistered). The dielectric measurements are performed with an electrical impedance analyzer in the frequency domain. The impedances are recorded in a cryocooler in the temperature range from 45K to 350K. The dielectric breakdown characteristics of the polymers are measured in a liquid nitrogen bath at atmospheric pressure. It is observed that PI and \\pmma\\ dissolved in toluene have the lowest dielectric losses for temperatures lower than $100\\ \\kelvin$. \\Blx\\ and PI have the smallest spread in their breakdown strength data.

  7. Graphene functionalized with poly(vinyl alcohol) as a Pickering stabilizer for suspension polymerization of poly(methyl methacrylate).

    PubMed

    Erdenedelger, Gansukh; Dao, Trung Dung; Jeong, Han Mo

    2016-08-15

    Two types of thermally reduced graphenes (TRGs) having different lateral sizes were non-covalently modified with poly(vinyl alcohol) to endow water-dispersibility. The modified TRGs were examined as Pickering stabilizers for the suspension polymerization of methyl methacrylate (MMA). They were effective graphene-based Pickering stabilizers for the system with almost all of the polymerized composite microparticles having a regular spherical shape. The particle size of the composite microparticles was tunable by the size or the amount of modified TRG used as stabilizer. The almost perfect core-shell structure of the composite microparticles effectively enhanced the thermal stability of the core PMMA. In addition, when the core-shell microparticles were compression molded into a monolith, the obtained composite exhibited an ultra-low percolation threshold of electrical conductivity of around 0.04vol%.

  8. A Room-Temperature Operation Formaldehyde Sensing Material Printed Using Blends of Reduced Graphene Oxide and Poly(methyl methacrylate)

    PubMed Central

    Chuang, Wen-Yu; Yang, Sung-Yuan; Wu, Wen-Jong; Lin, Chih-Ting

    2015-01-01

    This work demonstrates a printable blending material, i.e., reduced graphene oxide (RGO) mixed with poly(methyl methacrylate) (PMMA), for formaldehyde sensing. Based on experimental results, 2% RGO/10% PMMA is an optimal ratio for formaldehyde detection, which produced a 30.5% resistance variation in response to 1000 ppm formaldehyde and high selectivity compared to different volatile organic compounds (VOCs), humidity, CO, and NO. The demonstrated detection limit is 100 ppm with 1.51% resistance variation. Characterization of the developed formaldehyde sensing material was performed by Fourier-transform infrared (FTIR) spectrometry, scanning electron microscopy (SEM), and Raman spectroscopy. Based on Raman spectroscopy, the basic sensing mechanism is the band distortion of RGO due to blending with PMMA and the adsorption of formaldehyde. This work establishes insights into the formaldehyde sensing mechanism and explores a potential printable sensing material for diverse applications. PMID:26580624

  9. Expanded corn starch as a versatile material in atom transfer radical polymerization (ATRP) of styrene and methyl methacrylate.

    PubMed

    Bansal, Ankushi; Kumar, Arvind; Latha, Patnam Padma; Ray, Siddharth Sankar; Chatterjee, Alok Kumar

    2015-10-05

    Polymerization of styrene (St) and methyl methacrylate (MMA) was performed by surface initiated (SI) and activator generated by electron transfer (AGET) systems of atom transfer radical polymerization (ATRP) using renewable expanded corn starch (ECS) as a support. This prepared ECS is found to have V type crystallinity with 50 m(2)g(-1) surface area (<1m(2)g(-1) for corn starch (CS)) and average pore volume of 0.43 cm(3)g(-1) (<0.1cm(3)g(-1) for CS). In SI-ATRP, hydroxyl groups on ECS were converted into macro-initiator by replacing with 2-bromoisobutyryl bromide (BIBB) with a 0.06 degree of substitution determined from NMR. In AGET-ATRP, CuBr2/ligand complex get adsorbed on ECS (Cu(II)/ECS=10 wt.%) to catalyze the polymerization. Synthesized PS/PMMA was characterized by SEM, FT-IR, (1)H NMR.

  10. Biconvex intraocular lenses and Nd:YAG capsulotomy: experimental comparison of surface damage with different poly(methyl methacrylate) formulations.

    PubMed

    Downing, J E; Alberhasky, M T

    1990-11-01

    Biconvex posterior chamber lenses have optical advantages and decrease the risk of capsular opacification, but they are more likely to be pitted during ND:YAG capsulotomy because of apposition of the lens to the capsule. This study reports the likelihood of surface damage to different formulations of poly(methyl methacrylate) at the energy levels required to open posterior capsules. Molded lenses are more easily damaged than higher molecular weight lathe-cut materials (P less than .01), as expected. However, by keeping energy output low, even injection-molded lenses showed minimal damage, with mean pit size 39 +/- 39 microns at 1 mJ. By using a converging contact lens, low power, and keeping the focus behind the capsule, damage to all materials tested should be clinically insignificant.

  11. Autophobic dewetting of a poly(methyl methacrylate) thin film on a silicon wafer treated in good solvent vapor.

    PubMed

    Xue, Longjian; Han, Yanchun

    2009-05-05

    The wettability of thin poly(methyl methacrylate) (PMMA) films on a silicon wafer with a native oxide layer exposed to solvent vapors is dependent on the solvent properties. In the nonsolvent vapor, the film spread on the substrate with some protrusions generated on the film surface. In the good solvent vapor, dewetting happened. A new interface formed between the anchored PMMA chains and the swollen upper part of the film. Entropy effects caused the upper movable chains to dewet on the anchored chains. The rim instability depended on the surface tension of solvent (i.e., the finger was generated in acetone vapor (gamma(acetone) = 24 mN/m), not in dioxane vapor (gamma(dioxane) = 33 mN/m)). The spacing (lambda) that grew as an exponential function of film thickness h scaled as approximately h(1.31), whereas the mean size (D) of the resulting droplets grew linearly with h.

  12. Effect of Solvent on the Dielectric Properties of Nanocomposite Poly(methyl methacrylate)-Doped Titanium Dioxide Dielectric Films

    NASA Astrophysics Data System (ADS)

    Nyl Ismail, Lyly; Hafizah Nik Mohamad, Nik Noor; Salleh Shamsudin, Muhamad; Zulkefle, Habibah; Hanapiah Abdullah, Mohd; Herman, Sukreen Hana; Rusop, Mohamad

    2012-06-01

    A poly(methyl methacrylate)-doped titanium dioxide (PMMA:TiO2) nanocomposite film was obtained by spin coating the nanocomposite solution onto a silicon substrate. The nanocomposite solutions were prepared by dissolving the PMMA and TiO2 nanopowder in three different types of organic solvent, namely, toluene, tetrahydrofuran (THF), and acetone. We found that the dielectric properties of the PMMA:TiO2 nanocomposite are dependent on the type of solvent used. The dielectric properties measured at a frequency of 1 kHz showed that acetone gives the highest dielectric constant and capacitance compared with toluene and THF. Toluene gives the lowest dielectric loss among the three. The topography and roughness of the PMMA:TiO2 nanocomposite indicate that a particular solvent results in a different kind of surface morphology.

  13. Electrical detection of spin precession in freely suspended graphene spin valves on cross-linked poly(methyl methacrylate).

    PubMed

    Neumann, Ingmar; Van de Vondel, Joris; Bridoux, German; Costache, Marius V; Alzina, Francesc; Sotomayor Torres, Clivia M; Valenzuela, Sergio O

    2013-01-14

    Spin injection and detection is achieved in freely suspended graphene using cobalt electrodes and a nonlocal spin-valve geometry. The devices are fabricated with a single electron-beam-resist poly(methyl methacrylate) process that minimizes both the fabrication steps and the number of (aggressive) chemicals used, greatly reducing contamination and increasing the yield of high-quality, mechanically stable devices. As-grown devices can present mobilities exceeding 10(4) cm(2) V(-1) s(-1) at room temperature and, because the contacts deposited on graphene are only exposed to acetone and isopropanol, the method is compatible with almost any contacting material. Spin accumulation and spin precession are studied in these nonlocal spin valves. Fitting of Hanle spin precession data in bilayer and multilayer graphene yields a spin relaxation time of ∼125-250 ps and a spin diffusion length of 1.7-1.9 μm at room temperature.

  14. Chemical properties of 1,3-bis(3-methacryloxypropyl)-1,1,3,3-tetramethyldisiloxane-methyl methacrylate copolymer.

    PubMed

    Aoyagi, Yujin; Umemoto, Kozo; Kurata, Shigeaki

    2012-01-01

    This study evaluated the chemical properties such as water sorption, water solubility and solvent resistance of a new resin material consisting of 1,3-bis(3-methacryloxypropyl)-1,1,3,3-tetramethyldisiloxane (BMPMS) and methyl methacrylate (MMA). Water sorption was evaluated by immersing the specimens in water at 37±1°C for 1 week, water solubility was evaluated by keeping the specimens in a desiccator under dry conditions at 37±1°C until the weight became constant, and solvent resistance was evaluated by immersing the specimens in acetone for 1 week and measuring the dissolved weight of acetone volatilized from those liquids. The water sorption and solvent resistance of the new resin were improved with increasing amount of BMPMS, whereas the water solubility remained the same value and did not depend on the amount of BMPMS.

  15. Fabrication of ordered poly(methyl methacrylate) nanobowl arrays using SiO2 colloidal crystal templates.

    PubMed

    Deng, Lier; Fu, Ming; Tao, Yinglei; Guo, Xiaoyun

    2014-06-01

    A simple approach is presented for the fabrication of poly(methyl methacrylate) (PMMA) nanobowl arrays over cm2 areas using SiO2 colloidal crystal templates. SiO2 colloidal crystal templates were prepared on a clean glass substrate by self-assembled SiO2 spheres of 410 nm in diameter. The air between the silica spheres was filled by the superfluous monomer of PMMA that can be subsequently polymerized. After infiltration, the SiO2-PMMA templates were immersed in a 3 wt% hydrofluoric acid (HF) aqueous solution. After 24 h, silica spheres were etched and a free-standing nanobowl sheet was obtained. The size of the nanobowls could be controlled by the size of the SiO2 spheres and the area of the nanobowl sheet could be altered by the size of the glass substrate.

  16. Influence of fabrication conditions on characteristics of phenanthrenequinone-doped poly(methyl methacrylate) photopolymer for holographic memory

    NASA Astrophysics Data System (ADS)

    Lin, Shiuan Huei; Cho, Sheng-Lung; Lin, June-Hua; Hsu, Ken Y.; Chi, Sien

    2014-06-01

    In this paper, we experimentally investigate the influence of the fabrication conditions on holographic characteristics in phenanthrenequinone-doped poly(methyl methacrylate) (PQ:PMMA) bulk photopolymer. In our investigation, the PQ:PMMA bulk samples are fabricated by use of a two-step thermo-polymerization method. We firstly propose to monitor relative viscosity of the monomer solution during the sample preparation to obtain a reliable criterion for material fabrication. We then compare experimentally characteristics of 2-mm thick samples fabricated with different conditions for holographic memory. The results show that the conditions in the first step play a important rule for fabricating bulk PQ:PMMA samples with good optical uniformity. In addition, the conditions in the second step play the rule for controlling the concentration of residual monomer and determine holographic characteristics. These results can provide a useful rule for fabricating bulk PQ:PMMA photopolymers for further applications on volume holographic data storage.

  17. Kinetic study of Candida antarctica lipase B immobilization using poly(methyl methacrylate) nanoparticles obtained by miniemulsion polymerization as support.

    PubMed

    Valério, Alexsandra; Nicoletti, Gabrieli; Cipolatti, Eliane P; Ninow, Jorge L; Araújo, Pedro H H; Sayer, Cláudia; de Oliveira, Débora

    2015-03-01

    With the objective to obtain immobilized Candida antarctica lipase B (CalB) with good activity and improved utilization rate, this study evaluated the influence of enzyme and crodamol concentrations and initiator type on the CalB enzyme immobilization in nanoparticles consisting of poly(methyl methacrylate) (PMMA) obtained by miniemulsion polymerization. The kinetic study of immobilized CalB enzyme in PMMA nanoparticles was evaluated in terms of monomer conversion, particle size, zeta potential, and relative activity. The optimum immobilization condition for CalB was compared with free enzyme in the p-NPL hydrolysis activity measurement. Results showed a higher CalB enzyme stability after 20 hydrolysis cycles compared with free CalB enzyme; in particular, the relative immobilized enzyme activity was maintained up to 40%. In conclusion, PMMA nanoparticles proved to be a good support for the CalB enzyme immobilization and may be used as a feasible alternative catalyst in industrial processes.

  18. High optical and switching performance electrochromic devices based on a zinc oxide nanowire with poly(methyl methacrylate) gel electrolytes

    SciTech Connect

    Chun, Young Tea; Chu, Daping; Neeves, Matthew; Placido, Frank; Smithwick, Quinn

    2014-11-10

    High performance electrochromic devices have been fabricated and demonstrated utilizing a solid polymer electrolyte and zinc oxide (ZnO) nanowire (NW) array counter electrode. The poly(methyl methacrylate) based polymer electrolyte was spin coated upon hydrothermally grown ZnO NW array counter electrodes, while electron beam evaporated NiO{sub x} thin films formed the working electrodes. Excellent optical contrast and switching speeds were observed in the fabricated devices with active areas of 2 cm{sup 2}, exhibiting an optical contrast of 73.11% at the wavelength of 470 nm, combined with a fast switching time of 0.2 s and 0.4 s for bleaching and coloration, respectively.

  19. Detonation Characteristics of Plastic Explosives Based on Attractive Nitramines with Polyisobutylene and Poly(methyl methacrylate) Binders

    NASA Astrophysics Data System (ADS)

    Elbeih, Ahmed; Pachman, Jiri; Zeman, Svatopluk; Vávra, Pavel; Trzciński, Waldemar A.; Akštein, zbyněk

    2012-10-01

    Four highly brisant nitramines, RDX (1,3,5-trinitro-1,3,5-triazinane), HMX (1,3,5,7-tetranitro-1,3,5,7-tetrazocane), BCHMX (cis-1,3,4,6-tetranitro-octahydroimidazo-[4,5-d]imidazole), and ɛ-HNIW (ɛ-2,4,6,8,10,12-hexanitro-2,4,6,8,10,12-hexaazaisowurtzitane), were studied as extruded plastic explosives bonded by two plastic matrices based on polyisobutylene (C4 matrix) and poly-methylmethacrylate (plasticized by dioctyl-adipate) binders. The detonation velocities, D, were measured experimentally. Detonation parameters were also calculated by means of the Kamlet and Jacobs method and CHEETAH and EXPLO5 codes. These detonation parameters showed that plastic-bonded explosives (PBXs) based on BCHMX are more powerful explosives than those based on RDX. The Urizar coefficient for poly(methyl methacrylate) binder was also calculated.

  20. Thermal and Mechanical Properties of Poly(methyl methacrylate)/Poly(vinylidene fluoride-r-hexafluoro propylene) Blends

    NASA Astrophysics Data System (ADS)

    Lee, Steven; Conway, Maeve; Rende, Deniz; Ozisik, Rahmi

    Poly(vinylidene fluoride), PVDF, is a highly crystalline and rigid polymer, and is used in many applications where chemical inertness, resistance to various solvents and environmental degradation are required. Copolymerization of PVDF with hexafluoropropylene (HFP) tends to decrease the amount of crystallinity, thereby, resulting in a more flexible polymer, which provides new applications for PVDF. Various studies were undertaken to investigate the structure and properties of miscible blends of PVDF and poly(methyl methacrylate), PMMA; however, no studies were performed on the blends of P(VDF-HFP) random copolymers and PMMA. In the current study, we investigate the miscibility, and thermal and mechanical properties of P(VDF-HFP)/PMMA blends via differential scanning calorimetry, thermogravimetric analysis, and nanoindentation. Results indicate that increasing PMMA concentration leads to decreased crystallinity and shifting of the crystallization onset temperature during cooling to lower values. This material is based upon work supported by the National Science Foundation under Grant No. CMMI-1538730.

  1. Usefulness of a quick decalcification of bone sections embedded in methyl methacrylate[corrected]: an improved method for immunohistochemistry.

    PubMed

    Gomes, Samirah Abreu; dos Reis, Luciene Machado; de Oliveira, Ivone Braga; Noronha, Irene de Lourdes; Jorgetti, Vanda; Heilberg, Ita Pfeferman

    2008-01-01

    Immunohistochemistry of undecalcified bone sections embedded in methyl methacrylate (MMA) is not commonly employed because of potential destruction of tissue antigenicity by highly exothermic polymerization. The aim of the present study was to describe a new technique in which a quick decalcification of bone sections embedded in MMA improves the results for immunohistochemistry. The quality of interleukin 1alpha (IL-1alpha) immunostaining according to the present method was better than the conventional one. Immunostaining for osteoprotegerin (OPG) and the receptor activator of NF-kappaB ligand (RANKL) in bone sections of chronic kidney disease patients with mineral bone disorders (CKD-MBD) was stronger than in controls (postmortem healthy subjects). The present study suggested that this method is easy, fast, and effective to perform both histomorphometry and immunohistochemistry in the same bone fragment, yielding new insights into pathophysiological aspects and therapeutic approaches in bone disease.

  2. In situ Poly(methyl methacrylate)/Graphene Composite Gel Electrolytes for Highly Stable Dye-Sensitized Solar Cells.

    PubMed

    Kang, Yu-il; Moon, Jun Hyuk

    2015-11-01

    Dye-sensitized solar cells (DSCs) with long-term stability are produced using polymer-gel electrolytes (PGEs). In this study, we introduce the formation of PGEs using in situ gelation with poly(methyl methacrylate) (PMMA) particles and graphene fillers that are pre-deposited on the counter electrodes. We obtain a high concentration PMMA-based PGEs (i.e., over 10 wt%). A DSC composed of a PMMA/graphene composite PGEs exhibits an 8.49% photon-to-electric conversion efficiency, which is comparable to conventional liquid electrolyte DSCs. This finding is attributed to increased ion diffusivity and conductivity of the PMMA-based PGEs resulting from the incorporation of graphene nanofillers. The PMMA-based PGE DSCs exhibit highly stable long-term efficiencies, maintaining up to 90% of their initial efficiency during thermal soaking, whereas the efficiencies of liquid electrolyte cells decrease significantly, by up to 60%.

  3. UV-laser-assisted modification of poly(methyl methacrylate) and its application to capillary-driven-flow immunoassay

    NASA Astrophysics Data System (ADS)

    Fuchiwaki, Y.; Takaoka, H.

    2015-07-01

    A concave microchannel surface was formed by nanosecond pulse laser ablation to allow antibody immobilization on a capillary flow immunoassay chip. Microscopic analysis showed that UV laser ablation of poly(methyl methacrylate) at 193 nm and 1.76 J · cm-2 allowed excellent immobilization of Cy5 conjugated antibody. The concave structure was 10 µm deep and 260 µm wide and supported uniform antibody printing on the microchannel surface. The characteristics of immobilized antibodies on this surface and on a commercially available polymer coating were comparable. Quantitative analysis of procollagen type I C-peptide (PICP) at different concentrations provided a linear relationship in the range 0-600 ng ml-1 PICP, which is sufficient for clinical estimation of PICP in the blood. The results may provide a new benchmark for a mechatronic antibody immobilization-based capillary flow immunoassay chip.

