Toughening epoxy acrylate with polyurethane acrylates and hyper-branched polyester in three dimensional printing

NASA Astrophysics Data System (ADS)

Fang, Chao; Li, Ning; Liu, Yang; Lu, Gang

2018-05-01

In order to improve the toughness of epoxy acrylate (EA) in three dimensional printing (3D-printing), bifunctional polyurethane acrylate (PUA) and trifunctional PUA were firstly blended with EA. The multi-indicators orthogonal experiment, designed with the indicators of tensile strength, elongation at break and impact strength, was used to find out the optimal formulation. Then, hyper-branched polyesters (HBPs) was added to improve the toughness of the photocurable system. The microstructures of the cured specimens were characterized by optical microscopy and scanning electron microscopy. By analyzing their mechanical properties and microstructures, it was revealed that the best addition amounts of HBP are 10 wt%. Results indicated that their toughness improved a lot comparing with pure EA. The changes of mechanical properties were characterized by DMA. The addition of HBP could cause a loss in stiffness, elasticity modulus and thermostability.

Characterization of a resorbable poly(ester urethane) with biodegradable hard segments.

PubMed

Dempsey, David K; Robinson, Jennifer L; Iyer, Ananth V; Parakka, James P; Bezwada, Rao S; Cosgriff-Hernandez, Elizabeth M

2014-01-01

The rapid growth of regenerative medicine and drug delivery fields has generated a strong need for improved polymeric materials that degrade at a controlled rate into safe, non-cytotoxic by-products. Polyurethane thermoplastic elastomers offer several advantages over other polymeric materials including tunable mechanical properties, excellent fatigue strength, and versatile processing. The variable segmental chemistry in developing resorbable polyurethanes also enables fine control over the degradation profile as well as the mechanical properties. Linear aliphatic isocyanates are most commonly used in biodegradable polyurethane formulations; however, these aliphatic polyurethanes do not match the mechanical properties of their aromatic counterparts. In this study, a novel poly(ester urethane) (PEsU) synthesized with biodegradable aromatic isocyanates based on glycolic acid was characterized for potential use as a new resorbable material in medical devices. Infrared spectral analysis confirmed the aromatic and phase-separated nature of the PEsU. Uniaxial tensile testing displayed stress-strain behavior typical of a semi-crystalline polymer above its Tg, in agreement with calorimetric findings. PEsU outperformed aliphatic PCL-based polyurethanes likely due to the enhanced cohesion of the aromatic hard domains. Accelerated degradation of the PEsU using 0.1 M sodium hydroxide resulted in hydrolysis of the polyester soft segment on the surface, reduced molecular weight, surface cracking, and a 30% mass loss after four weeks. Calorimetric studies indicated a disruption of the soft segment crystallinity after incubation which corresponded with a drop in initial modulus of the PEsU. Finally, cytocompatibility testing with 3T3 mouse fibroblasts exhibited cell viability on PEsU films comparable to a commercial poly(ether urethane urea) after 24 h followed by 85% cell viability at 72 h. Overall, this new resorbable polyurethane shows strong potential for use in wide

Degradation of polyester polyurethane by a newly isolated soil bacterium, Bacillus subtilis strain MZA-75.

PubMed

Shah, Ziaullah; Krumholz, Lee; Aktas, Deniz Fulya; Hasan, Fariha; Khattak, Mutiullah; Shah, Aamer Ali

2013-11-01

A polyurethane (PU) degrading bacterial strain MZA-75 was isolated from soil through enrichment technique. The bacterium was identified through 16S rRNA gene sequencing, the phylogenetic analysis indicated the strain MZA-75 belonged to genus Bacillus having maximum similarity with Bacillus subtilis strain JBE0016. The degradation of PU films by strain MZA-75 in mineral salt medium (MSM) was analyzed by scanning electron microscopy (SEM), fourier transform infra-red spectroscopy (FT-IR) and gel permeation chromatography (GPC). SEM revealed the appearance of widespread cracks on the surface. FTIR spectrum showed decrease in ester functional group. Increase in polydispersity index was observed in GPC, which indicates chain scission as a result of microbial treatment. CO2 evolution and cell growth increased when PU was used as carbon source in MSM in Sturm test. Increase in both cell associated and extracellular esterases was observed in the presence of PU indicated by p-Nitrophenyl acetate (pNPA) hydrolysis assay. Analysis of cell free supernatant by gas chromatography-mass spectrometry (GC-MS) revealed that 1,4-butanediol and adipic acid monomers were produced. Bacillus subtilis strain MZA-75 can degrade the soft segment of polyester polyurethane, unfortunately no information about the fate of hard segment could be obtained. Growth of strain MZA-75 in the presence of these metabolites indicated mineralization of ester hydrolysis products into CO2 and H2O.

Chemical and enzymatic catalytic routes to polyesters and oligopeptides biobased materials

NASA Astrophysics Data System (ADS)

Zhu, Jianhui

My Ph.D research focuses on the synthesis and property studies of different biobased materials, including polyesters, polyurethanes and oligopeptides. The first study describes the synthesis, crystal structure and physico-mechanical properties of a bio-based polyester prepared from 2,5-furandicarboxylic acid (FDCA) and 1,4-butanediol. Melt-polycondensation experiments were conducted by a two-stage polymerization using titanium tetraisopropoxide (Ti[OiPr] 4) as catalyst. Polymerization conditions (catalyst concentration, reaction time and 2nd stage reaction temperature) were varied to optimize poly(butylene furan dicarboxylate), PBF, molecular weight. A series of PBFs with different Mw were characterized by Differential Scanning Calorimetry (DSC), Thermogravimetric Analysis (TGA), Dynamic Mechanical Thermal Analysis (DMTA), X-Ray diffraction and tensile testing. Influence of molecular weight and melting/crystallization enthalpy on PBF material tensile properties was explored. Cold-drawing tensile tests at room temperature for PBF with Mw 16K to 27K showed a brittle-to-ductile transition. When Mw reaches 38K, the Young's Modulus of PBF remains above 900 MPa, and the elongation at break increases to above 1000%. The mechanical properties, thermal properties and crystal structures of PBF were similar to petroleum derived poly(butylenes terephthalate), PBT. Fiber diagrams of uniaxially stretched PBF films were collected, indexed, and the unit cell was determined as triclinic (a=4.78(3) A, b=6.03(5) A, c=12.3(1) A, alpha=110.1(2)°, beta=121.1(3)°, gamma=100.6(2)°). A crystal structure was derived from this data and final atomic coordinates are reported. We concluded that there is a close similarity of the PBF structure to PBT alpha- and beta-forms. In the second study, a biobased long chain polyester polyol (PC14-OH) was synthesized from o-hydroxytetradecanoic acid (o-HOC14) and 1,4-butanediol. The first section about polyester polyurethanes describes the synthesis

The axial crushes behaviour on foam-filled round Jute/Polyester composite tubes

NASA Astrophysics Data System (ADS)

Othman, A.; Ismail, A. E.

2018-04-01

The present paper investigates the effect of axial loading compression on jute fibre reinforced polyester composite round tubes. The specimen of composite tube was fabricated by hand lay-up method of 120 mm length with fix 50.8 mm inner diameter to determine the behaviour of energy absorption on number of layers of 450 angle fibre and internally reinforced with and without foam filler material. The foam filler material used in this studies were polyurethane (PU) and polystyrene (PE) with average of 40 and 45 kg/m3 densities on the axial crushing load against displacement relations and on the failure modes. The number of layers of on this study were two; three and four were selected to calculate the crush force efficiency (CFE) and the specific energy absorption (SEA) of the composite tubes. Result indicated that the four layers’ jute/polyester show significant value in term of crushing load compared to 2 and 3 layers higher 60% for 2 layer and 3% compared to 3 layers. It has been found that the specific energy absorption of the jute/polyester tubes with polystyrene foam-filled is found higher respectively 10% to 12% than empty and polyurethane (PU) foam tubes. The increase in the number of layers from two to four increases the mean axial load from 1.01 KN to 3.60 KN for empty jute/polyester and from 2.11 KN to 4.26 KN for the polyurethane (PU) foam-filled jute/polyester tubes as well as for 3.60 KN to 5.58 KN for the polystyrene (PE) foam-filled jute/polyester. The author’s found that the failure of mechanism influence the characteristic of curve load against displacement obtained and conclude that an increasing number of layers and introduce filler material enhance the capability of specific absorbed energy.

Quasi-static axial crushes on woven jute/polyester AA6063T52 composite tubes

NASA Astrophysics Data System (ADS)

Othman, A.; Ismail, AE

2018-04-01

Quasi-static axial loading have been studied in this paper to determine the behaviour of jute/polyester wrapped on aluminium alloy 6063T52. The filler material also was include into crush box specimen, which is polyurethane (PU) and polystyrene (PE) rigid foam at ranging 40 and 45 kg/m3 densities. All specimen profile was fabricated using hand layup techniques and the length of each specimen were fixed at 100 mm as well as diameter and width of the tube at 50.8 mm. The two types of tubular cross-section were studied of round and square thin-walled profiles and the angle of fibre at 450 were analysed for four layers. Thin walled of aluminium was 1.9 mm and end frontal of each specimen of composite were chamfered at 450 to prevent catastrophic failure mode. The specific absorbed energy (SEA) and crush force efficiency (CFE) were analyses for each specimen to see the behaviour on jute/polyester wrapped on metallic structure can give influence the energy management for automotive application. Result show that the four layers’ jute/polyester with filler material show significant value in term of specific absorbed energy compared empty and polyurethane profiles higher 26.66% for empty and 15.19% compared to polyurethane profiles. It has been found that the thin walled square profile of the jute/polyester tubes with polystyrene foam-filled is found higher respectively 27.42% to 13.13% than empty and polyurethane (PU) foam tubes. An introduce filler material onto thin walled composite profiles gave major advantage increases the mean axial load of 31.87% from 32.94 kN to 48.35 kN from empty to polystyrene thin walled round jute/polyester profiles and 31.7% from 23.11 KN to 33.84 kN from empty to polystyrene thin walled square jute/polyester profiles. Failure mechanisms of the axially loaded composite tubes were also observed and discussed.

Novel non-cytotoxic, bioactive and biodegradable hybrid materials based on polyurethanes/TiO2 for biomedical applications.

PubMed

González-García, Dulce M; Téllez Jurado, L; Jiménez-Gallegos, R; Rodríguez-Lorenzo, Luis M

2017-06-01

Titanium compounds have demonstrated great interfacial properties with biological tissues whereas a wide variety of polyurethanes have also been successfully probed in medical applications. However, studies about hybrids based on polyurethanes/TiO 2 for medical applications are scarce. The aim of this work is to design novel biodegradable hybrid materials based on polyurethanes/TiO 2 (80% organic-20% inorganic) and to perform a preliminary study of the potential applications in bone regeneration. The hybrids have been prepared by a sol-gel reaction using titanium isopropoxide as precursor of the inorganic component and polyurethane as the organic one. A series of polyurethanes has been prepared using different polyesters glycol succinate as soft segment, and 1,6-diisocyanatohexane (HDI) and butanediol (BD) as linear hard segment. The spectroscopy techniques used allow to confirm the formation of the required polyurethanes by the identification of bands related to carboxylic groups (COOH), and the amine groups (NH), and also the TiOH bonds and the bonds related to the interconnected network between the inorganic and the organic components from hybrids. The results from SEM/EDS show a homogeneous distribution of the inorganic component into the organic matrix. The nontoxic character of the hybrid (H400) was probed using MG-63 cell line with over 90% of cell viability. Finally, the formation of a hydroxyapatite layer in the material surface after 21days of soaking in SBF shows the bioactive character. Copyright © 2017 Elsevier B.V. All rights reserved.

Fungal Communities Associated with the Biodegradation of Polyester Polyurethane Buried under Compost at Different Temperatures

PubMed Central

Zafar, Urooj; Houlden, Ashley

2013-01-01

Plastics play an essential role in the modern world due to their low cost and durability. However, accumulation of plastic waste in the environment causes wide-scale pollution with long-lasting effects, making plastic waste management expensive and problematic. Polyurethanes (PUs) are heteropolymers that made up ca. 7% of the total plastic production in Europe in 2011. Polyester PUs in particular have been extensively reported as susceptible to microbial biodegradation in the environment, particularly by fungi. In this study, we investigated the impact of composting on PUs, as composting is a microbially rich process that is increasingly being used for the processing of green waste and food waste as an economically viable alternative to landfill disposal. PU coupons were incubated for 12 weeks in fresh compost at 25°C, 45°C, and 50°C to emulate the thermophilic and maturation stages of the composting process. Incubation at all temperatures caused significant physical deterioration of the polyester PU coupons and was associated with extensive fungal colonization. Terminal restriction fragment length polymorphism (TRFLP) analysis and pyrosequencing of the fungal communities on the PU surface and in the surrounding compost revealed that the population on the surface of PU was different from the surrounding compost community, suggesting enrichment and selection. The most dominant fungi identified from the surfaces of PU coupons by pyrosequencing was Fusarium solani at 25°C, while at both 45°C and 50°C, Candida ethanolica was the dominant species. The results of this preliminary study suggest that the composting process has the potential to biodegrade PU waste if optimized further in the future. PMID:24056469

Fungal communities associated with the biodegradation of polyester polyurethane buried under compost at different temperatures.

PubMed

Zafar, Urooj; Houlden, Ashley; Robson, Geoffrey D

2013-12-01

Plastics play an essential role in the modern world due to their low cost and durability. However, accumulation of plastic waste in the environment causes wide-scale pollution with long-lasting effects, making plastic waste management expensive and problematic. Polyurethanes (PUs) are heteropolymers that made up ca. 7% of the total plastic production in Europe in 2011. Polyester PUs in particular have been extensively reported as susceptible to microbial biodegradation in the environment, particularly by fungi. In this study, we investigated the impact of composting on PUs, as composting is a microbially rich process that is increasingly being used for the processing of green waste and food waste as an economically viable alternative to landfill disposal. PU coupons were incubated for 12 weeks in fresh compost at 25°C, 45°C, and 50°C to emulate the thermophilic and maturation stages of the composting process. Incubation at all temperatures caused significant physical deterioration of the polyester PU coupons and was associated with extensive fungal colonization. Terminal restriction fragment length polymorphism (TRFLP) analysis and pyrosequencing of the fungal communities on the PU surface and in the surrounding compost revealed that the population on the surface of PU was different from the surrounding compost community, suggesting enrichment and selection. The most dominant fungi identified from the surfaces of PU coupons by pyrosequencing was Fusarium solani at 25°C, while at both 45°C and 50°C, Candida ethanolica was the dominant species. The results of this preliminary study suggest that the composting process has the potential to biodegrade PU waste if optimized further in the future.

Biodegradable polyurethane ureas with variable polyester or polycarbonate soft segments: effects of crystallinity, molecular weight, and composition on mechanical properties.

PubMed

Ma, Zuwei; Hong, Yi; Nelson, Devin M; Pichamuthu, Joseph E; Leeson, Cory E; Wagner, William R

2011-09-12

Biodegradable polyurethane urea (PUU) elastomers are ideal candidates for fabricating tissue engineering scaffolds with mechanical properties akin to strong and resilient soft tissues. PUU with a crystalline poly(ε-caprolactone) (PCL) macrodiol soft segment (SS) showed good elasticity and resilience at small strains (<50%) but showed poor resilience under large strains because of stress-induced crystallization of the PCL segments, with a permanent set of 677 ± 30% after tensile failure. To obtain softer and more resilient PUUs, we used noncrystalline poly(trimethylene carbonate) (PTMC) or poly(δ-valerolactone-co-ε-caprolactone) (PVLCL) macrodiols of different molecular weights as SSs that were reacted with 1,4-diisocyanatobutane and chain extended with 1,4-diaminobutane. Mechanical properties of the PUUs were characterized by tensile testing with static or cyclic loading and dynamic mechanical analysis. All of the PUUs synthesized showed large elongations at break (800-1400%) and high tensile strength (30-60 MPa). PUUs with noncrystalline SSs all showed improved elasticity and resilience relative to the crystalline PCL-based PUU, especially for the PUUs with high molecular weight SSs (PTMC 5400 M(n) and PVLCL 6000 M(n)), of which the permanent deformation after tensile failure was only 12 ± 7 and 39 ± 4%, respectively. The SS molecular weight also influenced the tensile modulus in an inverse fashion. Accelerated degradation studies in PBS containing 100 U/mL lipase showed significantly greater mass loss for the two polyester-based PUUs versus the polycarbonate-based PUU and for PVLCL versus PCL polyester PUUs. Basic cytocompatibility was demonstrated with primary vascular smooth muscle cell culture. The synthesized families of PUUs showed variable elastomeric behavior that could be explained in terms of the underlying molecular design and crystalline behavior. Depending on the application target of interest, these materials may provide options or guidance for

Some physical and mechanical properties of recycled polyurethane foam blends

NASA Astrophysics Data System (ADS)

Bledzki, A. K.; Zicans, J.; Merijs Meri, R.; Kardasz, D.

2008-09-01

Blends of secondary rigid polyurethane foams (RPUFs) with soft polyurethane foams (SPUFs) were investigated. The effect of SPUF content and its chemical nature on some physical and mechanical properties of the blends was evaluated. Owing to the stronger intermolecular interaction and higher values of cohesion energy, the blends of RPUFs with polyester SPUFs showed higher mechanical properties than those with polyether SPUFs. The density, hardness, ultimate strength, and the tensile, shear, and flexural moduli increased, while the impact toughness, ultimate elongation, and damping characteristics decreased with increasing RPUF content in the blends.

Actuators based on polyurethanes with different types of polyol

NASA Astrophysics Data System (ADS)

Lim, Hyun-Ok; Bark, Geong-Mi; Jo, Nam-Ju

2007-07-01

This study dealt with the electrostrictive responses of polyurethane (PU) actuators with different microphase separation structure, which was a promising candidate for a material used in polymer actuators. In order to construct PUs with different higher-order structure, we synthesized PUs with different diols; poly(neopentyl glycol adipate) (PNAD), poly(tetramethylene glycol) (PTMG), and poly(dimethyl siloxnae) (PDMS). Synthesized PU was characterized by FT-IR spectroscopy and GPC. Thermal analysis and mechanical properties of PU films were carried out with DSC and UTM, respectively. And PU actuator was formed in a monomorph type which made by carbon black electrodes on the both surfaces of PU film by spin coating method. Actuation behavior was mainly influenced on microphase separation structure and mechanical property of PU. In result, PU actuator with PNAD, polyester urethane, had the largest field-induced displacement.

Cell–material interactions on biphasic polyurethane matrix

PubMed Central

Dicesare, Patrick; Fox, Wade M.; Hill, Michael J.; Krishnan, G. Rajesh; Yang, Shuying; Sarkar, Debanjan

2013-01-01

Cell–matrix interaction is a key regulator for controlling stem cell fate in regenerative tissue engineering. These interactions are induced and controlled by the nanoscale features of extracellular matrix and are mimicked on synthetic matrices to control cell structure and functions. Recent studies have shown that nanostructured matrices can modulate stem cell behavior and exert specific role in tissue regeneration. In this study, we have demonstrated that nanostructured phase morphology of synthetic matrix can control adhesion, proliferation, organization and migration of human mesenchymal stem cells (MSCs). Nanostructured biodegradable polyurethanes (PU) with segmental composition exhibit biphasic morphology at nanoscale dimensions and can control cellular features of MSCs. Biodegradable PU with polyester soft segment and hard segment composed of aliphatic diisocyanates and dipeptide chain extender were designed to examine the effect polyurethane phase morphology. By altering the polyurethane composition, morphological architecture of PU was modulated and its effect was examined on MSC. Results show that MSCs can sense the nanoscale morphology of biphasic polyurethane matrix to exhibit distinct cellular features and, thus, signifies the relevance of matrix phase morphology. The role of nanostructured phases of a synthetic matrix in controlling cell–matrix interaction provides important insights for regulation of cell behavior on synthetic matrix and, therefore, is an important tool for engineering tissue regeneration. PMID:23255285

Novel route of synthesis for cellulose fiber-based hybrid polyurethane

NASA Astrophysics Data System (ADS)

Ikhwan, F. H.; Ilmiati, S.; Kurnia Adi, H.; Arumsari, R.; Chalid, M.

2017-07-01

Polyurethanes, obtained by the reaction of a diisocyanate compound with bifunctional or multifunctional reagent such as diols or polyols, have been studied intensively and well developed. The wide range modifier such as chemical structures and molecular weight to build polyurethanes led to designs of materials that may easily meet the functional product demand and to the extraordinary spreading of these materials in market. Properties of the obtained polymer are related to the chemical structure of polyurethane backbone. A number polyurethanes prepared from biomass-based monomers have been reported. Cellulose fiber, as a biomass material is containing abundant hydroxyl, promising material as chain extender for building hybrid polyurethanes. In previous researches, cellulose fiber was used as filler in synthesis of polyurethane composites. This paper reported a novel route of hybrid polyurethane synthesis, which a cellulose fiber was used as chain extender. The experiment performed by reacting 4,4’-Methylenebis (cyclohexyl isocyanate) (HMDI) and polyethylene glycol with variation of molecular weight to obtained pre-polyurethane, continued by adding micro fiber cellulose (MFC) with variation of type and composition in the mixture. The experiment was evaluated by NMR, FTIR, SEM and STA measurement. NMR and FTIR confirmed the reaction of the hybrid polyurethane. STA showed hybrid polyurethane has good thermal stability. SEM showed good distribution and dispersion of sorghum-based MFC.

Compliance Study of Endovascular Stent Grafts Incorporated with Polyester and Polyurethane Graft Materials in both Stented and Unstented Zones

PubMed Central

Guan, Ying; Wang, Lu; Lin, Jing; King, Martin W.

2016-01-01

Compliance mismatch between stent graft and host artery may induce complications and blood flow disorders. However, few studies have been reported on stent graft compliance. This study aims to explore the deformation and compliance of stent graft in stented and unstented zones under three pressure ranges. Compliance of two stent grafts incorporated with polyurethane graft (nitinol-PU) and polyester graft (nitinol-PET) materials respectively were tested; the stents used in the two stent grafts were identical. For the circumferential deformation of the stent grafts under each pressure range, the nitinol-PET stent graft was uniform in both zones. The nitinol-PU stent graft was circumferentially uniform in the stented zone, however, it was nonuniform in the unstented zone. The compliance of the PU graft material was 15 times higher than that of the PET graft. No significant difference in compliance was observed between stented and unstented zones of the nitinol-PET stent graft regardless of the applied pressure range. However, for the nitinol-PU stent graft, compliance of the unstented PU region was approximately twice that of the stented region; thus, compliance along the length of the nitinol-PU stent graft was not constant and different from that of the nitinol-PET stent graft. PMID:28773781

Bio-Based Polyurethane Containing Isosorbide for Use in Composites and Coatings

DTIC Science & Technology

2015-04-01

ARL-TR-7259 ● APR 2015 US Army Research Laboratory Bio-Based Polyurethane Containing Isosorbide for Use in Composites and...copyright notation hereon. ARL-TR-7259 ● APR 2015 US Army Research Laboratory Bio-Based Polyurethane Containing Isosorbide for Use...4. TITLE AND SUBTITLE Bio-Based Polyurethane Containing Isosorbide for Use in Composites and Coatings 5a. CONTRACT NUMBER 5b. GRANT NUMBER 5c

Thermal properties of poly(urethane-ester-siloxane)s based on hyperbranched polyester

NASA Astrophysics Data System (ADS)

Pergal, M. V.; Džunuzović, J. V.; Kićanović, M.; Vodnik, V.; Pergal, M. M.; Jovanović, S.

2011-12-01

Novel polyurethanes (PUs) were synthesized using hydroxy-terminated hyperbranched polyester (BH-20) and 4,4'-methylenediphenyl diisocyanate (MDI) as hard segments and hydroxy-terminated ethylene oxide-poly(dimethylsiloxane)-ethylene oxide triblock copolymer (PDMS-EO) as soft segment, with soft segment content ranging from 30 to 60 wt %. The PUs were synthesized by two-step solution polymerization method. The influence of the soft segment content on the structure, swelling behavior and thermal properties of PUs was investigated. According to the results obtained by swelling measurements, the increase of the hard segment content resulted in the increase of the crosslinking density of synthesized samples. DSC results showed that the glass transition temperatures increase from 36 to 65°C with increasing hard segment content. It was demonstrated using thermogravimetric analysis (TGA) that thermal stability of investigated PUs increases with increase of the soft PDMS-EO content. This was concluded from the temperatures corresponding to the 10 wt % loss, which represents the beginning of thermal degradation of samples.

Carbon Catabolite Repression and Impranil Polyurethane Degradation in Pseudomonas protegens Strain Pf-5

PubMed Central

Hung, Chia-Suei; Zingarelli, Sandra; Nadeau, Lloyd J.; Biffinger, Justin C.; Drake, Carrie A.; Crouch, Audra L.; Barlow, Daniel E.; Russell, John N.

2016-01-01

ABSTRACT Polyester polyurethane (PU) coatings are widely used to help protect underlying structural surfaces but are susceptible to biological degradation. PUs are susceptible to degradation by Pseudomonas species, due in part to the degradative activity of secreted hydrolytic enzymes. Microorganisms often respond to environmental cues by secreting enzymes or secondary metabolites to benefit their survival. This study investigated the impact of exposing several Pseudomonas strains to select carbon sources on the degradation of the colloidal polyester polyurethane Impranil DLN (Impranil). The prototypic Pseudomonas protegens strain Pf-5 exhibited Impranil-degrading activities when grown in sodium citrate but not in glucose-containing medium. Glucose also inhibited the induction of Impranil-degrading activity by citrate-fed Pf-5 in a dose-dependent manner. Biochemical and mutational analyses identified two extracellular lipases present in the Pf-5 culture supernatant (PueA and PueB) that were involved in degradation of Impranil. Deletion of the pueA gene reduced Impranil-clearing activities, while pueB deletion exhibited little effect. Removal of both genes was necessary to stop degradation of the polyurethane. Bioinformatic analysis showed that putative Cbr/Hfq/Crc-mediated regulatory elements were present in the intergenic sequences upstream of both pueA and pueB genes. Our results confirmed that both PueA and PueB extracellular enzymes act in concert to degrade Impranil. Furthermore, our data showed that carbon sources in the growth medium directly affected the levels of Impranil-degrading activity but that carbon source effects varied among Pseudomonas strains. This study uncovered an intricate and complicated regulation of P. protegens PU degradation activity controlled by carbon catabolite repression. IMPORTANCE Polyurethane (PU) coatings are commonly used to protect metals from corrosion. Microbiologically induced PU degradation might pose a substantial

Carbon Catabolite Repression and Impranil Polyurethane Degradation in Pseudomonas protegens Strain Pf-5.

PubMed

Hung, Chia-Suei; Zingarelli, Sandra; Nadeau, Lloyd J; Biffinger, Justin C; Drake, Carrie A; Crouch, Audra L; Barlow, Daniel E; Russell, John N; Crookes-Goodson, Wendy J

2016-10-15

Polyester polyurethane (PU) coatings are widely used to help protect underlying structural surfaces but are susceptible to biological degradation. PUs are susceptible to degradation by Pseudomonas species, due in part to the degradative activity of secreted hydrolytic enzymes. Microorganisms often respond to environmental cues by secreting enzymes or secondary metabolites to benefit their survival. This study investigated the impact of exposing several Pseudomonas strains to select carbon sources on the degradation of the colloidal polyester polyurethane Impranil DLN (Impranil). The prototypic Pseudomonas protegens strain Pf-5 exhibited Impranil-degrading activities when grown in sodium citrate but not in glucose-containing medium. Glucose also inhibited the induction of Impranil-degrading activity by citrate-fed Pf-5 in a dose-dependent manner. Biochemical and mutational analyses identified two extracellular lipases present in the Pf-5 culture supernatant (PueA and PueB) that were involved in degradation of Impranil. Deletion of the pueA gene reduced Impranil-clearing activities, while pueB deletion exhibited little effect. Removal of both genes was necessary to stop degradation of the polyurethane. Bioinformatic analysis showed that putative Cbr/Hfq/Crc-mediated regulatory elements were present in the intergenic sequences upstream of both pueA and pueB genes. Our results confirmed that both PueA and PueB extracellular enzymes act in concert to degrade Impranil. Furthermore, our data showed that carbon sources in the growth medium directly affected the levels of Impranil-degrading activity but that carbon source effects varied among Pseudomonas strains. This study uncovered an intricate and complicated regulation of P. protegens PU degradation activity controlled by carbon catabolite repression. Polyurethane (PU) coatings are commonly used to protect metals from corrosion. Microbiologically induced PU degradation might pose a substantial problem for the integrity

Fully glutathione degradable waterborne polyurethane nanocarriers: Preparation, redox-sensitivity, and triggered intracellular drug release.

PubMed

Omrani, Ismail; Babanejad, Niloofar; Shendi, Hasan Kashef; Nabid, Mohammad Reza

2017-01-01

Polyurethanes are important class of biomaterials that are extensively used in medical devices. In spite of their easy synthesis, polyurethanes that are fully degradable in response to the intracellular reducing environment are less explored for controlled drug delivery. Herein, a novel glutathione degradable waterborne polyurethane (WPU) nanocarrier for redox triggered intracellular delivery of a model lipophilic anticancer drug, doxorubicin (DOX) is reported. The WPU was prepared from polyaddition reaction of isophorone diisocyanate (IPDI) and a novel linear polyester polyol involving disulfide linkage, disulfide labeled chain extender, dimethylolpropionic acid (DMPA) using dibutyltin dilaurate (DBTDL) as a catalyst. The resulting polyurethane self-assembles into nanocarrier in water. The dynamic light scattering (DLS) measurements and scanning electron microscope (SEM) revealed fast swelling and disruption of nanocarriers under an intracellular reduction-mimicking environment. The in vitro release studies showed that DOX was released in a controlled and redox-dependent manner. MTT assays showed that DOX-loaded WPU had a high in vitro antitumor activity in both HDF noncancer cells and MCF- 7 cancer cells. In addition, it is found that the blank WPU nanocarriers are nontoxic to HDF and MCF-7 cells even at a high concentration of 2mg/mL. Hence, nanocarriers based on disulfide labeled WPU have appeared as a new class of biocompatible and redox-degradable nanovehicle for efficient intracellular drug delivery. Copyright © 2016 Elsevier B.V. All rights reserved.

49 CFR 173.165 - Polyester resin kits.

Code of Federal Regulations, 2011 CFR

2011-10-01

... 49 Transportation 2 2011-10-01 2011-10-01 false Polyester resin kits. 173.165 Section 173.165... Polyester resin kits. (a) Except for transportation by aircraft, polyester resin kits consisting of a base... will not interact dangerously in the event of leakage. (b) For transportation by aircraft, polyester...

Polyester synthases: natural catalysts for plastics.

PubMed Central

Rehm, Bernd H A

2003-01-01

Polyhydroxyalkanoates (PHAs) are biopolyesters composed of hydroxy fatty acids, which represent a complex class of storage polyesters. They are synthesized by a wide range of different Gram-positive and Gram-negative bacteria, as well as by some Archaea, and are deposited as insoluble cytoplasmic inclusions. Polyester synthases are the key enzymes of polyester biosynthesis and catalyse the conversion of (R)-hydroxyacyl-CoA thioesters to polyesters with the concomitant release of CoA. These soluble enzymes turn into amphipathic enzymes upon covalent catalysis of polyester-chain formation. A self-assembly process is initiated resulting in the formation of insoluble cytoplasmic inclusions with a phospholipid monolayer and covalently attached polyester synthases at the surface. Surface-attached polyester synthases show a marked increase in enzyme activity. These polyester synthases have only recently been biochemically characterized. An overview of these recent findings is provided. At present, 59 polyester synthase structural genes from 45 different bacteria have been cloned and the nucleotide sequences have been obtained. The multiple alignment of the primary structures of these polyester synthases show an overall identity of 8-96% with only eight strictly conserved amino acid residues. Polyester synthases can been assigned to four classes based on their substrate specificity and subunit composition. The current knowledge on the organization of the polyester synthase genes, and other genes encoding proteins related to PHA metabolism, is compiled. In addition, the primary structures of the 59 PHA synthases are aligned and analysed with respect to highly conserved amino acids, and biochemical features of polyester synthases are described. The proposed catalytic mechanism based on similarities to alpha/beta-hydrolases and mutational analysis is discussed. Different threading algorithms suggest that polyester synthases belong to the alpha/beta-hydrolase superfamily, with

Semi-aromatic polyesters based on a carbohydrate-derived rigid diol for engineering plastics.

PubMed

Wu, Jing; Eduard, Pieter; Thiyagarajan, Shanmugam; Noordover, Bart A J; van Es, Daan S; Koning, Cor E

2015-01-01

New carbohydrate-based polyesters were prepared from isoidide-2,5-dimethanol (extended isoidide, XII) through melt polymerization with dimethyl esters of terephthalic acid (TA) and furan-2,5-dicarboxylic acid (FDCA), yielding semi-crystalline prepolymers. Subsequent solid-state post-condensation (SSPC) gave high molecular weight (Mn =30 kg mol(-1) for FDCA) materials, the first examples of high Mn , semi-aromatic homopolyesters containing isohexide derivatives obtained via industrially relevant procedures. NMR spectroscopy showed that the stereo-configuration of XII was preserved under the applied conditions. The polyesters are thermally stable up to 380 °C. The TA- and FDCA-based polyesters have high Tg (105 °C and 94 °C, resp.) and Tm (284 °C and 250 °C, resp.) values. Its reactivity, stability, and ability to afford high Tg and Tm polyesters make XII a promising diol for the synthesis of engineering polymers. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

49 CFR 173.165 - Polyester resin kits.

Code of Federal Regulations, 2012 CFR

2012-10-01

... 49 Transportation 2 2012-10-01 2012-10-01 false Polyester resin kits. 173.165 Section 173.165... Polyester resin kits. (a) Except for transportation by aircraft, polyester resin kits consisting of a base... resin kits consisting of a base material component (Class 3, Packing Group II or III) and an activator...