  4. Searching for trans ethyl methyl ether in Orion KL★,★★

    PubMed Central

    Tercero, B.; Cernicharo, J.; López, A.; Brouillet, N.; Kolesniková, L.; Motiyenko, R. A.; Margulès, L.; Alonso, J. L.; Guillemin, J.-C.

    2015-01-01

    We report on the tentative detection of trans ethyl methyl ether (tEME), t-CH3CH2OCH3, through the identification of a large number of rotational lines from each one of the spin states of the molecule towards Orion KL. We also search for gauche-trans-n-propanol, Gt-n-CH3CH2CH2OH, an isomer of tEME in the same source. We have identified lines of both species in the IRAM 30 m line survey and in the ALMA Science Verification data. We have obtained ALMA maps to establish the spatial distribution of these species. Whereas tEME mainly arises from the compact ridge component of Orion, Gt-n-propanol appears at the emission peak of ethanol (south hot core). The derived column densities of these species at the location of their emission peaks are ≤(4.0 ± 0.8) × 1015 cm−2 and ≤(1.0 ± 0.2)× 1015 cm−2 for tEME and Gt-n-propanol, respectively. The rotational temperature is ~100 K for both molecules. We also provide maps of CH3OCOH, CH3CH2OCOH, CH3OCH3, CH3OH, and CH3CH2OH to compare the distribution of these organic saturated O-bearing species containing methyl and ethyl groups in this region. Abundance ratios of related species and upper limits to the abundances of non-detected ethers are provided. We derive an abundance ratio N(CH3OCH3)/N(tEME) ≥ 150 in the compact ridge of Orion. PMID:26869726

  5. Sub-5 nm Domains in Ordered Poly(cyclohexylethylene)-block-poly(methyl methacrylate) Block Polymers for Lithography.

    SciTech Connect

    Kennemur, Justin; Yao, Li; Bates, Frank Stephen; Hillmyer, Marc

    2014-01-01

    A series of poly(cyclohexylethylene)-block-poly- (methyl methacrylate) (PCHE PMMA) diblock copolymers with varying molar mass (4.9 kg/mol Mn 30.6 kg/mol) and narrow molar mass distribution were synthesized through a combination of anionic and atom transfer radical polymerization (ATRP) techniques. Heterogeneous catalytic hydrogenation of -(hydroxy)polystyrene (PS-OH) yielded -(hydroxy)poly(cyclohexylethylene) (PCHEOH) with little loss of hydroxyl functionality. PCHE-OH was reacted with -bromoisobutyryl bromide (BiBB) to produce an ATRP macroinitiator used for the polymerization of methyl methacrylate. PCHE PMMA is a glassy, thermally stable material with a large effective segment segment interaction parameter, eff = (144.4 6.2)/T (0.162 0.013), determined by meanfield analysis of order-to-disorder transition temperatures (TODT) measured by dynamic mechanical analysis and differential scanning calorimetry. Ordered lamellar domain pitches (9 D 33 nm) were identified by small-angle X-ray scattering from neat BCPs containing 43 52 vol % PCHE ( f PCHE). Atomic force microscopy was used to show 7.5 nm lamellar features (D = 14.8 nm) which are some of the smallest observed to date. The lowest molar mass sample (Mn = 4.9 kg/mol, f PCHE = 0.46) is characterized by TODT = 173 3 C and sub-5 nm nanodomains, which together with the sacrificial properties of PMMA and the high overall thermal stability place this material at the forefront of high- systems for advanced nanopatterning applications.

  6. CCSD(T) study of the far-infrared spectrum of ethyl methyl ether.

    PubMed

    Senent, M L; Ruiz, R; Villa, M; Domínguez-Gómez, R

    2009-02-14

    Band positions and intensities for the far-infrared bands of ethyl methyl ether are variationally determined from a three-dimensional (3D) potential energy surface calculated with CCSD(T)/cc-pVTZ theory. For this purpose, the energies of 181 selected geometries computed optimizing 3n-9 parameters are fitted to a 3D Fourier series depending on three torsional coordinates. The zero point vibrational energy correction and the search of a correct definition of the methyl torsional coordinate are taken into consideration for obtaining very accurate frequencies. In addition, second order perturbation theory is applied on the two molecular conformers, trans and cis-gauche, in order to test the validity of the 3D model. Consequently, a new assignment of previous experimental bands, congruent with the new ab initio results, is proposed. For the most stable trans-conformer, the nu(30), nu(29), and nu(28) fundamental transitions, computed at 115.3, 206.5, and 255.2 cm(-1), are correlated with the observed bands at 115.4, 202, and 248 cm(-1). For the cis-gauche the three band positions are computed at 91.0, 192.5, and 243.8 cm(-1). Calculations on the -d(3) isotopomer confirm our assignment. Intensities are determined at room temperature and at 10 K. Structural parameters, potential energy barriers, anharmonic frequencies for the 3n-9 neglected modes, and rotational parameters (rotational and centrifugal distortion constants), are also provided.

  7. CCSD(T) study of the far-infrared spectrum of ethyl methyl ether

    NASA Astrophysics Data System (ADS)

    Senent, M. L.; Ruiz, R.; Villa, M.; Domínguez-Gómez, R.

    2009-02-01

    Band positions and intensities for the far-infrared bands of ethyl methyl ether are variationally determined from a three-dimensional (3D) potential energy surface calculated with CCSD(T)/cc-pVTZ theory. For this purpose, the energies of 181 selected geometries computed optimizing 3n-9 parameters are fitted to a 3D Fourier series depending on three torsional coordinates. The zero point vibrational energy correction and the search of a correct definition of the methyl torsional coordinate are taken into consideration for obtaining very accurate frequencies. In addition, second order perturbation theory is applied on the two molecular conformers, trans and cis-gauche, in order to test the validity of the 3D model. Consequently, a new assignment of previous experimental bands, congruent with the new ab initio results, is proposed. For the most stable trans-conformer, the ν30, ν29, and ν28 fundamental transitions, computed at 115.3, 206.5, and 255.2 cm-1, are correlated with the observed bands at 115.4, 202, and 248 cm-1. For the cis-gauche the three band positions are computed at 91.0, 192.5, and 243.8 cm-1. Calculations on the -d3 isotopomer confirm our assignment. Intensities are determined at room temperature and at 10 K. Structural parameters, potential energy barriers, anharmonic frequencies for the 3n-9 neglected modes, and rotational parameters (rotational and centrifugal distortion constants), are also provided.

  8. DFT study on the adsorption of diethyl, ethyl methyl, and dimethyl ethers on the surface of gallium doped graphene

    NASA Astrophysics Data System (ADS)

    Shokuhi Rad, Ali; Sani, Emad; Binaeian, Ehsan; Peyravi, Majid; Jahanshahi, Mohsen

    2017-04-01

    In this study, we used density functional theory (DFT) to search on the adsorption properties of three important compounds of ether family; diethyl ether (DEE), ethyl methyl ether (EME), and dimethyl ether (DME) on the surface of Gallium doped graphene (GaG). We used three functionals (B3LYP, wb97xd, and MPW1PW91) for optimization and calculation of adsorption energy. After fully optimization, we scrutinized on the charge allocations on the adsorbed ethers as well as GaG (at the area of interaction) based on natural bond orbitals (NBO). Besides, we have calculated the amount of charge transfer upon adsorption of each analyte. We revel that GaG is an ideal adsorbent for chemisorption of all above-mentioned ethers. There is a little difference between the values of adsorption; -123.5, -120, and -118.3 kJ/mol (based on wb97xd) for DEE, EME, and DME, respectively. We found significant changes in the electronic structure of both adsorbent and adsorbate upon adsorption. Moreover, results of charge analyses confirm GaG is a p-type semiconductor.

  9. Computational study of cyclohexanone-monomer co-initiation mechanism in thermal homo-polymerization of methyl acrylate and methyl methacrylate.

    PubMed

    Liu, Shi; Srinivasan, Sriraj; Grady, Michael C; Soroush, Masoud; Rappe, Andrew M

    2012-06-07

    This paper presents a systematic computational study of the mechanism of cyclohexanone-monomer co-initiation in high-temperature homopolymerization of methyl acrylate (MA) and methyl methacrylate (MMA). Previous experimental studies of spontaneous thermal homopolymerization of MA and MMA showed higher monomer conversion in the presence of cyclohexanone than xylene. However, these studies did not reveal the initiation mechanism(s) or the initiating species. To identify the initiation mechanism and the initiating species, we explore four different mechanisms, (1) Kaim, (2) Flory, (3) α-position hydrogen transfer, and (4) Mayo, using first-principles density functional theory (DFT) and second-order Møller-Plesset perturbation theory (MP2) calculations. Transition-state geometries for each mechanism are determined using B3LYP/6-31G* and assessed with MP2/6-31G*. Activation energies and rate constants are calculated using transition-state theory. The harmonic oscillator approximation and tunneling corrections are applied to compute the reaction rate constants. This study indicates that α-position hydrogen transfer and Mayo mechanisms have comparable barriers and are capable of generating monoradicals for initiating polymerization of MA and MMA; these two mechanisms can cause cyclohexanone-monomer co-initiation in thermal polymerization of MA and MMA.

  10. UV-Curable Polyurethane-Methacrylate Co-Networks and Interpenetrating Networks

    DTIC Science & Technology

    1989-05-30

    were: methyl methacrylate (MMA), ethyl methacrylate (EMA), hydroxyethyl methacrylate ( HEMA ), butyl methacrylate (BMA), lauryl methacrylate (LMA), and...ACCESSION NO. 11. TITLE (include Security Classification) UV’V-Curable Polyurethane- Methacrylate Co-Networks and Interpenetrating Networks 12. PERSONAL...by block number 4 Castor oil was reacted in varying ratios with 6-isocyanatoethyl methacrylate to form a liquid urethane- methacrylate prepolymer. This

  11. Injectible bodily prosthetics employing methacrylic copolymer gels

    DOEpatents

    Mallapragada, Surya K.; Anderson, Brian C.

    2007-02-27

    The present invention provides novel block copolymers as structural supplements for injectible bodily prosthetics employed in medical or cosmetic procedures. The invention also includes the use of such block copolymers as nucleus pulposus replacement materials for the treatment of degenerative disc disorders and spinal injuries. The copolymers are constructed by polymerization of a tertiary amine methacrylate with either a (poly(ethylene oxide)-b-poly(propylene oxide)-b-poly(ethylene oxide) polymer, such as the commercially available Pluronic.RTM. polymers, or a poly(ethylene glycol) methyl ether polymer.

  12. Synthesis and an evaluation of the bioactivity of the C-glycoside of pseudopterosin A methyl ether.

    PubMed

    Zhong, Wei; Moya, Claudia; Jacobs, R S; Little, R Daniel

    2008-09-19

    The Suzuki-Miyaura cross-coupling protocol was applied to the synthesis of 1a, the C-glycoside analogue of PsA methyl ether. This marks the first construction of a C-glycoside for this class of marine natural products, thereby offering an opportunity to compare its bioactivity to the natural substances. Its activity profile resembled that of PsA (1) and PsA O-methyl ether (1b) when assayed for its anti-inflammatory activity and its ability to inhibit phagocytosis. We conclude that the intact structure is present when a pseudopterosin expresses its anti-inflammatory and phagocytosis inhibitory properties and that they are, therefore, not likely to be prodrugs. Results show that 1a is an effective binding agent toward the A2A and A3 adenosine receptors, displaying IC50 values of 20 and 10 microM, respectively.

  13. Electrospinning preparation and photoluminescence properties of poly (methyl methacrylate)/Eu{sup 3+} ions composite nanofibers and nanoribbons

    SciTech Connect

    Li, Maoying; Zhang, Zhenyi; Cao, Tieping; Sun, Yangyang; Liang, Pingping; Shao, Changlu; Liu, Yichun

    2012-02-15

    Graphical abstract: Nanofibers and nanoribbons of poly (methyl methacrylate)/Eu{sup 3+} ions composites were successfully prepared by using a simple electrospinning technique. And the photoluminescence properties of the above PMMA/Eu{sup 3+} ions composites were studied. Highlights: Black-Right-Pointing-Pointer Nanofibers and nanoribbons of PMMA/Eu{sup 3+} ions composites are fabricated by electrospinning. Black-Right-Pointing-Pointer Photoluminescence properties of as-electrospun PMMA/Eu{sup 3+} ions composites are studied. Black-Right-Pointing-Pointer The ratios of electric- and magnetic-dipole transitions are enhanced by increasing electrospinning voltage. -- Abstract: Nanofibers and nanoribbons of poly (methyl methacrylate) (PMMA)/Eu{sup 3+} ions composites with different concentration of Eu{sup 3+} ions were successfully prepared by using a simple electrospinning technique. From the results of scanning electron microscopy and energy-dispersive X-ray spectroscopy, we found that the morphology of the as-electrospun PMMA/Eu{sup 3+} ions composites could be changed from fiber to ribbon structure by adjusting the concentration of Eu{sup 3+} ions in the electrospun precursor solution. The coordination between the Eu{sup 3+} ions and PMMA molecules were investigated by Fourier transform infrared spectroscopy and differential thermal analysis. The photoluminescence (PL) properties of the as-electrospun PMMA/Eu{sup 3+} ions composites were studied in comparison to those of the Eu(NO{sub 3}){sub 3} powder. It was showed that the {sup 5}D{sub 0}-{sup 7}F{sub J} (J = 0, 1, 2, 3, 4) emission appeared in the PL spectra of the as-electrospun PMMA/Eu{sup 3+} ions composites, whereas the {sup 5}D{sub 0}-{sup 7}F{sub 0} emission was completely absent in the PL spectra of Eu(NO{sub 3}){sub 3} powder due to the different local environments surrounding Eu{sup 3+} ions. It was interesting to note that the intensity ratios of the electric-dipole and magnetic-dipole transitions for

  14. Synthesis of ultrathin poly(methyl methacrylate) model coatings bound via organosilanes to zinc and investigation of their delamination kinetics.

    PubMed

    Iqbal, Danish; Rechmann, Julian; Sarfraz, Adnan; Altin, Abdulrahman; Genchev, Georgi; Erbe, Andreas

    2014-10-22

    Polymer coatings are widely used to protect metals from corrosion. Coating adhesion to the base material is critical for good protection, but coatings may fail because of cathodic delamination. Most of the experimental studies on cathodic delamination use polymers to study the corrosion behavior under conditions where the interfacial chemistry at the metal(oxide)/polymer interface is not well-defined. Here, ultrathin linear and cross-linked poly(methyl methacrylate) [PMMA] coatings that are covalently bound to oxide-covered zinc via a silane linker have been prepared. For preparation, zinc was functionalized with vinyltrimethoxysilane (VTS), yielding a vinyl monomer-covered surface. These samples were subjected to thermally initiated free radical polymerization in the presence of methyl methacrylate (MMA) to yield surface-bound ultrathin PMMA films of 10-20 nm thickness, bound to the surface via Zn-O-Si bonds. A similar preparation was also carried out in the presence of different amounts of the cross-linkers ethylene glycol diacrylate and hexanediol diacrylate. Functionalized and polymer-coated zinc samples were characterized by infrared (IR) spectroscopy, secondary ion mass spectrometry (SIMS), ellipsometry, and X-ray photoelectron spectroscopy (XPS). Coating stability toward cathodic delamination has been evaluated by scanning Kelvin probe (SKP) experiments. In all cases, the covalently linked coatings show lower delamination rates of 0.02-0.2 mm h(-1) than coatings attached to the surface without covalent bonds (rates ∼10 mm h(-1)). Samples with a higher fraction of cross-linker delaminate slower, with rates down to 0.03-0.04 mm h(-1), compared to ∼0.3 mm h(-1) without cross-linker. Samples with longer hydrophobic alkyl chains also delaminate slower, with the lowest observed delamination rate of 0.028 mm h(-1) using hexanediol diacrylate. For the coatings studied here, delamination kinetics is not diffusion limited, but the rate is controlled by a chemical

  15. Facile Synthesis of Novel Polyethylene-Based A-B-C Block Copolymers Containing Poly(methyl methacrylate) Using a Living Polymerization System.

    PubMed

    Song, Xiangyang; Ma, Qiong; Cai, Zhengguo; Tanaka, Ryo; Shiono, Takeshi; Grubbs, Robert B

    2016-02-01

    Ethylene-propylene-methyl methacrylate (MMA) and ethylene-hexene-MMA A-B-C block copolymers with high molecular weight (>100,000) are synthesized using fluorenylamide-ligated titanium complex activated by modified methylaluminoxane and 2,6-di-tert-butyl-4-methylphenol for the first time. After diblock copolymerization of olefin is conducted completely, MMA is added and activated by aluminum Lewis acid to promote anionic polymerization. The length of polyolefin and poly (methyl methacrylate) (PMMA) is controllable precisely by the change of the additive amount of olefin and polymerization time, respectively. A soft amorphous polypropylene or polyhexene segment is located between two hard segments of semicrystalline polyethylene and glassy PMMA blocks.

  16. Preparation of a new micro-porous poly(methyl methacrylate)-grafted polyethylene separator for high performance Li secondary battery

    NASA Astrophysics Data System (ADS)

    Gwon, Sung-Jin; Choi, Jae-Hak; Sohn, Joon-Yong; Ihm, Young-Eon; Nho, Young-Chang

    2009-10-01

    In this study, micro-porous poly(methyl methacrylate)-grafted polyethylene separators (PE-g-PMMA) were prepared by a radiation-induced graft polymerization of methyl methacrylate onto a conventional PE separator followed by a phase inversion. After the phase inversion, the micro-pores were generated in the grafted PMMA layer. The prepared micro-porous PE-g-PMMA separators showed an improved electrolyte uptake and ionic conductivity due to their improved affinity with a liquid electrolyte and the presence of pores in the grafted PMMA layer. The PE-g-PMMA separators exhibited a lower thermal shrinkage compared to the original PE separator. The PE-g-PMMA separators showed a better oxidation stability up to 5.0 V when compared to the original PE separator (4.5 V).

  17. Synthesis of high-molecular-weight polymer of methyl chloride salt of N,N-dimethylaminoethyl methacrylate by radiation-induced polymerization at high pressure. [Gamma radiation

    SciTech Connect

    Ishigaki, I.; Okada, T.; Sasuga, T.; Takehisa, M.; Machi, S.

    1981-02-01

    Polymer of the methyl chloride salt of N,N-dimethylaminoethyl methacrylate and its copolymer with acrylamide are used as cationic flocculants for the treatment of waste water containing organic suspensions. As reported, radiation-induced polymerization is one of the most convenient methods because of its temperature independence of initiation and extremely large G-value. In general, a flocculant with higher molecular weight has larger flocculation effects. The high-molecular-weight products were prepared in high monomer concentration and a low dose rate. This paper concerns the polymerization and copolymerization of methyl chloride salt of N,N-dimethylaminoethyl methacrylate at high pressure, up to 7000 kg/cm/sup 2/, providing high-molecular-weight cationic flocculants.

  18. In situ synthesis of poly(methyl methacrylate)/MgAl layered double hydroxide nanocomposite with high transparency and enhanced thermal properties

    NASA Astrophysics Data System (ADS)

    Chen, Wei; Feng, Li; Qu, Baojun

    2004-04-01

    A novel poly(methyl methacrylate)/MgAl layered double hydroxide (LDH) nanocomposite (PMMA-MgAl NC) with high transparency and enhanced thermal properties was synthesized in situ by adding sodium hydroxide aqueous solution to an emulsion consisting of metal ion aqueous solution, sodium dodecyl sulfate, methyl methacrylate, and benzoyl peroxide, then followed by the thermal initiation polymerization. The basal spacing of PMMA-MgAl NC was 2.72 nm determined by X-ray diffraction measurement. The intercalated MgAl LDH particles of 60-120 nm width and 25-40 nm thickness were well dispersed at molecular level in the PMMA matrix. When the 50% weight loss was selected as a comparison point, the decomposition temperature of PMMA-MgAl NC sample with 30 wt% MgAl LDH (including dodecyl sulfate) was ca. 45 °C higher than that of pure PMMA.