Vegetable Oil-Based Hyperbranched Thermosetting Polyurethane/Clay Nanocomposites

PubMed Central

2009-01-01

The highly branched polyurethanes and vegetable oil-based polymer nanocomposites have been showing fruitful advantages across a spectrum of potential field of applications.Mesua ferreaL. seed oil-based hyperbranched polyurethane (HBPU)/clay nanocomposites were prepared at different dose levels by in situ polymerization technique. The performances of epoxy-cured thermosetting nanocomposites are reported for the first time. The partially exfoliated structure of clay layers was confirmed by XRD and TEM. FTIR spectra indicate the presence of H bonding between nanoclay and the polymer matrix. The present investigation outlines the significant improvement of tensile strength, scratch hardness, thermostability, water vapor permeability, and adhesive strength without much influencing impact resistance, bending, and elongation at break of the nanocomposites compared to pristine HBPU thermoset. An increment of two times the tensile strength, 6 °C of melting point, and 111 °C of thermo-stability were achieved by the formation of nanocomposites. An excellent shape recovery of about 96–99% was observed for the nanocomposites. Thus, the formation of partially exfoliated clay/vegetable oil-based hyperbranched polyurethane nanocomposites significantly improved the performance. PMID:20596546

Vegetable Oil-Based Hyperbranched Thermosetting Polyurethane/Clay Nanocomposites.

PubMed

Deka, Harekrishna; Karak, Niranjan

2009-04-25

The highly branched polyurethanes and vegetable oil-based polymer nanocomposites have been showing fruitful advantages across a spectrum of potential field of applications. Mesua ferrea L. seed oil-based hyperbranched polyurethane (HBPU)/clay nanocomposites were prepared at different dose levels by in situ polymerization technique. The performances of epoxy-cured thermosetting nanocomposites are reported for the first time. The partially exfoliated structure of clay layers was confirmed by XRD and TEM. FTIR spectra indicate the presence of H bonding between nanoclay and the polymer matrix. The present investigation outlines the significant improvement of tensile strength, scratch hardness, thermostability, water vapor permeability, and adhesive strength without much influencing impact resistance, bending, and elongation at break of the nanocomposites compared to pristine HBPU thermoset. An increment of two times the tensile strength, 6 degrees C of melting point, and 111 degrees C of thermo-stability were achieved by the formation of nanocomposites. An excellent shape recovery of about 96-99% was observed for the nanocomposites. Thus, the formation of partially exfoliated clay/vegetable oil-based hyperbranched polyurethane nanocomposites significantly improved the performance.

Green and selective polycondensation methods toward linear sorbitol-based polyesters: enzymatic versus organic and metal-based catalysis.

PubMed

Gustini, Liliana; Lavilla, Cristina; Janssen, William W T J; Martínez de Ilarduya, Antxon; Muñoz-Guerra, Sebastián; Koning, Cor E

2016-08-23

Renewable polyesters derived from a sugar alcohol (i.e., sorbitol) were synthesized by solvent-free polycondensation. The aim was to prepare linear polyesters with pendant hydroxyl groups along the polymer backbone. The performance of the sustainable biocatalyst SPRIN liposorb CALB [an immobilized form of Candida antarctica lipase B (CALB); SPRIN technologies] and the organo-base catalyst 1,5,7-triazabicyclo[4,4,0]dec-5-ene (TBD) were compared with two metal-based catalysts: dibutyl tin oxide (DBTO) and scandium trifluoromethanesulfonate [also known as scandium triflate, Sc(OTf)3 ]. For the four catalytic systems, the efficiency and selectivity for the incorporation of sorbitol were studied, mainly using (13) C and (31) P NMR spectroscopies, whereas side reactions, such as ether formation and dehydration of sorbitol, were evaluated using MALDI-TOF-MS. Especially the biocatalyst SPRIN liposorb CALB succeeded in incorporating sorbitol in a selective way without side reactions, leading to close-to-linear polyesters. By using a renewable hydroxyl-reactive curing agent based on l-lysine, transparent and glossy poly(ester urethane) networks were successfully synthesized offering a tangible example of bio-based coatings. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Highly stretchable nanoalginate based polyurethane elastomers.

PubMed

Daemi, Hamed; Barikani, Mehdi; Barmar, Mohammad

2013-06-20

Highly stretchable elastomeric samples based on cationic polyurethane dispersions-sodium alginate nanoparticles (CPUD/SA) were prepared by the solution blending of sodium alginate and aqueous polyurethane dispersions. CPUDs were synthesized by step growth polymerization technique using N-methyldiethanolamine (MDEA) as a source of cationic emulsifier. The chemical structure and thermal-mechanical properties of these systems were characterized using FTIR and DMTA, respectively. The presence of nanoalginate particles including nanobead and nanorod particles were proved by SEM and EDX. It was observed that thermal properties of composites increased with increasing SA content. All prepared samples were known as thermoplastic-elastomers with high percentages of elongation. Excellent compatibility of prepared nanocomposites was proved by the DMTA data. Copyright © 2013 Elsevier Ltd. All rights reserved.

Green waste cooking oil-based rigid polyurethane foam

NASA Astrophysics Data System (ADS)

Enderus, N. F.; Tahir, S. M.

2017-11-01

Polyurethane is a versatile polymer traditionally prepared using petroleum-based raw material. Petroleum, however, is a non-renewable material and polyurethane produced was found to be non-biodegradable. In quest for a more environmentally friendly alternative, wastecooking oil, a highly abundant domestic waste with easily derivatized structure, is a viable candidate to replace petroleum. In this study,an investigation to determine physical and chemical properties of rigid polyurethane (PU) foam from waste cooking oil (WCO) was carried out. WCO was first adsorbed by using coconut husk activated carbon adsorbent prior to be used for polyol synthesis. The purified WCO was then used to synthesize polyol via transesterification reaction to yield alcohol groups in the WCO chains structure. Finally, the WCO-based polyol was used to prepare rigid PU foam. The optimum formulation for PU formation was found to be 90 polyol: 60 glycerol: 54 water: 40 diethanolamine: 23 diisocyanate. The rigid PU foam has density of 208.4 kg/m3 with maximum compressive strength and capability to receive load at 0.03 MPa and 0.09 kN, respectively. WCO-based PU can potentially be used to replace petroleum-based PU as house construction materials such as insulation panels.

Stable Polyurethane Coatings for Electronic Circuits

NASA Technical Reports Server (NTRS)

Morris, D. E.

1983-01-01

Alkane-based polyurethanes resist deterioration while maintaining good dielectric properties. Weight loss after prolonged immersion in hot water far less for alkane-based polyurethanes than for more common ether based polyurethanes, at any given oxygen content. Major uses of polyurethanes are as connector potting materials and conformal coatings for printed circuit boards.

Polyurethane Ionophore-Based Thin Layer Membranes for Voltammetric Ion Activity Sensing.

PubMed

Cuartero, Maria; Crespo, Gaston A; Bakker, Eric

2016-06-07

We report on a plasticized polyurethane ionophore-based thin film material (of hundreds of nanometer thickness) for simultaneous voltammetric multianalyte ion activity detection triggered by the oxidation/reduction of an underlying poly(3-octylthiophene) film. This material provides excellent mechanical, physical, and chemical robustness compared to other polymers. Polyurethane films did not exhibit leaching of lipophilic additives after rinsing with a direct water jet and exhibited resistance to detachment from the underlying electrode surface, resulting in a voltammetric current response with less than <1.5% RSD variation (n = 50). In contrast, plasticized poly(vinyl chloride), polystyrene, and poly(acrylate) ionophore-based membranes of the same thickness and composition exhibited a significant deterioration of the signal after identical treatment. While previously reported works emphasized fundamental advancement of multi-ion detection with multi-ionophore-based thin films, polyurethane thin membranes allow one to achieve real world measurements without sacrificing analytical performance. Indeed, polyurethane membranes are demonstrated to be useful for the simultaneous determination of potassium and lithium in undiluted human serum and blood with attractive precision.

Starch based polyurethanes: A critical review updating recent literature.

PubMed

Zia, Fatima; Zia, Khalid Mahmood; Zuber, Mohammad; Kamal, Shagufta; Aslam, Nosheen

2015-12-10

Recent advancements in material science and technology made it obvious that use of renewable feed stock is the need of hour. Polymer industry steadily moved to get rid of its dependence on non-renewable resources. Starch, the second largest occurring biomass (renewable) on this planet provides a cheap and eco-friendly way to form huge variety of materials on blending with other biodegradable polymers. Specific structural versatility design for individual application and tailor-made properties have established the polyurethane (PU) as an important and popular class of synthetic biodegradable polymers. Blending of starch with polyurethane is relatively a developing area in PU chemistry but with lot of attraction for researchers. Herein, various starch based polyurethane materials including blends, grafts, copolymers, composites and nano-composites, as well as the prospects and latest developments are discussed. Additionally, an overview of starch based polymeric materials, including their potential applications are presented. Copyright © 2015 Elsevier Ltd. All rights reserved.

Synthesis of highly elastic biocompatible polyurethanes based on bio-based isosorbide and poly(tetramethylene glycol) and their properties

PubMed Central

Kim, Hyo-Jin; Kang, Min-Sil; Knowles, Jonathan C

2014-01-01

Bio-based high elastic polyurethanes were prepared from hexamethylene diisocyanate and various ratios of isosorbide to poly(tetramethylene glycol) as a diol by a simple one-shot bulk polymerization without a catalyst. Successful synthesis of the polyurethanes was confirmed by Fourier transform-infrared spectroscopy and 1H nuclear magnetic resonance. Thermal properties were determined by differential scanning calorimetry and thermogravimetric analysis. The glass transition temperature was −47.8℃. The test results showed that the poly(tetramethylene glycol)/isosorbide-based elastomer exhibited not only excellent stress–strain properties but also superior resilience to the existing polyether-based polyurethane elastomers. The static and dynamic properties of the polyether/isosorbide-based thermoplastic elastomer were more suitable for dynamic applications. Moreover, such rigid diols impart biocompatible and bioactive properties to thermoplastic polyurethane elastomers. Degradation tests performed at 37℃ in phosphate buffer solution showed a mass loss of 4–9% after 8 weeks, except for the polyurethane with the lowest isosorbide content, which showed an initial rapid weight loss. These polyurethanes offer significant promise due to soft, flexible and biocompatible properties for soft tissue augmentation and regeneration. PMID:24812276

Synthesis of highly elastic biocompatible polyurethanes based on bio-based isosorbide and poly(tetramethylene glycol) and their properties.

PubMed

Kim, Hyo-Jin; Kang, Min-Sil; Knowles, Jonathan C; Gong, Myoung-Seon

2014-09-01

Bio-based high elastic polyurethanes were prepared from hexamethylene diisocyanate and various ratios of isosorbide to poly(tetramethylene glycol) as a diol by a simple one-shot bulk polymerization without a catalyst. Successful synthesis of the polyurethanes was confirmed by Fourier transform-infrared spectroscopy and (1)H nuclear magnetic resonance. Thermal properties were determined by differential scanning calorimetry and thermogravimetric analysis. The glass transition temperature was -47.8℃. The test results showed that the poly(tetramethylene glycol)/isosorbide-based elastomer exhibited not only excellent stress-strain properties but also superior resilience to the existing polyether-based polyurethane elastomers. The static and dynamic properties of the polyether/isosorbide-based thermoplastic elastomer were more suitable for dynamic applications. Moreover, such rigid diols impart biocompatible and bioactive properties to thermoplastic polyurethane elastomers. Degradation tests performed at 37℃ in phosphate buffer solution showed a mass loss of 4-9% after 8 weeks, except for the polyurethane with the lowest isosorbide content, which showed an initial rapid weight loss. These polyurethanes offer significant promise due to soft, flexible and biocompatible properties for soft tissue augmentation and regeneration. © The Author(s) 2014 Reprints and permissions: sagepub.co.uk/journalsPermissions.nav.

The Effect of Plant Source on the Structural Properties of Lignin-based Polyurethane Blends

NASA Astrophysics Data System (ADS)

Lang, Jason; Dadmun, Mark

The development of polyurethane materials based on incorporating lignin from a variety of plant sources (softwood, hardwood, and non-wood) were synthesized. Further experiments study the physical properties of the resulting lignin-based polyurethane as a function of the lignin structure, which varies with plant source. Here, we report the effect that internal crosslinking of the lignin structure has on the modulus, hardness, glass transition temperature, and thermal decomposition of the synthesized lignin-based polyurethane composites. The lignins used in this work were a softwood kraft lignin, hardwood lignosulfonate, and a wheat straw soda lignin. The lignin, acting as a polyol and the hardblock segment, reacts with TDI-endcapped PPG (2,300 MN) as the rubbery softblock component to produce lignin-based polyurethanes with varying lignin content (10, 20, 30, 40, 50, and 60 wt%). Results show that the wheat straw lignin provides the superior mechanical properties and thermal resistance. These properties are correlated to the two-phase morphology of the resultant polyurethane.

Dipeptide-based polyphosphazene and polyester blends for bone tissue engineering.

PubMed

Deng, Meng; Nair, Lakshmi S; Nukavarapu, Syam P; Jiang, Tao; Kanner, William A; Li, Xudong; Kumbar, Sangamesh G; Weikel, Arlin L; Krogman, Nicholas R; Allcock, Harry R; Laurencin, Cato T

2010-06-01

Polyphosphazene-polyester blends are attractive materials for bone tissue engineering applications due to their controllable degradation pattern with non-toxic and neutral pH degradation products. In our ongoing quest for an ideal completely miscible polyphosphazene-polyester blend system, we report synthesis and characterization of a mixed-substituent biodegradable polyphosphazene poly[(glycine ethyl glycinato)(1)(phenyl phenoxy)(1)phosphazene] (PNGEG/PhPh) and its blends with a polyester. Two dipeptide-based blends namely 25:75 (Matrix1) and 50:50 (Matrix2) were produced at two different weight ratios of PNGEG/PhPh to poly(lactic acid-glycolic acid) (PLAGA). Blend miscibility was confirmed by differential scanning calorimetry, Fourier transform infrared spectroscopy, and scanning electron microscopy. Both blends resulted in higher tensile modulus and strength than the polyester. The blends showed a degradation rate in the order of Matrix2

Dipeptide-based Polyphosphazene and Polyester Blends for Bone Tissue Engineering

PubMed Central

Deng, Meng; Nair, Lakshmi S.; Nukavarapu, Syam P.; Jiang, Tao; Kanner, William A.; Li, Xudong; Kumbar, Sangamesh G.; Weikel, Arlin L.; Krogman, Nicholas R.; Allcock, Harry R.; Laurencin, Cato T.

2010-01-01

Polyphosphazene-polyester blends are attractive materials for bone tissue engineering applications due to their controllable degradation pattern with non-toxic and neutral pH degradation products. In our ongoing quest for an ideal completely miscible polyphosphazene-polyester blend system, we report synthesis and characterization of a mixed-substituent biodegradable polyphosphazene poly[(glycine ethyl glycinato)1(phenyl phenoxy)1phosphazene] (PNGEG/PhPh) and its blends with a polyester. Two dipeptide-based blends namely 25:75 (Matrix1) and 50:50 (Matrix2) were produced at two different weight ratios of PNGEG/PhPh to poly(lactic acid-glycolic acid) (PLAGA). Blend miscibility was confirmed by differential scanning calorimetry, Fourier transform infrared spectroscopy, and scanning electron microscopy. Both blends resulted in higher tensile modulus and strength than the polyester. The blends showed a degradation rate in the order of Matrix2 < Matrix1 < PLAGA in phosphate buffered saline at 37°C over 12 weeks. Significantly higher pH values of degradation media were observed for blends compared to PLAGA confirming the neutralization of PLAGA acidic degradation by polyphosphazene hydrolysis products. The blend components PLAGA and polyphosphazene exhibited a similar degradation pattern as characterized by the molecular weight loss. Furthermore, blends demonstrated significantly higher osteoblast growth rates compared to PLAGA while maintaining osteoblast phenotype over a 21-day culture. Both blends demonstrated improved biocompatibility in a rat subcutaneous implantation model compared to PLAGA over 12 weeks. PMID:20334909

Bio-Based Nanocomposites: An Alternative to Traditional Composites

ERIC Educational Resources Information Center

Tate, Jitendra S.; Akinola, Adekunle T.; Kabakov, Dmitri

2009-01-01

Polymer matrix composites (PMC), often referred to as fiber reinforced plastics (FRP), consist of fiber reinforcement (E-glass, S2-glass, aramid, carbon, or natural fibers) and polymer matrix/resin (polyester, vinyl ester, polyurethane, phenolic, and epoxies). Eglass/ polyester and E-glass/vinyl ester composites are extensively used in the marine,…

A new polyester based on allyl α-hydroxy glutarate as shell for magnetite nanoparticles

NASA Astrophysics Data System (ADS)

Nan, Alexandrina; Feher, Ioana Coralia

2017-12-01

Allyl side-chain-functionalized lactide was synthesized from commercially available glutamic acid and polymerized by ring opening polymerization using 4-dimethylaminopyridine as an organocatalyst in the presence of magnetic nanoparticles. The resulting magnetic nanostructures coated with the allyl-containing polyester were then functionalized with cysteine by thiol-ene click reaction leading to highly functionalized magnetic nano-platforms of practical interest. The polyester precursors were characterized by nuclear magnetic resonance and mass spectrometry. The morphology of magnetic nanostructures based on the functionalized polyester was determined by transmission electron microscopy TEM, while the chemical structure was investigated by FT-IR. TGA investigations and the magnetic properties of the magnetic nanostructures are also described.

Overall and specific migration from multilayer high barrier food contact materials - kinetic study of cyclic polyester oligomers migration.

PubMed

Úbeda, Sara; Aznar, Margarita; Vera, Paula; Nerín, Cristina; Henríquez, Luis; Taborda, Laura; Restrepo, Claudia

2017-10-01

Most multilayer high barrier materials used in food packaging have a polyurethane adhesive layer in their structures. In order to assess the safety of these materials, it is important to determine the compounds intentionally added to the adhesives (IAS) as well as those non-intentionally added substances (NIAS). During the manufacture of polyurethane adhesives, some by-products can be formed, such as cyclic polyester oligomers coming from the reaction between dicarboxylic acids and glycols. Since these compounds are not listed in the Regulation 10/2011/EU, they should not be found in migration above 0.01 mg/kg of simulant. In this study two flexible multilayer packaging materials were used and migration was evaluated in simulant A (ethanol 10% v/v), simulant B (acetic acid 3% w/v) and simulant ethanol 95% v/v during 10 days at 60ºC. Identification and quantification of non-volatile compounds was carried out by UPLC-MS-QTOF. Most of migrants were oligomers such as cyclic polyesters and caprolactam oligomers. Overall migration and specific migration of adipic acid-diethylene glycol and phthalic acid-diethylene glycol were monitored over time and analysed by UPLC-MS-TQ. In most cases, ethanol 95% v/v was the simulant with the highest concentration values. Overall migration kinetics followed a similar pattern than specific migration kinetics.

Gelatin-Modified Polyurethanes for Soft Tissue Scaffold

PubMed Central

Kucińska-Lipka, Justyna; Janik, Helena

2013-01-01

Recently, in the field of biomaterials for soft tissue scaffolds, the interest of their modification with natural polymersis growing. Synthetic polymers are often tough, and many of them do not possess fine biocompatibility. On the other hand, natural polymers are biocompatible but weak when used alone. The combination of natural and synthetic polymers gives the suitable properties for tissue engineering requirements. In our study, we modified gelatin synthetic polyurethanes prepared from polyester poly(ethylene-butylene adipate) (PEBA), aliphatic 1,6-hexamethylene diisocyanate (HDI), and two different chain extenders 1,4-butanediol (BDO) or 1-ethoxy-2-(2-hydroxyethoxy)ethanol (EHEE). From a chemical point of view, we replaced expensive components for building PU, such as 2,6-diisocyanato methyl caproate (LDI) and 1,4-diisocyanatobutane (BDI), with cost-effective HDI. The gelatin was added in situ (in the first step of synthesis) to polyurethane to increase biocompatibility and biodegradability of the obtained material. It appeared that the obtained gelatin-modified PU foams, in which chain extender was BDO, had enhanced interactions with media and their hydrolytic degradation profile was also improved for tissue engineering application. Furthermore, the gelatin introduction had positive impact on gelatin-modified PU foams by increasing their hemocompatibility. PMID:24363617

Sugar-based bicyclic monomers for aliphatic polyesters: a comparative appraisal of acetalized alditols and isosorbide

PubMed Central

Zakharova, Elena; Martínez de Ilarduya, Antxon; León, Salvador; Muñoz-Guerra, Sebastián

2017-01-01

Abstract Three series of polyalkanoates (adipates, suberates and sebacates) were synthesized using as monomers three sugar-based bicyclic diols derived from D-glucose (Glux-diol and isosorbide) and D-mannose (Manx-diol). Polycondensations were conducted in the melt applying similar reaction conditions for all cases. The aim was to compare the three bicyclic diols regarding their suitability to render aliphatic polyesters with enhanced thermal and mechanical properties. The ensuing polyesters had molecular weights (M w) in the 25,000–50,000 g mol−1 range with highest values being attained for Glux-diol. All the polyesters started to decompose above 300 °C and most of them did not display perceivable crystallinity. On the contrary, they had glass transition temperatures much higher than usually found in homologous polyesters made of alkanediols, and showed a stress–strain behavior consistent with their T g values. Glux-diol was particularly effective in increasing the T g and to render therefore polyesters with high elastic modulus and considerable mechanical strength. PMID:29491789

Influence of reaction condition on viscosity of polyurethane modified epoxy based on glycerol monooleate

NASA Astrophysics Data System (ADS)

Triwulandari, Evi; Ramadhan, Mohammad Kemilau; Ghozali, Muhammad

2017-01-01

Polyurethane modified epoxy based on glycerol monooleate (PME-GMO) was synthesized. GMO as polyol for synthesis of PME-GMO was synthesized via Fisher Esterification between oleic acid from palm oil and glycerol by using sulfuric acid as catalyst with time variation i.e. 3, 4, 5 and 6 hours at 160°C. Characterizations of GMO were carried out by analysis of acid number, hydroxyl value and FTIR. The data show that the conversion of oleic acid to ester compound is directly proportional with the increasing of reaction time but the enhancement is not significant after 3 hours. Furthermore, GMO product was used as polyol for modification of epoxy with polyurethane. Modification of epoxy with polyurethane was performed by reacted epoxy, tolonate and GMO simultaneously in one step. In this research, the reaction condition was varied i.e. time reaction (0.5; 1; 1.5; 2; 2.5 hours), composition of polyurethane used (10%, 20% toward epoxy) and rasio of tolonate and GMO (NCO/OH ratio) as component of polyurethane (1.5 and 2.5). Characterization of polyurethane modified epoxy based on glycerol (PME-GMO) was conducted by viscosity and FTIR analysis. The viscosity of PME-GMO increased with increasing of reaction time, polyurethane composition and NCO/OH ratio.

Alginate based polyurethanes: A review of recent advances and perspective.

PubMed

Zia, Khalid Mahmood; Zia, Fatima; Zuber, Mohammad; Rehman, Saima; Ahmad, Mirza Nadeem

2015-08-01

The trend of using biopolymers in combination with synthetic polymers was increasing rapidly from last two or three decades. Polysaccharide based biopolymers especially starch, cellulose, chitin, chitosan, alginate, etc. found extensive applications for different industrial uses, as they are biocompatible, biodegradable, bio-renewable resources and chiefly environment friendly. Segment block copolymer character of polyurethanes that endows them a broad range of versatility in terms of tailoring their properties was employed in conjunction with various natural polymers resulted in modified biomaterials. Alginate is biodegradable, biocompatible, bioactive, less toxic and low cost anionic polysaccharide, as a part of structural component of bacteria and brown algae (sea weed) is quite abundant in nature. It is used in combination with polyurethanes to form elastomers, nano-composites, hydrogels, etc. that especially revolutionized the food and biomedical industries. The review summarized the development in alginate based polyurethanes with their potential applications. Copyright © 2015 Elsevier B.V. All rights reserved.

Novel Poly(3-hydroxybutyrate-g-vinyl alcohol) Polyurethane Scaffold for Tissue Engineering

NASA Astrophysics Data System (ADS)

Reyes, Adriana Pétriz; Martínez Torres, Ataúlfo; Carreón Castro, Ma. Del Pilar; Rodríguez Talavera, José Rogelio; Muñoz, Susana Vargas; Aguilar, Víctor Manuel Velázquez; Torres, Maykel González

2016-08-01

The design of new synthetic grafted poly(3-hydroxybutyrate) as composite 3D-scaffolds is a convenient alternative for tissue engineering applications. The chemically modified poly(3-hydroxybutyrate) is receiving increasing attention for use as biomimetic copolymers for cell growth. As of yet, these copolymers cannot be used efficiently because of the lack of good mechanical properties. Here, we address this challenge, preparing a composite-scaffold of grafted poly(3-hydroxybutyrate) polyurethane for the first time. However, it is unclear if the composite structure and morphology can also offer a biological application. We obtained the polyurethane by mixing a polyester hydroxylated resin with polyisocyanate and the modified polyhydroxyalkanoates. The results show that the poly(3-hydroxybutyrate) grafted with poly(vinyl alcohol) can be successfully used as a chain extender to form a chemically-crosslinked thermosetting polymer. Furthermore, we show a proposal for the mechanism of the polyurethane synthesis, the analysis of its morphology and the ability of the scaffolds for growing mammalian cells. We demonstrated that astrocytes isolated from mouse cerebellum, and HEK293 can be cultured in the prepared material, and express efficiently fluorescent proteins by adenoviral transduction. We also tested the metabolism of Ca2+ to obtain evidence of the biological activity.

Development of Styrene-Grafted Polyurethane by Radiation-Based Techniques

PubMed Central

Jeong, Jin-Oh; Park, Jong-Seok; Lim, Youn-Mook

2016-01-01

Polyurethane (PU) is the fifth most common polymer in the general consumer market, following Polypropylene (PP), Polyethylene (PE), Polyvinyl chloride (PVC), and Polystyrene (PS), and the most common polymer for thermosetting resins. In particular, polyurethane has excellent hardness and heat resistance, is a widely used material for electronic products and automotive parts, and can be used to create products of various physical properties, including rigid and flexible foams, films, and fibers. However, the use of polar polymer polyurethane as an impact modifier of non-polar polymers is limited due to poor combustion resistance and impact resistance. In this study, we used gamma irradiation at 25 and 50 kGy to introduce the styrene of hydrophobic monomer on the polyurethane as an impact modifier of the non-polar polymer. To verify grafted styrene, we confirmed the phenyl group of styrene at 690 cm−1 by Attenuated Total Reflection Fourier Transform Infrared Spectroscopy (ATR-FTIR) and at 6.4–6.8 ppm by 1H-Nuclear Magnetic Resonance (1H-NMR). Scanning Electron Microscope (SEM), X-ray Photoelectron Spectroscopy (XPS), Thermogravimetric Analysis (TGA) and contact angle analysis were also used to confirm styrene introduction. This study has confirmed the possibility of applying high-functional composite through radiation-based techniques. PMID:28773561

Superficial physicochemical properties of polyurethane biomaterials as osteogenic regulators in human mesenchymal stem cells fates.

PubMed

Shahrousvand, Mohsen; Sadeghi, Gity Mir Mohamad; Shahrousvand, Ehsan; Ghollasi, Marzieh; Salimi, Ali

2017-08-01

All of the cells' interactions are done through their surfaces. Evaluation of surface physicochemical scaffolds along with other factors is important and determines the fate of stem cells. In this work, biodegradable and biocompatible polyester/polyether based polyurethanes (PUs) were synthesized by polycaprolactone diol (PCL) and poly (tetra methylene ether) glycol (PTMEG) as the soft segment. To assess better the impact of surface parameters such as stiffness and roughness effects on osteogenic differentiation of the human mesenchymal stem cell (hMSC), the dimension effect of substrates was eliminated and two-dimensional membranes were produced by synthesized polyurethane. Surface and bulk properties of prepared 2D membranes such as surface chemistry, roughness, stiffness and tensile behavior were evaluated by Attenuated total reflectance Fourier transform infrared (ATR-FTIR), atomic force microscopy (AFM) and tensile behavior. The prepared 2D PU films had suitable hydrophilicity, biodegradability, water absorption, surface roughness and bulk strength. The hMSCs showed greater osteogenesis expression in PU substrates with more roughness and stiffness than others. The results demonstrated that surface parameters along with other differentiation cues have a synergistic effect on stem cells fates. Copyright © 2017 Elsevier B.V. All rights reserved.

Synthesis, characterization of novel chitosan based water dispersible polyurethanes and their potential deployment as antibacterial textile finish.

PubMed

Arshad, Noureen; Zia, Khalid Mahmood; Jabeen, Farukh; Anjum, Muhammad Naveed; Akram, Nadia; Zuber, Mohammad

2018-05-01

Our current research work comprised of synthesis of a series of novel chitosan based water dispersible polyurethanes. The synthesis was carried out in three steps, in first step, the NCO end capped PU-prepolymer was formed through the reaction between Polyethylene glycol (PEG) (Mn = 600), Dimethylolpropionic acid (DMPA) and Isophorone diisocyanate (IPDI). In second step, the neutralization step was carried out by using Triethylamine (TEA) which resulted the formation of neutralized NCO terminated PU-prepolymer, after that the last step chain extension was performed by the addition of chitosan and followed the formation of dispersion by adding calculated amount of water. The proposed structure of CS-WDPUs was confirmed by using FTIR technique. The antimicrobial activities of the plain weave poly-cotton printed and dyed textile swatches after application of CS-WDPUs were also evaluated. The results showed that the chitosan incorporation in to PU backbone has markedly enhanced the antibacterial activity of WDPUs. These synthesized CS-WDPUs are eco-friendly antimicrobial finishes (using natural bioactive agents such as chitosan) with potential applications on polyester/cotton textiles. Copyright © 2018 Elsevier B.V. All rights reserved.

Preparation and Characterization of Soybean Oil-Based Polyurethanes for Digital Doming Applications

PubMed Central

Pantone, Vincenzo; Laurenza, Amelita Grazia; Annese, Cosimo; Fracassi, Francesco; Fini, Paola; Nacci, Angelo; Russo, Antonella; Fusco, Caterina

2017-01-01

Polyurethane-resin doming is currently one of the fastest growing markets in the field of industrial graphics and product identification. Semi-rigid bio-based polyurethanes were prepared deriving from soybean oil as a valuable alternative to fossil materials for digital doming and applied to digital mosaic technology. Bio-resins produced can favorably compete with the analogous fossil polymers, giving high-quality surface coatings (ascertained by SEM analyses). In addition, polyurethane synthesis was accomplished by using a mercury- and tin-free catalyst (the commercially available zinc derivative K22) bringing significant benefits in terms of cost efficiency and eco-sustainability. PMID:28773208

Studies on polyurethane adhesives and surface modification of hydrophobic substrates

NASA Astrophysics Data System (ADS)

Krishnamoorthy, Jayaraman

This thesis work deals with (a) Curing of reactive, hot-melt polyurethane adhesives and (b) Adsorption studies using different interactions. Research on polyurethanes involves characterization of polyurethane prepolymers and a novel mechanism to cure isocyanate-terminated polyurethane prepolymer by a "trigger" mechanism. Curing of isocyanate-terminated polyurethane prepolymers has been shown to be influenced by morphology and environmental conditions such as temperature and relative humidity. Although the initial composition, final morphology and curing kinetics are known, information regarding the intermediate prepolymer mixture is yet to be established. Polyurethane prepolymers prepared by the reaction of diisocyanates with the primary hydroxyls of polyester diol (PHMA) and secondary hydroxyls of polyether diol (PPG) were characterized. The morphology and crystallization kinetics of a polyurethane prepolymer was compared with a blend of PPG prepolymer (the product obtained by the reaction of PPG with diisocyanate) and a PHMA prepolymer (the product obtained by the reaction of PHMA with diisocyanate) to study the effect of copolymer formed in the polyurethane prepolymer on the above-mentioned properties. Although the morphology of the polyurethane prepolymer is determined in the first few minutes of application, the chemical curing of isocyanate-terminated prepolymer occurs over hours to days. In the literature, different techniques are described to follow the curing kinetics. But there is no established technique to control the curing of polyurethane prepolymer. To make the curing process independent of environmental factors, a novel approach using a trigger mechanism was designed and implemented by using ammonium salts as curing agents. Ammonium salts that are stable at room temperature but decompose on heating to yield active hydrogen-containing compounds, NH3 and H2O, were used as 'Trojan horses' to cure the prepolymer chemically. Research on adsorption

Isohexide and Sorbitol-Derived, Enzymatically Synthesized Renewable Polyesters with Enhanced Tg.

PubMed

Gustini, Liliana; Lavilla, Cristina; de Ilarduya, Antxon Martínez; Muñoz-Guerra, Sebastián; Koning, Cor E

2016-10-10

Sugar-based polyesters derived from sorbitol and isohexides were obtained via solvent-free enzymatic catalysis. Pendant hydroxyl groups, coming from the sorbitol units, were present along the polyester backbone, whereas the two isohexides, namely, isomannide and isoidide dimethyl ester monomers, were selected to introduce rigidity into the polyester chains. The feasibility of incorporating isomannide as a diol compared to the isoidide dimethyl ester as acyl-donor via lipase-catalyzed polycondensation was investigated. The presence of bicyclic units resulted in enhanced T g with respect to the parent sorbitol-containing polyester lacking isohexides. The different capability of the two isohexides to boost the thermal properties confirmed the more flexible character provided by the isoidide diester derivative. Solvent-borne coatings were prepared by cross-linking the sugar-based polyester polyols with polyisocyanates. The increased rigidity of the obtained sugar-based polyester polyols led to an enhancement in hardness of the resulting coatings.