  19. Fabrication of nanopatterned poly(ethylene glycol) brushes by molecular transfer printing from poly(styrene-block-methyl methacrylate) films to generate arrays of Au nanoparticles.

    PubMed

    Onses, M Serdar

    2015-01-27

    This article presents a soft lithographic approach using block copolymer (BCP) films to fabricate functional chemically patterned polymer brushes on the nanoscale. Hydroxyl-terminated poly(ethylene glycol) (PEG-OH) was transfer printed from the poly(methyl methacrylate) (PMMA) domains of self-assembled poly(styrene-block-methyl methacrylate) films to a substrate in conformal contact with the film to generate patterned PEG brushes mirroring the pattern of BCP domains. A key point in the study is that the chemistry of the functional transferred brushes is different from the chemistry of either block of the copolymer; PEG-OH is miscible only in the PMMA block and therefore transferred only from PMMA domains. The functionality of the PEG brushes was demonstrated by the selective immobilization of citrate-stabilized Au NPs (15 nm) and validated the generation of high-quality chemical patterns with sub-30-nm feature sizes.

  20. Adsorption of methyl tertiary butyl ether on granular zeolites: Batch and column studies.

    PubMed

    Abu-Lail, Laila; Bergendahl, John A; Thompson, Robert W

    2010-06-15

    Methyl tertiary butyl ether (MTBE) has been shown to be readily removed from water with powdered zeolites, but the passage of water through fixed-beds of very small powdered zeolites produces high friction losses not encountered in flow through larger sized granular materials. In this study, equilibrium and kinetic adsorption of MTBE onto granular zeolites, a coconut shell granular activated carbon (CS-1240), and a commercial carbon adsorbent (CCA) sample was evaluated. In addition, the effect of natural organic matter (NOM) on MTBE adsorption was evaluated. Batch adsorption experiments determined that ZSM-5 was the most effective granular zeolite for MTBE adsorption. Further equilibrium and kinetic experiments verified that granular ZSM-5 is superior to CS-1240 and CCA in removing MTBE from water. No competitive adsorption effects between NOM and MTBE were observed for adsorption to granular ZSM-5 or CS-1240, however there was competition between NOM and MTBE for adsorption onto the CCA granules. Fixed-bed adsorption experiments for longer run times were performed using granular ZSM-5. The bed depth service time model (BDST) was used to analyze the breakthrough data.

  1. Adsorption of Methyl Tertiary Butyl Ether on Granular Zeolites: Batch and Column Studies

    PubMed Central

    Abu-Lail, Laila; Bergendahl, John A.; Thompson, Robert W.

    2010-01-01

    Methyl tertiary butyl ether (MTBE) has been shown to be readily removed from water with powdered zeolites, but the passage of water through fixed beds of very small powdered zeolites produces high friction losses not encountered in flow through larger sized granular materials. In this study, equilibrium and kinetic adsorption of MTBE onto granular zeolites, a coconut shell granular activated carbon (CS-1240), and a commercial carbon adsorbent (CCA) sample was evaluated. In addition, the effect of natural organic matter (NOM) on MTBE adsorption was evaluated. Batch adsorption experiments determined that ZSM-5 was the most effective granular zeolite for MTBE adsorption. Further equilibrium and kinetic experiments verified that granular ZSM-5 is superior to CS-1240 and CCA in removing MTBE from water. No competitive-adsorption effects between NOM and MTBE were observed for adsorption to granular ZSM-5 or CS-1240, however there was competition between NOM and MTBE for adsorption onto the CCA granules. Fixed-bed adsorption experiments for longer run times were performed using granular ZSM-5. The bed depth service time model (BDST) was used to analyze the breakthrough data. PMID:20153106

  2. Environmental behavior and fate of methyl tert-butyl ether (MTBE)

    USGS Publications Warehouse

    Squillace, Paul J.; Pankow, James F.; Korte, Nic E.; Zogorski, John S.

    1996-01-01

    When gasoline that has been oxygenated with methyl tert-butyl ether (MTBE) comes in contact with water, large amounts of MTBE can dissolve; at 25 degrees Celsius the water solubility of MTBE is about 5,000 milligrams per liter for a gasoline that is 10 percent MTBE by weight. In contrast, for a nonoxygenated gasoline, the total hydrocarbon solubility in water is typically about 120 milligrams per liter. MTBE sorbs only weakly to soil and aquifer materials; therefore, sorption will not significantly retard MTBE's transport by ground water. In addition, MTBE generally resists degradation in ground water. The half-life of MTBE in the atmosphere can be as short as 3 days in a regional airshed. MTBE in the air tends to partition into atmospheric water, including precipitation. However, washout of gas-phase MTBE by precipitation would not, by itself, greatly alter the gas-phase concentration of the compound in the air. The partitioning of MTBE to precipitation is nevertheless strong enough to allow for up to 3 micrograms per liter or more inputs of MTBE to surface and ground water.

  3. Effect of methyl tert-butyl ether in standard tests for mutagenicity and environmental toxicity.

    PubMed

    Vosahlikova, Miluse; Cajthaml, Tomas; Demnerova, Katerina; Pazlarova, Jarmila

    2006-12-01

    Methyl tert-butyl ether (MTBE) is a synthetic compound that is used as a technological solution to problems created by air pollution from vehicle emissions. An important source of MTBE in the environment is leakage from underground storage tanks at gasoline stations or accidents during gasoline transport. The aim of this study was to evaluate the risk of MTBE leakage for the environment using the Microtox (Vibrio fischeri) toxicity test, Lactuca sativa seed germination test, and Ames bacterial mutagenicity test with Salmonella typhimurium his(-) strains TA98, TA100, YG1041, and YG1042, using both standard plate and preincubation protocols. The result of Microtox expressed as EC(50) was 33 mg (MTBE)/L. The effect of all tested MTBE concentration (0.05, 0.50, and 1.00% v/v) on Lactuca sativa roots elongation was negative and proved its toxicity. The highest tested concentration of MTBE that could be tested in Ames test was 3 mg (MTBE)/plate, because of cytotoxicity. No mutagenic response was observed at this or lower concentrations in any of the four strains used.

  4. The effect of materials selection on metals reduction in propylene glycol methyl ether acetate, PGMEA

    NASA Astrophysics Data System (ADS)

    Entezarian, Majid; Geiger, Bob

    2016-03-01

    The trend in microelectronics fabrication is to produce nano-features measuring down to 10 nm and finer. The PPT levels of organic and inorganic contaminants in the photoresist, solvent and cleaning solutions are becoming a major processing variable affecting the process capability and defectivity. The photoresist usually contains gels, metals, and particulates that could interfere with the lithography process and cause microbridging defects. Nano filters of 5 nm polypropylene, 5 nm polyethylene, and 10 nm natural nylon were used to filter propylene glycol methyl ether acetate PGMEA containing 50 ppb of Na, Mg, Al, Ca, Cr, Mn, Fe, Cu, Zn, and Pb. All filters were effective in removing trivalent Al, Cr, and Fe metals indicating the mechanism for their removal as mechanical sieving. However, the nylon was also very effective in removing the divalent metals showing adsorptive properties. Furthermore, the metal removal of the nylon membrane was studied as a function of surface chemistry. Natural and charged 40 nm nylon membranes were tested and found that charged nylon is more effective for metal removal.

  5. Biodegradation of potential diesel oxygenate additives: dibutyl maleate (DBM), and tripropylene glycol methyl ether (TGME).

    PubMed

    Marchetti, Alfredo A; Knize, Mark G; Chiarappa-Zucca, Marina L; Pletcher, Ronald J; Layton, David W

    2003-08-01

    The addition of oxygen-bearing compounds to diesel fuel considerably reduces particulate emissions. TGME and DBM have been identified as possible diesel additives based on their physicochemical characteristics and performance in engine tests. Although these compounds will reduce particulate emissions, their potential environmental impacts are unknown. As a means of characterizing their persistence in environmental media such as soil and groundwater, we conducted a series of biodegradation tests of DBM and TGME. Benzene and methyl tertiary butyl ether (MTBE) were also tested as reference compounds. Primary degradation of DBM fully occurred within 3 days, while TGME presented a lag phase of approximately 8 days and was not completely degraded by day 28. Benzene primary degradation occurred completely by day 3 and MTBE did not degrade at all. The total mineralized fractions of DBM and TGME achieved constant values as a function of time of approximately 65% and approximately 40%, respectively. Transport predictions show that, released to the environment, DBM and TGME would concentrate mostly in soils and waters with minimal impact to air. From an environmental standpoint, these results combined with the transport predictions indicate that DBM is a better choice than TGME as a diesel additive.

  6. Characterization methods for radiation crosslinked poly(vinyl methyl ether) hydrogels

    NASA Astrophysics Data System (ADS)

    Schmidt, Thomas; Querner, Claudia; Arndt, Karl-Friedrich

    2003-08-01

    The paper reviews recent results of radiation crosslinking of poly(vinyl methyl ether) (PVME). It will give an overview of possible characterization methods for both, soluble and crosslinked PVME. The irradiation of aqueous low concentrated PVME solutions with γ-rays of low doses results in structural changes of PVME molecules. We are able to monitor changes in the chemical structure by spectroscopic methods (IR, NMR) as well as the changes of molecular parameters (e.g. molecular weight, molecular weight distribution, branches) by classical methods for polymer characterization (size exclusion chromatography with diverse detector systems, SLS, viscosimetry). The characterization of the network parameters (crosslinking density νc, molecular weight of the network chains Mc) of PVME bulkgels crosslinked by irradiation at high dose values by classical methods (swelling and compression measurements) provides incorrect results because of the high porosity of the gels. PVME microgel particles can be prepared by irradiation of a phase separated diluted aqueous PVME solution above their lower critical solution temperature. These microgels with decreased dimensions were characterized by SLS, DLS and field emission scanning electron microscopy.

  7. Radiation crosslinking and scission parameters for poly(vinyl methyl ether) in aqueous solution

    NASA Astrophysics Data System (ADS)

    Janik, I.; Kasprzak, E.; Al-Zier, A.; Rosiak, J. M.

    2003-08-01

    In oxygen-free aqueous solutions, poly(vinyl methyl ether) (PVME) was subjected to gamma irradiation. In such conditions PVME radicals recombine by way of crosslinking. The major result of crosslinking is an increase in the average molecular weight of the polymer, which close to the gelation point tends to infinity. Further irradiation increases the amount of formed gel, while the soluble fraction - sol decreases. The basic parameters related to the radiation processing are gelation dose - Dg, as well as radiation yield of intermolecular crosslinking and scission, GX and GS, respectively. There are three general approaches for estimation of those parameters. The first method is based on the study of molecular weight changes before the gelation point. The second method combines the gel-sol as well as the swelling analysis results. The third one allows one to calculate the yield of crosslinking from the value of Dg. All of these methods of calculation were used in this work for determination of radiation parameters and results obtained are discussed.

  8. Kinetics of the oxidation of methyl tert-butyl ether (MTBE) by potassium permanganate.

    PubMed

    Damm, Jochen H; Hardacre, Christopher; Kalin, Robert M; Walsh, Kayleen P

    2002-08-01

    The occurrence of the fuel oxygenate methyl tert-butyl ether (MTBE) in the environment has received considerable scientific attention. The pollutant is frequently found in the groundwater due to leaking of underground storage tanks or pipelines. Concentrations of more than several mg/L MTBE were detected in groundwater at several places in the US and Germany in the last few years. In situ chemical oxidation is a promising treatment method for MTBE-contaminated plumes. This research investigated the reaction kinetics for the oxidation of MTBE by permanganate. Batch tests demonstrated that the oxidation of MTBE by permanganate is second order overall and first order individually with respect to permanganate and MTBE. The second-order rate constant was 1.426 x 10(-6) L/mg/h. The influence of pH on the reaction rate was demonstrated to have no significant effect. However, the rate of MTBE oxidation by potassium permanganate is 2-3 orders of magnitude lower than of other advanced oxidation processes. The slower rates of MTBE oxidation by permanganate limit the applicability of this process for rapid MTBE cleanup strategies. However, permanganate oxidation of MTBE has potential for passive oxidation risk management strategies.

  9. Evaluation of Methyl Fluoride and Dimethyl Ether as Inhibitors of Aerobic Methane Oxidation

    PubMed Central

    Oremland, Ronald S.; Culbertson, Charles W.

    1992-01-01

    Methyl fluoride (MF) and dimethyl ether (DME) were effective inhibitors of aerobic methanotrophy in a variety of soils. MF and DME blocked consumption of CH4 as well as the oxidation of 14CH4 to 14CO2, but neither MF nor DME affected the oxidation of [14C]methanol or [14C]formate to 14CO2. Cooxidation of ethane and propane by methane-oxidizing soils was also inhibited by MF. Nitrification (ammonia oxidation) in soils was inhibited by both MF and DME. Production of N2O via nitrification was inhibited by MF; however, MF did not affect N2O production associated with denitrification. Methanogenesis was partially inhibited by MF but not by DME. Methane oxidation was ∼100-fold more sensitive to MF than was methanogenesis, indicating that an optimum concentration could be employed to selectively block methanotrophy. MF inhibited methane oxidation by cell suspensions of Methylococcus capsulatus; however, DME was a much less effective inhibitor. PMID:16348771

  10. Toxicity of methyl tertiary butyl ether to Daphnia magna and photobacterium phosphoreum

    SciTech Connect

    Gupta, G.; Lin, Y.J.

    1995-10-01

    Methyl tertiary butyl ether (MTBE) is a liquid organic compound added to gasoline to increase its oxygen content and to reduce the emission of carbon monoxide during combustion in many urban areas. In order to meet the 1990 Clean Air Act amendments, gasoline must contain 2.7% oxygen (by weight) or 15% (by volume) of MTBE in gasoline to meet the regulations for the control of carbon monoxide emissions. Health effects caused by inhalation of MTBE include headaches, dizziness, irritated eyes and nausea; MTBE is one of cancer--causing chemicals. Intracaval injection of MTBE (0.2 mg/kg) caused the highest mortality (100%) in rats. General anesthetic effect induced by MTBE was found at or above 1200 mg/kg body weight; Rosenkranz and Klopman (1991) predicted that MTBE is neither a genotoxicant nor a carcinogen. Nevertheless, the safety of using MTBE in oxygenated fuels is now being questioned from its potential as groundwater pollutant. This study measures the toxicity of MTBE to Daphnia magna and Photobacterium phosphoreum. 13 refs.

  11. Generation Performance of a Fuel Cell Using Hydrogen and Di-methyl-ether (DME) Mixed Gas

    NASA Astrophysics Data System (ADS)

    Haraguchi, Tadao; Watanabe, Takashi; Yamashita, Masahiro; Tsutsumi, Yasuyuki; Yamashita, Susumu

    Di-methyl-ether (DME), an oxygenated hydrocarbon, can facilitate hydrogen manufacture by steam reforming reaction at low temperature. Methanol and DME steam reforming at 250-300°C, reforming DME into hydrogen, can be performed easily with small-scale and simple equipment. Whether the hydrogen output from the reformer for supply to the fuel cell includes DME, and how this affects the generation performance has yet to be confirmed. The purpose of this paper is to investigate the supply of a fuel cell with mixtures of DME and H2 in varying proportions and to clarify the effect on generation performance. Conclusions are as follows: (1) For a supply of DME and H2 mixed gas, DME is consumed after the H2 is consumed. By comparing the experimental values with theoretical values of consumption of pure H2, a mixture of DME and H2, and pure DME, it proved to be possible to roughly predict the experimental values by calculation. (2) The voltage value moved to near the DME voltage after the H2 was consumed, the current density increased after the H2 was consumed. (3) During continuous running the voltage load was observed to fluctuate.

  12. Biodegradation of Methyl tert-Butyl Ether by Co-Metabolism with a Pseudomonas sp. Strain

    PubMed Central

    Li, Shanshan; Wang, Shan; Yan, Wei

    2016-01-01

    Co-metabolic bioremediation is supposed to be an impressive and promising approach in the elimination technology of methyl tert-butyl ether (MTBE), which was found to be a common pollutant worldwide in the ground or underground water in recent years. In this paper, bacterial strain DZ13 (which can co-metabolically degrade MTBE) was isolated and named as Pseudomonas sp. DZ13 based on the result of 16S rRNA gene sequencing analysis. Strain DZ13 could grow on n-alkanes (C5-C8), accompanied with the co-metabolic degradation of MTBE. Diverse n-alkanes with different carbon number showed a significant influence on the degradation rate of MTBE and accumulation of tert-butyl alcohol (TBA). When Pseudomonas sp. DZ13 co-metabolically degraded MTBE with n-pentane as the growth substrate, a higher MTBE-degrading rate (Vmax = 38.1 nmol/min/mgprotein, Ks = 6.8 mmol/L) and lower TBA-accumulation was observed. In the continuous degradation experiment, the removal efficiency of MTBE by Pseudomonas sp. Strain DZ13 did not show an obvious decrease after five times of continuous addition. PMID:27608032

  13. Radiation crosslinking and scission of poly(vinyl methyl ether) in aqueous solution

    NASA Astrophysics Data System (ADS)

    Janik, Ireneusz; Rosiak, Janusz M.

    2002-03-01

    For a wide range of poly(vinyl methyl ether) (PMVE) concentrations (1-16 g dm -3), in anoxic conditions, polymer-derived radicals recombine in two major pathways: (i) crosslinking and (ii) disproportionation. Both these processes proceed inter- and intramolecularly. The radiation-chemical yields and kinetics of crosslinking have been studied by pulse radiolysis with light scattering intensity detection (LSI). In the absence of oxygen, G-values of intermolecular crosslinking were determined on the basis of LSI changes versus applied dose and compared with the results obtained previously for γ-irradiated samples. It has been found that the first half-life time of intermolecular crosslinking decreases with increasing dose per pulse. Addition of small amounts of macroradical scavenger (cysteamine hydrochloride) decreases, drastically, the increase of LSI signal. On increasing the PVME concentration, intermolecular crosslinking becomes more efficient. In the presence of oxygen, for diluted PVME solution (0.1 g dm -3), decrease of LSI signal consisting of the kinetic of a first-order reaction was observed. The rate constant of LSI decrease was found to be 1.1×10 3 s -1 and it was attributed to the main-chain scission.

  14. The 60Co- γ ray-initiated seeded-emulsion polymerization of methyl methacrylate in the presence of waterborne polyurethane seeds

    NASA Astrophysics Data System (ADS)

    Zhang, Guixi; Zhang, Zhicheng

    2004-09-01

    In this work, the waterborne polyurethane (WPU)/poly (methyl methacrylate) (PMMA) composite material was successfully prepared via 60Co- γ ray radiation-induced seeded emulsion polymerization. The kinetic curves of the synthesis of WPU have been obtained in MMA medium and in acetone medium, respectively. The FT-IR spectra were used to investigate the grafting efficiency of the PMMA on WPU backbone.