Structure-property studies of thermoplastic and thermosetting polyurethanes using palm and soya oils-based polyols.

PubMed

Mohammed, Issam Ahmed; Al-Mulla, Emad Abbas Jaffar; Kadar, Nurul Khizien Abdul; Ibrahim, Mazlan

2013-01-01

Palm and soya oils were converted to monoglycerides via transesterification of triglycerides with glycerol by one step process to produce renewable polyols. Thermoplastic polyurethanes (TPPUs) were prepared from the reaction of the monoglycerides which act as polyol with 4,4'-methylenediphenyldiisocyanate (MDI) whereas, thermosetting polyurethanes (TSPUs) were prepared from the reaction of glycerol, MDI and monoglycerides in one pot. Characterization of the polyurethanes was carried out by FT-IR, (1)H NMR, and iodine value and sol-gel fraction. The TSPUs showed good thermal properties compared to TPPUs as well as TSPUs exhibits good properties in pencil hardness and adhesion, however poorer in flexural and impact strength compared to TPPUs. The higher percentage of cross linked fraction, the higher degree of cross linking occurred, which is due to the higher number of double bond presents in the TSPUs. These were reflected in iodine value test as the highest iodine value of the soya-based thermosetting polyurethanes confirmed the highest degree of cross linking. Polyurethanes based on soya oil showed better properties compared to palm oil. This study is a breakthrough development of polyurethane resins using palm and soya oils as one of the raw materials.

Synthetic polyester-hydrolyzing enzymes from thermophilic actinomycetes.

PubMed

Wei, Ren; Oeser, Thorsten; Zimmermann, Wolfgang

2014-01-01

Thermophilic actinomycetes produce enzymes capable of hydrolyzing synthetic polyesters such as polyethylene terephthalate (PET). In addition to carboxylesterases, which have hydrolytic activity predominantly against PET oligomers, esterases related to cutinases also hydrolyze synthetic polymers. The production of these enzymes by actinomycetes as well as their recombinant expression in heterologous hosts is described and their catalytic activity against polyester substrates is compared. Assays to analyze the enzymatic hydrolysis of synthetic polyesters are evaluated, and a kinetic model describing the enzymatic heterogeneous hydrolysis process is discussed. Structure-function and structure-stability relationships of actinomycete polyester hydrolases are compared based on molecular dynamics simulations and recently solved protein structures. In addition, recent progress in enhancing their activity and thermal stability by random or site-directed mutagenesis is presented. © 2014 Elsevier Inc. All rights reserved.

Polycarbonate-based polyurethane as a polymer electrolyte matrix for all-solid-state lithium batteries

NASA Astrophysics Data System (ADS)

Bao, Junjie; Shi, Gaojian; Tao, Can; Wang, Chao; Zhu, Chen; Cheng, Liang; Qian, Gang; Chen, Chunhua

2018-06-01

Four kinds of polycarbonate-based polyurethane with 8-14 wt% hard segments content are synthesized via reactions of polycarbonatediol, hexamethylene diisocyanate and diethylene glycol. The mechanical strength of the polyurethanes increase with the increase of hard segments content. Solid polymer electrolytes composed of the polycarbonate-based polyurethanes and LiTFSI exhibits fascinating characteristics for all-solid-state lithium batteries with a high ionic conductivity of 1.12 × 10-4 S cm-1 at 80 °C, an electrochemical stability window up to 4.5 V (vs. Li+/Li), excellent mechanical strength and superior interfacial stability against lithium metal. The all-solid-state batteries using LiFePO4 cathode can deliver high discharge capacities (161, 158, 134 and 93 mAh g-1 at varied rates of 0.2, 0.5, 1 and 2 C) at 80 °C and excellent cycling performance (with 91% capacity retention after 600 cycles at 1 C). All the results indicate that such a polyurethane-based solid polymer electrolyte can be a promising candidate for all-solid-state lithium batteries.

Added value of lignin as lignin-based hybrid polyurethane for a compatibilizing agent

NASA Astrophysics Data System (ADS)

Ilmiati, S.; Haris Mustafa, J.; Yaumal, A.; Hanum, F.; Chalid, M.

2017-07-01

As biomass-based material, lignin contains abundant hydroxyl groups promising to be used as chain extender in building hybrid polyurethanes. Consisting of polyehtylene glycol (PEG) content as hydrophobic part and lignin as hydrophilic part, the hybrid PU is expected to be as a novel compatibilizing agent in new materials production such as polyblends and composites. The hybrid PU was synthesized via two reaction stages, viz. pre-polyurethanization through reacting 4,4'-Methylenebis (Cyclohexyl Isocyanate) (HMDI) and PEG as polyol, and chain extention through adding lignin in the pre-polyurethanization system. The composition effect of lignin in hybrid PU syntehsis, to chemical structure corelated to hydrophobic to hydrophilic ratio, thermal and morphological properties, was evaluated by measuring NMR, FTIR, DSC, TGA and FE-SEM. The experiments showed that addition of lignin was able to extend the pre-polyurethane into hybrid polyurethane and to increase the lignin/polyol ratio in the hybrid polyurethanes, which were indicated by NMR and FTIR Analysis. And change of the ratio lead to increase the glass transition from 60.9 until 62.1°C and degradation temperature from 413.9 until 416.0°C. Observation of the morphology implied that addition of lignin gave more agglomerations. A Further investigation for this characterization study should be focused on a feasibility for this modified lignin as a novel compatibilizing agent.

Synthesis, characterization, and biocompatibility of alternating block polyurethanes based on PLA and PEG.

PubMed

Mei, Tingzhen; Zhu, Yonghe; Ma, Tongcui; He, Tao; Li, Linjing; Wei, Chiju; Xu, Kaitian

2014-09-01

A series of alternating block polyurethanes (abbreviated as PULA-alt-PEG) and random block polyurethanes (abbreviated as PULA-ran-PEG) based on poly(L-lactic acid) (PLA) and poly(ethylene glycol) (PEG) were synthesized. The differences of PULA-alt/ran-PEG chemical structure, molecular weight, distribution, thermal properties, mechanical properties and static contact angle were systematically investigated. The PULA-alt/ran-PEG polyurethanes exhibited low T(g) (-47.3 ∼ -34.4°C), wide mechanical properties (stress σ(t): 4.6-32.6 MPa, modulus E: 11.4-323.9 MPa and strain ε: 468-1530%) and low water contact angle (35.4-51.4°). Scanning electron microscope (SEM) observation showed that PULA-alt-PEG film displays rougher and more patterned surface morphology than PULA-ran-PEG does, due to more regular structures of PULA-alt-PEG. Hydrolytic degradation shows that degradation rate of random block polyurethane series PULA-ran-PEG is higher than the alternating counterpart PULA-alt-PEG. PLA segment degradation is faster than urethane linkage and PEG segment almost does not degrade in the buffer solution. Platelet adhesion study showed that all the polyurethanes possess excellent hemocompatibility. The cell culture assay revealed that PULA-alt/ran-PEG polyurethanes were cell inert and unfavorable for the attachment of rat glial cell due to the hydrophilic characters of the materials. © 2013 Wiley Periodicals, Inc.

21 CFR 177.1590 - Polyester elastomers.

Code of Federal Regulations, 2010 CFR

2010-04-01

... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Polyester elastomers. 177.1590 Section 177.1590... Components of Single and Repeated Use Food Contact Surfaces § 177.1590 Polyester elastomers. The polyester...) For the purpose of this section, polyester elastomers are those produced by the ester exchange...

21 CFR 177.1590 - Polyester elastomers.

Code of Federal Regulations, 2011 CFR

2011-04-01

... 21 Food and Drugs 3 2011-04-01 2011-04-01 false Polyester elastomers. 177.1590 Section 177.1590... Components of Single and Repeated Use Food Contact Surfaces § 177.1590 Polyester elastomers. The polyester...) For the purpose of this section, polyester elastomers are those produced by the ester exchange...

Highly fluorinated polyurethanes

NASA Technical Reports Server (NTRS)

Stump, E. C., Jr.; Rochow, S. E. (Inventor)

1972-01-01

New polyurethanes containing a high degree of fluorine atoms are reported. The presence of the fluorine atoms in the polyurethane resins provides material having good thermal stability and chemical resistance. These polyurethanes are derived from a new hydroxy-terminated perfluoro polyether. The hydroxy terminated material is reacted with a diisocyanate to produce the polyurethanes. The polyurethanes can be used to form seals, coatings, potting material, hoses and the like.

Properties of honeycomb polyester knitted fabrics

NASA Astrophysics Data System (ADS)

Feng, A. F.

2016-07-01

The properties of honeycomb polyester weft-knitted fabrics were studied to understand their advantages. Seven honeycomb polyester weft-knitted fabrics and one common polyester weft-knitted fabric were selected for testing. Their bursting strengths, fuzzing and pilling, air permeability, abrasion resistance and moisture absorption and perspiration were studied. The results show that the honeycomb polyester weft-knitted fabrics have excellent moisture absorption and liberation. The smaller their thicknesses and area densities are, the better their moisture absorption and liberation will be. Their anti-fuzzing and anti-pilling is good, whereas their bursting strengths and abrasion resistance are poorer compared with common polyester fabric's. In order to improve the hygroscopic properties of the fabrics, the proportion of the honeycomb microporous structure modified polyester in the fabrics should not be less than 40%.

Investigation on the mechanical properties of palm-based flexible polyurethane foam

NASA Astrophysics Data System (ADS)

On, Ahmad Zuhdi Mohd; Badri, Khairiah Haji

2015-09-01

A series of modification polyurethane (PU) system was prepared by introducing palm kernel based polyol (PKO-p) to progressively replaced commercial polyether polyol from petrochemical based material. This paper describes the effect of PKO-p on the physical-mechanical properties of polyurethane foams. Stress-strain analysis in tensile mode was conducted with physicochemical analysis by performing Fourier transform infrared (FTIR). The morphological studies were observed by the optical microscope. The foam showed an increment on the modulus up to 458.3kPa as more incorporation of PKO-p introduced to the system. In contrast, tensile strength of PU foam depicted the highest up to 162 kPa at 60:40. The elongation at break showed decrement as the composition of the renewable polyol increased to a ratio 60/40 of PKO-p to petrochemical based polyol.

Degradability in vitro of polyurethanes based on synthetic atactic poly[(R,S)-3-hydroxybutyrate].

PubMed

Brzeska, J; Janeczek, H; Janik, H; Kowalczuk, M; Rutkowska, M

2015-01-01

The aim of the present study was to determine the degradability of aliphatic polyurethanes, based on a different amount of synthetic, atactic poly[(R,S)-3-hydroxybutyrate] (a-PHB), in hydrolytic (phosphate buffer) and oxidative (H2O2/CoCl2) solutions. The soft segments were built with atactic poly[(R,S)-3-hydroxybutyrate] and polycaprolactone or polyoxytetramethylenediols, whereas hard segments were the reaction product of 4,4'-methylenedicyclohexyl diisocyanate and 1,4-butanediol.The selected properties - density and morphology of polymer surfaces - which could influence the sensitivity of polymers to degradation processes - were analyzed.The analysis of molecular mass (GPC), thermal properties (DSC) and the sample weight changes were undertaken to estimate the degree of degradability of polymer samples after incubation in environments studied.Investigated polyurethanes were amorphous with the very low amount of crystalline phases of hard segments.The polyurethane synthesized with a poly[(R,S)-3-hydroxybutyrate] and polyoxytetramethylenediol at a molar ratio of NCO:OH=3.7:1 (prepolymer step) appeared as the most sensitive for both degradative solutions. Its weight and molecular mass losses were the highest in comparison to other investigated polyurethanes.It could be expected that playing with the amount of poly[(R,S)-3-hydroxybutyrate] in polyurethane synthesis the rate of polyurethane degradation after immersion in living body would be modeled.

Systematic computational and experimental investigation of lithium-ion transport mechanisms in polyester-based polymer electrolytes

DOE Office of Scientific and Technical Information (OSTI.GOV)

Webb, Michael A.; Jung, Yukyung; Pesko, Danielle M.

Understanding the mechanisms of lithium-ion transport in polymers is crucial for the design of polymer electrolytes. We combine modular synthesis, electrochemical characterization, and molecular simulation to investigate lithium-ion transport in a new family of polyester-based polymers and in poly(ethylene oxide) (PEO). Theoretical predictions of glass-transition temperatures and ionic conductivities in the polymers agree well with experimental measurements. Interestingly, both the experiments and simulations indicate that the ionic conductivity of PEO, relative to the polyesters, is far higher than would be expected from its relative glass-transition temperature. The simulations reveal that diffusion of the lithium cations in the polyesters proceeds viamore » a different mechanism than in PEO, and analysis of the distribution of available cation solvation sites in the various polymers provides a novel and intuitive way to explain the experimentally observed ionic conductivities. This work provides a platform for the evaluation and prediction of ionic conductivities in polymer electrolyte materials.« less

Systematic computational and experimental investigation of lithium-ion transport mechanisms in polyester-based polymer electrolytes

DOE PAGES

Webb, Michael A.; Jung, Yukyung; Pesko, Danielle M.; ...

2015-07-10

Understanding the mechanisms of lithium-ion transport in polymers is crucial for the design of polymer electrolytes. We combine modular synthesis, electrochemical characterization, and molecular simulation to investigate lithium-ion transport in a new family of polyester-based polymers and in poly(ethylene oxide) (PEO). Theoretical predictions of glass-transition temperatures and ionic conductivities in the polymers agree well with experimental measurements. Interestingly, both the experiments and simulations indicate that the ionic conductivity of PEO, relative to the polyesters, is far higher than would be expected from its relative glass-transition temperature. The simulations reveal that diffusion of the lithium cations in the polyesters proceeds viamore » a different mechanism than in PEO, and analysis of the distribution of available cation solvation sites in the various polymers provides a novel and intuitive way to explain the experimentally observed ionic conductivities. This work provides a platform for the evaluation and prediction of ionic conductivities in polymer electrolyte materials.« less

Systematic Computational and Experimental Investigation of Lithium-Ion Transport Mechanisms in Polyester-Based Polymer Electrolytes

PubMed Central

2015-01-01

Understanding the mechanisms of lithium-ion transport in polymers is crucial for the design of polymer electrolytes. We combine modular synthesis, electrochemical characterization, and molecular simulation to investigate lithium-ion transport in a new family of polyester-based polymers and in poly(ethylene oxide) (PEO). Theoretical predictions of glass-transition temperatures and ionic conductivities in the polymers agree well with experimental measurements. Interestingly, both the experiments and simulations indicate that the ionic conductivity of PEO, relative to the polyesters, is far higher than would be expected from its relative glass-transition temperature. The simulations reveal that diffusion of the lithium cations in the polyesters proceeds via a different mechanism than in PEO, and analysis of the distribution of available cation solvation sites in the various polymers provides a novel and intuitive way to explain the experimentally observed ionic conductivities. This work provides a platform for the evaluation and prediction of ionic conductivities in polymer electrolyte materials. PMID:27162971

Synthesis and characterization of gold nanotube/nanowire-polyurethane composite based on castor oil and polyethylene glycol.

PubMed

Ganji, Yasaman; Kasra, Mehran; Salahshour Kordestani, Soheila; Bagheri Hariri, Mohiedin

2014-09-01

Gold nanotubes/nanowires (GNT/NW) were synthesized by using the template-assisted electrodeposition technique and mixed with castor oil-polyethylene glycol based polyurethane (PU) to fabricate porous composite scaffolds for biomedical application. 100 and 50 ppm of GNT/NW were used to synthesize composites. The composite scaffolds were characterized by Fourier transform infrared spectroscopy, dynamic mechanical thermal analysis, differential scanning calorimetry, and scanning electron microscopy. Cell attachment on polyurethane-GNT/NW composites was investigated using fat-derived mesenchymal stem cells. Addition of 50 or 100 ppm GNT/NW had significant effects on thermal, mechanical, and cell attachment of polyurethane. Higher crosslink density and better cell attachment and proliferation were observed in polyurethane containing 50 ppm GNT/NW. The results revealed that GNT/NW formed hydrogen bonding with the polyurethane matrix and improved the thermomechanical properties of nanocomposites. Compared with pure PU, better cellular attachment on polyurethane-GNT/NW composites was observed resulting from the improved surface properties of composites. Copyright © 2014 Elsevier B.V. All rights reserved.

Sustained Release Drug Delivery Applications of Polyurethanes.

PubMed

Lowinger, Michael B; Barrett, Stephanie E; Zhang, Feng; Williams, Robert O

2018-05-09

Since their introduction over 50 years ago, polyurethanes have been applied to nearly every industry. This review describes applications of polyurethanes to the development of modified release drug delivery. Although drug delivery research leveraging polyurethanes has been ongoing for decades, there has been renewed and substantial interest in the field in recent years. The chemistry of polyurethanes and the mechanisms of drug release from sustained release dosage forms are briefly reviewed. Studies to assess the impact of intrinsic drug properties on release from polyurethane-based formulations are considered. The impact of hydrophilic water swelling polyurethanes on drug diffusivity and release rate is discussed. The role of pore formers in modulating drug release rate is examined. Finally, the value of assessing mechanical properties of the dosage form and approaches taken in the literature are described.

Preparation and characterization of plasticized palm-based polyurethane solid polymer electrolyte

DOE Office of Scientific and Technical Information (OSTI.GOV)

Daud, Farah Nadia; Ahmad, Azizan; Badri, Khairiah Haji

2013-11-27

Palm-based polyurethane solid polymer electrolyte was prepared via prepolymerization method between palm kernel oil based polyols (PKO-p) and 2,4’-diphenylmethane diisocyanate (2,4’-MDI) in acetone at room temperature with the vary amount of lithium trifuoromethanesulfonate (LiCF{sub 3}SO{sub 3}) salt and polyethylene glycol (PEG). The film was analyzed using attenuated total reflection infrared (ATR-IR) spectroscopy, electrochemical impedance spectroscopy (EIS) and X-ray diffractometry (XRD). EIS result indicated ionic conductivity obtained with 30 wt% LiCF3SO3 increased to 6.55 × 10{sup −6} S cm{sup −1} when 10 wt.% of plasticizer was added into the system. FTIR analysis showed the interaction between lithium ions and amine (-N-H)more » at 3600–3100 cm{sup −1}, carbonyl (-C=O) at 1750–1650 cm{sup −1} and ether (-C-O-C-) at 1150–1000 cm{sup −1} of the polyurethane forming polymer-salt complexes. The XRD result confirmed that LiCF{sub 3}SO{sub 3} salt completely dissociated within the polyurethane film with the absence of crystalline peaks of LiCF{sub 3}SO{sub 3}.« less

A microbial factory for lactate-based polyesters using a lactate-polymerizing enzyme

PubMed Central

Taguchi, Seiichi; Yamada, Miwa; Matsumoto, Ken'ichiro; Tajima, Kenji; Satoh, Yasuharu; Munekata, Masanobu; Ohno, Katsuhiro; Kohda, Katsunori; Shimamura, Takashi; Kambe, Hiromi; Obata, Shusei

2008-01-01

Polylactate (PLA) is synthesized as a representative bio-based polyester by the chemo-bio process on the basis of metal catalyst-mediated chemical polymerization of lactate (LA) supplied by microbial fermentation. To establish the one-step microbial process for synthesis of LA-based polyesters, we explored whether polyhydroxyalkanoate (PHA) synthase would exhibit polymerizing activity toward a LA-coenzyme A (CoA), based on the fact that PHA monomeric constituents, especially 3-hydroxybutyrate (3HB), are structurally analogous to LA. An engineered PHA synthase was discovered as a candidate by a two-phase in vitro polymerization system previously developed. An LA-CoA producing Escherichia coli strain with a CoA transferase gene was constructed, and the generation of LA-CoA was demonstrated by capillary electrophoresis/MS analysis. Next, when the engineered PHA synthase gene was introduced into the resultant recombinant strain, we confirmed the one-step biosynthesis of the LA-incorporated copolyester, P(6 mol% LA-co-94 mol% 3HB), with a number-average molecular weight of 1.9 × 105, as revealed by gel permeation chromatography, gas chromatography/MS, and NMR. PMID:18978031

Electrically conductive rigid polyurethane foam

DOEpatents

Neet, Thomas E.; Spieker, David A.

1985-03-19

A rigid, polyurethane foam comprises about 2-10 weight percent, based on the total foam weight, of a carbon black which is CONDUCTEX CC-40-220 or CONDUCTEX SC, whereby the rigid polyurethane foam is electrically conductive and has essentially the same mechanical properties as the same foam without carbon black added.

Alternating block polyurethanes based on PCL and PEG as potential nerve regeneration materials.

PubMed

Li, Guangyao; Li, Dandan; Niu, Yuqing; He, Tao; Chen, Kevin C; Xu, Kaitian

2014-03-01

Polyurethanes with regular and controlled block arrangement, i.e., alternating block polyurethanes (abbreviated as PUCL-alt-PEG) based on poly(ε-caprolactone) (PCL-diol) and poly(ethylene glycol) (PEG) was prepared via selectively coupling reaction between PCL-diol and diisocyanate end-capped PEG. Chemical structure, molecular weight, distribution, and thermal properties were systematically characterized by FTIR, (1)H NMR, GPC, DSC, and TGA. Hydrophilicity was studied by static contact angle of H2O and CH2I2. Film surface was observed by scanning electron microscope (SEM) and atomic force microscopy, and mechanical properties were assessed by universal test machine. Results show that alternating block polyurethanes give higher crystal degree, higher mechanical properties, and more hydrophilic and rougher (deep ravine) surface than their random counterpart, due to regular and controlled structure. Platelet adhesion illustrated that PUCL-alt-PEG has better hemocompatibility and the hemacompatibility was affected significantly by PEG content. Excellent hemocompatibility was obtained with high PEG content. CCK-8 assay and SEM observation revealed much better cell compatibility of fibroblast L929 and rat glial cells on the alternating block polyurethanes than that on random counterpart. Alternating block polyurethane PUC20-a-E4 with optimized composition, mechanical, surface properties, hemacompatibility, and highest cell growth and proliferation was achieved for potential use in nerve regeneration. Copyright © 2013 Wiley Periodicals, Inc.

Electrically conductive rigid polyurethane foam

DOEpatents

Neet, T.E.; Spieker, D.A.

1983-12-08

A rigid, moldable polyurethane foam comprises about 2 to 10 weight percent, based on the total foam weight, of a carbon black which is CONDUCTEX CC-40-220 or CONDUCTEX SC, whereby the rigid polyurethane foam is electrically conductive and has essentially the same mechanical properties as the same foam without carbon black added.

Repair of osteochondral defects with hyaluronan- and polyester-based scaffolds.

PubMed

Solchaga, Luis A; Temenoff, Johnna S; Gao, Jizong; Mikos, Antonios G; Caplan, Arnold I; Goldberg, Victor M

2005-04-01

The natural repair of osteochondral defects can be enhanced with biocompatible, biodegradable materials that support the repair process. It is our hypothesis that hyaluronan-based scaffolds are superior to synthetic scaffolds because they provide biological cues. We tested this thesis by comparing two hyaluronan-based scaffolds [auto cross-linked polysaccharide polymer (ACP) and HYAFF-11] to polyester-based scaffolds [poly(DL-lactic-co-glycolic acid) (PLGA) and poly(L-lactic acid) (PLLA)] with similar pore size, porosity and degradation times. Fifty-four rabbits received bilateral osteochondral defects. One defect received a hyaluronan-based scaffold and the contralateral defect received the corresponding polyester-based scaffold. Rabbits were euthanized 4, 12 and 20 weeks after surgery and the condyles dissected and processed for histology. Only ACP-treated defects presented bone at the base of the defect at 4 weeks. At 12 weeks, only defects treated with rapidly dissolving implants (ACP and PLGA) presented bone reconstitution consistently, while bone was present in only one third of those treated with slowly dissolving scaffolds (HYAFF-11 and PLLA). After 20 weeks, the articular surface of PLGA-treated defects presented fibrillation more frequently than in ACP-treated defects. The surface of defects treated with slowly dissolving scaffolds presented more cracks and fissures. The degradation rate of the scaffolds is critical for the repair process. Slowly dissolving scaffolds sustain thicker cartilage at the surface but, it frequently presents cracks and discontinuities. These scaffolds also delay bone formation at the base of the defects. Hyaluronan-based scaffolds appear to allow faster cell infiltration leading to faster tissue formation. The degradation of ACP leads to rapid bone formation while the slow degradation of HYAFF-11 prolongs the presence of cartilage and delays endochondral bone formation.

Synthesis of rigid polyurethane foams from phosphorylated biopolyols.

PubMed

de Haro, Juan Carlos; López-Pedrajas, Daniel; Pérez, Ángel; Rodríguez, Juan Francisco; Carmona, Manuel

2017-08-18

Renewable resources are playing a key role on the synthesis of biodegradable polyols. Moreover, the incorporation of covalently linked additives is increasing in importance in the polyurethane (PU) market. In this work, previously epoxidized grape seed oil and methyl oleate were transformed into phosphorylated biopolyols through an acid-catalyzed ring-opening hydrolysis in the presence of H 3 PO 4 . The formation of phosphate polyesters was confirmed by FT-IR and 31 P-NMR. However, the synthesis of a high-quality PU rigid foam was not possible using exclusively these polyols attending to their low hydroxyl value. In that way, different rigid PU foams were prepared from the phosphorylated biopolyols and the commercial polyol Alcupol R4520. It was observed that phosphorylated biopolyols can be incorporated up to a 57 wt.% in the PU synthesis without significant structural changes with respect to the commercial foam. Finally, thermogravimetric and EDAX analyses revealed an improvement of thermal stability by the formation of a protective phosphorocarbonaceous char layer.

Preparation of eugenol-based polyurethane

NASA Astrophysics Data System (ADS)

Li, Yupeng; Luo, Fang; Cheng, Chuanjie

2018-03-01

The regenerative eugenol was used as the starting material to prepare diol species by two steps, with a total yield of 28%. Furthermore, the prepared diol reacts with 1,6-hexadiisocyanate(HDI) to afford the corresponding polyurethane (PU). The structure of intermediates and PU are characterized by 1H-NMR or IR.

40 CFR 721.9507 - Polyester silane.

Code of Federal Regulations, 2011 CFR

2011-07-01

... 40 Protection of Environment 31 2011-07-01 2011-07-01 false Polyester silane. 721.9507 Section 721... Polyester silane. (a) Chemical substance and significant new uses subject to reporting. (1) The chemical substance identified as a polyester silane (P-95-1022) is subject to reporting under this section for the...

40 CFR 721.9507 - Polyester silane.

Code of Federal Regulations, 2010 CFR

2010-07-01

... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Polyester silane. 721.9507 Section 721... Polyester silane. (a) Chemical substance and significant new uses subject to reporting. (1) The chemical substance identified as a polyester silane (P-95-1022) is subject to reporting under this section for the...

(Citric acid–co–polycaprolactone triol) polyester

PubMed Central

Thomas, Lynda V.; Nair, Prabha D.

2011-01-01

Tissue engineering holds enormous challenges for materials science, wherein the ideal scaffold to be used is expected to be biocompatible, biodegradable and possess mechanical and physical properties that are suitable for target application. In this context, we have prepared degradable polyesters in different ratios by a simple polycondensation technique with citric acid and polycaprolactone triol. Differential scanning calorimetry indicated that the materials were amorphous based the absence of a crystalline melting peak and the presence of a glass transition temperature below 37°C. These polyesters were found to be hydrophilic and could be tailor-made into tubes and films. Porosity could also be introduced by addition of porogens. All the materials were non-cytotoxic in an in vitro cytotoxicity assay and may degrade via hydrolysis to non-toxic degradation products. These polyesters have potential implications in the field of soft tissue engineering on account of their similarity of properties. PMID:23507730

Bio-based rigid polyurethane foam from liquefied products of wood in the presence of polyhydric alcohols

Treesearch

Zhifeng Zheng; Hui Pan; Yuanbo Huang; Chung Y. Hse

2011-01-01

Rigid polyurethane foams were prepared from the liquefied wood polyols, which was obtained by the liquefaction of southern pine wood in the presence of polyhydric alcohols with sulfuric acid catalyst by using microwave-assistant as an energy source. The properties of liquefied biomass-based polyols and the rigid polyurethane foams were investigated. The results...

Red blood cell transport mechanisms in polyester thread-based blood typing devices.

PubMed

Nilghaz, Azadeh; Ballerini, David R; Guan, Liyun; Li, Lizi; Shen, Wei

2016-02-01

A recently developed blood typing diagnostic based on a polyester thread substrate has shown great promise for use in medical emergencies and in impoverished regions. The device is easy to use and transport, while also being inexpensive, accurate, and rapid. This study used a fluorescent confocal microscope to delve deeper into how red blood cells were behaving within the polyester thread-based diagnostic at the cellular level, and how plasma separation could be made to visibly occur on the thread, making it possible to identify blood type in a single step. Red blood cells were stained and the plasma phase dyed with fluorescent compounds to enable them to be visualised under the confocal microscope at high magnification. The mechanisms uncovered were in surprising contrast with those found for a similar, paper-based method. Red blood cell aggregates did not flow over each other within the thread substrate as expected, but suffered from a restriction to their flow which resulted in the chromatographic separation of the RBCs from the liquid phase of the blood. It is hoped that these results will lead to the optimisation of the method to enable more accurate and sensitive detection, increasing the range of blood systems that can be detected.

[A novel method based on Y-shaped cotton-polyester thread microfluidic channel].

PubMed

Wang, Lu; Shi, Yan-ru; Yan, Hong-tao

2014-08-01

A novel method based on Y-shaped microfluidic channel was firstly proposed in this study. The microfluidic channel was made of two cotton-polyester threads based on the capillary effect of cotton-polyester threads for the determination solutions. A special device was developed to fix the Y-shaped microfluidic channel by ourselves, through which the length and the tilt angle of the channel can be adjusted as requested. The spectrophotometry was compared with Scan-Adobe Photoshop software processing method. The former had a lower detection limit while the latter showed advantages in both convenience and fast operations and lower amount of samples. The proposed method was applied to the determination of nitrite. The linear ranges and detection limits are 1.0-70 micromol x L(-1), 0.66 micromol x L(-1) (spectrophotometry) and 50-450 micromol x L(-1), 45.10 micromol x L(-1) (Scan-Adobe Photoshop software processing method) respectively. This method has been successfully used to the determination of nitrite in soil samples and moat water with recoveries between 96.7% and 104%. It was proved that the proposed method was a low-cost, rapid and convenient analytical method with extensive application prospect.

Synthesis of Transesterified Palm Olein-Based Polyol and Rigid Polyurethanes from this Polyol.

PubMed

Arniza, Mohd Zan; Hoong, Seng Soi; Idris, Zainab; Yeong, Shoot Kian; Hassan, Hazimah Abu; Din, Ahmad Kushairi; Choo, Yuen May

Transesterification of palm olein with glycerol can increase the functionality by introducing additional hydroxyl groups to the triglyceride structure, an advantage compared to using palm olein directly as feedstock for producing palm-based polyol. The objective of this study was to synthesize transesterified palm olein-based polyol via a three-step reaction: (1) transesterification of palm olein, (2) epoxidation and (3) epoxide ring opening. Transesterification of palm olein yielded approximately 78 % monoglyceride and has an hydroxyl value of approximately 164 mg KOH g -1 . The effect of formic acid and hydrogen peroxide concentrations on the epoxidation reaction was studied. The relationships between epoxide ring-opening reaction time and residual oxirane oxygen content and hydroxyl value were monitored. The synthesized transesterified palm olein-based polyol has hydroxyl value between 300 and 330 mg KOH g -1 and average molecular weight between 1,000 and 1,100 Da. On the basis of the hydroxyl value and average molecular weight of the polyol, the transesterified palm olein-based polyol is suitable for producing rigid polyurethane foam, which can be designed to exhibit desirable properties. Rigid polyurethane foams were synthesized by substituting a portion of petroleum-based polyol with the transesterified palm olein-based polyol. It was observed that by increasing the amount of transesterified palm olein-based polyol, the core density and compressive strength were reduced but at the same time the insulation properties of the rigid polyurethane foam were improved.

The effect of oxidation on the enzyme-catalyzed hydrolytic biodegradation of poly(urethane)s.

PubMed

Labow, Rosalind S; Tang, Yiwen; McCloskey, Christopher B; Santerre, J Paul

2002-01-01

Although the biodegradation of polyurethanes (PU) by oxidative and hydrolytic agents has been studied extensively, few investigations have reported on the combination of their effects. Since neutrophils (PMN) arrive at an implanted device first and release HOCl, followed by monocyte-derived macrophages (MDM) which have potent esterase activities and oxidants of their own, the combined effect of oxidative and hydrolytic degradation on radiolabeled polycarbonate-polyurethanes (PCNU)s was investigated and compared to that of a polyester-PU (PESU) and a polyether-PU (PEU). The PCNUs were synthesized with PCN (MW = 1,000), and butanediol (14C-BD) and one of two diisocyanates, hexane-1,6-diisocyanate (14C-HDI) or methylene bis-p-phenyl diisocyanate (MDI). The PESU and PEU were synthesized using toluene-diisocyanate (14C-TDI), with polycaprolactone and polytetramethylene oxide as soft segments respectively, and ethylene diamine as the chain extender. The effect of pre-treatment with 0.1 mM HOC1 for 1 week on the HDI-based PCNUs and both TDI-based PUs resulted in a significant inhibition of radiolabel release (RR) elicited by cholesterol esterase (CE), when compared to buffer alone, whereas the MDI-based PCNU showed a small but significant increase. When PMN were activated on the HDI-based PCNU surface with phorbol myristate acetate (PMA), HOCl was released for 3 h, and was almost completely abolished by sodium azide (AZ). Simultaneously, the PMN-elicited RR, shown previously to be due to the esterolytic cleavage by serine proteases, was inhibited approximately 75% by PMA-activation of the cells, but significantly increased relative to the latter when AZ was added. Both in vitro oxidation by HOCl and the release of HOCI by PMN were associated with the inhibition of RR and suggest perturbations between oxidative and hydrolytic mechanisms of biodegradation.

Polyester Resin Hazards

PubMed Central

Bourne, L. B.; Milner, F. J. M.

1963-01-01

Polyester resins are being increasingly used in industry. These resins require the addition of catalysts and accelerators. The handling of polyester resin system materials may give rise to skin irritations, allergic reactions, and burns. The burns are probably due to styrene and organic peroxides. Atmospheric pollution from styrene and explosion and fire risks from organic peroxides must be prevented. Where dimethylaniline is used scrupulous cleanliness and no-touch technique must be enforced. Handling precautions are suggested. Images PMID:14014495

Polyester-Based (Bio)degradable Polymers as Environmentally Friendly Materials for Sustainable Development

PubMed Central

Rydz, Joanna; Sikorska, Wanda; Kyulavska, Mariya; Christova, Darinka

2014-01-01

This review focuses on the polyesters such as polylactide and polyhydroxyalkonoates, as well as polyamides produced from renewable resources, which are currently among the most promising (bio)degradable polymers. Synthetic pathways, favourable properties and utilisation (most important applications) of these attractive polymer families are outlined. Environmental impact and in particular (bio)degradation of aliphatic polyesters, polyamides and related copolymer structures are described in view of the potential applications in various fields. PMID:25551604

Design of Xylose-Based Semisynthetic Polyurethane Tissue Adhesives with Enhanced Bioactivity Properties.

PubMed

Balcioglu, Sevgi; Parlakpinar, Hakan; Vardi, Nigar; Denkbas, Emir Baki; Karaaslan, Merve Goksin; Gulgen, Selam; Taslidere, Elif; Koytepe, Suleyman; Ates, Burhan

2016-02-01

Developing biocompatible tissue adhesives with high adhesion properties is a highly desired goal of the tissue engineering due to adverse effects of the sutures. Therefore, our work involves synthesis, characterization, adhesion properties, protein adsorption, in vitro biodegradation, in vitro and in vivo biocompatibility properties of xylose-based semisynthetic polyurethane (NPU-PEG-X) bioadhesives. Xylose-based semisynthetic polyurethanes were developed by the reaction among 4,4'-methylenebis(cyclohexyl isocyanate) (MCI), xylose and polyethylene glycol 200 (PEG). Synthesized polyurethanes (PUs) showed good thermal stability and high adhesion strength. The highest values in adhesion strength were measured as 415.0 ± 48.8 and 94.0 ± 2.8 kPa for aluminum substrate and muscle tissue in 15% xylose containing PUs (NPU-PEG-X-15%), respectively. The biodegradation of NPU-PEG-X-15% was also determined as 19.96 ± 1.04% after 8 weeks of incubation. Relative cell viability of xylose containing PU was above 86%. Moreover, 10% xylose containing NPU-PEG-X (NPU-PEG-X-10%) sample has favorable tissue response, and inflammatory reaction between 1 and 6 weeks implantation period. With high adhesiveness and biocompatibility properties, NPU-PEG-X can be used in the medical field as supporting materials for preventing the fluid leakage after abdominal surgery or wound closure.

Surface Modification of Polyester Fiber with Perfluorooctyltrimethoxysilane

NASA Astrophysics Data System (ADS)

Wang, Xiangcheng; Liu, Yadong; Li, Dan; Tie, Zihan

2018-05-01

An excellent modified polyester fiber was prepared via chemical grafting between polyester fiber and perfluorooctyltrimethoxysilane (FAS-17), or silane coupler (KH-570), or Titanate coupler (DN-101) in isopropyl alcohol aqueous solution. Volume ratio of isopropyl alcohol in aqueous solution was 50:50, the mass concentration of FAS-17 is 2%, reacting on polyester fiber modified for 24h at 60 °C, the polyester fiber contact angle to water was 145 °, and the contact angle to peanut oil was 118 °, with excellent performance of amphiphobic property. KH-570 and DN-101 modified polymer fiber to be hydrophobic properties nearly as FAS-17, but modified polyester fiber have no amphiphobic property.

40 CFR 721.6485 - Hydroxy terminated polyester.

Code of Federal Regulations, 2011 CFR

2011-07-01

... 40 Protection of Environment 31 2011-07-01 2011-07-01 false Hydroxy terminated polyester. 721.6485... Substances § 721.6485 Hydroxy terminated polyester. (a) Chemical substance and significant new uses subject to reporting. (1) The chemical substance identified generically as a hydroxy terminated polyester...

40 CFR 721.6485 - Hydroxy terminated polyester.

Code of Federal Regulations, 2010 CFR

2010-07-01

... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Hydroxy terminated polyester. 721.6485... Substances § 721.6485 Hydroxy terminated polyester. (a) Chemical substance and significant new uses subject to reporting. (1) The chemical substance identified generically as a hydroxy terminated polyester...

Acid-degradable polyurethane particles for protein-based vaccines

PubMed Central

Bachelder, Eric M.; Beaudette, Tristan T.; Broaders, Kyle E.; Paramonov, Sergey E.; Dashe, Jesse; Fréchet, Jean M. J.

2009-01-01

Acid-degradable particles containing a model protein antigen, ovalbumin, were prepared from a polyurethane with acetal moieties embedded throughout the polymer, and characterized by dynamic light scattering and transmission electron microscopy. The small molecule degradation by-product of the particles was synthesized and tested in vitro for toxicity indicating an LC50 of 12,500 μg/ml. A new liquid chromatography-mass spectrometry technique was developed to monitor the in vitro degradation of these particles. The degradation by-product inside RAW macrophages was at its highest level after 24 hours of culture and was efficiently exocytosed until it was no longer detectable after four days. When tested in vitro, these particles induced a substantial increase in the presentation of the immunodominant ovalbumin-derived peptide SIINFEKL in both macrophages and dendritic cells. In addition, vaccination with these particles generated a cytotoxic T-lymphocyte response that was superior to both free ovalbumin and particles made from an analogous but slower-degrading acid-labile polyurethane polymer. Overall, we present a fully degradable polymer system with non-toxic by-products, which may find use in various biomedical applications including protein-based vaccines. PMID:18710254

Development of segmented polyurethane elastomers with low iodine content exhibiting radiopacity and blood compatibility.

PubMed

Dawlee, S; Jayabalan, Muthu

2011-10-01

Biofunctionally active and inherently radiopaque polymers are the emerging need for biomedical applications. Novel segmented polyurethane elastomer with inherent radiopacity was prepared using aliphatic chain extender 2,3-diiodo-2-butene-1,4-diol, polyol polytetramethylene glycol and 4,4'-methylenebis(phenyl isocyanate) (MDI) for blood compatible applications. Aliphatic polyurethane was also prepared using hexamethylene diisocyanate for comparison. X-ray analysis of the polyurethanes revealed good radiopacity even at a relatively low concentration of 3% iodine in aromatic polyurethane and 10% in aliphatic polyurethane. The polyurethanes also possessed excellent thermal stability. MDI-based polyurethane showed considerably higher tensile strength than the analogous HDI-based polyurethane. MDI-based aromatic polyurethane exhibited a dynamic surface morphology in aqueous medium, resulting in the segregation of hydrophilic domains which was more conducive to anti-thrombogenic properties. The polyurethane was cytocompatible with L929 fibroblast cells, non-hemolytic, and possessed good blood compatibility.

[Modern polyurethanes in cardiovascular surgery].

PubMed

Gostev, A A; Laktionov, P P; Karpenko, A A

Currently, there is great clinical demand for synthetic tissue-engineered cardiovascular prostheses with good long-term patency. Polyurethanes belong to the class of polymers with excellent bio- and hemocompatibility. They are known to possess good mechanical properties, but are prone to processes of degradation in conditions of functioning in living organisms. Attempts at solving this problem have resulted in the development of various new subclasses of polyurethanes such as thermoplastic polyether polyurethanes, polyurethanes with a silicone segment, polycarbonate polyurethanes and nanocomposite polyurethanes. This was accompanied and followed by offering a series of new technologies of production of implantable medical devices such as vascular grafts, heart valves and others. In the presented review, we discuss biological and mechanical properties of modern subclasses of polyurethanes, as well as modern methods of manufacturing implantable medical devices made of polyurethanes, especially small-diameter vascular prostheses.

Hydrophilic polyurethane matrix promotes chondrogenesis of mesenchymal stem cells☆

PubMed Central

Nalluri, Sandeep M.; Krishnan, G. Rajesh; Cheah, Calvin; Arzumand, Ayesha; Yuan, Yuan; Richardson, Caley A.; Yang, Shuying; Sarkar, Debanjan

2016-01-01

Segmental polyurethanes exhibit biphasic morphology and can control cell fate by providing distinct matrix guided signals to increase the chondrogenic potential of mesenchymal stem cells (MSCs). Polyethylene glycol (PEG) based hydrophilic polyurethanes can deliver differential signals to MSCs through their matrix phases where hard segments are cell-interactive domains and PEG based soft segments are minimally interactive with cells. These coordinated communications can modulate cell–matrix interactions to control cell shape and size for chondrogenesis. Biphasic character and hydrophilicity of polyurethanes with gel like architecture provide a synthetic matrix conducive for chondrogenesis of MSCs, as evidenced by deposition of cartilage-associated extracellular matrix. Compared to monophasic hydrogels, presence of cell interactive domains in hydrophilic polyurethanes gels can balance cell–cell and cell–matrix interactions. These results demonstrate the correlation between lineage commitment and the changes in cell shape, cell–matrix interaction, and cell–cell adhesion during chondrogenic differentiation which is regulated by polyurethane phase morphology, and thus, represent hydrophilic polyurethanes as promising synthetic matrices for cartilage regeneration. PMID:26046282

Hydrophilic polyurethane matrix promotes chondrogenesis of mesenchymal stem cells.

PubMed

Nalluri, Sandeep M; Krishnan, G Rajesh; Cheah, Calvin; Arzumand, Ayesha; Yuan, Yuan; Richardson, Caley A; Yang, Shuying; Sarkar, Debanjan

2015-09-01

Segmental polyurethanes exhibit biphasic morphology and can control cell fate by providing distinct matrix guided signals to increase the chondrogenic potential of mesenchymal stem cells (MSCs). Polyethylene glycol (PEG) based hydrophilic polyurethanes can deliver differential signals to MSCs through their matrix phases where hard segments are cell-interactive domains and PEG based soft segments are minimally interactive with cells. These coordinated communications can modulate cell-matrix interactions to control cell shape and size for chondrogenesis. Biphasic character and hydrophilicity of polyurethanes with gel like architecture provide a synthetic matrix conducive for chondrogenesis of MSCs, as evidenced by deposition of cartilage-associated extracellular matrix. Compared to monophasic hydrogels, presence of cell interactive domains in hydrophilic polyurethanes gels can balance cell-cell and cell-matrix interactions. These results demonstrate the correlation between lineage commitment and the changes in cell shape, cell-matrix interaction, and cell-cell adhesion during chondrogenic differentiation which is regulated by polyurethane phase morphology, and thus, represent hydrophilic polyurethanes as promising synthetic matrices for cartilage regeneration. Copyright © 2015 Elsevier B.V. All rights reserved.

Formulation, Preparation, and Characterization of Polyurethane Foams

ERIC Educational Resources Information Center

Pinto, Moises L.

2010-01-01

Preparation of laboratory-scale polyurethane foams is described with formulations that are easy to implement in experiments for undergraduate students. Particular attention is given to formulation aspects that are based on the main chemical reactions occurring in polyurethane production. This allows students to develop alternative formulations to…

Preparation and characterization of new biologically active polyurethane foams.

PubMed

Savelyev, Yuri; Veselov, Vitali; Markovskaya, Ludmila; Savelyeva, Olga; Akhranovich, Elena; Galatenko, Natalya; Robota, Ludmila; Travinskaya, Tamara

2014-12-01

Biologically active polyurethane foams are the fast-developed alternative to many applications of biomedical materials. Due to the polyurethane structure features and foam technology it is possible to incorporate into their structure the biologically active compounds of target purpose via structural-chemical modification of macromolecule. A series of new biologically active polyurethane foams (PUFs) was synthesized with polyethers (MM 2500-5000), polyesters MM (500-2200), 2,4(2,6) toluene diisocyanate, water as a foaming agent, catalysts, foam stabilizers and functional compounds. Different functional compounds: 1,4-di-N-oxy-2,3-bis-(oxymethyl)-quinoxaline (DOMQ), partial sodium salt of poly(acrylic acid) and 2,6-dimethyl-N,N-diethyl aminoacetatanilide hydrochloride were incorporated into the polymer structure/composition due to the chemical and/or physical bonding. Structural peculiarities of PUFs were studied by FTIR spectroscopy and X-ray scattering. Self-adhesion properties of PUFs were estimated by measuring of tensile strength at break of adhesive junction. The optical microscopy method was performed for the PUF morphology studies. Toxicological estimation of the PUFs was carried out in vitro and in vivo. The antibacterial action towards the Gram-positive and Gram-negative bacteria (Escherichia coli ATC 25922, E. coli ATC 2150, Klebsiella pneumoniae 6447, Staphylococcus aureus 180, Pseudomonas aeruginosa 8180, Proteus mirabilis F 403, P. mirabilis 6054, and Proteus vulgaris 8718) was studied by the disc method on the solid nutrient. Physic-chemical properties of the PUFs (density, tensile strength and elongation at break, water absorption and vapor permeability) showed that all studied PUFs are within the operational requirements for such materials and represent fine-cellular foams. Spectral studies confirmed the incorporation of DOMQ into the PUF's macrochain. PUFs are characterized by microheterogeneous structure. They are antibacterially active, non

Synthesis of improved polyester resins

NASA Technical Reports Server (NTRS)

Mcleod, A. H.; Delano, C. B.

1979-01-01

Eighteen aromatic unsaturated polyester prepolymers prepared by a modified interfacial condensation technique were investigated for their solubility in vinyl monomers and ability to provide high char yield forming unsaturated polyester resins. The best resin system contained a polyester prepolymer of phthalic, fumaric and diphenic acids reacted with 2,7-naphthalene diol and 9,9-bis(4-hydroxyphenyl)fluorene. This prepolymer is very soluble in styrene, divinyl benzene, triallyl cyanurate, diallyl isophthalate and methylvinylpyridine. It provided anaerobic char yields as high as 41 percent at 800 C. The combination of good solubility and char yield represents a significant improvement over state-of-the-art unsaturated polyester resins. The majority of the other prepolymers had only low or no solubility in vinyl monomers. Graphite composites from this prepolymer with styrene were investigated. The cause for the observed low shear strengths of the composites was not determined, however 12-week aging of the composites at 82 C showed that essentially no changes in the composites had occurred.

Molecular dynamics studies of polyurethane nanocomposite hydrogels

NASA Astrophysics Data System (ADS)

Strankowska, J.; Piszczyk, Ł.; Strankowski, M.; Danowska, M.; Szutkowski, K.; Jurga, S.; Kwela, J.

2013-10-01

Polyurethane PEO-based hydrogels have a broad range of biomedical applicability. They are attractive for drug-controlled delivery systems, surgical implants and wound healing dressings. In this study, a PEO based polyurethane hydrogels containing Cloisite® 30B, an organically modified clay mineral, was synthesized. Structure of nanocomposite hydrogels was determined using XRD technique. Its molecular dynamics was studied by means of NMR spectroscopy, DMA and DSC analysis. The mechanical properties and thermal stability of the systems were improved by incorporation of clay and controlled by varying the clay content in polymeric matrix. Molecular dynamics of polymer chains depends on interaction of Cloisite® 30B nanoparticles with soft segments of polyurethanes. The characteristic nanosize effect is observed.

[Current status of bio-based materials industry in China].

PubMed

Diao, Xiaoqian; Weng, Yunxuan; Huang, Zhigang; Yang, Nan; Wang, Xiyuan; Zhang, Min; Jin, Yujuan

2016-06-25

In recent years, bio-based materials are becoming a new dominant industry leading the scientific and technological innovation, and economic development of the world. We reviewed the new development of bio-based materials industry in China, analyzed the entire market of bio-based materials products comprehensively, and also stated the industry status of bio-based chemicals, such as lactic acid, 1,3-propanediol, and succinic acid; biodegradable bio-based polymers, such as co-polyester of diacid and diol, polylactic acid, carbon dioxide based copolymer, polyhydroxyalknoates, polycaprolactone, and thermoplastic bio-based plastics; non-biodegradable bio-based polymers, such as bio-based polyamide, polytrimethylene terephthalate, bio-based polyurethane, and bio-based fibers.

Bioengineering of Bacteria To Assemble Custom-Made Polyester Affinity Resins

PubMed Central

Hay, Iain D.; Du, Jinping; Burr, Natalie

2014-01-01

Proof of concept for the in vivo bacterial production of a polyester resin displaying various customizable affinity protein binding domains is provided. This was achieved by engineering various protein binding domains into a bacterial polyester-synthesizing enzyme. Affinity binding domains based on various structural folds and derived from molecular libraries were used to demonstrate the potential of this technique. Designed ankyrin repeat proteins (DARPins), engineered OB-fold domains (OBodies), and VHH domains from camelid antibodies (nanobodies) were employed. The respective resins were produced in a single bacterial fermentation step, and a simple purification protocol was developed. Purified resins were suitable for most lab-scale affinity chromatography purposes. All of the affinity domains tested produced polyester beads with specific affinity for the target protein. The binding capacity of these affinity resins ranged from 90 to 600 nmol of protein per wet gram of polyester affinity resin, enabling purification of a recombinant protein target from a complex bacterial cell lysate up to a purity level of 96% in one step. The polyester resin was efficiently produced by conventional lab-scale shake flask fermentation, resulting in bacteria accumulating up to 55% of their cellular dry weight as polyester. A further proof of concept demonstrating the practicality of this technique was obtained through the intracellular coproduction of a specific affinity resin and its target. This enables in vivo binding and purification of the coproduced “target protein.” Overall, this study provides evidence for the use of molecular engineering of polyester synthases toward the microbial production of specific bioseparation resins implementing previously selected binding domains. PMID:25344238

Soy-based UV resistant polyurethane pultruded composites.

DOT National Transportation Integrated Search

2012-02-01

Aliphatic polyurethane (PU) nanocomposites were synthesized using organically modified nanoclays. X-Ray diffraction results : confirmed good exfoliation of nanoclay particles in the PU resin system. With the addition of just 1% of nanoclay in the bas...

Polyester projects for India, Pakistan

DOE Office of Scientific and Technical Information (OSTI.GOV)

Siddiqi, R.

1993-02-10

India's Indo Rama Synthetics (Bombay) is planning a $186-million integrated polyester fiber and filament complex at Nagpur, Maharashtra. The complex will have annual capacities for 38,000 m.t. of polyester chips by polycondensation, 25,000 m.t. of polyester staple fiber, and 12,000 m.t. of polyester blended yarn. The company is negotiating with the main world suppliers of polycondensation technology. The first stage of the project is slated to begin production by the end of this year and be fully completed by 1994. In Pakistan, National Fibers Ltd. (PNF; Karachi) has signed a deal with Zimmer (Frankfurt) for technology, procurement, construction, and supportmore » work to expand polyester staple fiber capacity from 14,000 m.t./year to 52,000 m.t./year. The technology involves a continuous polymerization process. The project also calls for improvements to PNF's existing batch plant. It is scheduled for completion by the end of 1994. Total cost of the project is estimated at Rs1.745 billion ($70 million), out of which the foreign exchange component is Rs1.05 billion. The Islamic Development Bank (Jeddah; Saudi Arabia) has already approved a $27-million slice of the financing, while the balance of the foreign exchange loan is being arranged through suppliers credit. Local currency loans will be provided by other financial institutions in Pakistan.« less

Degradability of cross-linked polyurethanes based on synthetic polyhydroxybutyrate and modified with polylactide.

PubMed

Brzeska, Joanna; Morawska, Magda; Sikorska, Wanda; Tercjak, Agnieszka; Kowalczuk, Marek; Rutkowska, Maria

2017-01-01

In many areas of application of conventional non-degradable cross-linked polyurethanes (PUR), there is a need for their degradation under the influence of specific environmental factors. It is practiced by incorporation of sensitive to degradation compounds (usually of natural origin) into the polyurethane structure, or by mixing them with polyurethanes. Cross-linked polyurethanes (with 10 and 30%wt amount of synthetic poly([ R,S ]-3-hydroxybutyrate) (R,S-PHB) in soft segments) and their physical blends with poly([d,l]-lactide) (PDLLA) were investigated and then degraded under hydrolytic (phosphate buffer solution) and oxidative (CoCl 2 /H 2 O 2 ) conditions. The rate of degradation was monitored by changes of samples mass, morphology of surface and their thermal properties. Despite the small weight losses of samples, the changes of thermal properties of polymers and topography of their surface indicated that they were susceptible to gradual degradation under oxidative and hydrolytic conditions. Blends of PDLLA and polyurethane with 30 wt% of R,S -PHB in soft segments and PUR/PDLLA blends absorbed more water and degraded faster than polyurethane with low amount of R,S -PHB.

Castor Oil Based Polyurethanes: Synthesis and Characterization

NASA Astrophysics Data System (ADS)

Macalino, AD; Salen, VA; Reyes, LQ

2017-09-01

In this study, polyurethanes based on castor oil and 1,6-hexamethylene diisocyanate (HMDI) were synthesized with varying weight ratio of the castor oil and HMDI. The formation of urethane linkages was verified through the use of a fourier transform infrared spectroscopy (FTIR). The hydrophilicity of the films was evaluated through the use of a contact angle meter and it was found that the contact angle of all the films were below 90 degrees which confirms their hydrophilicity. The thermal stability of the PU films were studies through the use of a thermal gravimetric analyzer and found that all of the polyurethane films exhibited two weight loss events at elevated temperatures wherein the first weight loss event was observed to occur at 285°C to 384°C while the second weight loss event was observed at around 521°C to 551°C. The hardness, elastic modulus, and tensile elongation of the PU films were determined by using a universal testing machine (UTM) where it was found out that the hardness and the elastic modulus of the film is directly proportional with HMDI loading while the tensile elongation is inversely proportional to it. Lastly, it was known through the swelling studies of the PU films that it does not swell, this is due to the presence of unreacted triglycerides in the material, which prevents water from permeating to the films.

Molecular simulation of fibronectin adsorption onto polyurethane surfaces

USDA-ARS?s Scientific Manuscript database

Polyethylene glycol-based polyurethanes have been widely used in biomedical applications, however are prone to swelling. A natural polyol, castor oil can be incorporated into these polyurethanes to control the degree of the swelling, which alters mechanical properties and protein adsorption characte...

Bio-based polyurethane for tissue engineering applications: How hydroxyapatite nanoparticles influence the structure, thermal and biological behavior of polyurethane composites.

PubMed

Gabriel, Laís P; Santos, Maria Elizabeth M Dos; Jardini, André L; Bastos, Gilmara N T; Dias, Carmen G B T; Webster, Thomas J; Maciel Filho, Rubens

2017-01-01

In this work, thermoset polyurethane composites were prepared by the addition of hydroxyapatite nanoparticles using the reactants polyol polyether and an aliphatic diisocyanate. The polyol employed in this study was extracted from the Euterpe oleracea Mart. seeds from the Amazon Region of Brazil. The influence of hydroxyapatite nanoparticles on the structure and morphology of the composites was studied using scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS), the structure was evaluated by Fourier transform infrared spectroscopy (FT-IR), thermal properties were analyzed by thermogravimetry analysis (TGA), and biological properties were studied by in vitro and in vivo studies. It was found that the addition of HA nanoparticles promoted fibroblast adhesion while in vivo investigations with histology confirmed that the composites promoted connective tissue adherence and did not induce inflammation. In this manner, this study supports the further investigation of bio-based, polyurethane/hydroxyapatite composites as biocompatible scaffolds for numerous tissue engineering applications. Copyright © 2016 Elsevier Inc. All rights reserved.

Rigid Polyurethane Foams from Lignin Based-Polyols

NASA Astrophysics Data System (ADS)

Cateto, Carolina; Barreiro, Filomena; Rodrigues, Alírio; Belgacem, Naceur

2008-08-01

Rigid polyurethane (RPU) foams were synthesized using lignin-based polyols obtained by an oxypropylation process. Alcell, Indulin AT, Curan 27-11P and Sarkanda lignins have been oxypropylated using formulations deduced from an optimization study with Alcell. L/PO/C (ratio between lignin, PO and catalyst content) of 30/70/2 and 20/80/5 were used to obtain the desired polyols. The resulting RPU foams were characterized in terms of density, mechanical properties, conductivity and morphology. All Sarkanda lignin based polyols and the 30/70/2 Curan 27-11P polyol were found inadequate for RPU formulations. Alcell and Indulin AT based polyols and the 20/80/5 Curan 27-11P polyol resulted in RPU foams with properties very similar to those obtained from conventional commercial polyols. RPU foams produced with the 30/70/2 Alcell and the 30/70/2 Indulin AT polyols exhibited improved properties compared with those from 20/80/5 based formulations.

Multifunctional cationic polyurethanes designed for non-viral cancer gene therapy.

PubMed

Cheng, Jian; Tang, Xin; Zhao, Jie; Shi, Ting; Zhao, Peng; Lin, Chao

2016-01-01

Nano-polyplexes from bioreducible cationic polymers have a massive promise for cancer gene therapy. However, the feasibility of cationic polyurethanes for non-viral gene therapy is so far not well studied. In this work, a linear cationic polyurethane containing disulfide bonds, urethane linkages and protonable tertiary amino groups was successfully generated by stepwise polycondensation reaction between 2,2'-dithiodiethanol bis(p-nitrophenyl carbonate) and 1,4-bis(3-aminopropyl)piperazine (BAP). We confirmed that the cationic polyurethane (denoted as PUBAP) displayed superior gene delivery properties to its cationic polyamide analogue, thus causing higher in vitro transfection efficiency in MCF-7 and SKOV-3 cells. Besides, further folate-PEGylation and hydrophobic deoxycholic acid (DCA) conjugation to amino-containing PUBAP can be conducted to afford multifunctional polyurethane gene delivery system. After optimization, folate-decorated nano-polyplexes from the PUBAP conjugated with 8 folate-PEG chains and 12 DCA residues exhibited superb colloidal stability under physiological conditions, and performed rapid uptake via folate receptor-mediated endocytosis, efficient intracellular gene release and nucleus translocation into SKOV-3 cells in vitro and in vivo. Importantly, PUBAP based polyplexes possess low cytotoxicity as a result of PUBAP biodegradability. Therefore, marked growth inhibition of SKOV-3 tumor xenografted in Balb/c nude mice was achieved with negligible side effects on the mouse health after intravenous administration of PUBAP based polyplexes with a therapeutic plasmid encoding for TNF-related apoptosis-inducing ligand. This work provides a new insight into biomedical application of bio-responsive polyurethanes for cancer therapy. In this study, we have confirmed that disulfide-based cationic polyurethane presents a new non-viral vector for gene transfer and cancer gene therapy. The significance of this work includes: (1) design and synthesis of a

Polyesters from microorganisms.

PubMed

Kim, Y B; Lenz, R W

2001-01-01

Bacterial polyesters have been found to have useful properties for applications as thermoplastics, elastomers, and adhesives and are biodegradable and biocompatible. Poly(3-hydroxyalkanoates) (PHAs) and poly(beta-malate) are the most representative polyesters synthesized by microorganisms. PHAs containing a wide variety of repeating units can be produced by bacteria, including those containing many types of pendant functional groups which can be synthesized by microorganisms that are grown on unnatural organic substrates. Poly(beta-malate) is of interest primarily for medical applications, especially for drug delivery systems. In this chapter, the bacterial production and properties of poly(3-hydroxyalkanoates) and poly(beta-malate) are described with emphasis on the former.

Indirect three-dimensional printing: A method for fabricating polyurethane-urea based cardiac scaffolds.

PubMed

Hernández-Córdova, R; Mathew, D A; Balint, R; Carrillo-Escalante, H J; Cervantes-Uc, J M; Hidalgo-Bastida, L A; Hernández-Sánchez, F

2016-08-01

Biomaterial scaffolds are a key part of cardiac tissue engineering therapies. The group has recently synthesized a novel polycaprolactone based polyurethane-urea copolymer that showed improved mechanical properties compared with its previously published counterparts. The aim of this study was to explore whether indirect three-dimensional (3D) printing could provide a means to fabricate this novel, biodegradable polymer into a scaffold suitable for cardiac tissue engineering. Indirect 3D printing was carried out through printing water dissolvable poly(vinyl alcohol) porogens in three different sizes based on a wood-stack model, into which a polyurethane-urea solution was pressure injected. The porogens were removed, leading to soft polyurethane-urea scaffolds with regular tubular pores. The scaffolds were characterized for their compressive and tensile mechanical behavior; and their degradation was monitored for 12 months under simulated physiological conditions. Their compatibility with cardiac myocytes and performance in novel cardiac engineering-related techniques, such as aggregate seeding and bi-directional perfusion, was also assessed. The scaffolds were found to have mechanical properties similar to cardiac tissue, and good biocompatibility with cardiac myocytes. Furthermore, the incorporated cells preserved their phenotype with no signs of de-differentiation. The constructs worked well in perfusion experiments, showing enhanced seeding efficiency. © 2016 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 104A: 1912-1921, 2016. © 2016 Wiley Periodicals, Inc.

Temperature- and pH-responsive nanoparticles of biocompatible polyurethanes for doxorubicin delivery.

PubMed

Wang, Anning; Gao, Hui; Sun, Yanfang; Sun, Yu-long; Yang, Ying-Wei; Wu, Guolin; Wang, Yinong; Fan, Yunge; Ma, Jianbiao

2013-01-30

A series of temperature- and pH-responsive polyurethanes based on hexamethylene diisocyanate (HDI) and 4,4'-diphenylmethane diisocyanate (MDI) were synthesized by a coupling reaction with bis-1,4-(hydroxyethyl) piperazine (HEP), N-methyldiethanolamine (MDEA) and N-butyldiethanolamine (BDEA), respectively. The chemical structure, molecular weight, thermal property and crystallization properties were characterized by Fourier transform infrared (FT-IR) spectroscopy, nuclear magnetic resonance (NMR) spectroscopy, gel permeation chromatography (GPC), differential scanning calorimetry (DSC) and X-ray diffraction (XRD) spectroscopy. The resulting polyurethanes were then used to prepare nanoparticles either by direct dispersion method or dialysis method. Their pH and temperature responsibilities were evaluated by optical transmittance and size measurement in aqueous media. Interestingly, HDI-based and MDI-based polyurethanes exhibited different pH and temperature responsive properties. Nanoparticles based on HDI-HEP and HDI-MDEA were temperature-responsive, while MDI-based biomaterials were not. All of them showed pH-sensitive behavior. The possible responsive mechanism was investigated by (1)H NMR spectroscopy. The cytotoxicity of the polyurethanes was evaluated using methylthiazoletetrazolium (MTT) assay in vitro. It was shown that the HDI-based polyurethanes were non-toxic, and could be applied to doxorubicin (DOX) encapsulation. The experimental results indicated that DOX could be efficiently encapsulated into polyurethane nanoparticles and uptaken by Huh-7 cells. The loaded DOX molecules could be released from the drug-loaded polyurethane nanoparticles upon pH and temperature changes, responsively. Copyright © 2012 Elsevier B.V. All rights reserved.

Polyurethane-covered mammary implants: a 12-year experience.

PubMed

Gasperoni, C; Salgarello, M; Gargani, G

1992-10-01

Polyurethane-covered mammary implants are the implants of choice in aesthetic and reconstructive mammary surgery. These implants give very good results in regard to breast contour and consistency, and have a very low complication rate. We present our 12-year experience using polyurethane-covered prostheses. We place the implant mostly in the subglandular or subcutaneous site, and their capsular contracture rate is extremely low (3.3%). Based on our experience, we also review the other complications and side effects occurring with polyurethane prostheses and discuss them in detail.

Development of high-performance biodegradable rigid polyurethane foams using all bioresource-based polyols: Lignin and soy oil-derived polyols.

PubMed

Luo, Xiaogang; Xiao, Yuqin; Wu, Qiangxian; Zeng, Jian

2018-04-25

Development of biodegradable polyurethane materials is the most promising in the wider context of the "greening" of industrial chemistry. To tackle this challenge, a novel biodegradable polyurethane foam from all bioresource-based polyols (lignin and soy oil-derived polyols) and polymeric methyldiphenyl diisocyanate (pMDI) have been synthesized via a one-pot and self-rising process. All these foam samples have the internal cellular morphology and microstructure. FTIR result exhibits characteristic peaks of polyurethane, and indicates covalent bonds between soy-based polyurethane and lignin, and the lignin powders can react with pMDI via active -H and -CNO. In addition, hydrogen bonding also plays an important role in forming the 3D structures. These interactions and chemical bonds made the prepared foam samples form the 3D macromolecular structure with improved mechanical, thermal, and biodegradable properties. The reaction process is time-saving and cost-effective as it requires no blowing agent and minimum processing steps, while exploring the potential of using the higher content of nature bioresource constituents. Copyright © 2018 Elsevier B.V. All rights reserved.

40 CFR 721.10213 - Polyether polyester copolymer phosphate (generic).

Code of Federal Regulations, 2011 CFR

2011-07-01

... 40 Protection of Environment 31 2011-07-01 2011-07-01 false Polyether polyester copolymer... Specific Chemical Substances § 721.10213 Polyether polyester copolymer phosphate (generic). (a) Chemical... as polyether polyester copolymer phosphate (PMN P-09-253) is subject to reporting under this section...