  15. Surface structures of poly(methyl methacrylate) films influenced by chain entanglement in the corresponding film-formation solution.

    PubMed

    Xu, Jianquan; Liu, Yingjun; He, Jinsheng; Zhang, Rongping; Zuo, Biao; Wang, Xinping

    2014-11-28

    The effects of the properties of casting solution on the surface structure of poly(methyl methacrylate) (PMMA) films were systematically investigated. It was observed that the hydrophobicity of PMMA films increased with increasing viscosity of the corresponding polymer solution regardless of the film-formation techniques that were utilized. The ratio of the C-H symmetric stretching vibrations of methylene groups (hydrophobic components, with a peak at 2910 cm(-1)) to those of the ester methyl groups (relative hydrophilic components, with a peak at 2955 cm(-1)) from sum frequency generation (SFG) vibrational spectra, A2910/A2955, was used as a parameter to evaluate the structure on the film surface, which was related to the surface wettability of the films. The results showed that A2910/A2955 of cast PMMA films increased linearly with ηsp(0.3) (ηsp, the specific viscosity of the casting solution), whereas that of the corresponding spin-coated films showed a linear relationship defined as ηsp(0.3)E(0.26), where E is the average number of entanglement points per molecule (E = Mw/Me). These results indicate that a relative equilibrium conformation on the PMMA film surface, adopted from the perspective of thermodynamics, was easily achieved during film formation, when the conformation of the polymer chains in the corresponding casting solution was close to that in the bulk. For the spin-coated films, the chain entanglement structure in the casting solution was a more important factor for the resulting film to reach a relative equilibrium state, since this structure was in favor of maintaining the pristine conformation in casting solution under centrifugal force during spin-coating. This work may help to enhance the fundamental understanding of the formation of the film surface structure from polymer solution to the resulting solid film, which will affect not only the corresponding surface properties, but also the dynamics of the resulting thin films.

  16. Molecular dynamics study of the molecular weight dependence of surface tensions of normal alkanes and methyl methacrylate oligomers.

    PubMed

    Li, Chunli; Choi, Phillip

    2006-04-06

    Surface tensions (gamma) of normal alkanes and methyl methacrylate (MMA) oligomers at various molecular weights in the low molecular weight range were computed using a newly proposed molecular dynamics (MD) simulation strategy which was developed based on the definition of gamma = ( partial differential U/ partial differential sigma)n,V,S. The MD simulations, even with the use of a generic force field, reproduced the experimentally observed molecular weight dependence of gamma (i.e., gamma proportional Mn(-2/3), where Mn is the number-average molecular weight) for both series of oligomers. Analysis of the data reveals that solvent accessible surface area, one of the key input variables used for the calculation of gamma, exhibits an Mn(2/3) (rather than Mn(1)) dependence. The reason for such dependence is that solvent accessible surface area formed by the chainlike small molecules depends, to a larger extent, on their orientations rather than their size. However, this is not the case for high molecular weight molecules as solvent accessible surface area of such surfaces are determined by the orientations of their segments which are determined by the conformations of the molecules. This may explain why surface tension of polymers experimentally exhibits an Mn(-1) dependence. It is inferred that the corresponding molecular weight dependence of the entropy changes associated with molecules in the low and high molecular weight ranges would be different.

  17. Surface Molecularly Imprinted Polymer of Chitosan Grafted Poly(methyl methacrylate) for 5-Fluorouracil and Controlled Release

    PubMed Central

    Zheng, Xue-Fang; Lian, Qi; Yang, Hua; Wang, Xiuping

    2016-01-01

    The molecular surface imprinted graft copolymer of chitosan with methyl methacrylate (MIP-CS-g-PMMA) were prepared by free radical polymerization with 5-fluorouracil (5-FU) as the template molecule using initiator of ammonium persulfate as adsorption system. MIPs were characterized by FTIR, X-ray diffraction, thermo-gravimetric analysis, 1H NMR and SEM. The mechanism of graft copolymerization and factors affected graft reaction were studied in details, and the optimum reaction conditions (to the highest %G and %E as the standard) were obtained at [MMA] 1.2 mol/L, [Chitosan] 16.67 mol/L, [initiator] 0.0062 mol/L, temperature 60 °C and reaction time 7 h. MIPs exhibited high recognition selectivity and excellent combining affinity to template molecular. The in vitro release of the 5-FU was highly pH-dependent and time delayed. The release behavior showed that the drugs did not release in simulated gastric fluid (pH = 1.0), and the drug release was small in the simulated small intestinal fluid (pH = 6.8), and drug abrupt release will be produced in the simulated colon fluid (pH = 7.4), indicating excellent colon-specific drug delivery behavior. PMID:26892676

  18. Effect of reactive adhesives on the tensile bond strength of polyvinyl siloxane impression materials to methyl methacrylate tray material.

    PubMed

    Ona, Masahiro; Takahashi, Hidekazu; Sato, Masayuki; Igarashi, Yoshimasa; Wakabayashi, Noriyuki

    2010-05-01

    The effect of new adhesives on the bond strength of elastomeric impression materials to acrylic trays was evaluated. Two polyvinyl siloxane impression materials (Fusion and Imprinsis) with reactive adhesives and one (Examix) with a conventional adhesive were tested. Flat, double-sided plates of auto-polymerizing methyl methacrylate (10 x 10 x 2.5 mm) were prepared with one of the adhesives. Five specimens were prepared by injecting each impression material into a 2-mm gap between the two plates. Tensile tests were conducted until separation failure occurred. The mean bond strengths of Fusion (1.0 MPa) and Imprinsis (0.8 MPa) were significantly greater than that of Examix (0.2 MPa). On the contrary, one of five Fusion showed adhesive failure mode while all the Imprinsis exhibited mixed failure. The conflicting results were presumably attributed to the mean tear strength of Fusion (0.8 N/mm) being higher than that of Imprinsis (0.5 N/mm).

  19. Effects of water storage of E-glass fiber reinforced denture base polymers on residual methyl methacrylate content.

    PubMed

    Bayraktar, Gulsen; Duran, Ozlem; Bural, Canan; Guvener, Bora

    2004-07-15

    This study investigated the effect of water storage on residual methyl methacrylate (MMA) content of continuous E-glass fiber (Wetrotex International) reinforced denture base polymers. Heat-polymerization (short- and long-term boiling and conventional curing cycle using Meliodent), autopolymerization (processed in air at room temperature and in water at 60 degrees C with the use of Meliodent Rapid Repair), and microwave-polymerization (3 min at 500 W with the use of Acron MC) were employed. The residual MMA contents of 120 specimens were analyzed by high-performance liquid chromatography at deflasking (control) and after water (37 degrees C) storage of 1 day, 1 week, and 1 month. Bonferroni's pairwise comparison test was used for statistical analysis. Significant reduction were determined only in the long-term terminal boiled heat-polymerized test group at the end of 1 day (p < 0.01), 1 week (p < 0.05) and also 1 month of water storage (p < 0.01). Significant reduction in autopolymerized test groups started even after 1 week of water storage (p < 0.05). Microwave-polymerized test groups did not show a significant residual MMA reduction in all time intervals (p > 0.05). The polymerization methods and cycles applied to the glass fiber reinforced denture base polymers influence both the content and the reduction of residual MMA after water storage.

  20. Poly(methyl methacrylate) as a self-assembled gate dielectric for graphene field-effect transistors

    SciTech Connect

    Sanne, A.; Movva, H. C. P.; Kang, S.; McClellan, C.; Corbet, C. M.; Banerjee, S. K.

    2014-02-24

    We investigate poly(methyl methacrylate) (PMMA) as a low thermal budget organic gate dielectric for graphene field effect-transistors (GFETs) based on a simple process flow. We show that high temperature baking steps above the glass transition temperature (∼130 °C) can leave a self-assembled, thin PMMA film on graphene, where we get a gate dielectric almost for “free” without additional atomic layer deposition type steps. Electrical characterization of GFETs with PMMA as a gate dielectric yields a dielectric constant of k = 3.0. GFETs with thinner PMMA dielectrics have a lower dielectric constant due to decreased polarization arising from neutralization of dipoles and charged carriers as baking temperatures increase. The leakage through PMMA gate dielectric increases with decreasing dielectric thickness and increasing electric field. Unlike conventional high-k gate dielectrics, such low-k organic gate dielectrics are potentially attractive for devices such as the proposed Bilayer pseudoSpin Field-Effect Transistor or flexible high speed graphene electronics.

  1. Effect of silver ion-induced disorder on morphological, chemical and optical properties of poly (methyl methacrylate)

    NASA Astrophysics Data System (ADS)

    Arif, Shafaq; Saleemi, Farhat; Rafique, M. Shahid; Naab, Fabian; Toader, Ovidiu; Mahmood, Arshad; Aziz, Uzma

    2016-11-01

    Ion implantation is a versatile technique to tailor the surface properties of polymers in a controlled manner. In the present study, samples of poly (methyl methacrylate) (PMMA) have been implanted with 400 keV silver (Ag+) ion beam to various ion fluences ranging from 5 × 1013 to 5 × 1015 ions/cm2. The effect of Ag+ ion-induced disorder on morphological, chemical and optical properties of PMMA is analyzed using Atomic Force Microscope (AFM), Fourier transform infrared spectroscopy (FTIR) and ultraviolet-visible (UV-Vis) spectroscopy. Furthermore, the electrical conductivity of pristine and implanted PMMA is measured using four probe apparatus. The AFM images revealed the growth of nano-sized grainy structures and hillocks above the surface of implanted PMMA. The FTIR spectra confirmed the modifications in chemical structure of PMMA along with the formation of sbnd Cdbnd Csbnd carbon contents. The refractive index, extinction coefficient and photoconductivity of implanted PMMA have been found to increase as a function of ion fluence. Simultaneously, indirect optical band gap is reduced from 3.13 to 0.81 eV at a relatively high fluence (5 × 1015 ions/cm2). A linear correlation has been established between the band gap and Urbach energies. Moreover, the electrical conductivity of Ag+ implanted PMMA has increased from 2.14 × 10-10 (pristine) to 9.6 × 10-6 S/cm.

  2. Poly(methyl methacrylate) Surface Modification for Surfactant-Free Real-Time Toxicity Assay on Droplet Microfluidic Platform.

    PubMed

    Ortiz, Raphael; Chen, Jian Lin; Stuckey, David C; Steele, Terry W J

    2017-04-07

    Microfluidic droplet reactors have many potential uses, from analytical to synthesis. Stable operation requires preferential wetting of the channel surface by the continuous phase which is often not fulfilled by materials commonly used for lab-on-chip devices. Here we show that a silica nanoparticle (SiNP) layer coated onto a Poly(methyl methacrylate) (PMMA) and other thermoplastics surface enhances its wetting properties by creating nanoroughness, and allows simple grafting of hydrocarbon chains through silane chemistry. Using the unusual stability of silica sols at their isoelectric point, a dense SiNP layer is adsorbed onto PMMA and renders the surface superhydrophilic. Subsequently, a self-assembled dodecyltrichlorosilane (DTS) monolayer yields a superhydrophobic surface that allows the repeatable generation of aqueous droplets in a hexadecane continuous phase without surfactant addition. A SiNP-DTS modified chip has been used to monitor bacterial viability with a resazurin assay. The whole process involving sequential reagents injection, and multiplexed droplet fluorescence intensity monitoring is carried out on chip. Metabolic inhibition of the anaerobe Enterococcus faecalis by 30 mg L(-1) of NiCl2 was detected in 5 min.

  3. Fabrication of poly(methyl methacrylate)-MoS{sub 2}/graphene heterostructure for memory device application

    SciTech Connect

    Shinde, Sachin M.; Tanemura, Masaki; Kalita, Golap

    2014-12-07

    Combination of two dimensional graphene and semi-conducting molybdenum disulfide (MoS{sub 2}) is of great interest for various electronic device applications. Here, we demonstrate fabrication of a hybridized structure with the chemical vapor deposited graphene and MoS{sub 2} crystals to configure a memory device. Elongated hexagonal and rhombus shaped MoS{sub 2} crystals are synthesized by sulfurization of thermally evaporated molybdenum oxide (MoO{sub 3}) thin film. Scanning transmission electron microscope studies reveal atomic level structure of the synthesized high quality MoS{sub 2} crystals. In the prospect of a memory device fabrication, poly(methyl methacrylate) (PMMA) is used as an insulating dielectric material as well as a supporting layer to transfer the MoS{sub 2} crystals. In the fabricated device, PMMA-MoS{sub 2} and graphene layers act as the functional and electrode materials, respectively. Distinctive bistable electrical switching and nonvolatile rewritable memory effect is observed in the fabricated PMMA-MoS{sub 2}/graphene heterostructure. The developed material system and demonstrated memory device fabrication can be significant for next generation data storage applications.

  4. Sustained release of hydrophilic drug from polyphosphazenes/poly(methyl methacrylate) based microspheres and their degradation study.

    PubMed

    Akram, Muhammad; Yu, Haojie; Wang, Li; Khalid, Hamad; Abbasi, Nasir M; Zain-ul-Abdin; Chen, Yongsheng; Ren, Fujie; Saleem, Muhammad

    2016-01-01

    Drug delivery system is referred as an approach to deliver the therapeutic agents to the target site safely in order to achieve the maximum therapeutic effects. In this perspective, synthesis of three new polyphosphazenes and their blend fabrication system with poly(methyl methacrylate) is described and characterized with (1)H NMR, (31)P NMR, GPC and DSC. Furthermore, these novel blends were used to fabricate microspheres and evaluated for sustain release of hydrophilic drug (aspirin as model drug). Microspheres of the two blends showed excellent encapsulation efficacy (about 93%), controlled burst release (2.3% to 7.93%) and exhibited sustain in vitro drug release (13.44% to 32.77%) up to 218 h. At physiological conditions, the surface degradation of microspheres and diffusion process controlled the drug release sustainability. Furthermore, it was found that the degree of porosity was increased with degradation and the resulting porous network was responsible for water retention inside the microspheres. The percentage water retention was found to be interrelated with degradation time and percentage drug release.

  5. RAFT mediated polymerization of methyl methacrylate initiated by Bergman cyclization: access to high molecular weight narrow polydispersity polymers.

    PubMed

    Gerstel, Peter; Barner-Kowollik, Christopher

    2011-03-02

    The first RAFT mediated polymerization of methyl methacrylate initiated by diradicals derived from Bergman cyclization was performed employing 3,4-benzocyclodec-3-ene-1,5-diyne (BCDY) as diradical source and cyanoisopropyldithiobenzoate (CPDB) as RAFT agent. The polymerization was conducted in bulk at 80 °C for 3 h. The concentration of the enediyne was kept constant at 3.0 x 10⁻² mol · L⁻¹ and the RAFT agent concentration was varied between 0.0 mol · L⁻¹ and 2.4 x 10⁻¹ mol · L⁻¹. A detailed ESI-MS analysis reveals the absence of intramolecular termination reactions (ring formation) in the RAFT mediated system, which usually makes diradicalic initiation unfavorable. The presence of polymeric chains propagating at both ends could be confirmed. The conversion of the RAFT mediated polymerization was up to more than two times higher than the RAFT free polymerization at identical conditions. Thus, polymers with narrow polydispersities (1.1 ≤ PDI ≤ 1.5) even at very high molecular weights (near 400,000 Da) were obtained within modest reaction times.

  6. Facile synthesis of graphene by pyrolysis of poly(methyl methacrylate) on nickel particles in the confined microzones

    SciTech Connect

    Hong, Ningning; Yang, Wei; Bao, Chenlu; Jiang, Saihua; Song, Lei; Hu, Yuan

    2012-12-15

    Graphical abstract: Display Omitted Highlights: ► The GNWs with few defects were synthesized by pyrolyzing PMMA on nickel particles. ► PMMA as carbon source was easily prepared and safe to handle. ► Nickel microparticles were directly used as catalysts without any pre-treatment. ► The method can be used for the low cost and bulk production of graphene. -- Abstract: In this work, multi-layer graphene has been prepared by pyrolyzing poly(methyl methacrylate) (PMMA) on nickel microparticles in the confined microzones formed by organophilic montmorillonite (OMT). Gram-scale of product can be obtained per day by using this method. The obtained graphene was evaluated by scanning and transmission electron microscopy, X-ray diffraction, Raman spectroscopy, X-ray photoelectron spectroscopy, Fourier transform infrared spectroscopy and thermogravimetric analysis. Pyrolytic conditions such as the system composition of the composites, reaction temperature and the size of catalyst are important parameters affecting the morphology and yield of the final product. Based on the experimental observations and reported literatures, a possible formation process is discussed. The synthesis method of graphene is simple, low-cost, and scalable, which is promising for the application in many fields.

  7. Superparamagnetic poly(methyl methacrylate) nanoparticles surface modified with folic acid presenting cell uptake mediated by endocytosis

    NASA Astrophysics Data System (ADS)

    Feuser, Paulo Emilio; Jacques, Amanda Virtuoso; Arévalo, Juan Marcelo Carpio; Rocha, Maria Eliane Merlin; dos Santos-Silva, Maria Claudia; Sayer, Claudia; de Araújo, Pedro H. Hermes

    2016-04-01

    The encapsulation of superparamagnetic nanoparticles (MNPs) in polymeric nanoparticles (NPs) with modified surfaces can improve targeted delivery and induce cell death by hyperthermia. The goals of this study were to synthesize and characterize surface modified superparamagnetic poly(methyl methacrylate) with folic acid (FA) prepared by miniemulsion polymerization (MNPsPMMA-FA) and to evaluate their in vitro cytotoxicity and cellular uptake in non-tumor cells, murine fibroblast (L929) cells and tumor cells that overexpressed folate receptor (FR) β, and chronic myeloid leukemia cells in blast crisis (K562). Lastly, hemolysis assays were performed on human red blood cells. MNPsPMMA-FA presented an average mean diameter of 135 nm and a saturation magnetization (Ms) value of 37 emu/g of iron oxide, as well as superparamagnetic behavior. The MNPsPMMA-FA did not present cytotoxicity in L929 and K562 cells. Cellular uptake assays showed a higher uptake of MNPsPMMA-FA than MNPsPMMA in K562 cells when incubated at 37 °C. On the other hand, MNPsPMMA-FA showed a low uptake when endocytosis mechanisms were blocked at low temperature (4 °C), suggesting that the MNPsPMMA-FA uptake was mediated by endocytosis. High concentrations of MNPsPMMA-FA showed hemocompatibility when incubated for 24 h in human red blood cells. Therefore, our results suggest that these carrier systems can be an excellent alternative in targeted drug delivery via FR.

  8. Electric field poled polymeric nonlinear optical systems: molecular dynamics simulations of poly(methyl methacrylate) doped with disperse red chromophores.

    PubMed

    Tu, Yaoquan; Zhang, Qiong; Agren, Hans

    2007-04-12

    We demonstrate a complete procedure for simulations of electric field poled polymeric nonlinear optical systems with the purpose to evaluate the macroscopic electro-optic coefficients. The simulations cover the electric field poling effects on the chromophore order at the liquid state, the cooling procedure from the liquid to the solid state in the presence of the poling field, and the back-relaxation of the system after the removal of the field. We use Disperse Red chromophore molecules doped in a poly(methyl methacrylate) matrix for a numerical demonstration of the total procedure. On the basis of the simulation results, the polymer mobility and the static properties of the dopant chromophores are derived. In the liquid state, the chromophore molecules are closer to the side chains than to the backbones of the polymer matrix, and after the simulated annealing, the polymer matrix tends to be closely packed, leading to a significant change in the polymer structure around the chromophore molecules. Besides predicting the absolute macroscopic electro-optic coefficient values, the results are used to derive the microscopic origin of these values in terms of geometric and electronic structure, loading, poling, and back-relaxation effects, thereby aiding to establish design principles for optimum guest-host configurations.

  9. Human Fetal Osteoblast Response on Poly(Methyl Methacrylate)/Polystyrene Demixed Thin Film Blends: Surface Chemistry Vs Topography Effects.

    PubMed

    D'Sa, Raechelle A; Raj, Jog; Dickinson, Peter J; McCabe, Fiona; Meenan, Brian J

    2016-06-22

    Recent advances in materials sciences have allowed for the development and fabrication of biomaterials that are capable of providing requisite cues to instigate cells to respond in a predictable fashion. We have developed a series of poly(methyl methacrylate)/polystyrene (PMMA/PS) polymer demixed thin films with nanotopographies ranging from nanoislands to nanopits to study the response of human fetal osteoblast cells (hFOBs). When PMMA was in excess in the blend composition, a nanoisland topography dominated, whereas a nanopit topography dominated when PS was in excess. PMMA was found to segregate to the top of the nanoisland morphology with PS preferring the substrate interface. To further ascertain the effects of surface chemistry vs topography, we plasma treated the polymer demixed films using an atmospheric pressure dielectric barrier discharge reactor to alter the surface chemistry. Our results have shown that hFOBs did not have an increased short-term cellular response on pristine polymer demixed surfaces. However, increasing the hydrophilicty/wettability of the surfaces by oxygen functionalization causes an increase in the cellular response. These results indicate that topography alone is not sufficient to induce a positive cellular response, but the underlying surface chemistry is also important in regulating cell function.

  10. Investigation of cross-linking poly(methyl methacrylate) as a guiding material in block copolymer directed self-assembly

    NASA Astrophysics Data System (ADS)

    Seidel, Robert; Rincon Delgadillo, Paulina; Ramirez-Hernandez, Abelardo; Wu, Hengpeng; Her, Youngjun; Yin, Jian; Nealey, Paul; de Pablo, Juan; Gronheid, Roel

    2014-03-01

    Directed self-assembly (DDSA) of block copolymers ((BCP) is attracting a growing amount of interest as a techhnique to expand traditional lithography beyond its current limits. It has reecently been demonstrated that chemoepitaxy can be used to successfully ddirect BCP assembly to form large arrays off high-density features. The imec DSA LiNe flow uses lithography and trim-etch to produce a "prepattern" of cross-linked polystyrene (PS) stripes, which in turn guide the formation of assembled BCPP structures. Thhe entire process is predicated on the preferential interaction of the respective BCP domains with particular regionss of the underlying prepattern. The use of polystyrene as the guiding material is not uniquely required, however, and in fact may not even be preferable. This study investigates an alternate chemistry -- crosslinked poly(methyl methacrylate), X-PMMA, -- as the underlying polymer mat, providing a route to higher auto-affinity and therefore a stronger guiding ability. In addition to tthe advantages of the chemistry under investigation, this study explores the broader theme of extending BCP DSA to other materials.

  11. Poly(methyl methacrylate) and thiophene-coated single-walled carbon nanotubes for volatile organic compound discrimination

    NASA Astrophysics Data System (ADS)

    Muangrat, Worawut; Chodjarusawad, Thanawee; Maolanon, Rungroj; Pratontep, Sirapat; Porntheeraphat, Supanit; Wongwiriyapan, Winadda

    2016-02-01

    Poly(methyl methacrylate) (PMMA) and thiophene-coated single-walled carbon nanotubes (SWNTs) were fabricated for use in volatile organic compound (VOC) detection. Pristine SWNTs were separately coated with PMMA (PMMA/SWNTs) and thiophene (thiophene/SWNTs) by spin-coating. Pristine SWNTs showed the highest response to methanol, while PMMA/SWNTs enabled 5.4-fold improved dichloromethane detection and thiophene/SWNTs enabled 1.4-fold improved acetone detection compared with pristine SWNTs. The sensor response of PMMA/SWNTs to dichloromethane and that of thiophene/SWNTs to acetone can be attributed to the Hildebrand solubility parameter (HSP). The more similar the HSP, the higher the sensor response. The sensor response of pristine SWNTs to methanol is related to the diffusion coefficient and molecular size. The relationships between the vapor concentration and sensor response of PMMA/SWNTs to dichloromethane and thiophene/SWNTs to acetone are based on Henry’s adsorption isotherm, while that of pristine SWNTs to methanol is based on the Henry-clustering model. Principal component analysis (PCA) results show that dichloromethane, acetone, and methanol were successfully discriminated.

  12. Solvent quality effects on scaling behavior of poly(methyl methacrylate) brushes in the moderate- and high-density regimes.

    PubMed

    Moh, Lionel C H; Losego, Mark D; Braun, Paul V

    2011-04-05

    Herein, we give a detailed experimental analysis for scaling law behavior in the "moderately dense" and "high-density" brush regimes for poly(methyl methacrylate) brushes swollen in a range of solvent conditions. This expansive experimental analysis aims to validate decades of mean field theory predictions on power law scaling behavior of grafted polymer chains. Brushes with grafting densities (σ) ranging from 0.1 to 0.8 nm(-2) are prepared by atom-transfer radical polymerization. The swollen thickness (h) is characterized using liquid cell ellipsometry, and the solvent quality is varied using mixtures of acetone and methanol. In a good solvent, the exponential scaling behavior (h ∝ σ(n)) has the typical n = 1/3 dependency for grafting densities of σ ≤ 0.4 nm(-2). For grafting densities of >0.4 nm(-2), n increases, indicating the transition from the moderately dense to the high-density brush regime. However, in a poor solvent, the scaling behavior is independent of σ and scales as h ∝ σ(0.80), approaching the theoretical expectations of h ∝ σ(1). An abrupt transition between these scaling law behaviors occurs at the Θ-solvent condition of ∼45% (v/v) methanol in acetone. While our experimental results parallel trends predicted by mean field theory, differences are observed and appear to be attributed to self-solvation of the polymer, polydispersity in the molecular weight, and chain termination.

  13. Facile iron-mediated dispersant-free suspension polymerization of methyl methacrylate via reverse ATRP in water.

    PubMed

    Cao, Jun; Zhang, Lifen; Jiang, Xiaowu; Tian, Chun; Zhao, Xiaoning; Ke, Qi; Pan, Xiangqiang; Cheng, Zhenping; Zhu, Xiulin

    2013-11-01

    An iron-mediated reverse ATRP of methyl methacrylate (MMA) is successfully carried out in water in the absence of any dispersants, using a water-soluble 2,2'-azobis(2-methylpropionamidine) dihydrochloride (V-50) as the initiator and the stabilizer, and using an oil-soluble N,N-butyldithiocarbamate ferrum (Fe(S2 CN(C4 H9 )2 )3 ) as the catalyst without adding any additional ligands. Micron-sized PMMA particles with UV light-sensitive -S2 CN(C4 H9 )2 end group are obtained, and monomer droplet nucleation and suspension polymerization mechanism are proposed. Polymerization results demonstrated typical "living"/controlled characteristics of ATRP: first-order polymerization kinetics, linear increase of molecular weights with monomer conversion and narrow molecular weight distributions for the resultant PMMA particles. NMR spectroscopy and chain-extension experiments under UV light irradiation confirm the attachment and livingness of UV light-sensitive -S2 CN(C4 H9 )2 group in the chain end.

  14. Methyl methacrylate-induced changes in CNS (central nervous system) activity. 1 March 1978-28 February 1980

    SciTech Connect

    Innes, D.L.

    1980-01-01

    Experiments were performed to determine if methyl-methacrylate (MMA) monomer vapor in air caused central nervous system (CNS) changes in exposed rats. Rats were exposed to 400 parts per million (ppm) MMA vapor for 60 minutes. The only significant changes occurred in the lateral hypothalamic and ventral hippocampal nuclei. Several substudies suggested that the changes in the hippocampal neuronal firing rates were related to the perception of the MMA odor and dependent on an intact nervous connection to the receptors in the nose. In a subchronic study no consistent long term changes in neuronal activity were detected. However, a decrease in neuronal activity was detected during the first week of exposure. In another study, the exposure levels of MMA ranged from 50 to 800 ppm. The lateral hypothalamic and ventral hippocampal nuclei responded as before, but not at the 50 ppm level. The author concludes that the threshold exposure concentration for the observed effects are the same as or slightly less than the current threshold limit value for MMA vapor in the workplace.

  15. Gene delivery efficacy of polyethyleneimine-introduced chitosan shell/poly(methyl methacrylate) core nanoparticles for rat mesenchymal stem cells.

    PubMed

    Pimpha, Nuttaporn; Sunintaboon, Panya; Inphonlek, Supharat; Tabata, Yasuhiko

    2010-01-01

    This work investigated polyethyleneimine (PEI)-introduced chitosan (CS) (CS/PEI) nanoparticles as non-viral carrier of plasmid DNA for rat mesenchymal stem cells (MSCs). The CS/PEI nanoparticles were prepared by the emulsifier-free emulsion polymerization of methyl methacrylate monomer induced by a small amount of t-butyl hydroperxide in the presence of different concentrations of PEI mixed with CS. The resulting nanoparticles were characterized by their surface properties and buffering capacity. In vitro gene transfection was also evaluated. The introduction of PEI affected the surface charge, dispersing stability and buffering capacity of the nanoparticles. The CS/PEI nanoparticles formed a complex upon mixing with a plasmid DNA of luciferase. The complex enhanced the level of gene transfection and prolonged the time period of expression for MSCs, compared with those of plasmid DNA-original CS and PEI nanoparticles. Cytotoxicity of CS/PEI complexes with plasmid DNA was significantly low, depending on the amount of PEI introduced. It is concluded that the CS/PEI nanoparticle was a promising carrier for gene delivery of MSCs.

  16. Surface Molecularly Imprinted Polymer of Chitosan Grafted Poly(methyl methacrylate) for 5-Fluorouracil and Controlled Release.

    PubMed

    Zheng, Xue-Fang; Lian, Qi; Yang, Hua; Wang, Xiuping

    2016-02-19

    The molecular surface imprinted graft copolymer of chitosan with methyl methacrylate (MIP-CS-g-PMMA) were prepared by free radical polymerization with 5-fluorouracil (5-FU) as the template molecule using initiator of ammonium persulfate as adsorption system. MIPs were characterized by FTIR, X-ray diffraction, thermo-gravimetric analysis, (1)H NMR and SEM. The mechanism of graft copolymerization and factors affected graft reaction were studied in details, and the optimum reaction conditions (to the highest %G and %E as the standard) were obtained at [MMA] 1.2 mol/L, [Chitosan] 16.67 mol/L, [initiator] 0.0062 mol/L, temperature 60 °C and reaction time 7 h. MIPs exhibited high recognition selectivity and excellent combining affinity to template molecular. The in vitro release of the 5-FU was highly pH-dependent and time delayed. The release behavior showed that the drugs did not release in simulated gastric fluid (pH = 1.0), and the drug release was small in the simulated small intestinal fluid (pH = 6.8), and drug abrupt release will be produced in the simulated colon fluid (pH = 7.4), indicating excellent colon-specific drug delivery behavior.

  17. Sidechain Dynamics Explain Dissimilar Strength of Nanoconfinement Effect in Polystyrene and Poly(methyl methacrylate) Free Standing Thin Films

    NASA Astrophysics Data System (ADS)

    Hsu, David; Xia, Wenjie; Song, Jake; Keten, Sinan

    Despite substantially similar bulk glass transition temperature (Tg) and other bulk properties, polystyrene (PS) and poly(methyl-methacrylate) (PMMA) exhibit characteristically different Tg depression in the free-standing ultrathin film configuration. The mechanism for this disparate Tg-nanoconfinement effect due to the free surfaces has not been fully explained. Here we utilize recently established chemically specific coarse grain (CG) models to qualitatively reproduce contrasting thickness dependent Tg and length scale of enhanced chain relaxation gradient in the interfacial layer. Vibrational mode analysis is utilized to uncover a relationship between the amplitude and frequency of sidechain fluctuations of reduced order models and the degree of Tg-nanoconfinement. By systematic variation of the distribution of mass in the sidechain versus the backbone, we demonstrate inertia-driven differences in sidechain fluctuations and Tg-nanoconfinement in the CG model. We hypothesize that mass distribution and sidechain flexibility are governing factors causing PS and PMMA free surface effect differences and also provide insight into broader nanoconfinement phenomena from past experiments. D.H., W.X., J.S., and S.K. acknowledge support by the University Partnership Initiative between Northwestern University and The Dow Chemical Company.

  18. Surface Modification of Poly(methyl methacrylate) by Hydrogen-Plasma Exposure and Its Sputtering Characteristics by Ultraviolet Light Irradiation

    NASA Astrophysics Data System (ADS)

    Yoshimura, Satoru; Ikuse, Kazumasa; Sugimoto, Satoshi; Murai, Kensuke; Honjo, Kuniaki; Kiuchi, Masato; Hamaguchi, Satoshi

    2013-09-01

    Surface modification of poly(methyl methacrylate) (PMMA) films by hydrogen-plasma exposure has been studied in the light of sputtering resistance of polymer-based materials in plasma etching processes. Surface measurements of PMMA were performed with X-ray photoelectron spectroscopy, Fourier transform infrared spectroscopy, Raman spectroscopy, and spectroscopic ellipsometry. It has been found that oxygen atoms are preferentially removed from the surface when a PMMA film is subjected to hydrogen-plasma exposure, with the depth of modification being about 40 nm in the case we examined. Hydrogen-plasma exposure is also found to reduce the sputtering yields of PMMA by ultraviolet light irradiation, as in the case of Ar+ ion irradiation [S. Yoshimura et al.: J. Vac. Soc. Jpn. 56 (2013) 129]. The results suggest that PMMA films become hardened and more sputtering resistant due to the formation of a thick (i.e., 40 nm in the case of this study) amorphous carbon layer by hydrogen-plasma exposure. Hydrogen-plasma exposure is thus an effective technique to increase etching resistance of polymer films.

  19. Synthesis of hydroxyethyl-methacrylate-(L)-histidine methyl ester cryogels. Application on the separation of bovine immunoglobulin G.

    PubMed

    Elkak, Assem; Hamade, Amar; Bereli, Nilay; Armutcu, Canan; Denizli, Adil

    2017-02-21

    In this study cryogels based 2-hydroxyethyl methacrylate (HEMA) functionalized with N-methacryloyl-L-histidine methyl ester (MAH) were synthesized and used for the adsorption and separation of bovine IgG. Two series of cryogels functionalized with 5 and 10 mg of MAH as pseudobioaffinity ligand were prepared and characterized by swelling test, FTIR and SEM analysis. The adsorption efficiency of the bovine immunoglobulin into cryogels is discussed with respect to the following chromatographic parameters: pH, flow rate, initial IgG concentration, adsorption time and ionic strength. Our results show good adsorption of bovine immunoglobulin under mild separation conditions at pH 7.4. The maximum binding capacity was determined (32.4 mg/g of cryogel) and demonstrates the efficiency of the used cryogels. This efficacy is clearly seen upon increasing the maximum binding capacity from 23.2 mg (obtained with cryogels with 5 mg MAH) to 32.4 mg/g (for cryogel with 10 mg MAH ligand concentration). The purity of separated fractions was evaluated by sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE). Together our observations highlights poly (HEMA-MAH) as an efficient adsorbent for bovine immunoglobulins G separation.

  20. Poly(methyl methacrylate) microchip device integrated with gold nanoelectrode ensemble for in-column biochemical reaction and electrochemical detection.

    PubMed

    Liao, Kuo-Tang; Chen, Chun-Mao; Huang, Hsuan-Jung; Lin, Che-Hsin

    2007-09-21

    This paper proposes a poly(methyl methacrylate) (PMMA) based microchip with an integrated gold nanoelectrode ensemble (GNEE) and a quartet-T loading channel for in-column urea/urease reactions and electrochemical detections. The on-chip GNEE electrode is fabricated using an electrodeless deposition process on a thin polycarbonate (PC) film and bonded directly onto a PMMA substrate to carry out high-performance electrochemical detections. The in-column bio-catalytic reaction of urea/urease is successfully demonstrated utilizing a novel approach based on the different electrokinetic mobilities of urea and urease in capillary electrophoresis (CE) channel. The experimental results significantly show that the GNEE electrode provides a better detection response for the reaction product of ammonia (NH(4)(+)) than a conventional planar gold electrode. The detection results demonstrate a satisfactory determination coefficient (R(2) value) and high reproducibility with a detection limit of 14.8 and 62.8 microM while detecting standard ammonia solution and the urea/urease reaction product of NH(4)(+), respectively. These results confirm the capability of the proposed device for the high-resolution CE-electrochemical detection (CE-ED) of bioanalytical reactions.

  1. 2-diethylaminoethyl-dextran methyl methacrylate copolymer nonviral vector: still a long way toward the safety of aerosol gene therapy.

    PubMed

    Zarogoulidis, P; Hohenforst-Schmidt, W; Darwiche, K; Krauss, L; Sparopoulou, D; Sakkas, L; Gschwendtner, A; Huang, H; Turner, F J; Freitag, L; Zarogoulidis, K

    2013-10-01

    Revealing the lung tumor genome has directed the current treatment strategies toward targeted therapy. First line treatments targeting the genome of lung tumor cells have been approved and are on the market. However, they are limited by the small number of patients with the current investigated genetic mutations. Novel treatment administration modalities have been also investigated in an effort to increase the local drug deposition and disease control. In the current study, we investigated the safety of the new nonviral vector 2-diethylaminoethyl-dextran methyl methacrylate copolymer (DDMC; Ryujyu Science), which belongs to the 2-diethylaminoethyl-dextran family by aerosol administration. Thirty male BALBC mice, 2 month old, were included and divided into three groups. However, pathological findings indicated severe emphysema within three aerosol sessions. In addition, the CytoViva technique was applied for the first time to display the nonviral particles within the pulmonary tissue and emphysema lesions, and a spectral library of the nonviral vector was also established. Although our results in BALBC mice prevented us from further investigation of the DDMC nonviral vector as a vehicle for gene therapy, further investigation in animals with larger airways is warranted to properly evaluate the safety of the vector.

  2. Thermo-mechanical response of poly(methyl methacrylate) (PMMA) large volumes exposed to time-dependent environmental conditions

    NASA Astrophysics Data System (ADS)

    Fraldi, M.; Esposito, L.; Perrella, G.; Cutolo, A.

    2014-02-01

    Low thermal conductivity and elevated absorbance of large bulky volumes of poly(methyl methacrylate) (PMMA) exposed to moderately aggressive environmental conditions may cooperate to determine critical mechanical conditions, kindling unexpected high thermal stresses values which lead the material to failure. From the engineering point of view, this can be explained as the result of two concomitant phenomena which activate a cascade of events: very sharp thermal gradients engendered by transient thermal processes induced by cyclic environmental conditions, combined with significant bulk heat generation due to the high thermal inertia of massive PMMA volumes, in turn aggravating the steepness of the thermal gradients, may in fact ingenerate severe stress regimes, potentially undermining the structural stability of the material. Moving from these considerations, the present study is aimed to investigate possible rupture of PMMA blocks experiencing heating processes as a consequence of their exposure to outdoor cyclic environmental conditions. The problem is approached by means of both rigorous analytical arguments and the Finite Element based numerical methods, finally exploiting the theoretical outcomes to formulate a hypothesis which might explain the still unclear phenomenon of the sudden breaking of the PMMA structure, named Huge Wine Glass and designed by the world famous Japanese architect Toyo Ito, which occurred in Pescara (Italy) in 2009.