Biocompatible epoxy modified bio-based polyurethane nanocomposites: mechanical property, cytotoxicity and biodegradation.

PubMed

Dutta, Suvangshu; Karak, Niranjan; Saikia, Jyoti Prasad; Konwar, Bolin Kumar

2009-12-01

Epoxy modified Mesua ferrea L. seed oil (MFLSO) based polyurethane nanocomposites with different weight % of clay loadings (1%, 2.5% and 5%) have been evaluated as biocompatible materials. The nanocomposites were prepared by ex situ solution technique under high mechanical shearing and ultrasonication at room temperature. The partially exfoliated nanocomposites were characterized by Fourier transform infra-red (FTIR), X-ray diffraction (XRD), scanning electron microscopy (SEM) and transmission electron microscopy (TEM) techniques. The mechanical properties such as tensile strength and scratch hardness were improved 2 and 5 times, respectively by nanocomposites formation. Even the impact resistance improved a little. The thermostability of the nanocomposites was enhanced by about 40 degrees C. Biodegradation study confirmed 5-10 fold increase in biodegradation rate for the nanocomposites compared to the pristine polymers. All the nanocomposites showed non-cytotoxicity as evident from RBC hemolysis inhibition observed in anti-hemolytic assay carried over the sterilized films. The study reveals that the epoxy modified MFLSO based polyurethane nanocomposites deserve the potential to be applicable as biomaterials.

One-Pot Conversion of Epoxidized Soybean Oil (ESO) into Soy-Based Polyurethanes by MoCl₂O₂ Catalysis.

PubMed

Pantone, Vincenzo; Annese, Cosimo; Fusco, Caterina; Fini, Paola; Nacci, Angelo; Russo, Antonella; D'Accolti, Lucia

2017-02-21

An innovative and eco-friendly one-pot synthesis of bio-based polyurethanes is proposed via the epoxy-ring opening of epoxidized soybean oil (ESO) with methanol, followed by the reaction of methoxy bio-polyols intermediates with 2,6-tolyl-diisocyanate (TDI). Both synthetic steps, methanolysis and polyurethane linkage formation, are promoted by a unique catalyst, molybdenum(VI) dichloride dioxide (MoCl₂O₂), which makes this procedure an efficient, cost-effective, and environmentally safer method amenable to industrial scale-up.

Fiber Reinforced Polyester Resins Polymerized by Microwave Source

NASA Astrophysics Data System (ADS)

Visco, A. M.; Calabrese, L.; Cianciafara, P.; Bonaccorsi, L.; Proverbio, E.

2007-12-01

Polyester resin based composite materials are widely used in the manufacture of fiberglass boats. Production time of fiberglass laminate components could be strongly reduced by using an intense energy source as well as microwaves. In this work a polyester resin was used with 2% by weight of catalyst and reinforced with chopped or woven glass fabric. Pure resin and composite samples were cured by microwaves exposition for different radiation times. A three point bending test was performed on all the cured samples by using an universal testing machine and the resulting fracture surfaces were observed by means of scanning electron microscopy (SEM). The results of mechanical and microscopy analyses evidenced that microwave activation lowers curing time of the composite while good mechanical properties were retained. Microwaves exposition time is crucial for mechanical performance of the composite. It was evidenced that short exposition times suffice for resin activation while long exposure times cause fast cross linking and premature matrix fracture. Furthermore high-radiation times induce bubbles growth or defects nucleation within the sample, decreasing composite performance. On the basis of such results microwave curing activation of polyester resin based composites could be proposed as a valid alternative method for faster processing of laminated materials employed for large-scale applications.

Hydroxyapatite-silver nanoparticles coatings on porous polyurethane scaffold.

PubMed

Ciobanu, Gabriela; Ilisei, Simona; Luca, Constantin

2014-02-01

The present paper is focused on a study regarding the possibility of obtaining hydroxyapatite-silver nanoparticle coatings on porous polyurethane scaffold. The method applied is based on a combined strategy involving hydroxyapatite biomimetic deposition on polyurethane surface using a Supersaturated Calcification Solution (SCS), combined with silver ions reduction and in-situ crystallization processes on hydroxyapatite-polyurethane surface by sample immersing in AgNO3 solution. The morphology, composition and phase structure of the prepared samples were characterized by scanning electron microscopy coupled with energy dispersive X-ray spectroscopy (SEM-EDX), X-ray diffraction (XRD), UV-Vis spectroscopy and X-ray photoelectron spectroscopy (XPS) measurements. The data obtained show that a layer of hydroxyapatite was deposited on porous polyurethane support and the silver nanoparticles (average size 34.71 nm) were dispersed among and even on the hydroxyapatite crystals. Hydroxyapatite/polyurethane surface acts as a reducer and a stabilizing agent for silver ions. The surface plasmon resonance peak in UV-Vis absorption spectra showed an absorption maximum at 415 nm, indicating formation of silver nanoparticles. The hydroxyapatite-silver polyurethane scaffolds were tested against Staphylococcus aureus and Escherichia coli and the obtained data were indicative of good antibacterial properties of the materials. © 2013.

RHEOLOGY OF CONCENTRATED SOLUTIONS OF HYPERBRANCHED POLYESTERS

EPA Science Inventory

The solution rheology of different generations of hyperbranched polyesters in N-methyl-2- pyrrolidinone (NMP) solvent was examined in this study. The solutions exhibited Newtonian behavior over a wide range of polyester concentrations. Also, the relative viscosities of poly(amido...

21 CFR 175.260 - Partial phosphoric acid esters of polyester resins.

Code of Federal Regulations, 2011 CFR

2011-04-01

... 21 Food and Drugs 3 2011-04-01 2011-04-01 false Partial phosphoric acid esters of polyester resins... of polyester resins. Partial phosphoric acid esters of polyester resins identified in this section... prescribed conditions: (a) For the purpose of this section, partial phosphoric acid esters of polyester...

Multiwalled carbon nanotube coated polyester fabric as textile based flexible counter electrode for dye sensitized solar cell.

PubMed

Arbab, Alvira Ayoub; Sun, Kyung Chul; Sahito, Iftikhar Ali; Qadir, Muhammad Bilal; Jeong, Sung Hoon

2015-05-21

Textile wearable electronics offers the combined advantages of both electronics and textile characteristics. The essential properties of these flexible electronics such as lightweight, stretchable, and wearable power sources are in strong demand. Here, we have developed a facile route to fabricate multi walled carbon nanotube (MWCNT) coated polyester fabric as a flexible counter electrode (CE) for dye sensitized solar cells (DSSCs). A variety of MWCNT and enzymes with different structures were used to generate individual enzyme-dispersed MWCNT (E-MWCNT) suspensions by non-covalent functionalization. A highly concentrated colloidal suspension of E-MWCNT was deposited on polyester fabric via a simple tape casting method using an air drying technique. In view of the E-MWCNT coating, the surface structure is represented by topologically randomly assembled tubular graphene units. This surface morphology has a high density of colloidal edge states and oxygen-containing surface groups which execute multiple catalytic sites for iodide reduction. A highly conductive E-MWCNT coated fabric electrode with a surface resistance of 15 Ω sq(-1) demonstrated 5.69% power conversion efficiency (PCE) when used as a flexible CE for DSSCs. High photo voltaic performance of our suggested system of E-MWCNT fabric-based DSSCs is associated with high sheet conductivity, low charge transfer resistance (RCT), and excellent electro catalytic activity (ECA). Such a conductive fabric demonstrated stable conductivity against bending cycles and strong mechanical adhesion of E-MWCNT on polyester fabric. Moreover, the polyester fabric is hydrophobic and, therefore, has good sealing capacity and retains the polymer gel electrolyte without seepage. This facile E-MWCNT fabric CE configuration provides a concrete fundamental background towards the development of textile-integrated solar cells.

Blends of polyester ionomers with polar polymers: Interactions, reactions, and compatibilization

NASA Astrophysics Data System (ADS)

Boykin, Timothy Lamar

The compatibility of amorphous and semicrystalline polyester ionomers with various polar polymers (i.e., polyesters and polyamides) has been investigated for their potential use as minor component compatibilizers. The degree of compatibility (i.e., ranging from incompatible to miscible) between the polyester ionomers and the polar polymers was determined by evaluating the effect of blend composition on the melting behavior and phase behavior of binary blends. In addition, the origin of compatibility and/or incompatibility for each of the binary blends (i.e., polyamide/ionomer and polyester/ionomer) was determined by evaluating blends prepared by both solution and melt mixed methods. Subsequent to investigation of the binary blends, the effect of polyester ionomer addition on the compatibility of polyamide/polyester blends was investigated by evaluating the mechanical properties and phase morphology of ionomer compatibilized polyamide/polyester blends. Polyester ionomers (amorphous and semicrystalline) were shown to exhibit a high degree of compatibility (even miscibility) with polyamides, such as nylon 6,6 (N66). Compatibility was attributed to specific interactions between the metal counterion of the polyester ionomer and the amide groups of N66. The degree of compatibility (or miscibility) was shown to be dependent on the counterion type of the ionomer, with the highest degree exhibited by blends containing the divalent form of the polyester ionomers. Although polyester ionomers were shown to exhibit incompatibility with both poly(ethylene terephthalate) (PET) and poly(butylene terephthalate) (PBT), increasing the time of melt processing significantly enhanced the compatibility of the polyester ionomers with both PET and PBT. The observed enhancement in compatibility was attributed to ester-ester interchange between the polyester blend components, which was confirmed by NMR spectroscopy. The addition of polyester ionomers as a minor component compatibilizer (i

Thermoplastic polyurethanes with controlled morphology based on methylenediphenyldiisocyanate/isosorbide/butanediol hard segments: Thermoplastic polyurethanes with controlled morphology

DOE Office of Scientific and Technical Information (OSTI.GOV)

Javni, Ivan; Bilić, Olivera; Bilić, Nikola

2015-06-30

Isosorbide, a cyclic, rigid and renewable diol was used as a chain extender in two series of thermoplastic polyurethanes. Isosorbide was used in combination with butane diol or alone to examine the effects on polyurethane morphology. Two series of materials were prepared -one with dispersed hard domains in the matrix of polytetramethylene ether glycol soft segments of molecular weight 1400 (at 70% soft segment concentration-SSC) and the other with co-continuous soft and hard phases at 50% SSC. Morphology of materials was studied by optical and atomic force microscopy, as well as with ultra small angle x-ray scattering (USAXS). The radiusmore » of spherical hard domains, correlation lengths, mean separation distances and boundary layer thickness were measured as a function of isosorbide content.« less

Polyurethane membranes for surgical gown applications

NASA Astrophysics Data System (ADS)

Ukpabi, Pauline Ozoemena

The Occupational Safety and Health Administration (OSHA) recently issued a directive requiring all employers to supply personnel protective equipment to employees who are at risk of exposure to blood or other potentially infectious body fluids. For the healthcare worker, a wide variety of surgical gowns is available commercially but there are concerns over their barrier effectiveness and/or wearer comfort. To successfully create a barrier fabric which combines resistance to fluid penetration with comfort, a complete understanding of the relationship between membrane structure and functional properties is required. In this study, we investigated the surface properties of hydrophilicity and hydrophobicity in polyurethane membranes intended for use in surgical gowns. The polyurethane membranes were grafted with side chains of varying lengths, polyethylene glycol (PEG) being used for the hydrophilic modifications and perfluoroalkyl compounds (a monofunctional acid and a difunctional amino alcohol) for the hydrophobic modifications. The hydrophilic treatment was intended to improve the comfort properties of monolithic membranes without adversely affecting their barrier properties. The hydrophobic treatment, on the other hand, was intended to improve the fluid repellency and hence barrier properties of microporous membranes without adversely affecting their comfort properties. Reflection infrared spectroscopy showed that fluorine was successfully grafted onto the polyurethane backbone during the hydrophobic modification, but was not sensitive enough to detect PEG grafting in leached polyethylene glycol-treated polyurethanes. X-ray photoelectron spectroscopy showed that the perfluoroalkylated polyurethanes contained up to 40% fluorine on their surfaces and the PEG-treated polyurethanes showed an increase in their C-O content over the unmodified polyurethane. Scanning electron microscopy not only showed that perfluoroalkylation yielded polyurethane membranes with very

Modification of HTPB-based polyurethane with temperature-sensitive poly(N-isopropyl acrylamide) for biomaterial usage.

PubMed

Yang, Jen Ming; Yang, Shu Jyuan; Lin, Hao Tzu; Chen, Jan Kan

2007-01-01

Hydroxyl-terminated polybutadiene (HTPB)-based polyurethane with dimethyol propionic acid (DPA) as chain extender was synthesized by solution polymerization. The HTPB-based polyurethane was modified by UV radiation with N-isopropyl acrylamide monomer to get poly(N-isopropyl acrylamide)-modified polyurethane (PUDPANIPAAm). The cohesive energy (E(coh)), molar volume (V), solubility parameter (delta), molecular weight (W(M)), volume per gram (V(g)), and the density (1/V(g)) of PUDPANIPAAm were calculated by group contribution methods. To evaluate the application of PUDPANIPAAm for wound dressing and transplantation of cell sheet, the measurement of water content, water vapor transmission rate, and gas permeation on the PUDPANIPAAm membrane was evaluated. The biocompatibility of these membranes, cell adhesion, and proliferation assay were conducted in the cell culture. The effect of thermosensitivity of poly(N-isopropyl acrylamide) on cell detachment was also evaluated in the primary study. The results showed that these PUDPANIPAAm membranes are thermosensitive. The modification of PU with poly(N-isopropyl acrylamide) reduced the water vapor transmission rate and permeability of gas through PUDPANIPAAm membrane. PUDPANIPAAm membranes could support cell adhesion and growth. Owing to the thermosensitive nature of poly(N-isopropyl acrylamide), the relative cell numbers detached from PUDPANIPAAm membranes were larger than those detached from the polystyrene dish. 2006 Wiley Periodicals, Inc.

Development of novel biocompatible hybrid nanocomposites based on polyurethane-silica prepared by sol gel process.

PubMed

Rashti, Ali; Yahyaei, Hossein; Firoozi, Saman; Ramezani, Sara; Rahiminejad, Ali; Karimi, Roya; Farzaneh, Khadijeh; Mohseni, Mohsen; Ghanbari, Hossein

2016-12-01

Due to high biocompatibility, polyurethane has found many applications, particularly in development of biomedical devices. A new nanocomposite based on thermoset polyurethane and silica nanoparticles was synthesized using sol-gel method. Sol-gel process was fulfilled in two acidic and basic conditions by using tetraethylorthosilicate (TEOS) and trimethoxyisocyanatesilane as precursors. The hybrid films characterized for mechanical and surface properties using tensile strength, contact angle, ATR-FTIR and scanning electron microscopy. Biocompatibility and cytotoxicity of the hybrids were assessed using standard MTT, LDH and TUNEL assays. The results revealed that incorporation of silica nanoparticles was significantly improved tensile strength and mechanical properties of the hybrids. Based on the contact angle results, silica nanoparticles increased hydrophilicity of the hybrids. Biocompatibility by using human lung epithelial cell line (MRC-5) demonstrated that the hybrids were significantly less cytotoxic compared to pristine polymer as tested by MTT and LDH assays. TUNEL assay revealed no signs of apoptosis in all tested samples. The results of this study demonstrated that incorporation of silica nanoparticles into polyurethane lead to the enhancement of biocompatibility, indicating that these hybrids could potentially be used in biomedical field in particular as a new coating for medical implants. Copyright © 2016 Elsevier B.V. All rights reserved.

Microfabricated polyester conical microwells for cell culture applications†

PubMed Central

Selimović, Šeila; Piraino, Francesco; Bae, Hojae; Rasponi, Marco; Redaelli, Alberto

2012-01-01

Over the past few years there has been a great deal of interest in reducing experimental systems to a lab-on-a-chip scale. There has been particular interest in conducting high-throughput screening studies using microscale devices, for example in stem cell research. Microwells have emerged as the structure of choice for such tests. Most manufacturing approaches for microwell fabrication are based on photolithography, soft lithography, and etching. However, some of these approaches require extensive equipment, lengthy fabrication process, and modifications to the existing microwell patterns are costly. Here we show a convenient, fast, and low-cost method for fabricating microwells for cell culture applications by laser ablation of a polyester film coated with silicone glue. Microwell diameter was controlled by adjusting the laser power and speed, and the well depth by stacking several layers of film. By using this setup, a device containing hundreds of microwells can be fabricated in a few minutes to analyze cell behavior. Murine embryonic stem cells and human hepatoblastoma cells were seeded in polyester microwells of different sizes and showed that after 9 days in culture cell aggregates were formed without a noticeable deleterious effect of the polyester film and glue. These results show that the polyester microwell platform may be useful for cell culture applications. The ease of fabrication adds to the appeal of this device as minimal technological skill and equipment is required. PMID:21614380

Development of polyurethanes for bone repair.

PubMed

Marzec, M; Kucińska-Lipka, J; Kalaszczyńska, I; Janik, H

2017-11-01

The purpose of this paper is to review recent developments on polyurethanes aimed at the design, synthesis, modifications, and biological properties in the field of bone tissue engineering. Different polyurethane systems are presented and discussed in terms of biodegradation, biocompatibility and bioactivity. A comprehensive discussion is provided of the influence of hard to soft segments ratio, catalysts, stiffness and hydrophilicity of polyurethanes. Interaction with various cells, behavior in vivo and current strategies in enhancing bioactivity of polyurethanes are described. The discussion on the incorporation of biomolecules and growth factors, surface modifications, and obtaining polyurethane-ceramics composites strategies is held. The main emphasis is placed on the progress of polyurethane applications in bone regeneration, including bone void fillers, shape memory scaffolds, and drug carrier. Copyright © 2017 Elsevier B.V. All rights reserved.

Development of electroactive nanofibers based on thermoplastic polyurethane and poly(o-ethoxyaniline) for biological applications.

PubMed

Cruz, Karina Ferreira Noronha; Formaggio, Daniela Maria Ducatti; Tada, Dayane Batista; Cristovan, Fernando Henrique; Guerrini, Lilia Müller

2017-02-01

Electroactive nanofibers based on thermoplastic polyurethane (TPU) and poly(alkoxy anilines) produced by electrospinning has been explored for biomaterials applications. The thermoplastic polyurethane is a biocompatible polymer with good mechanical properties. The production of TPU nanofibers requires the application of high voltage during electrospinning in order to prepare uniform mats due to its weak ability to elongate during the process. To overcome this limitation, a conductive polymer can be incorporated to the process, allowing generates mats without defects. In this study, poly(o-ethoxyaniline) POEA doped with dodecylbenzene sulfonic acid (DBSA) was blended with thermoplastic polyurethane (TPU) by solution method. Films were produced by casting and nanofibers were prepared by electrospinning. The effect of the POEA on morphology, distribution of diameter and cell viability of the nanofibers was evaluated. The results demonstrated that the incorporation of POEA in TPU provided to the mats a suitable morphology for cellular growth. © 2016 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 105A: 601-607, 2017. © 2016 Wiley Periodicals, Inc.

100% Solids Polyurethane Sequestration Coating

DTIC Science & Technology

2014-04-11

Distribution Unlimited 100% Solids Polyurethane Sequestration Coating The views, opinions and/or findings contained in this report are those of the...Papers published in non peer-reviewed journals: 100% Solids Polyurethane Sequestration Coating Report Title Report developed under Topic #CBD13-101...Final Technical Report Contract #: W911NF-13-P-0010 Proposal #: 63958CHSB1 Project: 100% Solids Polyurethane Sequestration Coating

Microbial degradation of aliphatic and aliphatic-aromatic co-polyesters.

PubMed

Shah, Aamer Ali; Kato, Satoshi; Shintani, Noboru; Kamini, Numbi Ramudu; Nakajima-Kambe, Toshiaki

2014-04-01

Biodegradable plastics (BPs) have attracted much attention since more than a decade because they can easily be degraded by microorganisms in the environment. The development of aliphatic-aromatic co-polyesters has combined excellent mechanical properties with biodegradability and an ideal replacement for the conventional nondegradable thermoplastics. The microorganisms degrading these polyesters are widely distributed in various environments. Although various aliphatic, aromatic, and aliphatic-aromatic co-polyester-degrading microorganisms and their enzymes have been studied and characterized, there are still many groups of microorganisms and enzymes with varying properties awaiting various applications. In this review, we have reported some new microorganisms and their enzymes which could degrade various aliphatic, aromatic, as well as aliphatic-aromatic co-polyesters like poly(butylene succinate) (PBS), poly(butylene succinate)-co-(butylene adipate) (PBSA), poly(ε-caprolactone) (PCL), poly(ethylene succinate) (PES), poly(L-lactic acid) (PLA), poly(3-hydroxybutyrate) and poly(3-hydoxybutyrate-co-3-hydroxyvalterate) (PHB/PHBV), poly(ethylene terephthalate) (PET), poly(butylene terephthalate) (PBT), poly(butylene adipate-co-terephthalate (PBAT), poly(butylene succinate-co-terephthalate) (PBST), and poly(butylene succinate/terephthalate/isophthalate)-co-(lactate) (PBSTIL). The mechanism of degradation of aliphatic as well as aliphatic-aromatic co-polyesters has also been discussed. The degradation ability of microorganisms against various polyesters might be useful for the treatment and recycling of biodegradable wastes or bioremediation of the polyester-contaminated environments.

Comparison of clinical explants and accelerated hydrolytic aging to improve biostability assessment of silicone-based polyurethanes.

PubMed

Cosgriff-Hernandez, Elizabeth; Tkatchouk, Ekaterina; Touchet, Tyler; Sears, Nick; Kishan, Alysha; Jenney, Christopher; Padsalgikar, Ajay D; Chen, Emily

2016-07-01

Although silicone-based polyurethanes have demonstrated increased oxidative stability, there have been conflicting reports of the long-term hydrolytic stability of Optim™ and PurSil(®) 35 based on recent temperature-accelerated hydrolysis studies. The goal of the current study was to identify in vitro-in vivo correlations to determine the relevance of this accelerated in vitro model for predicting clinical outcomes. Temperature-accelerated hydrolytic aging of three commonly used cardiac lead insulation materials, Optim™, Elasthane™ 55D, Elasthane™ 80A, and a related silicone-polyurethane, PurSil(®) 35, was performed. After 1 year at 85°C, similar losses in Mn and Mz were observed for the poly(ether urethanes), but an increase in Mz loss as compared to Mn loss was observed for the silicone-based polyurethanes. A similar trend of increased Mz loss as compared to Mn loss was observed in explanted Optim™ leads after 2-3 years; however, no statistically significant Mn loss was detected between 2-3 and 7-8 years of implantation. Given this preferential loss of high molecular weight chains, it was hypothesized that the observed differences between the polyurethanes were due to allophanate dissociation rather than backbone chain scission. Following full dissociation of the small percentage of allophanates in vivo, the observed molecular weight stability and proven clinical performance of Optim™ was attributed to the well-documented stability of the urethane bond under physiological conditions. This allophanate dissociation reaction is incompatible with the first order mechanism proposed in previous temperature-accelerated hydrolysis studies and may be the reason for the model's inaccurate prediction of significant and progressive molecular weight loss in vivo. © 2016 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 104A: 1805-1816, 2016. © 2016 Wiley Periodicals, Inc.

Synthesis and wound healing of alternating block polyurethanes based on poly(lactic acid) (PLA) and poly(ethylene glycol) (PEG).

PubMed

Li, Linjing; Liu, Xiangyu; Niu, Yuqing; Ye, Jianfu; Huang, Shuiwen; Liu, Chao; Xu, Kaitian

2017-07-01

Alternating block polyurethanes (abbreviated as PULA-alt-PEG) and random block polyurethanes (abbreviated as PULA-ran-PEG) based on biodegradable poly(lactic acid) (PLA) and poly(ethylene glycol) (PEG) were prepared. Results showed that alternating block polyurethane gives higher crystal degree, higher mechanical properties, more patterned and rougher surface than the random counterpart, due to the regular and controlled structure. Water absorptions of the polyurethanes were in the range of 620 to 780%. Cytocompatibility of the amphiphilic block polyurethanes (PU) (water static angle 41.4°-61.8°) was assessed by CCK-8 assay using human embryonic kidney (HEK293) cells. Wound healing evaluation of the PU foam scaffolds was carried out by full-thickness SD rat model experiment, with medical gauze as control. It was found that the skin of rat in PU groups was fully covered with new epithelium without any significant adverse reactions and PU dressings give much rapid and better healing than medical gauze. Histological examination revealed that PU dressings suppress the infiltration of inflammatory cells and accelerate fibroblast proliferation. It was also demonstrated that PULA-alt-PEG exhibits obvious better healing effect than PULA-ran-PEG does. This study has demonstrated that without further modification, plain alternating block polyurethane scaffold would help wound recovery efficiently. © 2016 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 105B: 1200-1209, 2017. © 2016 Wiley Periodicals, Inc.

21 CFR 177.2420 - Polyester resins, cross-linked.

Code of Federal Regulations, 2014 CFR

2014-04-01

... following prescribed conditions: (a) The cross-linked polyester resins are produced by the condensation of... fiber Polyester fiber produced by the condensation of one or more of the acids listed in paragraph (a)(1...

Studies on thermo-mechanical properties of chemically treated jute-polyester composite

NASA Astrophysics Data System (ADS)

Chaudhari, Vikas; Chandekar, Harichandra; Saboo, Jayesh; Mascarenhas, Adlete

2018-03-01

The effect of chemical treatments on jute-polyester composites is studied in this paper. The jute fabrics are chemically treated with NaOH and benzoyl chloride and its tensile and visco-elastic properties are compared with untreated jute composite. The NaOH treated jute-polyester composite show superior tensile strength and modulus compared to other jute-polyester composites. The glass transition temperature obtained from DMA shift to higher temperature for composites in comparison to polyester resin, this is due to restriction of mobility in chains due to introduction of jute reinforcement. The DMA results also show favourable results towards NaOH treatment i.e. higher storage modulus and lower tan δ values relative to untreated jute-polyester composite. The benzoyl treated jute-polyester composite however do not show promising results which may be attributed to the fact that the adhesion properties associated with similar ester functional groups in the benzoyl treated jute fabric and polyester resin were not obtained.

21 CFR 177.2420 - Polyester resins, cross-linked.

Code of Federal Regulations, 2013 CFR

2013-04-01

... polyester resins are produced by the condensation of one or more of the acids listed in paragraph (a)(1) of.... Reinforcements: Asbestos Glass fiber Polyester fiber produced by the condensation of one or more of the acids...

21 CFR 177.2420 - Polyester resins, cross-linked.

Code of Federal Regulations, 2012 CFR

2012-04-01

... polyester resins are produced by the condensation of one or more of the acids listed in paragraph (a)(1) of.... Reinforcements: Asbestos Glass fiber Polyester fiber produced by the condensation of one or more of the acids...

40 CFR 721.8095 - Silylated polyurethane.

Code of Federal Regulations, 2010 CFR

2010-07-01

... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Silylated polyurethane. 721.8095... Substances § 721.8095 Silylated polyurethane. (a) Chemical substance and significant new uses subject to reporting. (1) The chemical substance identified generically as a silylated polyurethane (PMN P-95-1356) is...

40 CFR 721.8090 - Polyurethane polymer.

Code of Federal Regulations, 2010 CFR

2010-07-01

... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Polyurethane polymer. 721.8090 Section... Substances § 721.8090 Polyurethane polymer. (a) Chemical substance and significant new uses subject to reporting. (1) The chemical substance identified generically as a polyurethane polymer (P-94-47) is subject...

40 CFR 721.8090 - Polyurethane polymer.

Code of Federal Regulations, 2011 CFR

2011-07-01

... 40 Protection of Environment 31 2011-07-01 2011-07-01 false Polyurethane polymer. 721.8090 Section... Substances § 721.8090 Polyurethane polymer. (a) Chemical substance and significant new uses subject to reporting. (1) The chemical substance identified generically as a polyurethane polymer (P-94-47) is subject...

40 CFR 721.8090 - Polyurethane polymer.

Code of Federal Regulations, 2012 CFR

2012-07-01

... 40 Protection of Environment 32 2012-07-01 2012-07-01 false Polyurethane polymer. 721.8090 Section... Substances § 721.8090 Polyurethane polymer. (a) Chemical substance and significant new uses subject to reporting. (1) The chemical substance identified generically as a polyurethane polymer (P-94-47) is subject...

40 CFR 721.8090 - Polyurethane polymer.

Code of Federal Regulations, 2013 CFR

2013-07-01

... 40 Protection of Environment 32 2013-07-01 2013-07-01 false Polyurethane polymer. 721.8090 Section... Substances § 721.8090 Polyurethane polymer. (a) Chemical substance and significant new uses subject to reporting. (1) The chemical substance identified generically as a polyurethane polymer (P-94-47) is subject...

40 CFR 721.8090 - Polyurethane polymer.

Code of Federal Regulations, 2014 CFR

2014-07-01

... 40 Protection of Environment 31 2014-07-01 2014-07-01 false Polyurethane polymer. 721.8090 Section... Substances § 721.8090 Polyurethane polymer. (a) Chemical substance and significant new uses subject to reporting. (1) The chemical substance identified generically as a polyurethane polymer (P-94-47) is subject...

Bio-based hyperbranched thermosetting polyurethane/triethanolamine functionalized multi-walled carbon nanotube nanocomposites as shape memory materials.

PubMed

Kalita, Hemjyoti; Karak, Niranjan

2014-07-01

Here, bio-based shape memory polymers have generated immense interest in recent times. Here, Bio-based hyperbranched polyurethane/triethanolamine functionalized multi-walled carbon nanotube (TEA-f-MWCNT) nanocomposites were prepared by in-situ pre-polymerization technique. The Fourier transform infrared spectroscopy and the transmission electron microscopic studies showed the strong interfacial adhesion and the homogeneous distribution of TEA-f-MWCNT in the polyurethane matrix. The prepared epoxy cured thermosetting nanocomposites exhibited enhanced tensile strength (6.5-34.5 MPa), scratch hardness (3.0-7.5 kg) and thermal stability (241-288 degrees C). The nanocomposites showed excellent shape fixity and shape recovery. The shape recovery time decreases (24-10 s) with the increase of TEA-f-MWCNT content in the nanocomposites. Thus the studied nanocomposites have potential to be used as advanced shape memory materials.

Polyurethane Filler for Electroplating

NASA Technical Reports Server (NTRS)

Beasley, J. L.

1984-01-01

Polyurethane foam proves suitable as filler for slots in parts electroplated with copper or nickel. Polyurethane causes less contamination of plating bath and of cleaning and filtering tanks than wax fillers used previously. Direct cost of maintenance and indirect cost of reduced operating time during tank cleaning also reduced.

In vitro analysis of polyurethane foam as a topical hemostatic agent.

PubMed

Broekema, Ferdinand I; van Oeveren, Wim; Zuidema, Johan; Visscher, Susan H; Bos, Rudolf R M

2011-04-01

Topical hemostatic agents can be used to treat problematic bleedings in patients who undergo surgery. Widely used are the collagen- and gelatin-based hemostats. This study aimed to develop a fully synthetic, biodegradable hemostatic agent to avoid exposure to animal antigens. In this in vitro study the suitability of different newly developed polyurethane-based foams as a hemostatic agent has been evaluated and compared to commonly used agents. An experimental in vitro test model was used in which human blood flowed through the test material. Different modified polyurethane foams were compared to collagen and gelatin. The best coagulation was achieved with collagen. The results of the polyurethane foam improved significantly by increasing the amount of polyethylene glycol. Therefore, the increase of the PEG concentration seems a promising approach. Additional in vivo studies will have to be implemented to assess the application of polyurethane foam as a topical hemostatic agent.

Study on moisture absorption and sweat discharge of honeycomb polyester fiber

NASA Astrophysics Data System (ADS)

Feng, Aifen; Zhang, Yongjiu

2015-07-01

The moisture absorption and liberation properties of honeycomb polyester fiber were studied in order to understand its moisture absorption and sweat discharge. Through testing moisture absorption and liberation regains of honeycomb polyester fiber and normal polyester fiber in standard atmospheric conditions, their moisture absorption and liberation curves were depicted, and the regression equations of moisture regains to time during their reaching the balance of moisture absorption and moisture liberation were obtained according to the curves. Their moisture absorption and liberation rate curves were analyzed and the regression equations of the rates to time were obtained. The results shows that the moisture regain of honeycomb polyester fiber is much bigger than the normal polyester fiber's, and the initial moisture absorption and moisture liberation rates of the former are much higher than the latter's, so that the moisture absorbance and sweat discharge of honeycomb polyester fiber are excellent.

Mechanical Properties of Unsaturated Polyester / Montmorillonite Composites

DTIC Science & Technology

2001-11-01

Montmorillonite Composites DISTRIBUTION: Approved for public release, distribution unlimited This paper is part of the following report: TITLE: Nanophase and...Mechanical Properties of Unsaturated Polyester / Montmorillonite Composites A. Baran Inceoglu and Ulku Yilmazer Middle East Technical University, Chemical...analysed the nature of the curing agent on structure. Kornmann, Berglund and Giannelis [8] studied nanocomposites based on montmorillonite modified

A facile fabrication of multifunctional knit polyester fabric based on chitosan and polyaniline polymer nanocomposite

NASA Astrophysics Data System (ADS)

Tang, Xiaoning; Tian, Mingwei; Qu, Lijun; Zhu, Shifeng; Guo, Xiaoqing; Han, Guangting; Sun, Kaikai; Hu, Xili; Wang, Yujiao; Xu, Xiaoqi

2014-10-01

Knit polyester fabric was successively modified and decorated with chitosan layer and polyaniline polymer nanocomposite layer in this paper. The fabric was firstly treated with chitosan to form a stable layer through the pad-dry-cure process, and then the polyaniline polymer nanocomposite layer was established on the outer layer by in situ chemical polymerization method using ammonium persulfate as oxidant and chlorhydric acid as dopant. The surface morphology of coated fabric was characterized by scanning electron microscopy (SEM), and the co-existence of chitosan layer and granular polyaniline polymer nanocomposite was confirmed and well dispersed on the fabric surface. The resultant fabric was endowed with remarkable electrical conductivity properties and efficient water-repellent capability, which also have been found stable after water laundering. In addition, the photocatalytic decomposition activity for reactive red dye was observed when the multifunctional knit polyester fabric was exposed to the illumination of ultraviolet lamp. These results indicated that chitosan and polyaniline polymer nanocomposite could form ideal multifunctional coatings on the surface of knit polyester fabric.