  3. Nanotopographic Substrates of Poly (Methyl Methacrylate) Do Not Strongly Influence the Osteogenic Phenotype of Mesenchymal Stem Cells In Vitro

    PubMed Central

    Janson, Isaac A.; Kong, Yen P.; Putnam, Andrew J.

    2014-01-01

    The chemical, mechanical, and topographical features of the extracellular matrix (ECM) have all been documented to influence cell adhesion, gene expression, migration, proliferation, and differentiation. Topography plays a key role in the architecture and functionality of various tissues in vivo, thus raising the possibility that topographic cues can be instructive when incorporated into biomaterials for regenerative applications. In the literature, there are discrepancies regarding the potential roles of nanotopography to enhance the osteogenic phenotype of mesenchymal stem cells (MSC). In this study, we used thin film substrates of poly(methyl methacrylate) (PMMA) with nanoscale gratings to investigate the influence of nanotopography on the osteogenic phenotype of MSCs, focusing in particular on their ability to produce mineral similar to native bone. Topography influenced focal adhesion size and MSC alignment, and enhanced MSC proliferation after 14 days of culture. However, the osteogenic phenotype was minimally influenced by surface topography. Specifically, alkaline phosphatase (ALP) expression was not increased on nanotopographic films, nor was calcium deposition improved after 21 days in culture. Ca: P ratios were similar to native mouse bone on films with gratings of 415 nm width and 200 nm depth (G415) and 303 nm width and 190 nm depth (G303). Notably, all surfaces had Ca∶P ratios significantly lower than G415 films. Collectively, these data suggest that, PMMA films with nanogratings are poor drivers of an osteogenic phenotype. PMID:24594848

  4. Dynamic modification of poly(methyl methacrylate) chips using poly(vinyl alcohol) for glycosaminoglycan disaccharide isomer separation.

    PubMed

    Zhang, Yong; Ping, Guichen; Kaji, Noritada; Tokeshi, Manabu; Baba, Yoshinobu

    2007-09-01

    We describe a microchip electrophoresis (MCE) method for the assay of unsaturated disaccharides of chondroitin sulfates, dermatan sulfates, and hyaluronic acid (HA). Poly(vinyl alcohol) (PVA) could be irreversibly adsorbed onto poly(methyl methacrylate) (PMMA) substrates and this approach was applicable for dynamic coating. The characteristics of the PMMA surface with PVA coating were evaluated in terms of the wettability, EOF, and adsorption of 2-aminoacridone (AMAC)-labeled disaccharide. The water contact angle decreased from 73 degrees on a pristine PMMA surface to 37.5 degrees on a PVA-coated surface, indicating that the PVA coating increased hydrophilicity. EOF was reduced approximately twofold and was relatively stable. Scanning electron microscopy and fluorescence microscopy images showed that adsorption of AMAC-labeled disaccharides was dramatically suppressed. Using the PVA coating, baseline separation of two pairs of glycosaminoglycan (GAG) disaccharide isomers, DeltaDi-diS(B)/DeltaDi-diS(D) and DeltaDi-0S/DeltaDi-HA, was achieved in Tris-borate buffer within 130 s by MCE.

  5. Charging of poly(methyl methacrylate) (PMMA) colloids in cyclohexyl bromide: locking, size dependence, and particle mixtures.

    PubMed

    van der Linden, Marjolein N; Stiefelhagen, Johan C P; Heessels-Gürboğa, Gülşen; van der Hoeven, Jessi E S; Elbers, Nina A; Dijkstra, Marjolein; van Blaaderen, Alfons

    2015-01-13

    We studied suspensions of sterically stabilized poly(methyl methacrylate) (PMMA) particles in the solvent cyclohexyl bromide (CHB; εr = 7.92). We performed microelectrophoresis measurements on suspensions containing a single particle species and on binary mixtures, using confocal microscopy to measure the velocity profiles of the particles. We measured the charge of so-called locked PMMA particles, for which the steric stabilizer, a comb-graft stabilizer of poly(12-hydroxystearic acid) (PHSA) grafted on a backbone of PMMA, was covalently bonded to the particle, and for unlocked particles, for which the stabilizer was adsorbed to the surface of the particle. We observed that locked particles had a significantly higher charge than unlocked particles. We found that the charge increase upon locking was due to chemical coupling of 2-(dimethylamino)ethanol to the PMMA particles, which was used as a catalyst for the locking reaction. For particles of different size we obtained the surface potential and charge from the electrophoretic mobility of the particles. For locked particles we found that the relatively high surface potential (∼ +5.1 kBT/e or +130 mV) was roughly constant for all particle diameters we investigated (1.2 μm < σ < 4.4 μm), and that the particle charge was proportional to the square of the diameter.

  6. Glyco-Nanoparticles Made from Self-Assembly of Maltoheptaose-block-Poly(methyl methacrylate): Micelle, Reverse Micelle, and Encapsulation.

    PubMed

    Zepon, Karine M; Otsuka, Issei; Bouilhac, Cécile; Muniz, Edvani C; Soldi, Valdir; Borsali, Redouane

    2015-07-13

    The synthesis and the solution-state self-assembly of the "hybrid" diblock copolymers, maltoheptaose-block-poly(methyl methacrylate) (MH-b-PMMA), into large compound micelles (LCMs) and reverve micelle-type nanoparticles, are reported in this paper. The copolymers were self-assembled in water and acetone by direct dissolution method, and the morphologies of the nanoparticles were investigated by dynamic light scattering (DLS), nanoparticle tracking analysis (NTA), transmission electron microscopy (TEM), atomic force microscopy (AFM), proton nuclear magnetic resonance ((1)H NMR), and fluorescence spectroscopy as a function of the volume fraction of the copolymer hydrophobic block, copolymer concentration, stirring speed, and solvent polarity. The DLS measurements and TEM images showed that the hydrodynamic radius (Rh) of the LCMs obtained in water increases with the copolymer concentration. Apart from that, increasing the stirring speed leads to polydispersed aggregations of the LCMs. On the other hand, in acetone, the copolymers self-assembled into reverse micelle-type nanoparticles having Rh values of about 6 nm and micellar aggregates, as revealed the results obtained from DLS, AFM, and (1)H NMR analyses. The variation in micellar structure, that is, conformational inversion from LCMs to reverse micelle-type structures in response to polarity of the solvent, was investigated by apparent water contact angle (WCA) and (1)H NMR analyses. This conformational inversion of the nanoparticles was further confirmed by encapsulation and release of hydrophobic guest molecule, Nile red, characterized by fluorescence spectroscopy.

  7. Role of poly(ethylene glycol) in surfactant-free emulsion polymerization of styrene and methyl methacrylate.

    PubMed

    Shi, Yiming; Shan, Guorong; Shang, Yue

    2013-03-05

    Through zeta potential and surface tension measurements and a series of polymerization experiments, the role of poly(ethylene glycol) (PEG) in the process of surfactant-free polymerization of styrene (St)/methyl methacrylate (MMA) has been investigated experimentally. Nanoscale and stable copolymer particles were formed after an abnormal process, in which the nucleation and growth of particles was different from that in previously proposed mechanisms. It has been observed that PEG can exist in both the monomer and the aqueous phases at high temperature. PEG in the aqueous phase could form copolymer particles with a loose structure, making them prone to enter the monomer phase. Entry of these copolymer particles into the monomer phase would introduce excess PEG. From the ternary phase diagram, a solubility curve could be delineated in the ternary system of PEG/monomer/copolymer. The system used the ternary solubility property to regenerate copolymer particles in the monomer phase, which maintained their morphology until the end of the polymerization. At the end, consumption of the monomer resulted in the volume contraction of the particles, and the surface potential increased. This increasing potential is a driving force to prevent particles from stacking, leading to the formation of nanoscale and stable particles.

  8. Antifouling properties of poly(methyl methacrylate) films grafted with poly(ethylene glycol) monoacrylate immersed in seawater.

    PubMed

    Iguerb, O; Poleunis, C; Mazéas, F; Compère, C; Bertrand, P

    2008-11-04

    Biofouling of all structures immersed in seawater constitutes an important problem, and many strategies are currently being developed to tackle it. In this context, our previous work shows that poly(ethylene glycol) monoacrylate (PEGA) macromonomer grafted on preoxidized poly(methyl methacrylate) (PMMAox) films exhibits an excellent repellency against the bovine serum albumin used as a model protein. This study aims to evaluate the following: (1) the prevention of a marine extract material adsorption by the modified surfaces and (2) the antifouling property of the PEGA-g-PMMAox substrates when immersed in natural seawater during two seasons (season 1: end of April-beginning of May 2007, and season 2: end of October-beginning of November 2007). The antifouling performances of the PEGA-g-PMMAox films are investigated for different PEG chain lengths and macromonomer concentrations into the PEGA-based coatings. These two parameters are followed as a function of the immersion time, which evolves up to 14 days. The influence of the PEGA layer on marine compounds (proteins and phospholipids) adsorption is evidenced by time-of-flight secondary ion mass spectrometry (ToF-SIMS) and X-ray photoelectron spectroscopy (XPS). It was found that the antifouling efficiency of the PEGA-grafted surfaces increases with both PEGA concentration and PEG chain length.

  9. Temperature dependent luminescence of a europium complex incorporated in poly(methyl methacrylate).

    PubMed

    Liang, Hao; Xie, Fang; Ren, Xiaojun; Chen, Yifa; Chen, Biao; Guo, Fuquan

    2013-12-01

    An europium β-diketonate complex with a dipyrazolyltriazine derivative ligand, Eu(TTA)3DPBT, has been incorporated into poly(methyl methacryate) (PMMA). The influence of temperature on its luminescence properties has been investigated. The fluorescence emission spectra and luminescence lifetimes showed temperature sensitivity. The analysis of the relative intensity ratio (R) of (5)D0 → (7)F2 to (5)D0 → (7)F1 transition and Judd-Ofelt experimental intensity parameters Ω2 indicated that the local structure and asymmetry in the vicinity of europium ions show no obvious change when the temperature is increased.

  10. Microbial degradation of methyl tert-butyl ether and tert-butyl alcohol in the subsurface

    NASA Astrophysics Data System (ADS)

    Schmidt, Torsten C.; Schirmer, Mario; Weiß, Holger; Haderlein, Stefan B.

    2004-06-01

    The fate of fuel oxygenates such as methyl tert-butyl ether (MTBE) in the subsurface is governed by their degradability under various redox conditions. The key intermediate in degradation of MTBE and ethyl tert-butyl ether (ETBE) is tert-butyl alcohol (TBA) which was often found as accumulating intermediate or dead-end product in lab studies using microcosms or isolated cell suspensions. This review discusses in detail the thermodynamics of the degradation processes utilizing various terminal electron acceptors, and the aerobic degradation pathways of MTBE and TBA. It summarizes the present knowledge on MTBE and TBA degradation gained from either microcosm or pure culture studies and emphasizes the potential of compound-specific isotope analysis (CSIA) for identification and quantification of degradation processes of slowly biodegradable pollutants such as MTBE and TBA. Microcosm studies demonstrated that MTBE and TBA may be biodegradable under oxic and nearly all anoxic conditions, although results of various studies are often contradictory, which suggests that site-specific conditions are important parameters. So far, TBA degradation has not been shown under methanogenic conditions and it is currently widely accepted that TBA is a recalcitrant dead-end product of MTBE under these conditions. Reliable in situ degradation rates for MTBE and TBA under various geochemical conditions are not yet available. Furthermore, degradation pathways under anoxic conditions have not yet been elucidated. All pure cultures capable of MTBE or TBA degradation isolated so far use oxygen as terminal electron acceptor. In general, compared with hydrocarbons present in gasoline, fuel oxygenates biodegrade much slower, if at all. The presence of MTBE and related compounds in groundwater therefore frequently limits the use of in situ biodegradation as remediation option at gasoline-contaminated sites. Though degradation of MTBE and TBA in field studies has been reported under oxic

  11. Microbial degradation and fate in the environment of methyl tert-butyl ether and related fuel oxygenates.

    PubMed

    Fayolle, F; Vandecasteele, J P; Monot, F

    2001-08-01

    Oxygenates, mainly methyl tert-butyl ether (MTBE), are commonly added to gasoline to enhance octane index and improve combustion efficiency. Other oxygenates used as gasoline additives are ethers such as ethyl tert-butyl ether (ETBE), tert-amyl methyl ether (TAME), and alcohols such as tert-butyl alcohol (TBA). As a result of its wide use, MTBE has been detected, mainly in the USA, in groundwater and surface waters, and is a cause of concern because of its possible health effects and other undesirable consequences. MTBE is a water-soluble and mobile compound that generates long pollution plumes in aquifers impacted by gasoline releases from leaking tanks. Field observations concur in estimating that, because of recalcitrance to biodegradation, natural attenuation is slow (half-life of at least 2 years). However, quite significant advances have been made in recent years concerning the microbiology of the degradation of MTBE and other oxygenated gasoline additives. The recalcitrance of these compounds results from the presence in their structure of an ether bond and of a tertiary carbon structure. For the most part, only aerobic microbial degradation systems have been reported so far. Consortia capable of mineralizing MTBE have been selected. Multiple instances of the cometabolism of MTBE with pure strains or with microflorae, growing on n-alkanes, isoalkanes, cyclohexane or ethers (diethyl ether, ETBE), have been described. MTBE was converted into TBA in all cases and was sometimes further degraded, but it was not used as a carbon source by the pure strains. However, mineralization of MTBE and TBA by several pure bacterial strains using these compounds as sole carbon and energy source has recently been reported. The pathways of metabolism of MTBE involve the initial attack by a monooxygenase. In several cases, the enzyme was characterized as a cytochrome P-450. After oxygenation, the release of a C -unit as formaldehyde or formate leads to the production of TBA

  12. Exposure to methyl tert-butyl ether and benzene among service station attendants and operators.

    PubMed

    Hartle, R

    1993-12-01

    Concerns for atmospheric pollution from auto exhaust have led to the blending of "oxygenates" with motor fuels. The most common oxygenate, methyl tert-butyl ether (MTBE) is currently required within several metropolitan areas (Denver and Phoenix) in the range of 12% of the motor fuel. Amendments to the Clean Air Act may expand this requirement to as many as 44 other areas of the United States in the near future. In consideration of the magnitude of potential uncontrolled exposures from its extensive use and a related concern involving the potential influence of MTBE blending on exposures to other constituents of gasoline (particularly benzene), an evaluation of exposures among service station attendants and operators was undertaken at the request, and in cooperation with, the American Petroleum Institute during the latter part of 1990. For application of the survey results to a broad audience, three categories or types of service stations were identified with regard to MTBE use and exposure potential: a) service stations that do not use MTBE or use it only as an octane enhancer, b) service stations with seasonal requirements to use 12-15% MTBE (the Denver, Colorado, and Phoenix, Arizona, metropolitan areas), and c) service stations equipped with stage II (active) vapor recovery systems (several coastal areas, most notably Southern California). At the two sampled service stations that use only minimal amounts of MTBE (less than 1%), only 1 of 32 personal breathing zone (PBZ) samples from attendants was above the analytical limit of detection, reported at 0.16 ppm. The geometric mean concentration of benzene among this same population (n = 32) was 0.04 ppm.(ABSTRACT TRUNCATED AT 250 WORDS)

  13. Risk characterization of methyl tertiary butyl ether (MTBE) in tap water.

    PubMed

    Stern, B R; Tardiff, R G

    1997-12-01

    Methyl tertiary butyl ether (MTBE) can enter surface water and groundwater through wet atmospheric deposition or as a result of fuel leaks and spills. About 30% of the U.S. population lives in areas where MTBE is in regular use. Ninety-five percent of this population is unlikely to be exposed to MTBE in tap water at concentrations exceeding 2 ppb, and most will be exposed to concentrations that are much lower and may be zero. About 5% of this population may be exposed to higher levels of MTBE in tap water, resulting from fuel tank leaks and spills into surface or groundwater used for potable water supplies. This paper describes the concentration ranges found and anticipated in surface and groundwater, and estimates the distribution of doses experienced by humans using water containing MTBE to drink, prepare food, and shower/bathe. The toxic properties (including potency) of MTBE when ingested, inhaled, and in contact with the skin are summarized. Using a range of human toxic potency values derived from animal studies, margins of exposure (MOE) associated with alternative chronic exposure scenarios are estimated to range from 1700 to 140,000. Maximum concentrations of MTBE in tap water anticipated not to cause adverse health effects are determined to range from 700 to 14,000 ppb. The results of this analysis demonstrate that no health risks are likely to be associated with chronic and subchronic human exposures to MTBE in tap water. Although some individuals may be exposed to very high concentrations of MTBE in tap water immediately following a localized spill, these exposures are likely to be brief in duration due to large-scale dilution and rapid volatilization of MTBE, the institution of emergency response and remediation measures to minimize human exposures, and the low taste and odor thresholds of MTBE which ensure that its presence in tap water is readily detected at concentrations well below the threshold for human injury.

  14. Urinary methyl tert-butyl ether and benzene as biomarkers of exposure to urban traffic.

    PubMed

    Campo, Laura; Cattaneo, Andrea; Consonni, Dario; Scibetta, Licia; Costamagna, Paolo; Cavallo, Domenico M; Bertazzi, Pier Alberto; Fustinoni, Silvia

    2011-02-01

    Methyl tert-butyl ether (MTBE) and benzene are added to gasoline to improve the combustion process and are found in the urban environment as a consequence of vehicular traffic. Herein we evaluate urinary MTBE (MTBE-U) and benzene (BEN-U) as biomarkers of exposure to urban traffic. Milan urban policemen (130 total) were investigated in May, July, October, and December for a total of 171 work shifts. Personal exposure to airborne benzene and carbon monoxide (CO), and atmospheric data, were measured during the work shift, while personal characteristics were collected by a questionnaire. A time/activity diary was completed by each subject during the work shift. Spot urine samples were obtained for the determination of MTBE-U and BEN-U. Median personal exposure to CO and airborne benzene were 3.3 mg/m(3) and 9.6 μg/m(3), respectively; median urinary levels in end-of-shift (ES) samples were 147 ng/L (MTBE-U) and 207 ng/L (BEN-U). The time spent on traffic duty at crossing was about 40% of work time. Multiple linear regression models, taking into account within-subject correlations, were applied to investigate the role of urban pollution, atmospheric conditions, job variables and personal characteristics on the level of biomarkers. MTBE-U was influenced by the month of sampling and positively correlated to the time spent in traffic guarding, CO exposure and atmospheric pressure, while negatively correlated to wind speed (R(2) for total model 0.63, P<0.001). BEN-U was influenced by the month and smoking habit, and positively correlated to urinary creatinine; moreover, an interaction between CO and smoking was found (R(2)=0.62, P<0.001). These results suggest that MTBE-U is a reliable marker for assessing urban traffic exposure, while BEN-U is determined mainly by personal characteristics.

  15. Methyl tert butyl ether targets developing vasculature in zebrafish (Danio rerio) embryos

    PubMed Central

    Bonventre, Josephine A.; White, Lori A.; Cooper, Keith R.

    2015-01-01

    Disruption of vascular endothelial growth factor (VEGF) signaling during early development results in abnormal angiogenesis and increased vascular lesions. Embryonic exposure to 0.625 to 10 mM methyl tert butyl ether (MTBE), a highly water soluble gasoline additive, resulted in a dose dependent increase in pooled blood in the common cardinal vein (CCV), cranial hemorrhages and abnormal intersegmental vessels (ISVs). The EC50s for the lesions ranked in terms of likelihood to occur with MTBE exposure were: pooled blood in the CCV, 3.2 mM [95 % CI: 2.2 – 4.7] > cranial hemorrhage, 11 mM [5.9 – 20.5] > abnormal ISV, 14.5 mM [6.5 – 32.4]. Organ systems other than the vascular system appear to develop normally, which suggests MTBE toxicity targets developing blood vessels. Equal molar concentrations (0.625 to 10 mM) of the primary metabolites, tertiary butyl alcohol (TBA) and formaldehyde, did not result in vascular lesions, which suggested that the parent compound is responsible for the toxicity. Stage specific exposures were carried out to determine the developmental period most sensitive to MTBE vascular disruption. Embryos treated until 6-somites or treated after Prim-5 stages did not exhibit a significant increase in lesions, while embryos treated between 6-somites and Prim-5 had a significant increase in vascular lesions (p ≤ 0.05). During the critical window for MTBE-induced vascular toxicity, expression of vegfa, vegfc, and flk1/kdr were significantly decreased 50, 70 and 40%, respectively. This is the first study to characterize disruption in vascular development following embryonic exposure to MTBE. The unique specificity of MTBE to disrupt angiogenesis may be mediated by the down regulation of critical genes in the VEGF pathway. PMID:21684239

  16. Methyl tert-butyl ether biodegradation by indigenous aquifer microorganisms under natural and artificial oxic conditions

    USGS Publications Warehouse

    Landmeyer, J.E.; Chapelle, F.H.; Herlong, H.H.; Bradley, P.M.

    2001-01-01

    Microbial communities indigenous to a shallow groundwater system near Beaufort, SC, degraded milligram per liter concentrations of methyl tert-butyl ether (MTBE) under natural and artificial oxic conditions. Significant MTBE biodegradation was observed where anoxic, MTBE-contaminated groundwater discharged to a concrete-lined ditch. In the anoxic groundwater adjacent to the ditch, concentrations of MTBE were > 1 mg/L. Where groundwater discharge occurs, dissolved oxygen (DO) concentrations beneath the ditch exceeded 1.0 mg/L to a depth of 1.5 m, and MTBE concentrations decreased to <1 ??g/L prior to discharge. MTBE mass flux calculations indicate that 96% of MTBE mass loss occurs in the relatively small oxic zone prior to discharge. Samples of a natural microbial biofilm present in the oxic zone beneath the ditch completely degraded [U-14C]MTBE to [14C]CO2 in laboratory liquid culture studies, with no accumulation of intermediate compounds. Upgradient of the ditch in the anoxic, MTBE and BTEX-contaminated aquifer, addition of a soluble oxygen release compound resulted in oxic conditions and rapid MTBE biodegradation by indigenous microorganisms. In an observation well located closest to the oxygen addition area, DO concentrations increased from 0.4 to 12 mg/L in <60 days and MTBE concentrations decreased from 20 to 3 mg/L. In the same time period at a downgradient observation well, DO increased from <0.2 to 2 mg/L and MTBE concentrations decreased from 30 to <5 mg/L. These results indicate that microorganisms indigenous to the groundwater system at this site can degrade milligram per liter concentrations of MTBE under natural and artificial oxic conditions.

  17. Hepatitis B surface antibody purification with hepatitis B surface antibody imprinted poly(hydroxyethyl methacrylate-N-methacryloyl-L-tyrosine methyl ester) particles.

    PubMed

    Uzun, Lokman; Say, Ridvon; Unal, Serhat; Denizli, Adil

    2009-01-15

    Hepatitis B surface antibody imprinted poly(hydroxyethyl methacrylate-N-methacryloyl-L-tyrosine methyl ester) particles were prepared for the purification of hepatitis B surface antibody from human plasma. N-methacryloyl-L-tyrosine methyl ester was chosen as a complexing agent for hepatitis B surface antibodies. Hepatitis B surface antibody imprinted poly(hydroxyethyl methacrylate-N-methacryloyl-L-tyrosine methyl ester) particles were characterized by surface area measurements, swelling test, scanning electron microscopy, elemental analysis, and Fourier transform infrared spectroscopy. Ethylene glycol (1.0M) was used as desorption agent. Adsorption studies were performed from hepatitis B surface antibody and anti-hepatitis A antibody positive human plasma. Effects of antibody concentration, contact time, N-methacryloyl-L-tyrosine methyl ester content and temperature on the adsorption capacity were investigated. The amount of hepatitis B surface antibody adsorbed per unit mass increased with increasing hepatitis B surface antibody concentration, then reached saturation. Maximum hepatitis B surface antibody adsorption amount was 21.4 mIU/mg. Adsorption process reached the equilibrium in 60 min. Competitive adsorption of hepatitis B surface antibody, total anti-hepatitis A antibody and total immunoglobulin E was investigated for showing the selectivity. Hepatitis B surface antibody-imprinted particles could adsorb hepatitis B surface antibody 18.3 times more than anti-hepatitis A antibody and 2.2 times more than immunoglobulin E. It can be concluded that hepatitis B surface antibody-imprinted particles have significant selectivity for hepatitis B surface antibody.

  18. Effect of emulsion polymerization and magnetic field on the adsorption of albumin on poly(methyl methacrylate)-based biomaterial surfaces.

    PubMed

    Nita, Loredana E; Chiriac, Aurica P

    2010-08-01

    The adsorption of bovine serum albumin (BSA) onto the surfaces of poly(methyl methacrylate) (PMMA) and of methyl methacrylate copolymer with 2,3-epoxypropyl methacrylate, it was investigated. The polymeric matrices were obtained through radical emulsion polymerization with and without the presence of a continuous external magnetic field (MF) of 1,500 Gs intensity. Two types of surfactant agents were used for polymers' synthesis: a classic one sodium lauryl sulphate (SLS) and beta-cyclodextrin (CD). The protein adsorption was conducted in the presence as well as in the absence of MF, by varying the coupling conditions, respectively, the temperature, pH and albumin/polymer ratio. The study underlines the assistance of MF during the adsorption process, materialized into growth of the BSA adsorbed quantity. Thus, MF presence during adsorption determines the doubling of the BSA adsorbed quantity onto the surface of polymers prepared in the MF. The adsorption process was also related to the tensioactive used for the synthesis of polymeric matrices. The higher content of the adsorbed BSA corresponds to the polymers with CD instead of SLS. The fact was attributed to the catalytic activity of the MF, which determines the molecules distortions, the growth of distance interactions and the modifications of the angles between bonds, with benefit effect upon adsorption.

  19. Synthesis and characterization of poly(methyl methacrylate)-based experimental bone cements reinforced with TiO2-SrO nanotubes.

    PubMed

    Khaled, S M Z; Charpentier, Paul A; Rizkalla, Amin S

    2010-08-01

    In an attempt to overcome existing limitations of experimental bone cements we here demonstrate a simple approach to synthesizing strontium-modified titania nanotubes (n-SrO-TiO(2) tubes) and functionalize them using the bifunctional monomer methacrylic acid. Then, using 'grafting from' polymerization with methyl methacrylate, experimental bone cements were produced with excellent mechanical properties, radiopacity and biocompatibility. Transmission electron microscopy (TEM), scanning electron microscopy (SEM), energy-dispersive spectroscopy mapping and backscattered SEM micrographs revealed a uniform distribution of SrO throughout the titanium matrix, with retention of the nanotubular morphology. Nanocomposites were then reinforced with 1, 2, 4 and 6 wt.% of the functionalized metal oxide nanotubes. Under the mixing and dispersion regime employed in this study, 2 wt.% appeared optimal, exhibiting a more uniform dispersion and stronger adhesion of the nanotubes in the poly(methyl methacrylate) matrix, as shown by TEM and SEM. Moreover, this optimum loading provided a significant increase in the fracture toughness (K(IC)) (20%) and flexural strength (40%) in comparison with the control matrix (unfilled) at P<0.05. Examination of the fracture surfaces by SEM showed that toughening was provided by the nanotubes interlocking with the acrylic matrix and crack bridging during fracture. On modifying the n-TiO(2) tubes with strontium oxide the nanocomposites exhibited a similar radiopacity to a commercial bone cement (CMW 1), while exhibiting a significant enhancement of osteoblast cell proliferation (242%) in vitro compared with the control at P<0.05.

  20. Corrosion resistance of siloxane-poly(methyl methacrylate) hybrid films modified with acetic acid on tin plate substrates: Influence of tetraethoxysilane addition

    NASA Astrophysics Data System (ADS)

    Kunst, S. R.; Cardoso, H. R. P.; Oliveira, C. T.; Santana, J. A.; Sarmento, V. H. V.; Muller, I. L.; Malfatti, C. F.

    2014-04-01

    The aim of this paper is to study the corrosion resistance of hybrid films. Tin plate was coated with a siloxane-poly (methyl methacrylate) (PMMA) hybrid film prepared by sol-gel route with covalent bonds between the organic (PMMA) and inorganic (siloxane) phases obtained by hydrolysis and polycondensation of 3-(trimethoxysilylpropyl) methacrylate (TMSM) and polymerization of methyl methacrylate (MMA) using benzoyl peroxide (BPO) as a thermic initiator. Hydrolysis reactions were catalyzed by acetic acid solution avoiding the use of chlorine or stronger acids in the film preparation. The effect of the addition of tetraethoxysilane (TEOS) on the protective properties of the film was evaluated. The hydrophobicity of the film was determined by contact angle measurements, and the morphology was evaluated by scanning electron microscopy (SEM) and profilometry. The local nanostructure was investigated by Fourier transform infrared spectroscopy (FT-IR). The electrochemical behavior of the films was assessed by open circuit potential monitoring, potentiodynamic polarization and electrochemical impedance spectroscopy (EIS) measurements in a 0.05 M NaCl solution. The mechanical behavior was evaluated by tribology. The results highlighted that the siloxane-PMMA hybrid films modified with acetic acid are promising anti-corrosive coatings that acts as an efficient diffusion barrier, protecting tin plates against corrosion. However, the coating properties were affected by the TEOS addition, which contributed for the thickness increase and irregular surface coverage.

  1. Poly(methyl methacrylate) particles for local drug delivery using shock wave lithotripsy: In vitro proof of concept experiment.

    PubMed

    Shaked, Eliav; Shani, Yoav; Zilberman, Meital; Scheinowitz, Mickey

    2015-08-01

    To leverage current local drug delivery systems methodology, there is vast use of polymeric particles serving as drug carriers to assure minimal invasive therapy with little systemic distribution of the released drug. There is an increasing interest in poly(methyl methacrylate) (PMMA) serving as carriers in drug delivery. The study aims to develop PMMA carriers for localized drug delivery and release system, combining innovative biomaterial technology and shock wave lithotripsy (SWL), and to study the effect of SWL on various concentrations of PMMA particles. We prepared PMMA particles that contain horseradish peroxidase (HRP) using a double emulsion technique, and investigated the mechanism of in vitro drug release from the carriers following exposure to SWL. We investigated the correlation between production method modifications, concentrations of the carriers subjected to SWL, and shock wave patterns. We successfully produced PMMA particles as drug carriers and stimulated the release of their contents by SWL; their polymeric shell can be shattered externally by SWL treatment, leading to release of the encapsulated drug. HRP enzyme activity was maintained following the encapsulation process and exposure to high dose of SWL pulses. Increased shock wave number results in increased shattering and greater fragmentation of PMMA particles. The results demonstrate a dose-response release of HRP; quantitation of the encapsulated HRP from the carriers rises with the number of SWL. Moreover, increased concentration of particles subjected to the same dose of SWL results in a significant increase of the total HRP release. Our research offers novel technique and insights into new, site-specific drug delivery and release systems.

  2. Mechanical characterization and validation of poly (methyl methacrylate)/multi walled carbon nanotube composite for the polycentric knee joint.

    PubMed

    Arun, S; Kanagaraj, S

    2015-10-01

    Trans femoral amputation is one of the most uncomfortable surgeries in patient׳s life, where the prosthesis consisting of a socket, knee joint, pylon and foot is used to do the walking activities. The artificial prosthetic knee joint imitates the functions of human knee to achieve the flexion-extension for the above knee amputee. The objective of present work is to develop a light weight composite material for the knee joint to reduce the metabolic cost of an amputee. Hence, an attempt was made to study the mechanical properties of multi walled carbon nanotubes (MWCNT) reinforced Poly (methyl methacrylate) (PMMA) prepared through melt mixing technique and optimize the concentration of reinforcement. The PMMA nanocomposites were prepared by reinforcing 0, 0.1, 0.2, 0.25, 0.3 and 0.4 wt% of MWCNT using injection moulding machine via twin screw extruder. It is observed that the tensile and flexural strength of PMMA, which were studied as per ASTM D638 and D790, respectively, were increased by 32.9% and 26.3% till 0.25 wt% reinforcement of MWCNT. The experimental results of strength and modulus were compared with theoretical prediction, where a good correlation was noted. It is concluded that the mechanical properties of PMMA were found to be increased to maximum at 0.25 wt% reinforcement of MWCNT, where the Pukanszky model and modified Halpin-Tsai model are suggested to predict the strength and modulus, respectively, of the PMMA/MWCNT composite, which can be opted as a suitable materiel for the development of polycentric knee joint.

  3. Interchain coupled chain dynamics of poly(ethylene oxide) in blends with poly(methyl methacrylate): Coupling model analysis

    NASA Astrophysics Data System (ADS)

    Ngai, K. L.; Wang, Li-Min

    2011-11-01

    Quasielastic neutron scattering and molecular dynamics simulation data from poly(ethylene oxide) (PEO)/poly(methyl methacrylate) (PMMA) blends found that for short times the self-dynamics of PEO chain follows the Rouse model, but at longer times past tc = 1-2 ns it becomes slower and departs from the Rouse model in dependences on time, momentum transfer, and temperature. To explain the anomalies, others had proposed the random Rouse model (RRM) in which each monomer has different mobility taken from a broad log-normal distribution. Despite the success of the RRM, Diddens et al. [Eur. Phys. Lett. 95, 56003 (2011)] extracted the distribution of friction coefficients from the MD simulations of a PEO/PMMA blend and found that the distribution is much narrower than expected from the RRM. We propose a simpler alternative explanation of the data by utilizing alone the observed crossover of PEO chain dynamics at tc. The present problem is just a special case of a general property of relaxation in interacting systems, which is the crossover from independent relaxation to coupled many-body relaxation at some tc determined by the interaction potential and intermolecular coupling/constraints. The generality is brought out vividly by pointing out that the crossover also had been observed by neutron scattering from entangled chains relaxation in monodisperse homopolymers, and from the segmental α-relaxation of PEO in blends with PMMA. The properties of all the relaxation processes in connection with the crossover are similar, despite the length scales of the relaxation in these systems are widely different.

  4. Properties of radiation cured vinyl-divinyl copolymers. Part I. Thermomechanical properties of crosslinked methyl methacrylate polymers

    SciTech Connect

    Micko, M.M.; Paszner, L.

    1980-01-01

    Radiation copolymerization (crosslinking) of methyl methacrylate (MMA) with a series of divinyl monomers containing 1 to 4 ethyleneglycol connecting units between the terminal reactive divinyl units was found to provide numerous improvements in the thermomechanical properties of the copolymers. Thermoplastic poly-MMA was converted to a thermoset copolymer with only small additions (2 to 5%) of the divinyl crosslinking agent. When the measured thermomechanical properties (glass transition temperature, Tg, thermal distortion temperature, TDT; and thermomechanical deformation degree, TDD) of the above crosslinked copolymers were related to the respective crosslink densities (expressed by the copolymer connection number, CN/sub co/) the crosslink efficiency increased in terms of the above parameters in a reverse order as observed for acceleration, i.e., TEGDMA < TrEGDMA < DEGDMA < EGDMA. This observation is readily explained by the relation between segmental mobility of the respective macromolecules of the copolymers formed and the critical thermomechanical parameters which can be determined for such solid copolymers. Segmental mobility of the crosslinking agent increases with increasing molecular bridge length and hence the increased temperature sensitivity of the copolymers to thermal softening and distortion as the bridge length increases from a single ethyleneglycol (EGDMA) to four ethyleneglycol (TEGDMA) units in the bridge connecting the vinyl functions of the divinyl monomers. For all copolymers of this study, the linear thermomechanical deformation coefficient, representing thermal deformation between the plastic and rubbery states, remained relatively constant across a broad temperature interval until the respective TDT temperatures are reached, and decreased exponentially with the divinyl monomer concentration in the copolymer regardless of the connecting bridge length.

  5. Synthesis of poly(methyl methacrylate) core/chitosan-mixed-polyethyleneimine shell nanoparticles and their antibacterial property.

    PubMed

    Inphonlek, Supharat; Pimpha, Nuttaporn; Sunintaboon, Panya

    2010-06-01

    The core-shell nanoparticles possessing poly(methyl methacrylate) (PMMA) core coated with chitosan (CS), polyethyleneimine (PEI), and chitosan-mixed-polyethyleneimine (CS/PEI) shells were synthesized in this work. The emulsifier-free emulsion polymerization triggered by a redox initiating system from t-butylhydroperoxide (TBHP) and amine groups on CS and/or PEI was used as a synthetic method. In the CS/PEI systems, the amount of CS was kept constant (0.5g), while the amount of PEI was varied from 0.1 to 0.5g. The surface and physico-chemical properties of prepared nanoparticles were then examined. FTIR spectra indicated the presence of grafted PMMA on CS and/or PEI, and the weight fraction of incorporated PEI in the CS/PEI nanoparticles. All nanoparticles were spherical in shape with uniform size distribution illustrated by scanning electron microscopy (SEM). The introduction of PEI to CS nanoparticles yielded the higher monomer conversion, grafting efficiency, and grafting percentage compared with the CS nanoparticles. The size of CS/PEI nanoparticles was smaller than the original CS and PEI nanoparticles, and tended to decrease with increasing amount of PEI introduced. The introduction of PEI also brought the higher colloidal stability to the nanoparticles as indicated by zeta-potential measurement and isoelectric point analysis. The nanoparticles exhibited a promising antibacterial activity against Staphylococcus aureus and Escherichia coli. The nanoparticle-bacteria interaction was studied via SEM. The results suggested that they would be useful as effective antibacterial agents.