Graded porous polyurethane foam: a potential scaffold for oro-maxillary bone regeneration.

PubMed

Giannitelli, S M; Basoli, F; Mozetic, P; Piva, P; Bartuli, F N; Luciani, F; Arcuri, C; Trombetta, M; Rainer, A; Licoccia, S

2015-06-01

Bone tissue engineering applications demand for biomaterials offering a substrate for cell adhesion, migration, and proliferation, while inferring suitable mechanical properties to the construct. In the present study, polyurethane (PU) foams were synthesized to develop a graded porous material-characterized by a dense shell and a porous core-for the treatment of oro-maxillary bone defects. Foam was synthesized via a one-pot reaction starting from a polyisocyanate and a biocompatible polyester diol, using water as a foaming agent. Different foaming conditions were examined, with the aim of creating a dense/porous functional graded material that would perform at the same time as an osteoconductive scaffold for bone defect regeneration and as a membrane-barrier to gingival tissue ingrowth. The obtained PU was characterized in terms of morphological and mechanical properties. Biocompatibility assessment was performed in combination with bone-marrow-derived human mesenchymal stromal cells (hBMSCs). Our findings confirm that the material is potentially suitable for guided bone regeneration applications. Copyright © 2015 Elsevier B.V. All rights reserved.

Developing photoreceptor-based models of visual attraction in riverine tsetse, for use in the engineering of more-attractive polyester fabrics for control devices.

PubMed

Santer, Roger D

2017-03-01

Riverine tsetse transmit the parasites that cause the most prevalent form of human African trypanosomiasis, Gambian HAT. In response to the imperative for cheap and efficient tsetse control, insecticide-treated 'tiny targets' have been developed through refinement of tsetse attractants based on blue fabric panels. However, modern blue polyesters used for this purpose attract many less tsetse than traditional phthalogen blue cottons. Therefore, colour engineering polyesters for improved attractiveness has great potential for tiny target development. Because flies have markedly different photoreceptor spectral sensitivities from humans, and the responses of these photoreceptors provide the inputs to their visually guided behaviours, it is essential that polyester colour engineering be guided by fly photoreceptor-based explanations of tsetse attraction. To this end, tsetse attraction to differently coloured fabrics was recently modelled using the calculated excitations elicited in a generic set of fly photoreceptors as predictors. However, electrophysiological data from tsetse indicate the potential for modified spectral sensitivities versus the generic pattern, and processing of fly photoreceptor responses within segregated achromatic and chromatic channels has long been hypothesised. Thus, I constructed photoreceptor-based models explaining the attraction of G. f. fuscipes to differently coloured tiny targets recorded in a previously published investigation, under differing assumptions about tsetse spectral sensitivities and organisation of visual processing. Models separating photoreceptor responses into achromatic and chromatic channels explained attraction better than earlier models combining weighted photoreceptor responses in a single mechanism, regardless of the spectral sensitivities assumed. However, common principles for fabric colour engineering were evident across the complete set of models examined, and were consistent with earlier work. Tools for the

Developing photoreceptor-based models of visual attraction in riverine tsetse, for use in the engineering of more-attractive polyester fabrics for control devices

PubMed Central

2017-01-01

Riverine tsetse transmit the parasites that cause the most prevalent form of human African trypanosomiasis, Gambian HAT. In response to the imperative for cheap and efficient tsetse control, insecticide-treated ‘tiny targets’ have been developed through refinement of tsetse attractants based on blue fabric panels. However, modern blue polyesters used for this purpose attract many less tsetse than traditional phthalogen blue cottons. Therefore, colour engineering polyesters for improved attractiveness has great potential for tiny target development. Because flies have markedly different photoreceptor spectral sensitivities from humans, and the responses of these photoreceptors provide the inputs to their visually guided behaviours, it is essential that polyester colour engineering be guided by fly photoreceptor-based explanations of tsetse attraction. To this end, tsetse attraction to differently coloured fabrics was recently modelled using the calculated excitations elicited in a generic set of fly photoreceptors as predictors. However, electrophysiological data from tsetse indicate the potential for modified spectral sensitivities versus the generic pattern, and processing of fly photoreceptor responses within segregated achromatic and chromatic channels has long been hypothesised. Thus, I constructed photoreceptor-based models explaining the attraction of G. f. fuscipes to differently coloured tiny targets recorded in a previously published investigation, under differing assumptions about tsetse spectral sensitivities and organisation of visual processing. Models separating photoreceptor responses into achromatic and chromatic channels explained attraction better than earlier models combining weighted photoreceptor responses in a single mechanism, regardless of the spectral sensitivities assumed. However, common principles for fabric colour engineering were evident across the complete set of models examined, and were consistent with earlier work. Tools for

Thermal Stability of Aqueous Polyurethanes Depending on the Applied Catalysts

PubMed Central

Cakic, Suzana; Nikolic, Goran; Lacnjevac, Caslav; Gligoric, Miladin; Stamenkovic, Jakov; Rajkovic, Milos B.; Barac, Miroljub

2006-01-01

The thermal stability of aqueous polyurethanes has been measured applying the thermogravimetric analysis. The aqueous polyurethanes (aqPUR) with catalysts of different selectivity have been studied by use of the dynamic method. To obtain degradations of 0.025, 0.05, and 0.10, employing the dynamic method, the heating rates of 0.5, 1, 2, 5, and 10 °C min-1 have been used in the range of 30-500 °C. Using the more selective catalysts in the aqueous polyurethanes, the total resulting time of the decompositon has been on the increase at all degrees of the degradation and at the particular starting temperature. This paper shows that the dynamic method based on the thermogravimetric analysis can be used to assess the thermal stability of the aqueous polyurethanes using the catalysts of different selectivity.

Liquid crystal polyester thermosets

DOEpatents

Benicewicz, Brian C.; Hoyt, Andrea E.

1992-01-01

The present invention provides (1) curable liquid crystalline polyester monomers represented by the formula: R.sup.1 --A.sup.1 --B.sup.1 --A.sup.2 --B.sup.2 --A.sup.3 --R.sup.2 where R.sup.1 and R.sup.2 are radicals selected from the group consisting of maleimide, substituted maleimide, nadimide, substituted naimide, ethynyl, and (C(R.sup.3).sub.2).sub.2 where R.sup.3 is hydrogen with the proviso that the two carbon atoms of (C(R.sup.3).sub.2).sub.2 are bound on the aromatic ring of A.sup.1 or A.sup.3 to adjacent carbon atoms, A.sup.1 and A.sup.3 are 1,4-phenylene and the same where said group contains one or more substituents selected from the group consisting of halo, e.g., fluoro, chloro, bromo, or iodo, nitro lower alkyl, e.g., methyl, ethyl, or propyl, alkoxy, e.g., methoxy, ethoxy, or propoxy, and fluoroalkyl, e.g., trifluoromethyl, pentafluoroethyl and the like, A.sup.2 is selected from the group consisting of 1,4-phenylene, 4,4'-biphenyl, 2,6-naphthylene and the same where said groups contain one or more substituents selected from the group consisting of halo, e.g., fluoro, chloro, bromo, or iodo, nitro, lower alkyl, e.g., methyl, ethyl, and propyl, lower alkoxy, e.g., methoxy, ethoxy, or propoxy, and fluoroalkyl or fluoroalkoxy, e.g., trifluoromethyl, pentafluoroethyl and the like, and B.sup.1 and B.sup.2 are selected from the group consisting of --C(O)--O-- and --O--C(O)--, (2) thermoset liquid crystalline polyester compositions comprised of heat-cured segments derived from monomers represented by the formula: R.sup.1 --A.sup.1 --B.sup.1 --A.sup.2 --B.sup.2 --A.sup.3 --R.sup.2 as described above, (3) curable blends of at least two of the polyester monomers and (4) processes of preparing the curable liquid crystalline polyester monomers.

Evaluation of DNA damage and cytotoxicity of polyurethane-based nano- and microparticles as promising biomaterials for drug delivery systems

NASA Astrophysics Data System (ADS)

Caon, Thiago; Zanetti-Ramos, Betina Giehl; Lemos-Senna, Elenara; Cloutet, Eric; Cramail, Henri; Borsali, Redouane; Soldi, Valdir; Simões, Cláudia Maria Oliveira

2010-06-01

The in vitro cytotoxicity and DNA damage evaluation of biodegradable polyurethane-based micro- and nanoparticles were carried out on animal fibroblasts. For cytotoxicity measurement and primary DNA damage evaluation, MTT and Comet assays were used, respectively. Different formulations were tested to evaluate the influence of chemical composition and physicochemical characteristics of particles on cell toxicity. No inhibition of cells growth surrounding the polyurethane particles was observed. On the other hand, a decrease of cell viability was verified when the anionic surfactant sodium dodecyl sulfate (SDS) was used as droplets stabilizer of monomeric phase. Polyurethane nanoparticles stabilized with Tween 80 and Pluronic F68 caused minor cytotoxic effects. These results indicated that the surface charge plays an important role on cytotoxicity. Particles synthesized from MDI displayed a higher cytotoxicity than those synthesized from IPDI. Size and physicochemical properties of the particles may explain the higher degree of DNA damage produced by two tested formulations. In this way, a rational choice of particles' constituents based on their cytotoxicity and genotoxicity could be very useful for conceiving biomaterials to be used as drug delivering systems.

Experimental Study of Fire Hazards of Thermal-Insulation Material in Diesel Locomotive: Aluminum-Polyurethane

PubMed Central

Zhang, Taolin; Zhou, Xiaodong; Yang, Lizhong

2016-01-01

This work investigated experimentally and theoretically the fire hazards of thermal-insulation materials used in diesel locomotives under different radiation heat fluxes. Based on the experimental results, the critical heat flux for ignition was determined to be 6.15 kW/m2 and 16.39 kW/m2 for pure polyurethane and aluminum-polyurethane respectively. A theoretical model was established for both to predict the fire behaviors under different circumstances. The fire behavior of the materials was evaluated based on the flashover and the total heat release rate (HRR). The fire hazards levels were classified based on different experimental results. It was found that the fire resistance performance of aluminum-polyurethane is much better than that of pure-polyurethane under various external heat fluxes. The concentration of toxic pyrolysis volatiles generated from aluminum-polyurethane materials is much higher than that of pure polyurethane materials, especially when the heat flux is below 50 kW/m2. The hazard index HI during peak width time was proposed based on the comprehensive impact of time and concentrations. The predicted HI in this model coincides with the existed N-gas and FED models which are generally used to evaluate the fire gas hazard in previous researches. The integrated model named HNF was proposed as well to estimate the fire hazards of materials by interpolation and weighted average calculation. PMID:28773295

Experimental Study of Fire Hazards of Thermal-Insulation Material in Diesel Locomotive: Aluminum-Polyurethane.

PubMed

Zhang, Taolin; Zhou, Xiaodong; Yang, Lizhong

2016-03-05

This work investigated experimentally and theoretically the fire hazards of thermal-insulation materials used in diesel locomotives under different radiation heat fluxes. Based on the experimental results, the critical heat flux for ignition was determined to be 6.15 kW/m² and 16.39 kW/m² for pure polyurethane and aluminum-polyurethane respectively. A theoretical model was established for both to predict the fire behaviors under different circumstances. The fire behavior of the materials was evaluated based on the flashover and the total heat release rate (HRR). The fire hazards levels were classified based on different experimental results. It was found that the fire resistance performance of aluminum-polyurethane is much better than that of pure-polyurethane under various external heat fluxes. The concentration of toxic pyrolysis volatiles generated from aluminum-polyurethane materials is much higher than that of pure polyurethane materials, especially when the heat flux is below 50 kW/m². The hazard index HI during peak width time was proposed based on the comprehensive impact of time and concentrations. The predicted HI in this model coincides with the existed N-gas and FED models which are generally used to evaluate the fire gas hazard in previous researches. The integrated model named HNF was proposed as well to estimate the fire hazards of materials by interpolation and weighted average calculation.

Functionalised polyurethane for efficient laser micromachining

NASA Astrophysics Data System (ADS)

Brodie, G. W. J.; Kang, H.; MacMillan, F. J.; Jin, J.; Simpson, M. C.

2017-02-01

Pulsed laser ablation is a valuable tool that offers a much cleaner and more flexible etching process than conventional lithographic techniques. Although much research has been undertaken on commercially available polymers, many challenges still remain, including contamination by debris on the surface, a rough etched appearance and high ablation thresholds. Functionalizing polymers with a photosensitive group is a novel way and effective way to improve the efficiency of laser micromachining. In this study, several polyurethane films grafted with different concentrations of the chromophore anthracene have been synthesized which are specifically designed for 248 nm KrF excimer laser ablation. A series of lines etched with a changing number of pulses and fluences by the nanosecond laser were applied to each polyurethane film. The resultant ablation behaviours were studied through optical interference tomography and Scanning Electron Microscopy. The anthracene grafted polyurethanes showed a vast improvement in both edge quality and the presence of debris compared with the unmodified polyurethane. Under the same laser fluence and number of pulses the spots etched in the anthracene contained polyurethane show sharp depth profiles and smooth surfaces, whereas the spots etched in polyurethane without anthracene group grafted present rough cavities with debris according to the SEM images. The addition of a small amount of anthracene (1.47%) shows a reduction in ablation threshold from unmodified polyurethane showing that the desired effect can be achieved with very little modification to the polymer.

76 FR 58040 - Certain Polyester Staple Fiber From Korea and Taiwan

Federal Register 2010, 2011, 2012, 2013, 2014

2011-09-19

... Polyester Staple Fiber From Korea and Taiwan Determination On the basis of the record \\1\\ developed in the... antidumping duty orders on certain polyester staple fiber from Korea and Taiwan would be likely to lead to...), entitled Certain Polyester Staple Fiber From Korea and Taiwan: Investigation Nos. 731-TA-825 and 826...

Photocrosslinkable biodegradable elastomers based on cinnamate-functionalized polyesters.

PubMed

Zhu, Congcong; Kustra, Stephen R; Bettinger, Christopher J

2013-07-01

Synthetic biodegradable elastomers are an emerging class of materials that play a critical role in supporting innovations in bioabsorbable medical implants. This paper describes the synthesis and characterization of poly(glycerol-co-sebacate)-cinnamate (PGS-CinA), a biodegradable elastomer based on hyperbranched polyesters derivatized with pendant cinnamate groups. PGS-CinA can be prepared via photodimerization in the absence of photoinitiators using monomers that are found in common foods. The resulting network exhibits a Young's modulus of 50.5-152.1kPa and a projected in vitro degradation half-life time between 90 and 140days. PGS-CinA elastomers are intrinsically cell-adherent and support rapid proliferation of fibroblasts. Spreading and proliferation of fibroblasts are loosely governed by the substrate stiffness within the range of Young's moduli in PGS-CinA networks that were prepared. The thermo-mechanical properties, biodegradability and intrinsic support of cell attachment and proliferation suggest that PGS-CinA networks are broadly applicable for use in next generation bioabsorable materials including temporary medical devices and scaffolds for soft tissue engineering. Copyright © 2013 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

40 CFR 721.9959 - Polyurethane polymer (generic).

Code of Federal Regulations, 2010 CFR

2010-07-01

... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Polyurethane polymer (generic). 721... Substances § 721.9959 Polyurethane polymer (generic). (a) Chemical substance and significant new uses subject to reporting. (1) The chemical substance identified generically as a polyurethane polymer (PMN P-01...

40 CFR 721.9959 - Polyurethane polymer (generic).

Code of Federal Regulations, 2011 CFR

2011-07-01

... 40 Protection of Environment 31 2011-07-01 2011-07-01 false Polyurethane polymer (generic). 721... Substances § 721.9959 Polyurethane polymer (generic). (a) Chemical substance and significant new uses subject to reporting. (1) The chemical substance identified generically as a polyurethane polymer (PMN P-01...

40 CFR 721.9959 - Polyurethane polymer (generic).

Code of Federal Regulations, 2013 CFR

2013-07-01

... 40 Protection of Environment 32 2013-07-01 2013-07-01 false Polyurethane polymer (generic). 721... Substances § 721.9959 Polyurethane polymer (generic). (a) Chemical substance and significant new uses subject to reporting. (1) The chemical substance identified generically as a polyurethane polymer (PMN P-01...

40 CFR 721.9959 - Polyurethane polymer (generic).

Code of Federal Regulations, 2014 CFR

2014-07-01

... 40 Protection of Environment 31 2014-07-01 2014-07-01 false Polyurethane polymer (generic). 721... Substances § 721.9959 Polyurethane polymer (generic). (a) Chemical substance and significant new uses subject to reporting. (1) The chemical substance identified generically as a polyurethane polymer (PMN P-01...

40 CFR 721.9959 - Polyurethane polymer (generic).

Code of Federal Regulations, 2012 CFR

2012-07-01

... 40 Protection of Environment 32 2012-07-01 2012-07-01 false Polyurethane polymer (generic). 721... Substances § 721.9959 Polyurethane polymer (generic). (a) Chemical substance and significant new uses subject to reporting. (1) The chemical substance identified generically as a polyurethane polymer (PMN P-01...

Optically active polyurethane@indium tin oxide nanocomposite: Preparation, characterization and study of infrared emissivity

DOE Office of Scientific and Technical Information (OSTI.GOV)

Yang, Yong; Zhou, Yuming, E-mail: ymzhou@seu.edu.cn; Ge, Jianhua

Highlights: ► Silane coupling agent of KH550 was used to connect the ITO and polyurethanes. ► Infrared emissivity values of the hybrids were compared and analyzed. ► Interfacial synergistic action and orderly secondary structure were the key factors. -- Abstract: Optically active polyurethane@indium tin oxide and racemic polyurethane@indium tin oxide nanocomposites (LPU@ITO and RPU@ITO) were prepared by grafting the organics onto the surfaces of modified ITO nanoparticles. LPU@ITO and RPU@ITO composites based on the chiral and racemic tyrosine were characterized by FT-IR, UV–vis spectroscopy, X-ray diffraction (XRD), SEM, TEM, and thermogravimetric analysis (TGA), and the infrared emissivity values (8–14 μm)more » were investigated in addition. The results indicated that the polyurethanes had been successfully grafted onto the surfaces of ITO without destroying the crystalline structure. Both composites possessed the lower infrared emissivity values than the bare ITO nanoparticles, which indicated that the interfacial interaction had great effect on the infrared emissivity. Furthermore, LPU@ITO based on the optically active polyurethane had the virtue of regular secondary structure and more interfacial synergistic actions between organics and inorganics, thus it exhibited lower infrared emissivity value than RPU@ITO based on the racemic polyurethane.« less

Biodegradation Of thermoplastic polyurethanes from vegetable oils

USDA-ARS?s Scientific Manuscript database

Thermoplastic urethanes based on polyricinoleic acid soft segments and MDI/BD hard segments with varied soft segment concentration were prepared. Soft segment concentration was varied fro, 40 to 70 wt %. Biodegradation was studied by respirometry. Segmented polyurethanes with soft segments based ...

Sodium hydrogen carbonate as an alternative blowing agent in the preparation of palm-based polyurethane foam

NASA Astrophysics Data System (ADS)

Shakir, Amira Shakim Abdul; Badri, Khairiah Haji; Hua, Chia Chin

2016-11-01

An environmental-friendly blowing agent has been used to fabricate flexible polyurethane (PU) foam. Polyurethane foam was prepared from palm kernel oil-based monoester polyol (PKO-p) via prepolymerization method. Acetone has been used as solvent in this study. The developed polyurethane foam was characterized using tensile, differential scanning calorimetry analysis (DSC), thermogravimetric analysis (TGA), optical microscope and drop shape analyzer. The mechanical properties of the PU-reference (PU-R) and PU-NaHCO3 foam was analyzed by tensile using ASTM D 3574-01. From the results, the elongation of PU- NaHCO3 shows reduction to 26.3 % compared to PU-R. The DSC showed two glass transition temperatures in all samples that belonged to the PU-R and PU-NaHCO3. TGA revealed that the incorporation of sodium hydrogen carbonate into the PU system did not show significant difference as compared to the control PU. The morphology of both PU was investigated using optical microscope. Contact angle has been measured to determine the hydrophobicity of the PU. The PU- NaHCO3 exhibited an increase in contact angle (93.1°).

Application of polyurethane foam as a sorbent for trace metal pre-concentration — A review

NASA Astrophysics Data System (ADS)

Lemos, V. A.; Santos, M. S.; Santos, E. S.; Santos, M. J. S.; dos Santos, W. N. L.; Souza, A. S.; de Jesus, D. S.; das Virgens, C. F.; Carvalho, M. S.; Oleszczuk, N.; Vale, M. G. R.; Welz, B.; Ferreira, S. L. C.

2007-01-01

The first publication on the use of polyurethane foam (PUF) for sorption processes dates back to 1970, and soon after the material was applied for separation processes. The application of PUF as a sorbent for solid phase extraction of inorganic analytes for separation and pre-concentration purposes is reviewed. The physical and chemical characteristics of PUF (polyether and polyester type) are discussed and an introduction to the characterization of these sorption processes using different types of isotherms is given. Separation and pre-concentration methods using unloaded and loaded PUF in batch and on-line procedures with continuous flow and flow injection systems are presented. Methods for the direct solid sampling analysis of the PUF after pre-concentration are discussed as well as approaches for speciation analysis. Thermodynamic proprieties of some extraction processes are evaluated and the interpretation of determined parameters, such as enthalpy, entropy and Gibbs free energy in light of the physico-chemical processes is explained.

Characterization of poly(L-lactide/Propylene glycol) based polyurethane films using ATR-FTIR spectroscopy

NASA Astrophysics Data System (ADS)

Manap, Siti Munirah; Ahmad, Azizan; Anuar, Farah Hannan

2016-11-01

A polyurethane films consisting of PLLA, PPG and PLLA-PPG were prepared using solution casting method. Three types of polyurethane were prepared: PPLA:PMDI, PPG:PMDI and PLLA-PPG:PMDI in the presence of polymeric diphenylmethane diisocyanate (PMDI) as the coupling agent and catalyst, Sn(Oct)2. The aim of this research was to improve the physicals properties of PLLA and PPG homopolymers through copolymerization between the two polymers. The homopolymers and polyurethane films were characterized using ATR-FTIR spectroscopy. Chemical reaction between PLLA, PPG and PMDI before and after the reaction were confirmed by observing the shifting of wavenumber for the carbonyl and ether group. Other than that, the additional band for N-H after the reaction indicated that the reaction was successful.

75 FR 42784 - Greige Polyester/Cotton Printcloth From China

Federal Register 2010, 2011, 2012, 2013, 2014

2010-07-22

... INTERNATIONAL TRADE COMMISSION [Investigation No. 731-TA-101 (Third Review)] Greige Polyester/Cotton Printcloth From China AGENCY: United States International Trade Commission. ACTION: Termination of... revocation of the antidumping duty order on greige polyester/cotton printcloth from China would be likely to...

Design and Fabrication of an Elastomer Test Machine.

DTIC Science & Technology

1988-05-01

provided by the Army Materials Technology Laboratories, were tested with the ETM at U.C.N.W. RUBBER 15 TP14AX 15 NAT25A 15 SBR26 NBR 6 FIBREGLASS REINFORCED...stationary, tilted and rotational) are comparable with 0001 AM and 0001 AN samples. SAMPLE NBR 62 This is a matt black, rubber based sample described as a... RUBBER 0001 AM 0001 AN 0001 AE -6- POLYURETHANE ECP 1 S ECP 2 Morbay 2690 Budd 20 1080 (Polyester) ) Gallagher Corporation A8 (Polyester) ) All

Simulation on the Performance of a Driven Fan Made by Polyester/Epoxy interpenetrate polymer network (IPN)

NASA Astrophysics Data System (ADS)

Fahrul Hassan, Mohd; Jamri, Azmil; Nawawi, Azli; Zaini Yunos, Muhamad; Fauzi Ahmad, Md; Adzila, Sharifah; Nasrull Abdol Rahman, Mohd

2017-08-01

The main purpose of this study is to investigate the performance of a driven fan design made by Polyester/Epoxy interpenetrate polymer network (IPN) material that specifically used for turbocharger compressor. Polyester/Epoxy IPN is polymer plastics that was used as replacements for traditional polymers and has been widely used in a variety of applications because of their limitless conformations. Simulation based on several parameters which are air pressure, air velocity and air temperature have been carried out for a driven fan design performance of two different materials, aluminum alloy (existing driven fan design) and Polyester/Epoxy IPN using SolidWorks Flow Simulation software. Results from both simulations were analyzed and compared where both materials show similar performance in terms of air pressure and air velocity due to similar geometric and dimension, but Polyester/Epoxy IPN produces lower air temperature than aluminum alloy. This study shows a preliminary result of the potential Polyester/Epoxy IPN to be used as a driven fan design material. In the future, further studies will be conducted on detail simulation and experimental analysis.

The bactericidal activity of glutaraldehyde-impregnated polyurethane.

PubMed

Sehmi, Sandeep K; Allan, Elaine; MacRobert, Alexander J; Parkin, Ivan

2016-10-01

Although glutaraldehyde is known to be bactericidal in solution, its potential use to create novel antibacterial polymers suitable for use in healthcare environments has not been evaluated. Here, novel materials were prepared in which glutaraldehyde was either incorporated into polyurethane using a simple "swell-encapsulation-shrink" method (hereafter referred to as "glutaraldehyde-impregnated polyurethane"), or simply applied to the polymer surface (hereafter referred to as "glutaraldehyde-coated polyurethane"). The antibacterial activity of glutaraldehyde-impregnated and glutaraldehyde-coated polyurethane samples was tested against Escherichia coli and Staphylococcus aureus. Glutaraldehyde-impregnated polyurethane resulted in a 99.9% reduction in the numbers of E. coli within 2 h and a similar reduction of S. aureus within 1 h, whereas only a minimal reduction in bacterial numbers was observed when the biocide was bound to the polymer surface. After 15 days, however, the bactericidal activity of the impregnated material was substantially reduced presumably due to polymerization of glutaraldehyde. Thus, although glutaraldehyde retains antibacterial activity when impregnated into polyurethane, activity is not maintained for extended periods of time. Future work should examine the potential of chemical modification of glutaraldehyde and/or polyurethane to improve the useful lifespan of this novel antibacterial polymer. © 2016 The Authors. MicrobiologyOpen published by John Wiley & Sons Ltd.

Degradation of microbial polyesters.

PubMed

Tokiwa, Yutaka; Calabia, Buenaventurada P

2004-08-01

Microbial polyhydroxyalkanoates (PHAs), one of the largest groups of thermoplastic polyesters are receiving much attention as biodegradable substitutes for non-degradable plastics. Poly(D-3-hydroxybutyrate) (PHB) is the most ubiquitous and most intensively studied PHA. Microorganisms degrading these polyesters are widely distributed in various environments. Although various PHB-degrading microorganisms and PHB depolymerases have been studied and characterized, there are still many groups of microorganisms and enzymes with varying properties awaiting various applications. Distributions of PHB-degrading microorganisms, factors affecting the biodegradability of PHB, and microbial and enzymatic degradation of PHB are discussed in this review. We also propose an application of a new isolated, thermophilic PHB-degrading microorganism, Streptomyces strain MG, for producing pure monomers of PHA and useful chemicals, including D-3-hydroxycarboxylic acids such as D-3-hydroxybutyric acid, by enzymatic degradation of PHB.

Isolation and characterization of a bacterium that degrades various polyester-based biodegradable plastics.

PubMed

Teeraphatpornchai, T; Nakajima-Kambe, T; Shigeno-Akutsu, Y; Nakayama, M; Nomura, N; Nakahara, T; Uchiyama, H

2003-01-01

Microorganisms isolated from soil samples were screened for their ability to degrade various biodegradable polyester-based plastics. The most active strain, designated as strain TB-13, was selected as the best strain for degrading these plastics. From its phenotypic and genetic characteristics, strain TB-13 was closely related to Paenibacillus amyloyticus. It could degrade poly(lactic acid), poly(butylene succinate), poly(butylene succinate-co-adipate), poly(caprolactone) and poly(ethylene succinate) but not poly(hydroxybutylate-co-valerate). However, it could not utilize these plastics as sole carbon sources. Both protease and esterase activities, which may be involved in the degradation of plastic, were constitutively detected in the culture broth.

75 FR 23300 - Greige Polyester/Cotton Printcloth From China

Federal Register 2010, 2011, 2012, 2013, 2014

2010-05-03

.../Cotton Printcloth From China AGENCY: United States International Trade Commission. ACTION: Institution of a five-year review concerning the antidumping duty order on greige polyester/cotton printcloth from... antidumping duty order on greige polyester/cotton printcloth from China would be likely to lead to...

Recent advances in aliphatic polyesters for drug delivery applications.

PubMed

Washington, Katherine E; Kularatne, Ruvanthi N; Karmegam, Vasanthy; Biewer, Michael C; Stefan, Mihaela C

2017-07-01

The use of aliphatic polyesters in drug delivery applications has been a field of significant interest spanning decades. Drug delivery strategies have made abundant use of polyesters in their structures owing to their biocompatibility and biodegradability. The properties afforded from these materials provide many avenues for the tunability of drug delivery systems to suit individual needs of diverse applications. Polyesters can be formed in several different ways, but the most prevalent is the ring-opening polymerization of cyclic esters. When used to form amphiphilic block copolymers, these materials can be utilized to form various drug carriers such as nanoparticles, micelles, and polymersomes. These drug delivery systems can be tailored through the addition of targeting moieties and the addition of stimuli-responsive groups into the polymer chains. There are also different types of polyesters that can be used to modify the degradation rates or mechanical properties. Here, we discuss the reasons that polyesters have become so popular, the current research focuses, and what the future holds for these materials in drug delivery applications. WIREs Nanomed Nanobiotechnol 2017, 9:e1446. doi: 10.1002/wnan.1446 For further resources related to this article, please visit the WIREs website. © 2016 Wiley Periodicals, Inc.

Polyurethane Masks Large Areas in Electroplating

NASA Technical Reports Server (NTRS)

Beasley, J. L.

1985-01-01

Polyurethane foam provides effective mask in electroplating of copper or nickel. Thin layer of Turco maskant painted on area to be masked: Layer ensures polyurethane foam removed easily after served its purpose. Component A, isocyanate, and component B, polyol, mixed together and brushed or sprayed on mask area. Mixture reacts, yielding polyurethane foam. Foam prevents deposition of nickel or copper on covered area. New method saves time, increases productivity and uses less material than older procedures.

Degradation of polyurethane by bacterium isolated from soil and assessment of polyurethanolytic activity of a Pseudomonas putida strain.

PubMed

Peng, Yu-Huei; Shih, Yang-hsin; Lai, Yen-Chun; Liu, Yuan-Zan; Liu, Ying-Tong; Lin, Nai-Chun

2014-01-01

The increasing usage and the persistence of polyester polyurethane (PU) generate significant sources of environmental pollution. The effective and environmental friendly bioremediation techniques for this refractory waste are in high demand. In this study, three novel PU degrading bacteria were isolated from farm soils and activated sludge. Based upon 16S ribosomal RNA gene sequence blast, their identities were determined. Particularly robust activity was observed in Pseudomonas putida; it spent 4 days to degrade 92% of Impranil DLN(TM) for supporting its growth. The optimum temperature and pH for DLN removal by P. putida were 25 °C and 8.4, respectively. The degradation and transformation of DLN investigated by Fourier transformed infrared spectroscopy show the decrease in ester functional group and the emergence of amide group. The polyurethanolytic activities were both presented in the extracellular fraction and in the cytosol. Esterase activity was detected in the cell lysate. A 45-kDa protein bearing polyurethanolytic activity was also detected in the extracellular medium. This study presented high PU degrading activity of P. putida and demonstrated its responsible enzymes during the PU degradation process, which could be applied in the bioremediation and management of plastic wastes.

The In Vivo Pericapsular Tissue Response to Modern Polyurethane Breast Implants.

PubMed

Frame, James; Kamel, Dia; Olivan, Marcelo; Cintra, Henrique

2015-10-01

capsular contracture rate, up to 10 years after implantation, compared to contemporary silicone implants. A more permanent matrix equivalent to polyurethane may be the solution for reducing long-term capsular contracture. This journal requires that authors assign a level of evidence to each article. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors www.springer.com/00266 .

Water-free synthesis of polyurethane foams using highly reactive diisocyanates derived from 5-hydroxymethylfurfural.

PubMed

Neumann, Christopher N D; Bulach, Winfried D; Rehahn, Matthias; Klein, Roland

2011-09-01

This paper reports on the synthesis of a new highly reactive diisocyanate monomer based on hydroxymethylfurfural. It further describes its catalyst-free conversion to linear-chain thermoplastic polyurethanes as well as to cross-linked polyurethane foams. In addition, a novel strategy for the synthesis of polyurethane foams without the necessity of using water is developed. Nitrogen is utilized herein as blowing agent which is formed during Curtius rearrangement of a new furan based carboxylic azide into its corresponding diisocyanate. Copyright © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Polyester Fabric's Fluorescent Dyeing in Supercritical Carbon Dioxide and its Fluorescence Imaging.