  6. Effect of additive particles on mechanical, thermal, and cell functioning properties of poly(methyl methacrylate) cement

    PubMed Central

    Khandaker, Morshed; Vaughan, Melville B; Morris, Tracy L; White, Jeremiah J; Meng, Zhaotong

    2014-01-01

    The most common bone cement material used clinically today for orthopedic surgery is poly(methyl methacrylate) (PMMA). Conventional PMMA bone cement has several mechanical, thermal, and biological disadvantages. To overcome these problems, researchers have investigated combinations of PMMA bone cement and several bioactive particles (micrometers to nanometers in size), such as magnesium oxide, hydroxyapatite, chitosan, barium sulfate, and silica. A study comparing the effect of these individual additives on the mechanical, thermal, and cell functional properties of PMMA would be important to enable selection of suitable additives and design improved PMMA cement for orthopedic applications. Therefore, the goal of this study was to determine the effect of inclusion of magnesium oxide, hydroxyapatite, chitosan, barium sulfate, and silica additives in PMMA on the mechanical, thermal, and cell functional performance of PMMA. American Society for Testing and Materials standard three-point bend flexural and fracture tests were conducted to determine the flexural strength, flexural modulus, and fracture toughness of the different PMMA samples. A custom-made temperature measurement system was used to determine maximum curing temperature and the time needed for each PMMA sample to reach its maximum curing temperature. Osteoblast adhesion and proliferation experiments were performed to determine cell viability using the different PMMA cements. We found that flexural strength and fracture toughness were significantly greater for PMMA specimens that incorporated silica than for the other specimens. All additives prolonged the time taken to reach maximum curing temperature and significantly improved cell adhesion of the PMMA samples. The results of this study could be useful for improving the union of implant-PMMA or bone-PMMA interfaces by incorporating nanoparticles into PMMA cement for orthopedic and orthodontic applications. PMID:24920906

  7. Kinetics for the Sequential Infiltration Synthesis of Alumina in Poly(methyl methacrylate): An Infrared Spectroscopic Study

    SciTech Connect

    Biswas, Mahua; Libera, Joseph A.; Darling, Seth B.; Elam, Jeffrey W.

    2015-01-01

    Sequential infiltration synthesis (SIS) is a method for growing inorganic materials within polymers in an atomically controlled fashion. This technique can increase the etch resistance of optical, electron-beam, and block copolymer (BCP) lithography resists and is also a flexible strategy for nanomaterials synthesis. Despite this broad utility, the kinetics of SIS remain poorly understood, and this knowledge gap must be bridged in order to gain firm control over the growth of inorganic materials inside polymer films at a large scale. In this paper, we explore the reaction kinetics for Al2O3 SIS in PMMA using in situ Fourier transform infrared spectroscopy. First, we establish the kinetics for saturation adsorption and desorption of trimethyl aluminum (TMA) in PMMA over a range of PMMA film thicknesses deposited on silicon substrates. These observations guide the selection of TMA dose and purge times during SIS lithography to achieve robust organic/inorganic structures. Next, we examine the effects of TMA desorption on BCP lithography by performing SIS on silicon surfaces coated with polystyrene-block-poly(methyl methacrylate) films. After etching the organic components, the substrates are examined using scanning electron microcopy to evaluate the resulting Al2O3 patterns. Finally, we examine the effects of temperature on Al2O3 SIS in PMMA to elucidate the infiltration kinetics. The insights provided by these measurements will help extend SIS lithography to larger substrate sizes for eventual commercialization and expand our knowledge of precursor-polymer interactions that will benefit the SIS of a wide range of inorganic materials in the future.

  8. Interchain coupled chain dynamics of poly(ethylene oxide) in blends with poly(methyl methacrylate): coupling model analysis.

    PubMed

    Ngai, K L; Wang, Li-Min

    2011-11-21

    Quasielastic neutron scattering and molecular dynamics simulation data from poly(ethylene oxide) (PEO)/poly(methyl methacrylate) (PMMA) blends found that for short times the self-dynamics of PEO chain follows the Rouse model, but at longer times past t(c) = 1-2 ns it becomes slower and departs from the Rouse model in dependences on time, momentum transfer, and temperature. To explain the anomalies, others had proposed the random Rouse model (RRM) in which each monomer has different mobility taken from a broad log-normal distribution. Despite the success of the RRM, Diddens et al. [Eur. Phys. Lett. 95, 56003 (2011)] extracted the distribution of friction coefficients from the MD simulations of a PEO/PMMA blend and found that the distribution is much narrower than expected from the RRM. We propose a simpler alternative explanation of the data by utilizing alone the observed crossover of PEO chain dynamics at t(c). The present problem is just a special case of a general property of relaxation in interacting systems, which is the crossover from independent relaxation to coupled many-body relaxation at some t(c) determined by the interaction potential and intermolecular coupling/constraints. The generality is brought out vividly by pointing out that the crossover also had been observed by neutron scattering from entangled chains relaxation in monodisperse homopolymers, and from the segmental α-relaxation of PEO in blends with PMMA. The properties of all the relaxation processes in connection with the crossover are similar, despite the length scales of the relaxation in these systems are widely different.

  9. Acid-base properties, deactivation, and in situ regeneration of condensation catalysts for synthesis of methyl methacrylate

    SciTech Connect

    Gogate, M.R.; Spivey, J.J.; Zoeller, J.R.

    1996-12-31

    Condensation reaction of a propionate with formaldehyde is a novel route for synthesis of methyl methacrylate (MMA). The reaction mechanism involves a proton abstraction from the propionate on the basic sites and activation of the aliphatic aldehyde on the acidic sites of the catalyst. The acid-base properties of ternary V-Si-P oxide catalysts and their relation to the NWA yield in the vapor phase condensation of formaldehyde with propionic anhydride has been studied for the first time. Five different V-Si-P catalysts with different atomic ratios of vanadium, silicon, and phosphorous were synthesized, characterized, and tested in a fixed-bed microreactor system. A V-Si-P 1:10:2.8 catalyst gave the maximum condensation yield of 56% based on HCHO fed at 300{degrees}C and 2 atm and at a space velocity of 290 cc/g cat{center_dot}h. A parameter called the ``q-ratio`` has been defined to correlate the condensation yields to the acid-base properties. The correlation of q-ratio with the condensation yield shows that higher q-ratios are more desirable. The long-term deactivation studies on the V-Si-P 1: 10:2.8 catalyst at 300{degrees}C and 2 atm and at a space velocity of 290 cc/g cat{center_dot}h show that the catalyst activity drops by a factor of nearly 20 over a 180 h period. The activity can be restored to about 78% of the initial activity by a mild oxidative regeneration at 300{degrees}C and 2 atm. The performance of V-Si-P catalyst has been compared to a Ta/SiO{sub 2} catalyst. The Ta- catalyst is more stable and has a higher on-stream catalyst life.

  10. U.S. Geological Survey laboratory method for methyl tert-Butyl ether and other fuel oxygenates

    USGS Publications Warehouse

    Raese, Jon W.; Rose, Donna L.; Sandstrom, Mark W.

    1995-01-01

    Methyl tert-butyl ether (MTBE) was found in shallow ground-water samples in a study of 8 urban and 20 agricultural areas throughout the United States in 1993 and 1994 (Squillace and others, 1995, p. 1). The compound is added to gasoline either seasonally or year round in many parts of the United States to increase the octane level and to reduce carbon monoxide and ozone levels in the air. The U.S. Geological Survey (USGS) National Water Quality Laboratory (NWQL), near Denver, uses state-of-the-art technology to analyze samples for MTBE as part of the USGS water-quality studies. In addition, the NWQL offers custom analyses to determine two other fuel oxygenates--ethyl tert-butyl ether (ETBE) and tert-amyl methyl ether (TAME). The NWQL was not able to obtain a reference standard for tert-amyl ethyl ether (TAEE), another possible fuel oxygenate (Shelley and Fouhy, 1994, p. 63). The shallow ground-water samples were collected as part of the USGS National Water-Quality Assessment Program. These samples were collected from 211 urban wells or springs and 562 agricultural wells sampled by the USGS in 1993 and 1994. The wells were keyed to specific land-use areas to assess the effects of different uses on ground-water quality (Squillace and others, 1995, p. 2). Ground-water samples were preserved on site to pH less than or equal to 2 with a solution of 1:1 hydrochloric acid. All samples were analyzed at the NWQL within 2 weeks after collection. The purpose of this fact sheet is to explain briefly the analytical method implemented by the USGS for determining MTBE and other fuel oxygenates. The scope is necessarily limited to an overview of the analytical method (instrumentation, sample preparation, calibration and quantitation, identification, and preservation of samples) and method performance (reagent blanks, accuracy, and precision).

  11. Gas Phase Conformations and Methyl Internal Rotation for 2-PHENYLETHYL Methyl Ether and its Argon Van Der Waals Complex from Fourier Transform Microwave Spectroscopy

    NASA Astrophysics Data System (ADS)

    Gurusinghe, Ranil M.; Tubergen, Michael

    2015-06-01

    A mini-cavity microwave spectrometer was used to record the rotational spectra arising from 2-phenylethyl methyl ether and its weakly bonded argon complex in the frequency range of 10.5 - 22 GHz. Rotational spectra were found for two stable conformations of the monomer: anti-anti and gauche-anti, which are 1.4 kJ mol-1 apart in energy at wB97XD/6-311++G(d,p) level. Doubled rotational transitions, arising from internal motion of the methyl group, were observed for both conformers. The program XIAM was used to fit the rotational constants, centrifugal distortion constants, and barrier to internal rotation to the measured transition frequencies of the A and E internal rotation states. The best global fit values of the rotational constants for the anti-anti conformer are A= 3799.066(3) MHz, B= 577.95180(17) MHz, C= 544.7325(3) MHz and the A state rotational constants of the gauche-anti conformer are A= 2676.1202(7) MHz, B= 760.77250(2) MHz, C= 684.78901(2) MHz. The rotational spectrum of 2-phenylethyl methyl ether - argon complex is consistent with the geometry where argon atom lies above the plane of the benzene moiety of gauche-anti conformer. Tunneling splittings were too small to resolve within experimental accuracy, likely due to an increase in three fold potential barrier when the argon complex is formed. Fitted rotational constants are A= 1061.23373(16) MHz, B= 699.81754(7) MHz, C= 518.33553(7) MHz. The lowest energy solvated ether - water complex with strong intermolecular hydrogen bonding has been identified theoretically. Progress on the assignment of the water complex will also be presented.

  12. Characterization and comparison of methacrylic acid with 2-acrylamido-2-methyl-1-propanesulfonic acid in the preparation of monolithic column for capillary electrochromatography.

    PubMed

    Horiguchi, Daisuke; Ohyama, Kaname; Masunaga, Tomoko; Fujita, Yoshiko; Ali, Marwa Fathy Bakr; Kishikawa, Naoya; Kuroda, Naotaka

    2013-01-01

    Butyl methacrylate (BMA)-ethylene dimethacrylate (EDMA)-methacrylic acid (MAA) and BMA-EDMA-2-acrylamido-2-methyl-1-propanesulfonic acid (AMPS) monolithic columns were prepared by varying the percentage of ionic monomers for capillary electrochromatography. Monolithic columns with a higher content of ionic monomers provided better column efficiency, and the performance of BMA-EDMA-MAA monoliths was better than BMA-EDMA-AMPS. To characterize and optimize BMA-EDMA-MAA monoliths, the effects of the content of cross-linker and the total monomer in the polymerization mixture on column performance were also studied. Plate heights of 8.2 µm for the unretained solute (thiourea) and 12.6 µm for the retained solute (naphthalene) were achieved with a monolithic column using 2.5% MAA (Column I).

  13. Synthesis and applications of shell cross-linked thermoresponsive hybrid micelles based on poly(N-isopropylacrylamide-co-3-(trimethoxysilyl)propyl methacrylate)-b-poly(methyl methacrylate).

    PubMed

    Wei, Hua; Cheng, Cheng; Chang, Cong; Chen, Wen-Qin; Cheng, Si-Xue; Zhang, Xian-Zheng; Zhuo, Ren-Xi

    2008-05-06

    Shell cross-linked (SCL) thermoresponsive hybrid micelles consisting of a cross-linked thermoresponsive hybrid hydrophilic shell and a hydrophobic core domain were synthesized from poly(N-isopropylacrylamide-co-3- (trimethoxysilyl)propyl methacrylate)-b-polymethyl methacrylate (P(NIPAAm-co-MPMA)-b-PMMA) amphiphilic block copolymers. Transmission electron microscopy (TEM) images showed that the SCL micelles formed regularly globular nanoparticles. The SCL micelles showed reversible dispersion/aggregation in response to temperature cycles through an outer polymer shell lower critical solution temperature (LCST) for PNIPAAm at around 33 degrees C, observed by turbidity measurements and dynamic light scattering (DLS). The drug loading and in vitro drug release properties of the SCL micelles bearing a silica-reinforced PNIPAAm shell were further studied, which showed that the SCL micelles exhibited a much improved entrapment efficiency (EE) as well as a slower release rate which allowed the entrapped molecules to be slowly released over a much longer period of time as compared with pure PNIPAAm-b-PMMA micelles.

  14. Expression of 6-phosphofructo-2-kinase/ fructose-2,6-bisphosphatase-3 and VEGF mRNA in rat liver, lung and heart: effect of methyl tertbutyl ether.

    PubMed

    Minchenko, D O; Kundieva, A V; Tsuchihara, K; Yavorovsky, O P; Paustovsky, Y O; Esumi, H; Minchenko, O H

    2009-01-01

    The main goal of this work was investigation of the effect of methyl tertbutyl ether, ecologically dangerous chemical compound, on the expression of 6-phosphofructo-2-kinase/fructose-2,6-bisphosphatase-3 (PFKFB-3) and vascular endothelial growth factor (VEGF) mRNA in different rat organs. Expression of PFKFB-3 and VEGF is a hypoxia inducible factor (HIF)-dependent process which significantly increases under hypoxia, in malignant tumors and other pathology. In this study we have shown that PFKFB-3 and VEGF mRNA expression in the liver, lung, and heart changes in rats, treated with methyl tertbutyl ether for two months, in organ-specific manner. Expression of alternative splice variants of PFKFB-3 mRNA as well as VEGF mRNA also changes in organ-specific manner in rats, treated with methyl tertbutyl ether. The effect of methyl tertbutyl ether on the expression of PFKFB-3 and VEGF mRNA and its alternative splice variants is dose-dependent. Results of this investigation clearly demonstrated that methyl tertbutyl ether affects the expression of PFKFB-3, a key regulatory enzyme of glycolysis, as well as VEGF, very important factor of angiogenesis, in an organ-specific and dose-dependent manner.

  15. Methyl tert-butyl ether biodegradation by microbial consortia obtained from soil samples of gasoline-polluted sites in Mexico.

    PubMed

    Morales, Marcia; Velázquez, Elia; Jan, Janet; Revah, Sergio; González, Uriel; Razo-Flores, Elías

    2004-02-01

    Microbial consortia obtained from soil samples of gasoline-polluted sites were individually enriched with pentane, hexane, isooctane and toluene. Cometabolism with methyl tert-butyl ether, (MTBE), gave maximum degradation rates of 49, 12, 32 and 0 mg g(-1)protein h(-1), respectively. MTBE was fully degraded even when pentane was completely depleted with a cometabolic coefficient of 1 mgMTBE mg(-1)pentane. The analysis of 16S rDNA from isolated microorganisms in the pentane-adapted consortia showed that microorganisms could be assigned to Pseudomonas. This is the first work reporting the cometabolic mineralization of MTBE by consortium of this genus.

  16. Separation of Dimethyl Ether from Syn-Gas Components by Poly(dimethylsiloxane) and Poly(4-methyl-1-pentene) Membranes

    SciTech Connect

    Christopher J. Orme; Frederick F. Stewart

    2011-05-01

    Permeability and selectivity in gas transport through poly(4-methyl-1-pentene) (TPX) and poly(dimethylsiloxane) (PDMS) using variable temperature mixed gas experiments is reported. Selected gases include H2, CO, CH4, CO2, and dimethyl ether (DME). The DME data is the first to be reported through these membranes. In this paper, the chosen polymers reflect both rubbery and crystalline materials. Rubbery polymers tend to be weakly size sieving, which, in this work, has resulted in larger permeabilities, lower separation factors, and lower activation energies of permeation (Ep). Conversely, the crystalline TPX membranes showed much greater sensitivity to penetrant size; although the gas condensability also played a role in transport.

  17. 3-(Imidazolyl methyl)-3-aza-bicyclo[3.1.0]hexan-6-yl)methyl ethers: a novel series of mGluR2 positive allosteric modulators.

    PubMed

    Zhang, Lei; Rogers, Bruce N; Duplantier, Allen J; McHardy, Stanley F; Efremov, Ivan; Berke, Helen; Qian, Weimin; Zhang, Andy Q; Maklad, Noha; Candler, John; Doran, Angela C; Lazzaro, John T; Ganong, Alan H

    2008-10-15

    The synthesis and structure-activity relationship (SAR) of a novel series of 3-(imidazolyl methyl)-3-aza-bicyclo[3.1.0]hexan-6-yl)methyl ethers, derived from a high throughput screening (HTS), are described. Subsequent optimization led to identification of potent, metabolically stable and orally available mGluR2 positive allosteric modulators (PAMs).

  18. Surface-initiated Polymerization of Azidopropyl Methacrylate and its Film Elaboration via Click Chemistry.

    PubMed

    Saha, Sampa; Bruening, Merlin L; Baker, Gregory L

    2012-11-27

    Azidopropyl methacrylate (AzPMA), a functional monomer with a pendent azido group, polymerizes from surfaces and provides polymer brushes amenable to subsequent elaboration via click chemistry. In DMF at 50 °C, click reactions between poly(AzPMA) brushes and an alkynylated dye proceed with >90% conversion in a few minutes. However, in aqueous solutions, reaction with an alkyne-containing poly(ethylene glycol) methyl ether (mPEG, Mn=5000) gives <10% conversion after a 12-h reaction at room temperature. Formation of copolymers with AzPMA and polyethylene glycol methyl ether methacrylate (mPEGMA) enables control over the hydrophilicity and functional group density in the copolymer to increase the yield of aqueous click reactions. The copolymers show reaction efficiencies as high as 60%. These studies suggest that for aqueous applications such as bioconjugation via click chemistry, control over brush hydrophilicity is vital.

  19. pH-sensitive methacrylic copolymer gels and the production thereof

    DOEpatents

    Mallapragada, Surya K.; Anderson, Brian C.

    2007-05-15

    The present invention provides novel gel forming methacrylic blocking copolymers that exhibit cationic pH-sensitive behavior as well as good water solubility. The copolymers are constructed by polymerization of a tertiary amine methacrylate with either a (poly(ethylene oxide)-b-poly(propylene oxide)-b-poly(ethylene oxide) polymer, such as the commercially available Pluronic.RTM. polymers, or a poly(ethylene glycol)methyl ether polymer. The polymers may be used for drug and gene delivery, protein separation, as structural supplements, and more.

  20. Photovoltaic and thermal properties of electrolytes based on electrospun poly(vinylidene fluoride-hexafluoro propylene)/poly(methyl methacrylate) nanofibers for dye-sensitized solar cells.

    PubMed

    Jang, Young-Wook; Won, Du-Hyun; Kim, Young-Keun; Hwang, Won-Pill; Jang, Sung-Il; Jeong, Sung-Hoon; Kim, Mi-Ra; Lee, Jin-Kook

    2014-08-01

    We prepared electrospun polymer nanofibers by electrospnning method and investigated about their applications to dye-sensitized solar cells (DSSCs). Electrospun polymer nanofibers applied to the polymer matrix in electrolyte for DSSCs. To improve the stiffness of polymer nanofiber, poly(vinylidene fluoride-hexafluoro propylene)/Poly(methyl methacrylate) (PVDF-HFP/PMMA) blend nanofibers were prepared and examined. In the electrospun PVDF-HFP/PMMA (1:1) blend nanofibers, the best results of VOC, JSC, FF, and efficiency of the DSSC devices showed 0.71 V, 12.8 mA/cm2, 0.61, and 5.56% under AM 1.5 illumination.