PubMed

Xiong, Xiaoqing; Xu, Yanyan; Zheng, Laijiu; Yan, Jun; Zhao, Hongjuan; Zhang, Juan; Sun, Yanfeng

2017-03-01

As one of the most important coumarin-like dyes, disperse fluorescent Yellow 82 exhibits exceptionally large two-photon effects. Here, it was firstly introduced into the supercritical CO 2 dyeing polyester fabrics in this work. Results of the present work showed that the dyeing parameters such as the dyeing time, pressure and temperature had remarkable influences on the color strength of fabrics. The optimized dyeing condition in supercritical CO 2 dyeing has been proposed that the dyeing time was 60 min; the pressure was 25 MPa and the temperature was 120 °C. As a result, acceptable products were obtained with the wash and rub fastness rating at 5 or 4-5. The polyester fabrics dyed with fluorescent dyes can be satisfied for the requirement of manufacturing warning clothing. Importantly, the confocal microscopy imaging technology was successfully introduced into textile fields to observe the distribution and fluorescence intensity of disperse fluorescent Yellow 82 on polyester fabrics. As far as we know, this is the first report about supercritical CO 2 dyeing polyester fabrics based on disperse fluorescent dyes. It will be very helpful for the further design of new fluorescent functional dyes suitable for supercritical CO 2 dyeing technique.

Solvent stimulated actuation of polyurethane-based shape memory polymer foams using dimethyl sulfoxide and ethanol

NASA Astrophysics Data System (ADS)

Boyle, A. J.; Weems, A. C.; Hasan, S. M.; Nash, L. D.; Monroe, M. B. B.; Maitland, D. J.

2016-07-01

Solvent exposure has been investigated to trigger actuation of shape memory polymers (SMPs) as an alternative to direct heating. This study aimed to investigate the feasibility of using dimethyl sulfoxide (DMSO) and ethanol (EtOH) to stimulate polyurethane-based SMP foam actuation and the required solvent concentrations in water for rapid actuation of hydrophobic SMP foams. SMP foams exhibited decreased T g when submerged in DMSO and EtOH when compared to water submersion. Kinetic DMA experiments showed minimal or no relaxation for all SMP foams in water within 30 min, while SMP foams submerged in EtOH exhibited rapid relaxation within 1 min of submersion. SMP foams expanded rapidly in high concentrations of DMSO and EtOH solutions, where complete recovery over 30 min was observed in DMSO concentrations greater than 90% and in EtOH concentrations greater than 20%. This study demonstrates that both DMSO and EtOH are effective at triggering volume recovery of polyurethane-based SMP foams, including in aqueous environments, and provides promise for use of this actuation technique in various applications.

Response of Polyurethane to Shock Waves: An Experimental Investigation

NASA Astrophysics Data System (ADS)

Jayaram, V.; Rao, Keshava Subba; Thanganayaki, N.; Kumara, H. K. T.; Reddy, K. P. J.

Formation of polyurethane (PU) in vacuum environment and controlling density of polyurethane foams are the present day challenges. Polyurethane exists in numerous forms ranging from flexible to rigid and lightweight foams to tough, stiff elastomers [1]. PU can be used to produce lightweight foams for insulation or hard rubber used as wheels to transport heavy loads and it can be used in high pressure applications. The largest volumes of commercial PU elastomers are made from toluene diisocyanate (TDI) or diphenylmethane-4, 4'-diisocyanate (MDI) [2]. Linear polyurethanes can be processed into final products by any of the standard thermoplastic processes (injection molding, extrusion, thermoforming) as well as by low pressure cast processes in presence of catalysts. Tin, tetrabutyl titanate and zirconium chelates are few effective catalysts used to produce polyurethane for particular application [3]. Thermoset elastomers are formed due to irreversible cross-links, when polymers are chemically cured. Highly porous biodegradable PU was synthesized by thermally induced phase separation technique used in tissue engineering and also in bio-degradable based fluids [4]. Properties of PU like hardness, stress/strain modulus, tear strength etc, was determine using ASTM (American Society for Testing and Materials) standard methods. PU possesses extremely high mechanical properties, excellent abrasion, tear and extrusion resistance. It has outstanding low-temperature limit (-600C) and high temperature limit up to (1500C).

77 FR 60720 - Certain Polyester Staple Fiber From China

Federal Register 2010, 2011, 2012, 2013, 2014

2012-10-04

... Fiber From China Determination On the basis of the record \\1\\ developed in the subject five-year review... certain polyester staple fiber from China would be likely to lead to continuation or recurrence of... (September 2012), entitled Certain Polyester Staple Fiber from China: Investigation No. 731-TA-1104 (Review...

Micro-thermal analysis of polyester coatings

NASA Astrophysics Data System (ADS)

Fischer, Hartmut R.

2010-04-01

The application and suitability of micro-thermal analysis to detect changes in the chemical and physical properties of coating due to ageing and especially photo-degradation is demonstrated using a model polyester coating based on neopentyl glycol isophthalic acid. The changes in chemical structure like chain scission and cross-linking are manifested by a shift of the LTA detectable Tg and by a change of the slope of the part of the LTA graph responsible for the penetration of the hot sensor into the material after passing the glass transition temperature. As such LTA is a valuable tool to have a quick look into coating surfaces and especially their ageing. The photo-degradation of polyester in air leads to the formation of a cross-linked network at a surface layer of about 3-4 μm coupled with an increase in hardness and of the glass transition temperature by ˜90 K, the effect is less drastic for a photo-degradation in a nitrogen environment. Moreover, the presence of a non-equilibrium dense surface layer with a higher Tg formed during the drying of the coating formulation and the film solidification can be shown.

Interior microelectrolysis oxidation of polyester wastewater and its treatment technology.

PubMed

Yang, Xiaoyi

2009-09-30

This paper has investigated the effects of interior microelectrolysis pretreatment on polyester wastewater treatment and analyzed its mechanism on COD and surfactant removal. The efficiency of interior microelectrolysis is mainly influenced by solution pH, aeration and reaction time. Contaminants can be removed not only by redox reaction and flocculation in the result of ferrous and ferric hydroxides but also by electrophoresis under electric fields created by electron flow. pH confirms the chemical states of surfactants, Fe(II)/Fe(III) ratio and the redox potential, and thus influences the effects of electrophoresis, flocculation and redox action on contaminant removal. Anaerobic and aerobic batch tests were performed to study the degradation of polyester wastewater. The results imply that interior microelectrolysis and anaerobic pretreatment are lacking of effectiveness if applied individually in treating polyester wastewater in spite of their individual advantages. The interior microelectrolysis-anaerobic-aerobic process was investigated to treat polyester wastewater with comparison with interior microelectrolysis-aerobic process and anaerobic-aerobic process. High COD removal efficiencies have been gotten by the combination of interior microelectrolysis with anaerobic technology and aerobic technology. The results also imply that only biological treatment was less effective in polyester wastewater treatment.

Polyester polymer concrete overlay.

DOT National Transportation Integrated Search

2013-01-01

Polyester polymer concrete (PPC) was used in a trial application on a section of pavement that suffers from extensive studded tire wear. The purpose of the trial section is to determine if PPC is a possible repair strategy for this type of pavement d...

Study on Energy Absorption Capacity of Steel-Polyester Hybrid Fiber Reinforced Concrete Under Uni-axial Compression

NASA Astrophysics Data System (ADS)

Chella Gifta, C.; Prabavathy, S.

2018-05-01

This work presents the energy absorption capacity of hybrid fiber reinforced concrete made with hooked end steel fibers (0.5 and 0.75%) and straight polyester fibers (0.5, 0.8, 1.0 and 2.0%). Compressive toughness (energy absorption capacity) under uni-axial compression was evaluated on 100 × 200 mm size cylindrical specimens with varying steel and polyester fiber content. Efficiency of the hybrid fiber reinforcement is studied with respect to fiber type, size and volume fractions in this investigation. The vertical displacement under uni-axial compression was measured under the applied loads and the load-deformation curves were plotted. From these curves the toughness values were calculated and the results were compared with steel and polyester as individual fibers. The hybridization of 0.5% steel + 0.5% polyester performed well in post peak region due to the addition of polyester fibers with steel fibers and the energy absorption value was 23% greater than 0.5% steel FRC. Peak stress values were also higher in hybrid series than single fiber and based on the results it is concluded that hybrid fiber reinforcement improves the toughness characteristics of concrete without affecting workability.

Method of making thermally removable polyurethanes

DOEpatents

Loy, Douglas A.; Wheeler, David R.; McElhanon, James R.; Saunders, Randall S.; Durbin-Voss, Marvie Lou

2002-01-01

A method of making a thermally-removable polyurethane material by heating a mixture of a maleimide compound and a furan compound, and introducing alcohol and isocyanate functional groups, where the alcohol group and the isocyanate group reacts to form the urethane linkages and the furan compound and the maleimide compound react to form the thermally weak Diels-Alder adducts that are incorporated into the backbone of the urethane linkages during the formation of the polyurethane material at temperatures from above room temperature to less than approximately 90.degree. C. The polyurethane material can be easily removed within approximately an hour by heating to temperatures greater than approximately 90.degree. C. in a polar solvent. The polyurethane material can be used in protecting electronic components that may require subsequent removal of the solid material for component repair, modification or quality control.

Electrical conductivity of rigid polyurethane foam at high temperature

NASA Astrophysics Data System (ADS)

Johnson, R. T., Jr.

1982-08-01

The electrical conductivity of rigid polyurethane foam, used for electronic encapsulation, was measured during thermal decomposition to 3400 C. At higher temperatures the conductance continues to increase. With pressure loaded electrical leads, sample softening results in eventual contact between electrodes which produces electrical shorting. Air and nitrogen environments show no significant dependence of the conductivity on the atmosphere over the temperature range. The insulating characteristics of polyurethane foam below approx. 2700 C are similar to those for silicone based materials used for electronic case housings and are better than those for phenolics. At higher temperatures (greater than or equal to 2700 C) the phenolics appear to be better insulators to approx. 5000 C and the silicones to approx. 6000 C. It is concluded that the Sylgard 184/GMB encapsulant is a significantly better insulator at high temperature than the rigid polyurethane foam.

Waterborne Polymeric Films.

DTIC Science & Technology

1979-12-01

resin types: 1) acrylic latex, 2) acrylic solution polymer, 3) epoxy emulsions, 4) polyurethane, 5) butadiene elastomeric latex, 6) polyester/ alkyd , 7...emulsions and the class of polyester/ alkyd resins were evaluated only as network, crosslinked films. -53- j z I, ACRYLIC SOLUTIONLATEX URE THANE ACRYLIC ...amount of "plasticizing" monomer such as ethyl acrylate . 2.3.1.3 Aqueous Polyester Alkyd Resins As indicated in section 2.2.7 of this report,

Facile preparation of antibacterial, highly elastic silvered polyurethane nanofiber fabrics using silver carbamate and their dermal wound healing properties.

PubMed

Hong, Suk-Min; Kim, Jong-Wan; Knowles, Jonathan C; Gong, Myoung-Seon

2017-02-01

In this study, polycarbonate diol/isosorbide-based antibacterial polyurethane nanofiber fabrics containing Ag nanoparticles were prepared by electrospinning process. Bio-based highly elastic polyurethane was prepared from hexamethylene diisocyanate and isosorbide/polycarbonate diol (8/2) by a simple one-shot bulk polymerization. Ag nanoparticles were formed using simple thermal reduction of silver 2-ethylhexylcarbamate at 120℃. The structural and morphological properties of polyurethane/Ag nanofibers were characterized by X-ray diffraction and scanning electron microscopy. The polyurethane nanofiber fabrics were flexible, with breaking strains from 355% to 950% under 7.28 to 23.1 MPa tensile stress. The antibacterial effects of the treated polyurethane/Ag fabrics against Staphylococcus aureus and methicillin resistant Staphylococcus aureus were examined and found to be excellent. Cell proliferation using the immortalized human keratinocyte HaCaT cell line was performed in order to determine cell viability in the presence of polyurethane and polyurethane/Ag fabrics, showing cytocompatiblility and a lack of toxicity.

Eco-friendly surface modification on polyester fabrics by esterase treatment

NASA Astrophysics Data System (ADS)

Wu, Jindan; Cai, Guoqiang; Liu, Jinqiang; Ge, Huayun; Wang, Jiping

2014-03-01

Currently, traditional alkali deweighting technology is widely used to improve the hydrophilicity of polyester fabrics. However, the wastewater and heavy chemicals in the effluent cause enormous damage to the environment. Esterase treatment, which is feasible in mild conditions with high selectivity, can provide a clean and efficient way for polyester modification. Under the optimum conditions, the polyester fabric hydrolysis process of esterase had a linear kinetics. X-ray photoelectron spectrometry (XPS) results showed that hydroxyl and carboxyl groups were produced only on the surface of modified fiber without changing the chemical composition of the bulk. These fibers exhibited much improved fabric wicking, as well as greatly improved oily stain removal performance. Compared to the harsh alkali hydrolysis, the enzyme treatment led to smaller weight loss and better fiber integrity. The esterase treatment technology is promising to produce higher-quality polyester textiles with an environmental friendly approach.

Various nanoparticle morphologies and surface properties of waterborne polyurethane controlled by water

PubMed Central

Zhou, Xing; Fang, Changqing; Lei, Wanqing; Du, Jie; Huang, Tingyi; Li, Yan; Cheng, Youliang

2016-01-01

Water plays important roles in organic reactions such as polyurethane synthesis, and the aqueous solution environment affects polymer morphology and other properties. This paper focuses on the morphology and surface properties of waterborne polyurethane resulting from the organic reaction in water involving different forms (solid and liquid), temperatures and aqueous solutions. We provide evidence from TEM observations that the appearance of polyurethane nanoparticles in aqueous solutions presents diverse forms, including imperfect spheres, perfect spheres, perfect and homogenous spheres and tubes. Based on the results on FTIR, GPC, AFM and XRD experiments, we suggest that the shape of the nanoparticles may be decided by the crimp degree (i.e., the degree of polyurethane chains intertangling in the water environment) and order degree, which are determined by the molecular weight (Mn) and hydrogen bonds. Meanwhile, solid water and high-temperature water can both reduce hard segments that gather on the polyurethane film surface to reduce hydrophilic groups and produce a soft surface. Our findings show that water may play key roles in aqueous polymer formation and bring order to molecular chains. PMID:27687001

Facile preparation of mussel-inspired polyurethane hydrogel and its rapid curing behavior.

PubMed

Sun, Peiyu; Wang, Jing; Yao, Xiong; Peng, Ying; Tu, Xiaoxiong; Du, Pengfei; Zheng, Zhen; Wang, Xinling

2014-08-13

A facile method was found to incorporate a mussel-inspired adhesive moiety into synthetic polymers, and mussel mimetic polyurethanes were developed as adhesive hydrogels. In these polymers, a urethane backbone was substituted for the polyamide chain of mussel adhesive proteins, and dopamine was appended to mimic the adhesive moiety of adhesive proteins. A series of mussel mimetic polyurethanes were created through a step-growth polymerization based on hexamethylene diisocyanate as a hard segment, PEG having different molecular weights as a soft segment, and lysine-dopamine as a chain extender. Upon a treatment with Fe(3+), the aqueous mussel mimetic polyurethane solutions can be triggered by pH adjustment to form adhesive hydrogels instantaneously; these materials can be used as injectable adhesive hydrogels. Upon a treatment with NaIO4, the mussel mimetic polyurethane solutions can be cured in a controllable period of time. The successful combination of the unique mussel-inspired adhesive moiety with a tunable polyurethane structure can result in a new kind of mussel-inspired adhesive polymers.

Synthesis and molecular characterization of chitosan based polyurethane elastomers using aromatic diisocyanate.

PubMed

Zia, Khalid Mahmood; Anjum, Sohail; Zuber, Mohammad; Mujahid, Muhammad; Jamil, Tahir

2014-05-01

The present research work was performed to synthesize a new series of chitosan based polyurethane elastomers (PUEs) using poly(ɛ-caprolactone) (PCL). The chitosan based PUEs were prepared by step-growth polymerization technique using poly(ɛ-caprolactone) (PCL) and 2,4-toluene diisocyanate (TDI). In the second step the PU prepolymer was extended with different mole ratios of chitosan and 1,4-butane diol (BDO). Molecular engineering was carried out during the synthesis. The conventional spectroscopic characterization of the synthesized samples using FT-IR confirms the existence of the proposed chitosan based PUEs structure. Internal morphology of the prepared PUEs was studied using SEM analysis. The SEM images confirmed the incorporation of chitosan molecules into the PU backbone. Copyright © 2014 Elsevier B.V. All rights reserved.

Degradation rates of glycerol polyesters at acidic and basic conditions

USDA-ARS?s Scientific Manuscript database

Polyesters prepared from glycerol with mixtures of adipic and citric acids were evaluated in the laboratory to estimate degradation rates over a range of pH conditions. These renewable polymers provide a market for glycerol that is generated during biodiesel production. The polyesters were prepared...

Stabilized unsaturated polyesters

NASA Technical Reports Server (NTRS)

Vogl, O.; Borsig, E. (Inventor)

1985-01-01

An unsaturated polyester, such as propylene glycolmaleic acid phthalic acid prepolymer dissolved in styrene is interpolymerized with an ultraviolet absorber and/or an antioxidant. The unsaturated chain may be filled with H or lower alkyl such as methyl and tertiary alkyl such as tertiary butyl. A polymer stable to exposure to the outdoors without degradation by ultraviolet radiation, thermal and/or photooxidation is formed.

Thermal degradation behavior and X-ray diffraction studies of chitosan based polyurethane bio-nanocomposites using different diisocyanates.

PubMed

Javaid, Muhammad Asif; Rizwan, Muhammad; Khera, Rasheed Ahmad; Zia, Khalid Mahmood; Saito, Kei; Zuber, Muhammad; Iqbal, Javed; Langer, Peter

2018-05-29

Five different samples of chitosan based polyurethane bio-nanocomposites (PUBNCs) were synthesized by step growth polymerization technique. Five different diisocyanates were used by keeping hydroxyl terminated polybutadiene (HTPB)/1,4-butane diol (1,4-BDO)/chitosan (CS) and montmorillonite (MMT) clay ratios constant (PUR1-PUR5). For comparative studies, PUR-6 was prepared without CS and clay components. Molecular characterizations of polyurethane (PU) films were carried out by FTIR and NMR which was found to have confirmatory evidence of the proposed structures. X-ray diffraction angles (2θ), d-spacing and intensities of chitosan based samples (PUR1-PUR5) and PUR-6 indicated that crystalline behavior of PUBNCs is influenced by varying diisocyanate structures. TGA/DTA results revealed that chitosan increased thermal stability of PU samples; it also enhanced the mechanical strength and decreased the glass transition temperature (T g ) of all the samples. Based on the above mentioned facts this study suggests the best usage of PUs according to the operational and environmental conditions. Copyright © 2018 Elsevier B.V. All rights reserved.

Unidirectional fibers and polyurethane elastomer matrix based composites synthesis and properties. Ph.D. Thesis

NASA Technical Reports Server (NTRS)

Chakar, A.

1984-01-01

A study of the properties and manufacturing techniques for long-fiber reinforced elastomeric composites for flexible and damping structural materials is presented. Attention is given to the usage of polyurethane in the matrix to obtain plastic elastomeric matrices and vitreous transition temperatures which vary from -80 C to 10 C, as well as assure good fiber adhesion. Various polyurethane formulations synthesized from diisocyanate prepolymers are examined in terms of mechanical and thermal properties. The principal reinforcing fiber selected is a unidirectional glass cloth.

Synthesis of lipase-catalysed silicone-polyesters and silicone-polyamides at elevated temperatures.

PubMed

Frampton, Mark B; Zelisko, Paul M

2013-10-18

More and more enzymes are being explored as alternatives to conventional catalysts in chemical reactions. To utilize these biocatalysts to their fullest, it is incumbent on researchers to gain a complete understanding of the reaction conditions that particular enzymes will tolerate. To this end siloxane-containing polyesters and polyamides have been produced via N435-mediated catalysis at temperatures well above the normal denaturation temperature for free CalB. Low molecular weight disiloxane-based acceptors release the enzyme from its acylated state with equal proficiency while longer chain siloxanes favours polyester synthesis. The thermal tolerance of the enzyme catalyst is increased using longer chain diesters and generally more hydrophobic substrates.

78 FR 51707 - Certain Polyester Staple Fiber From the Republic of Korea: Rescission of Antidumping Duty...

Federal Register 2010, 2011, 2012, 2013, 2014

2013-08-21

... DEPARTMENT OF COMMERCE International Trade Administration [A-580-839] Certain Polyester Staple... certain polyester staple fiber (polyester staple fiber) from the Republic of Korea (Korea) for the period..., 2013, the Department initiated an administrative review of the antidumping duty order on polyester...

Microwave-assisted synthesis of cyclodextrin polyurethanes

USDA-ARS?s Scientific Manuscript database

Cyclodextrin (CD) has often been incorporated into polyurethanes in order to facilitate its use in encapsulation or removal of organic species for various applications. In this work a microwave-assisted method has been developed to produce polyurethanes consisting of alpha-, ß-, and gamma-CD and thr...

Synthesis and characterization of cellulose nanocrystals as reinforcing agent in solely palm based polyurethane foam

NASA Astrophysics Data System (ADS)

Septevani, Athanasia Amanda; Annamalai, Pratheep K.; Martin, Darren J.

2017-11-01

The increasing awareness of the environment and the economy of petroleum resources has driven the development of alternative processes and raw materials based on sustainable and renewable biomaterials with excellent properties. This study is aimed to use biologically renewable cellulose nanocrystals (CNC) as reinforcing agent to enhance the properties of polyurethane foams (PUF) based on solely palm-polyol. Rod-like shape cellulose nanocrystals (CNC) was successfully isolated from cotton based resources via strong acid hydrolysis with the average width, length and aspect ratio about 14.7 ± 4.9 nm, 167.7 ± 23.2 nm and 11.4, respectively. The crystallinity of CNC was confirmed by using X-ray diffraction (XRD) and differential scanning calorimetry (DSC) and was found at 82.8% and 83.8%, respectively. This obtained cellulose nanocrystals (CNC) at a loading of 0.4 wt. % was then incorporated via solvent-free sonication method in the model of palm based polyurethane foam. The preliminary results showed that the effect of CNC on the mechanical properties afforded a significant improvement on the compressive strength and modulus without affecting much their tensile strength. The results on thermal stability and thermal transitions were found unchanged whereas the storage modulus revealed substantial improvement with the presence of CNC with almost two fold from 0.7 MPa to 1.3 MPa (˜86 %).

Bacterial polyesters: biosynthesis, biodegradable plastics and biotechnology.

PubMed

Lenz, Robert W; Marchessault, Robert H

2005-01-01

The discovery and chemical identification, in the 1920s, of the aliphatic polyester: poly(3-hydroxybutyrate), PHB, as a granular component in bacterial cells proceeded without any of the controversies which marked the recognition of macromolecules by Staudinger. Some thirty years after its discovery, PHB was recognized as the prototypical biodegradable thermoplastic to solve the waste disposal challenge. The development effort led by Imperial Chemical Industries Ltd., encouraged interdisciplinary research from genetic engineering and biotechnology to the study of enzymes involved in biosynthesis and biodegradation. From the simple PHB homopolyester discovered by Maurice Lemoigne in the mid-twenties, a family of over 100 different aliphatic polyesters of the same general structure has been discovered. Depending on bacterial species and substrates, these high molecular weight stereoregular polyesters have emerged as a new family of natural polymers ranking with nucleic acids, polyamides, polyisoprenoids, polyphenols, polyphosphates, and polysaccharides. In this historical review, the chemical, biochemical and microbial highlights are linked to personalities and locations involved with the events covering a discovery timespan of 75 years.

Flame retardant spandex type polyurethanes

NASA Technical Reports Server (NTRS)

Howarth, J. T.; Sheth, S.; Sidman, K. R.; Massucco, A. A. (Inventor)

1978-01-01

Flame retardant elastomeric compositions were developed, comprised of: (1) spandex type polyurethane having incorporated into the polymer chain, halogen containing polyols; (2) conventional spandex type polyurethanes in physical admixture flame retardant additives; and (3) fluoroelastomeric resins in physical admixture with flame retardant additives. Methods of preparing fibers of the flame retardant elastomeric materials are presented and articles of manufacture comprised of the elastomeric materials are mentioned.

75 FR 43921 - Certain Polyester Staple Fiber From Taiwan: Final Results of Antidumping Duty Administrative Review

Federal Register 2010, 2011, 2012, 2013, 2014

2010-07-27

... DEPARTMENT OF COMMERCE International Trade Administration [A-583-833] Certain Polyester Staple... certain polyester staple fiber from Taiwan. The period of review is May 1, 2008, through April 30, 2009... polyester staple fiber (PSF) from Taiwan. See Certain Polyester Staple Fiber From Taiwan: Preliminary...

Skeletal myotube formation enhanced by electrospun polyurethane carbon nanotube scaffolds

PubMed Central

Sirivisoot, Sirinrath; Harrison, Benjamin S

2011-01-01

Background This study examined the effects of electrically conductive materials made from electrospun single- or multiwalled carbon nanotubes with polyurethane to promote myoblast differentiation into myotubes in the presence and absence of electrical stimulation. Methods and results After electrical stimulation, the number of multinucleated myotubes on the electrospun polyurethane carbon nanotube scaffolds was significantly larger than that on nonconductive electrospun polyurethane scaffolds (5% and 10% w/v polyurethane). In the absence of electrical stimulation, myoblasts also differentiated on the electrospun polyurethane carbon nanotube scaffolds, as evidenced by expression of Myf-5 and myosin heavy chains. The myotube number and length were significantly greater on the electrospun carbon nanotubes with 10% w/v polyurethane than on those with 5% w/v polyurethane. The results suggest that, in the absence of electrical stimulation, skeletal myotube formation is dependent on the morphology of the electrospun scaffolds, while with electrical stimulation it is dependent on the electrical conductivity of the scaffolds. Conclusion This study indicates that electrospun polyurethane carbon nanotubes can be used to modulate skeletal myotube formation with or without application of electrical stimulation. PMID:22072883

Flammability and thermal properties studies of nonwoven flax reinforced acrylic based polyester composites

NASA Astrophysics Data System (ADS)

Rasyid, M. F. Ahmad; Salim, M. S.; Akil, H. M.; Ishak, Z. A. Mohd.

2017-12-01

In the pursuit of green and more sustainable product, natural fibre reinforced composites originating from renewable resources has gained interest in recent years. These natural fibres exhibit good mechanical properties, low production costs, and good environmental properties. However, one of the disadvantages of natural fibre reinforced composites is their high flammability that limits their application in many fields. Within this research, the effect of sodium silicate on the flammability and thermal properties of flax reinforced acrylic based polyester composites has been investigated. Sodium silicate is applied as binder and flame retardant system in impregnation process of the natural flax fiber mats. The addition of sodium silicate significantly improved the flame retardant efficiency but reduced the degree of crosslinking of the composites.

Efficient continuous dryer for flexible polyurethane foam and cleaning apparatus

DOEpatents

Jody, Bassam; Daniels, Edward; Libera, Joseph A.

1999-01-01

A method of cleaning polyurethane foams where the material is transported through a wash station while alternately soaking the polyurethane foam in an organic solvent and squeezing solvent from the polyurethane foam a number of times. Then the polyurethane foam is sent through a rinse or solvent transfer station for reducing the concentration of solvent in the foam. The rinsed polyurethane foam is sent to a drying station wherein the foam is repeatedly squeezed while being exposed to hot air to remove wet air from the foam.

SOLUTION RHEOLOGY OF HYPERBRANCHED POLYESTERS AND THEIR BLENDS WITH LINEAR POLYMERS

EPA Science Inventory

In this study, the rheological properties of different generations of hyperbranched polyesters in 1-methyl-2-pyrrolidinone solvent and their blends with poly(2-hydroxyethyl methacrylate) have ben investigated. All the hyperbranched polyester solutions exhibited Newtonian behavior...

Radiation cured polyester compositions containing metal-properties

NASA Astrophysics Data System (ADS)

Szalińska, H.; Pietrzak, M.; Gonerski, A.

The subject of the studies was unsaturated polyester resin, Polimal-109 and its compositions containing acrylates of: sodium, potassium, calcium, magnesium, barium, manganese, iron, cobalt, copper and acrylic acid. Polyester resin modified with acrylic acid salts was cured with 60Co gamma radiation. Measurements of Vicat softening temperature, water absorption, creep current resistance, volume and surface resistivity, the tangent of dielectric loss angle and permittivity of radiation cured compositions were carried out. The results of the studies presented testify to the fact that the properties of cross-linked polymers alter after ionogenic compounds have been introduced into them.

Efficient continuous dryer for flexible polyurethane foam and cleaning apparatus

DOEpatents

Jody, B.; Daniels, E.; Libera, J.A.

1999-03-16

A method of cleaning polyurethane foams where the material is transported through a wash station while alternately soaking the polyurethane foam in an organic solvent and squeezing solvent from the polyurethane foam a number of times. Then the polyurethane foam is sent through a rinse or solvent transfer station for reducing the concentration of solvent in the foam. The rinsed polyurethane foam is sent to a drying station wherein the foam is repeatedly squeezed while being exposed to hot air to remove wet air from the foam. 4 figs.

Biodegradable polyester-based eco-composites containing hemp fibers modified with macrocyclic oligomers

NASA Astrophysics Data System (ADS)

Conzatti, Lucia; Utzeri, Roberto; Hodge, Philip; Stagnaro, Paola

2016-05-01

An original compatibilizing pathway for hemp fibers/poly(1,4-butylene adipate-co-terephtalate) (PBAT) eco-composites was explored exploiting the capability of macrocyclic oligomers (MCOs), obtained by cyclodepolymerization (CDP) of PBAT at high dilution, of being re-converted into linear chains by entropically-driven ring-opening polymerization (ED-ROP) that occurs simply heating the MCOS in the bulk. CDP reaction of PBAT was carried out varying solvent, catalyst and reaction time. Selected MCOs were used to adjust the conditions of the ED-ROP reaction. The best experimental conditions were then adopted to modify hemp fibers. Eco-composites based on PBAT and hemp fibers as obtained or modified with PBAT macrocyclics or oligomers were prepared by different process strategies. The best fiber-PBAT compatibility was observed when the fibers were modified with PBAT oligomers before incorporation in the polyester matrix.

Fabrication of polysiloxane-modified polyurethane sponge as low-cost organics/water separation and selective absorption material.

PubMed

Cui, Zhengshan; He, Wanxia; Liu, Jun; Wei, Wei; Jiang, Liang; Huang, Jun; Lv, Xiaomeng

2016-10-01

Through sol-gel and dip-coating processes, commercial polyurethane sponge modified by polysiloxane was fabricated under low temperature (60 °C) and atmosphere. The contact angle of the obtained polysiloxane/polyurethane sponge is 145 ± 5°. Hence, the polysiloxane/polyurethane sponge could float on water and selectively absorb organics from the surface of the water, indicating simultaneous properties of hydrophobicity and oleophilicity. The absorbent maximum value is 50-150 times of its own weight. The polysiloxane/polyurethane sponge exhibited excellent recyclability, which could be reused by squeezing the sponge due to its high mechanical stability and flexibility. Thermogravimetry-differential thermal analysis test indicated that the polysiloxane/polyurethane sponge exhibited good thermal stability and the stable contact angle of samples tested under increasing temperature indicated its good weather resistance. Due to the commercial property of polyurethane sponge and easy-handling of polysiloxane, the polysiloxane/polyurethane sponge can be easily scaled up to recover a large-area oil spill in water and further work based on the designed equipment has been under consideration.

Effects of glass scraps powder and glass fiber on mechanical properties of polyester composites

NASA Astrophysics Data System (ADS)

Sonsakul, K.; Boongsood, W.

2017-11-01

One concern in bus manufacturing is the high cost of glass fiber reinforced in polyester composites parts. The composites of glass fiber and polyester are low elongation and high strength, and glass scraps powder displays high hardness and good chemical compatibility with the polymer matrix and glass fiber. This research aimed to study the effects of glass scraps powder and glass fiber on mechanical performance of polyester composites. Glass fiber was randomly oriented fiber and used as new. Glass scraps were obtained from a bus factory and crushed to powder sizes of 120 and 240 μm by a ball mill. Polyester composites were prepared using Vacuum Infusion Process (VIP).Polyester reinforced with 3 layers of glass fiber was an initial condition. Then, one layer of glass fiber was replaced with glass scraps powder. Flexural strength, tensile strength, impact strength and hardness of the polyester composites were determined. Hardness was increased with a combination of smaller size and higher volume of glass scraps powder. Pictures of specimens obtained by using scanning electron microscope (SEM) confirmed that the powder of glass scraps packed in the layers of glass fiber in polyester composites.

Synthesis and characterization of chitosan/curcumin blends based polyurethanes.

PubMed

Zia, Fatima; Zia, Khalid Mahmood; Zuber, Mohammad; Rehman, Saima; Tabasum, Shazia; Sultana, Salma

2016-11-01

In this work, new hexamethylene diisocyanate (HMDI) and hyroxylterminated polybutadiene (HTPB) based polyurethanes (PUs) were prepared following step growth polymerization by the introduction of varying mole ratio of chitosan (CH) and curcumin (CUR). Structural study of blends through infrared spectroscopy confirmed the incorporation of CH and CUR into the backbone of the PU. The scanning electron microscopic (SEM) study confirmed the well dispersion of incorporated chitosan/curcumin and homogeneity of surface of synthesized samples. Thermogravimetric analysis (TGA) of PU blends indicated a better thermal stability with 0.25M:0.75M of chitosan to curcumin. Mechanical properties such as modulus and tensile strength of PU blends were found to be better with higher contents of chitosan and curcumin. The same extender composition (1mol BDO, 075mol chitosan and 0.25mol curcumin) based PU showed higher substantial of antimicrobial activity as compared to the all other PUs. On the whole, this work is actually a step towards the generation of novel biocompatible materials preferably useful for biomedical applications. Copyright © 2016 Elsevier B.V. All rights reserved.

Marine biofouling resistance of polyurethane with biodegradation and hydrolyzation.

PubMed

Xu, Wentao; Ma, Chunfeng; Ma, Jielin; Gan, Tiansheng; Zhang, Guangzhao

2014-03-26

We have prepared polyurethane with poly(ε-caprolactone) (PCL) as the segments of the main chain and poly(triisopropylsilyl acrylate) (PTIPSA) as the side chains by a combination of radical polymerization and a condensation reaction. Quartz crystal microbalance with dissipation studies show that polyurethane can degrade in the presence of enzyme and the degradation rate decreases with the PTIPSA content. Our studies also demonstrate that polyurethane is able to hydrolyze in artificial seawater and the hydrolysis rate increases as the PTIPSA content increases. Moreover, hydrolysis leads to a hydrophilic surface that is favorable to reduction of the frictional drag under dynamic conditions. Marine field tests reveal that polyurethane has good antifouling ability because polyurethane with a biodegradable PCL main chain and hydrolyzable PTIPSA side chains can form a self-renewal surface. Polyurethane was also used to carry and release a relatively environmentally friendly antifoulant, and the combined system exhibits a much higher antifouling performance even in a static marine environment.

New polyurethane nanocomposites based on soya oil.

PubMed

Mohammed, Issam Ahmed; Abd Khadir, Nurul Khizrien; Jaffar Al-Mulla, Emad Abbas

2014-01-01

New polyurethane (PU) nanocomposites were prepared from a dispersion of 0 - 5% montmorillonite (MMT) clay with isocyanate and soya oil polyol that was synthesized via transesterification of triglycerides to reduce petroleum dependence. FT-IR spectra indicate the presence of hydrogen bonding between nanoclay and the polymer matrix, whereas the exfoliated structure of clay layers was confirmed by X-ray diffraction (XRD) and transmission electron microscopy (TEM). Optical microscopy, mechanical and thermal analyses were done to investigate significant improvement of the nanocomposites. The results showed PU-3% nanoclay (NC) showed optimum results in mechanical properties such as tensile and flexural strength but the lowest in impact strength.

Highly fluorinated polyurethanes

NASA Technical Reports Server (NTRS)

Stump, E. C., Jr.; Rochow, S. E. (Inventor)

1973-01-01

The reaction perfluorinated hydroxyl terminated polyether with diisocyanate to form polyurethane is discussed. Data are given on the resin's oxidation stability, chemical resistance, and low temperature flexibility.

Pressure polymerization of polyester

DOEpatents

Maurer, Charles J.; Shaw, Gordon; Smith, Vicky S.; Buelow, Steven J.; Tumas, William; Contreras, Veronica; Martinez, Ronald J.

2000-08-29

A process is disclosed for the preparation of a polyester polymer or polyester copolymer under superatmospheric pressure conditions in a pipe or tubular reaction under turbannular flow conditions. Reaction material having a glycol equivalents to carboxylic acid equivalents mole ratio of from 1.0:1 to 1.2:1, together with a superatmospheric dense gaseous medium are fed co-currently to the reactor. Dicarboxylic acid and/or diol raw materials may be injected into any of the reaction zones in the process during operation to achieve the overall desired mole ratio balance. The process operates at temperatures of from about 220.degree. C. to about 320.degree. C., with turbannular flow achieved before the polymer product and gas exit the reactor process. The pressure in the reaction zones can be in the range from 15 psia to 2500 psia. A polymer product having a DP of a greater than 40, more preferably at least about 70, is achieved by the transfer of water from the reacting material polymer melt to the gaseous medium in the reactor.

Chemical speciation of polyurethane polymers by soft-x-ray spectromicroscopy

DOE Office of Scientific and Technical Information (OSTI.GOV)

Rightor, E.G.; Hitchcock, A.P.; Urquhart, S.G.

1997-04-01

Polyurethane polymers are a versatile class of materials which have numerous applications in modern life, from automotive body panels, to insulation, to household furnishings. Phase segregation helps to determine the physical properties of several types of polyurethanes. Polymer scientists believe that understanding the connections between formulation chemistry, the chemical nature of the segregated phases, and the physical properties of the resulting polymer, would greatly advance development of improved polyurethane materials. However, the sub-micron size of segregated features precludes their chemical analysis by existing methods, leaving only indirect means of characterizing these features. For the past several years the authors havemore » been developing near edge X-ray absorption spectromicroscopy to study the chemical nature of individual segregated phases. Part of this work has involved studies of molecular analogues and model polymers, in conjunction with quantum calculations, in order to identify the characteristic near edge spectral transitions of important chemical groups. This spectroscopic base is allowing the authors to study phase segregation in polyurethanes by taking advantage of several unique capabilities of scanning transmission x-ray microscopy (STXM) - high spatial resolution ({approximately} 0.1 {mu}m), high spectral resolution ({approximately}0.1 eV at the C 1s edge), and the ability to record images and spectra with relatively low radiation damage. The beamline 7.0 STXM at ALS is being used to study microtomed sections or cast films of polyurethanes. Based on the pioneering work of Ade, Kirz and collaborators at the NSLS X-1A STXM, it is clear that scanning X-ray transmission microscopy using soft X-rays can provide information about the chemical origin of phase segregation in radiation-sensitive materials on a sub-micron scale. This information is difficult or impossible to obtain by other means.« less

Organically Modified Nanoclay-Reinforced Rigid Polyurethane Films

NASA Astrophysics Data System (ADS)

Park, Yong Tae; Qian, Yuqiang; Lindsay, Chris; Stein, Andreas; Macosko, Christopher

2012-02-01

The nanodispersion of vermiculite in polyurethanes was investigated to produce organoclay-reinforced rigid gas barrier films. Reducing gas transport can improve the insulation performance of closed cell polyurethane foam. In a previous study, the dispersion of vermiculite in polyurethanes without organic modification was not sufficient due to the non-uniform dispersion morphology. When vermiculite was modified by cation exchange with long-chain quaternary ammonium cations, the dispersion in methylene diphenyl diisocyanate (MDI) was significantly improved. Dispersion was improved by combining high intensity dispersive mixing with efficient distributive mixing. Polymerization conditions were also optimized in order to provide a high state of nanodispersion in the polyurethane nanocomposite. The dispersions were characterized using rheological, microscopic and scattering/diffraction techniques. The final nanocomposites showed enhancement of mechanical properties and reduction in permeability to carbon dioxide at low clay concentration (around 2 wt percent).

Polyurethane-acrylate-based hydrophobic film: Facile fabrication, characterization, and application

NASA Astrophysics Data System (ADS)

Park, Jongsung; Nguyen, Bui Quoc Huy; Kim, Ji-Kwan; Shanmugasundaram, Arunkumar; Lee, Dong-Weon

2018-06-01

Polyurethane-acrylate (PUA) is a versatile UV-curable polymer with a short curing time at room temperature, whose surface structure can be flexibly modified by applying various micropatterns. In this paper, we propose a facile and cost-effective fabrication method for the continuous production of an optically transparent PUA-based superhydrophobic thin film. Poly(dimethylsiloxane) (PDMS) was employed as a soft mold for the fabrication of PUA films through the roll-to-roll technique. In addition, nanosilica was spray-coated onto the PUA surface to further improve the hydrophobicity. The fabricated PUA thin film showed the highest static water contact angle (WCA) of ∼140°. The high durability of the PUA film was also demonstrated through mechanical impacting tests. Furthermore, only ∼2% of voltage loss was observed in the solar panel covered with the PUA-based superhydrophobic film. These obtained results indicate the feasibility of applying the film as a protective layer in applications requiring a high transparency and a self-cleaning effect.

Time-dependent crashworthiness of polyurethane foam

NASA Astrophysics Data System (ADS)

Basit, Munshi Mahbubul; Cheon, Seong Sik

2018-05-01

Time-dependent stress-strain relationship as well as crashworthiness of polyurethane foam was investigated under constant impact energy with different velocities, considering inertia and strain-rate effects simultaneously during the impact testing. Even though the impact energies were same, the percentage in increase in densification strain due to higher impact velocities was found, which yielded the wider plateau region, i.e. growth in crashworthiness. This phenomenon is analyzed by the microstructure of polyurethane foam obtained from scanning electron microscopy. The equations, coupled with the Sherwood-Frost model and the impulse-momentum theory, were employed to build the constitutive equation of the polyurethane foam and calculate energy absorption capacity of the foam. The nominal stress-strain curves obtained from the constitutive equation were compared with results from impact tests and were found to be in good agreement. This study is dedicated to guiding designer use polyurethane foam in crashworthiness structures such as an automotive bumper system by providing crashworthiness data, determining the crush mode, and addressing a mathematical model of the crashworthiness.

Polyurethane-Foam Maskant

NASA Technical Reports Server (NTRS)

Bodemeijer, R.

1985-01-01

Brown wax previously used to mask hardware replaced with polyurethane foam in electroplating and electroforming operations. Foam easier to apply and remove than wax and does not contaminate electrolytes.

Coating processes for increasing the moisture resistance of polyurethane baffle material

NASA Technical Reports Server (NTRS)

Bilow, N.; Sawko, P.

1974-01-01

An investigation was conducted with the objective to improve the hydrolytic stability of reticulated polyurethane baffle material. This material is used in fuel tanks of aircraft and ground vehicles. The most commonly used foam of this type is hydrolytically unstable. Potential moisture barrier coatings which were evaluated include Parylene, epoxy-polysulfide, polyether based polyurethanes, polysulfides, polyolefin rubbers, and several other materials. Parylene coatings of at least 0.2 mil were found to provide the greatest improvement in hydrolytic stability.

Thermal Degradation Mechanism of a Thermostable Polyester Stabilized with an Open-Cage Oligomeric Silsesquioxane

PubMed Central

Gozalbo, Ana; Mestre, Sergio; Sanz, Vicente

2017-01-01

A polyester composite was prepared through the polymerization of an unsaturated ester resin with styrene and an open-cage oligomeric silsesquioxane with methacrylate groups. The effect of the open-cage oligomeric silsesquioxane on the thermal stability of the thermostable polyester was studied using both thermogravimetric analysis and differential thermal analysis. The results showed that the methacryl oligomeric silsesquioxane improved the thermal stability of the polyester. The decomposition mechanism of the polyester/oligomer silsesquioxane composite was proposed by Fourier transform infrared spectroscopy (FTIR) analysis of the volatiles. PMID:29295542

The Modification of Polyurethane Foams Using New Boroorganic Polyols (II) Polyurethane Foams from Boron-Modified Hydroxypropyl Urea Derivatives

PubMed Central

2014-01-01

The work focuses on research related to determination of application possibility of new, ecofriendly boroorganic polyols in rigid polyurethane foams production. Polyols were obtained from hydroxypropyl urea derivatives esterified with boric acid and propylene carbonate. The influence of esterification type on properties of polyols and next on polyurethane foams properties was determined. Nitrogen and boron impacts on the foams' properties were discussed, for instance, on their physical, mechanical, and electric properties. Boron presence causes improvement of dimensional stability and thermal stability of polyurethane foams. They can be applied even at temperature 150°C. Unfortunately, introducing boron in polyurethanes foams affects deterioration of their water absorption, which increases as compared to the foams that do not contain boron. However, presence of both boron and nitrogen determines the decrease of the foams combustibility. Main impact on the decrease combustibility of the obtained foams has nitrogen presence, but in case of proper boron and nitrogen ratio their synergic activity on the combustibility decrease can be easily seen. PMID:24587721

Reversibly pH-responsive polyurethane membranes for on-demand intravaginal drug delivery.

PubMed

Kim, Seungil; Chen, Yufei; Ho, Emmanuel A; Liu, Song

2017-01-01

To provide better protection for women against sexually transmitted infections, on-demand intravaginal drug delivery was attempted by synthesizing reversibly pH-sensitive polyether-polyurethane copolymers using poly(ethylene glycol) (PEG) and 1,4-bis(2-hydroxyethyl)piperazine (HEP). Chemical structure and thermo-characteristics of the synthesized polyurethanes were confirmed by attenuated total reflectance-Fourier transform infrared spectroscopy (ATR-FTIR), 1 H-nuclear magnetic resonance ( 1 H-NMR), and melting point testing. Membranes were cast by solvent evaporation method using the prepared pH-sensitive polyurethanes. The impact of varying pH on membrane swelling and surface morphology was evaluated via swelling ratio change and scanning electron microscopy (SEM). The prepared pH-responsive membranes showed two times higher swelling ratio at pH 4 than pH 7 and pH-triggered switchable surface morphology change. The anionic anti-inflammatory drug diclofenac sodium (NaDF) was used as a model compound for release studies. The prepared pH-responsive polyurethane membranes allowed continuous NaDF release for 24h and around 20% release of total NaDF within 3h at pH 7 but little-to-no drug release at pH 4.5. NaDF permeation across the prepared membranes demonstrated a reversible pH-responsiveness. The pH-responsive polyurethane membranes did not show any noticeable negative impact on vaginal epithelial cell viability or induction of pro-inflammatory cytokine production compared to controls. Overall, the non-cytotoxic HEP-based pH-responsive polyurethane demonstrated its potential to be used in membrane-based implants such as intravaginal rings to achieve on-demand "on-and-off" intravaginal drug delivery. A reversible and sharp switch between "off" and "on" drug release is achieved for the first time through new pH-sensitive polyurethane membranes, which can serve as window membranes in reservoir-type intravaginal rings for on-demand drug delivery to prevent sexually

Polyurethane-Coated Breast Implants Revisited: A 30-Year Follow-Up

PubMed Central

Castel, Nikki; Soon-Sutton, Taylor; Deptula, Peter; Flaherty, Anna

2015-01-01

Background Polyurethane coating of breast implants has been shown to reduce capsular contracture in short-term follow-up studies. This 30-year study is the longest examination of the use of polyurethane-coated implants and their correlation with capsular contracture. Methods This study evaluates the senior surgeon's (F.D.P.) experience with the use of polyurethane-coated implants in aesthetic breast augmentation in 382 patients over 30 years. Follow-up evaluations were conducted for six months after surgery. After the six-month follow-up period, 76 patients returned for reoperation. The gross findings, histology, and associated capsular contracture were noted at the time of explantation. Results No patient during the six-month follow-up period demonstrated capsular contracture. For those who underwent reoperation for capsular contracture, Baker II/III contractures were noted nine to 10 years after surgery and Baker IV contractures were noted 12 to 21 years after surgery. None of the explanted implants had macroscopic evidence of polyurethane, which was only found during the first five years after surgery. The microscopic presence of polyurethane was noted in all capsules up to 30 years after the original operation. Conclusions An inverse correlation was found between the amount of polyurethane coating on the implant and the occurrence of capsular contracture. Increasingly severe capsular contracture was associated with a decreased amount of polyurethane coating on the surface of the implants. No contracture occurred in patients whose implants showed incomplete biodegradation of polyurethane, as indicated by the visible presence of polyurethane coating. We recommend research to find a non-toxic, non-biodegradable synthetic material as an alternative to polyurethane. PMID:25798390

Polyurethane/fluor-hydroxyapatite nanocomposite scaffolds for bone tissue engineering. Part I: morphological, physical, and mechanical characterization

PubMed Central

Asefnejad, Azadeh; Behnamghader, Aliasghar; Khorasani, Mohammad Taghi; Farsadzadeh, Babak

2011-01-01

In this study, new nano-fluor-hydroxyapatite (nFHA)/polyurethane composite scaffolds were fabricated for potential use in bone tissue engineering. Polyester urethane samples were synthesized from polycaprolactone, hexamethylene diisocyanate, and 1,4-butanediol as chain extender. Nano fluor-hydroxyapatite (nFHA) was successfully synthesized by sol-gel method. The solid–liquid phase separation and solvent sublimation methods were used for preparation of the porous composites. Mechanical properties, chemical structure, and morphological characteristics of the samples were investigated by compressive test, Fourier transform infrared, and scanning electron microscopy (SEM) techniques, respectively. The effect of nFHA powder content on porosity and pore morphology was investigated. SEM images demonstrated that the scaffolds were constituted of interconnected and homogeneously distributed pores. The pore size of the scaffolds was in the range 50–250 μm. The result obtained in this research revealed that the porosity and pore average size decreased and compressive modulus increased with nFHA percentage. Considering morphological, physical, and mechanical properties, the scaffold with a higher ratio of nFHA has suitable potential use in tissue regeneration. PMID:21289986

Chondrocyte-based intraoperative processing strategies for the biological augmentation of a polyurethane meniscus replacement.

PubMed

Vedicherla, Srujana; Romanazzo, Sara; Kelly, Daniel J; Buckley, Conor T; Moran, Cathal J

2017-11-28

Purpose/aim of study: Menisectomies account for over 1.5 million surgical interventions in Europe annually, and there is a growing interest in regenerative strategies to improve outcomes in meniscal replacement. The overall objective of this study was to evaluate the role of intraoperatively applied fresh chondrocyte (FC) isolates compared to minced cartilage (MC) fragments, used without cell isolation, to improve bioactivity and tissue integration when combined with a polyurethane replacement. First, to optimize the intraoperative cell isolation protocol, caprine articular cartilage biopsies were digested with 750 U/ml or 3000 U/ml collagenase type II (ratio of 10 ml per g of tissue) for 30 min, 1 h or 12 h with constant agitation and compared to culture-expanded chondrocytes in terms of matrix deposition when cultured on polyurethane scaffolds. Finally, FCs and MC-augmented polyurethane scaffolds were evaluated in a caprine meniscal explant model to assess the potential enhancements on tissue integration strength. Adequate numbers of FCs were harvested using a 30 min chondrocyte isolation protocol and were found to demonstrate improved matrix deposition compared to standard culture-expanded cells in vitro. Upon evaluation in a meniscus explant defect model, both FCs and MC showed improved matrix deposition at the tissue-scaffold interface and enhanced push-out strength, fourfold and 2.5-fold, respectively, compared with the acellular implant. Herein, we have demonstrated a novel approach that could be applied intraoperatively, using FCs or MC for improved tissue integration with a polyurethane meniscal replacement.

Design and development of low cost polyurethane biopolymer based on castor oil and glycerol for biomedical applications

PubMed Central

Tan, A. C. W.; Polo‐Cambronell, B. J.; Provaggi, E.; Ardila‐Suárez, C.; Ramirez‐Caballero, G. E.; Baldovino‐Medrano, V. G.

2017-01-01

Abstract In the current study, we present the synthesis of novel low cost bio‐polyurethane compositions with variable mechanical properties based on castor oil and glycerol for biomedical applications. A detailed investigation of the physicochemical properties of the polymer was carried out by using mechanical testing, ATR‐FTIR, and X‐ray photoelectron spectroscopy (XPS). Polymers were also tested in short term in‐vitro cell culture with human mesenchymal stem cells to evaluate their biocompatibility for potential applications as biomaterial. FTIR analysis confirmed the synthesis of castor oil and glycerol based PU polymers. FTIR also showed that the addition of glycerol as co‐polyol increases crosslinking within the polymer backbone hence enhancing the bulk mechanical properties of the polymer. XPS data showed that glycerol incorporation leads to an enrichment of oxidized organic species on the surface of the polymers. Preliminary investigation into in vitro biocompatibility showed that serum protein adsorption can be controlled by varying the glycerol content with polymer backbone. An alamar blue assay looking at the metabolic activity of the cells indicated that castor oil based PU and its variants containing glycerol are non‐toxic to the cells. This study opens an avenue for using low cost bio‐polyurethane based on castor oil and glycerol for biomedical applications. PMID:29159831

Synthesis of a Novel Biodegradable Polyurethane with Phosphatidylcholines

PubMed Central

Cao, Jun; Chen, Niancao; Chen, Yuanwei; Luo, Xianglin

2010-01-01

A novel polyurethane was successfully synthesized by chain-extension of biodegradable poly (l-lactide) functionalized phosphatidylcholine (PC) with hexamethylene diisocyanate (HDI) as chain extender (PUR-PC). The molecular weights, glass transition temperature (Tg) increased significantly after the chain-extension. The hydrophilicity of PUR-PC was better than the one without PC, according to a water absorption test. Moreover, the number of adhesive platelets and anamorphic platelets on PUR-PC film were both less than those on PUR film. These preliminary results suggest that this novel polyurethane might be a better scaffold than traditional biodegradable polyurethanes for tissue engineering due to its better blood compatibility. Besides, this study also provides a new method to prepare PC-modified biodegradable polyurethanes. PMID:20480047

75 FR 47795 - Certain Polyester Staple Fiber from Korea: Rescission of Antidumping Duty Administrative Review

Federal Register 2010, 2011, 2012, 2013, 2014

2010-08-09

... DEPARTMENT OF COMMERCE International Trade Administration [A-580-839] Certain Polyester Staple... Polyester staple fiber (``PSF'') covered by the scope of the order is defined as synthetic staple fibers, not carded, combed or otherwise processed for spinning, of polyesters measuring 3.3 decitex (3 denier...

75 FR 4044 - Polyester Staple Fiber From Taiwan: Initiation and Preliminary Results of Changed-Circumstances...

Federal Register 2010, 2011, 2012, 2013, 2014

2010-01-26

... DEPARTMENT OF COMMERCE International Trade Administration [A-583-833] Polyester Staple Fiber From... Commerce is initiating a changed- circumstances review of the antidumping duty order on polyester staple... previously accorded to Far Eastern Textile Limited with regard to the antidumping duty order on polyester...

76 FR 52935 - Certain Polyester Staple Fiber From Korea: Rescission of Antidumping Duty Administrative Review

Federal Register 2010, 2011, 2012, 2013, 2014

2011-08-24

... DEPARTMENT OF COMMERCE International Trade Administration [A-580-839] Certain Polyester Staple... on polyester staple fiber from Korea. See Antidumping or Countervailing Duty Order, Finding, or..., 76 FR 37781 (June 28, 2011). Scope of the Order Polyester staple fiber covered by the scope of the...

High-strain slide-ring shape-memory polycaprolactone-based polyurethane.

PubMed

Wu, Ruiqing; Lai, Jingjuan; Pan, Yi; Zheng, Zhaohui; Ding, Xiaobin

2018-06-06

To enable shape-memory polymer networks to achieve recoverable high deformability with a simultaneous high shape-fixity ratio and shape-recovery ratio, novel semi-crystalline slide-ring shape-memory polycaprolactone-based polyurethane (SR-SMPCLU) with movable net-points constructed by a topologically interlocked slide-ring structure was designed and fabricated. The SR-SMPCLU not only exhibited good shape fixity, almost complete shape recovery, and a fast shape-recovery speed, it also showed an outstanding recoverable high-strain capacity with 95.83% Rr under a deformation strain of 1410% due to the pulley effect of the topological slide-ring structure. Furthermore, the SR-SMPCLU system maintained excellent shape-memory performance with increasing the training cycle numbers at 45% and even 280% deformation strain. The effects of the slide-ring cross-linker content, deformation strain, and successive shape-memory cycles on the shape-memory performance were investigated. A possible mechanism for the shape-memory effect of the SR-SMPCLU system is proposed.

Liquefaction of corn stover and preparation of polyester from the liquefied polyol.

PubMed

Yu, Fei; Liu, Yuhuan; Pan, Xuejun; Lin, Xiangyang; Liu, Chengmei; Chen, Paul; Ruan, Roger

2006-01-01

This research investigated a novel process to prepare polyester from corn stover through liquefaction and crosslinking processes. First, corn stover was liquefied in organic solvents (90 wt% ethylene glycol and 10 wt% ethylene carbonate) with catalysts at moderate temperature under atmospheric pressure. The effect of liquefaction temperature, biomass content, and type of catalyst, such as H2SO4, HCl, H3PO4, and ZnCl2, was evaluated. Higher liquefaction yield was achieved in 2 wt% sulfuric acid, 1/4 (w/w) stover to liquefying reagent ratio; 160 degrees C temperature, in 2 h. The liquefied corn stover was rich in polyols, which can be directly used as feedstock for making polymers without further separation or purification. Second, polyester was made from the liquefied corn stover by crosslinking with multifunctional carboxylic acids and/or cyclic acid anhydrides. The tensile strength of polyester is about 5 MPa and the elongation is around 35%. The polyester is stable in cold water and organic solvents and readily biodegradable as indicated by 82% weight loss when buried in damp soil for 10 mo. The results indicate that this novel polyester could be used for the biodegradable garden mulch film production.

Non-destructive and fast identification of cotton-polyester blend fabrics by the portable near-infrared spectrometer.

PubMed

Li, Wen-xia; Li, Feng; Zhao, Guo-liang; Tang, Shi-jun; Liu, Xiao-ying

2014-12-01

A series of 376 cotton-polyester (PET) blend fabrics were studied by a portable near-infrared (NIR) spectrometer. A NIR semi-quantitative-qualitative calibration model was established by Partial Least Squares (PLS) method combined with qualitative identification coefficient. In this process, PLS method in a quantitative analysis was used as a correction method, and the qualitative identification coefficient was set by the content of cotton and polyester in blend fabrics. Cotton-polyester blend fabrics were identified qualitatively by the model and their relative contents were obtained quantitatively, the model can be used for semi-quantitative identification analysis. In the course of establishing the model, the noise and baseline drift of the spectra were eliminated by Savitzky-Golay(S-G) derivative. The influence of waveband selection and different pre-processing method was also studied in the qualitative calibration model. The major absorption bands of 100% cotton samples were in the 1400~1600 nm region, and the one for 100% polyester were around 1600~1800 nm, the absorption intensity was enhancing with the content increasing of cotton or polyester. Therefore, the cotton-polyester's major absorption region was selected as the base waveband, the optimal waveband (1100~2500 nm) was found by expanding the waveband in two directions (the correlation coefficient was 0.6, and wave-point number was 934). The validation samples were predicted by the calibration model, the results showed that the model evaluation parameters was optimum in the 1100~2500 nm region, and the combination of S-G derivative, multiplicative scatter correction (MSC) and mean centering was used as the pre-processing method. RC (relational coefficient of calibration) value was 0.978, RP (relational coefficient of prediction) value was 0.940, SEC (standard error of calibration) value was 1.264, SEP (standard error of prediction) value was 1.590, and the sample's recognition accuracy was up to 93

75 FR 39208 - Polyester Staple Fiber from Taiwan: Final Results of Changed-Circumstances Antidumping Duty...

Federal Register 2010, 2011, 2012, 2013, 2014

2010-07-08

... DEPARTMENT OF COMMERCE International Trade Administration [A-583-833] Polyester Staple Fiber from... Eastern Textile Limited with regard to the antidumping duty order on polyester staple fiber from Taiwan... on polyester staple fiber from Taiwan to determine whether FENC was the successor-in-interest to FET...

Polyurethane foam-covered breast implants: a justified choice?

PubMed

Scarpa, C; Borso, G F; Vindigni, V; Bassetto, F

2015-01-01

Even if the safety of the polyurethane prosthesis has been the subject of many studies and professional and public controversies. Nowadays, polyurethane covered implants are very popular in plastic surgery for the treatment of capsular contracture. We have identified 41 papers (1 is a communication of the FDA) by using search browsers such as Pubmed, Medline, and eMedicine. Eleven manuscripts have been used for an introduction, and the remaining thirty have been subdivided into three tables whose results have been summarized in three main chapters: (1) capsular formation and contracture, (2) complications, (3) biodegradation and cancer risk. (1) The polyurethanic capsule is a well defined foreign body reaction characterized by synovial metaplasia, a thin layer of disarranged collagen fibers and a high vascularization. These features make possible a "young" capsule and a low occurrence of capsular contracture even over a long period (10 years); (2) the polyurethane implants may be difficult to remove but there is no evidence that they cause an increase in the other complications; (3) there is no evidence of polyurethane related cancer in long-term studies (after 5 years). Polyurethane foam covered breast implants remain a valid choice for the treatment of capsular contracture even if it would be very useful to verify the ease of removal of the prosthesis and to continue investigations on biodegradation products.

Intrinsically radiopaque polyurethanes with chain extender 4,4'-isopropylidenebis [2-(2,6-diiodophenoxy)ethanol] for biomedical applications.

PubMed

Dawlee, S; Jayabalan, M

2015-05-01

Radiopaque polyurethanes are used for medical applications as it allows post-operative assessment of the biomaterial devices using X-ray. Inherently, radiopaque polyurethanes based on polytetramethylene glycol (PTMG), polypropylene glycol, 4,4'-methylenebis(phenyl isocyanate), and a new iodinated chain extender 4,4'-isopropylidenebis[2-(2,6-diiodophenoxy)ethanol] with flexible spacers were synthesized and characterized. The iodinated polyurethanes were clear, optically transparent, and had high molecular weights. The polyurethanes also possessed excellent radiopacity and high thermal stability. The biocompatibility of the most promising iodinated polyurethane was evaluated both in vitro (cytotoxicity evaluation by direct contact and MTT assay, using L929 mouse fibroblast cells) and in vivo (toxicology studies in rabbits and subcutaneous implantation in rats). The material was nontoxic and well tolerated by the animals. Thus, these radiopaque and transparent polyurethanes are expected to have potential for various biomedical applications. © The Author(s) 2014 Reprints and permissions: sagepub.co.uk/journalsPermissions.nav.

Polyurethane retainers for ball bearings

NASA Technical Reports Server (NTRS)

Christy, R. I.

1973-01-01

Evaluation of a new ball bearing retainer material is reported. A special composite polyurethane foam ball retainer has been developed that has virtually zero wear, is chemically inert to hydrocarbon lubricants, and stores up to 60 times as much lubricant per unit volume as the most commonly used retainer material, cotton phenolic. This new retainer concept shows promise of years of ball bearing operation without reoiling, based on life testing in high vacuum.

Chitin based polyurethanes using hydroxyl terminated polybutadiene, part III: surface characteristics.

PubMed

Zia, Khalid Mahmood; Zuber, Mohammad; Saif, Muhammad Jawwad; Jawaid, Mohammad; Mahmood, Kashif; Shahid, Muhammad; Anjum, Muhammad Naveed; Ahmad, Mirza Nadeem

2013-11-01

Hydroxy terminated polybutadiene (HTPB)-chitin based polyurethanes (PUs) with controlled hydrophobicity were synthesized using HTPB and toluene diisocyanate (TDI). The prepolymer was extended with different mass ratios of chitin and 1,4-butane diol (BDO). The effect of chitin contents in chain extender (CE) proportions on surface properties was studied and investigated. Incorporation of chitin contents into the final PU showed decrease in contact angle value of water drop, water absorption (%) and swelling behavior. The antibacterial activity of the prepared samples was affected by varying the chitin contents in the chemical composition of the final PU. The results demonstrated that the use of prepared material can be suggested as non-absorbable suture. Copyright © 2013 Elsevier B.V. All rights reserved.

Physico-mechanical and wear properties of novel sustainable sour-weed fiber reinforced polyester composites

NASA Astrophysics Data System (ADS)

Patel, Vinay Kumar; Chauhan, Shivani; Katiyar, Jitendra Kumar

2018-04-01

In this study, a novel natural fiber i.e. Sour-weed botanically known as ‘Rumex acetosella’ has been first time introduced as natural reinforcements to polyester matrix. The natural fiber based polyester composites were fabricated by hand lay-up technique using different sizes and different weight percentages. In Sour-weed/Polyester composites, physical (density, water absorption and hardness), mechanical properties (tensile and impact properties) and wear properties (sand abrasion and sliding wear) were investigated for different sizes of sour weed of 0.6 mm, 5 mm, 10 mm, 15 mm and 20 mm at 3, 6 and 9 weight percent loading, respectively in polyester matrix. Furthermore, on average value of results, the multi-criteria optimization technique i.e. TOPSIS was employed to decide the ranking of the composites. From the optimized results, it was observed that Sour-weed composite reinforced with fiber’s size of 15 mm at 6 wt% loading demonstrated the best ranked composite exhibiting best overall properties as average tensile strength of 34.33 MPa, average impact strength of 10 Joule, average hardness of 12 Hv, average specific sand abrasion wear rate of 0.0607 mm3 N‑1m‑1, average specific sliding wear rate of 0.002 90 mm3 N‑1m‑1, average percentage of water absorption of 3.446% and average density of 1.013 among all fabricated composites.

Rigid polyurethane foam/cellulose whisker nanocomposites: preparation, characterization, and properties.

PubMed

Li, Yang; Ren, Hongfeng; Ragauskas, Arthur J

2011-08-01

Novel rigid polyurethane nanocomposite foams have been prepared by the polymerization of a sucrose-based polyol, a glycerol-based polyol and polymeric diphenylmethane diisocyanate in the presence of cellulose whiskers. Varying amounts of sulfuric acid hydrolyzed cellulose whiskers (0.25, 0.50, 0.75 and 1.00 wt%) prepared from a commercial fully bleached softwood kraft pulp were incorporated to investigate the effect of its dosage on the mechanical and thermal properties of polyurethane nanocomposites. Fourier transform infrared spectra of the nanocomposite foams suggested that additional hydrogen bonds were developed and crosslinking occurred between the hydroxyl groups of cellulose whiskers and isocyanate groups which increased the phase separation of soft and hard segments in the polyurethane. The closed cells of control foam and nanocomposite foams were homogeneously dispersed and the cell sizes were approximately 350 microm in diameter as observed by scanning electron microscope. A substantial improvement of mechanical properties at low whisker content (< or = 1.00 wt%) was obtained, especially the compressive strength and modulus at 1.00 wt% whiskers content which were increased by 269.7% and 210.0%, respectively. Thermal stability of the nanocomposites was also enhanced as determined by differential scanning calorimetry and thermogravimetric analysis.

Thermoresponsive Polyurethane Bearing Oligo(Ethylene Glycol) as Side Chain Without Polyol at Polymer Backbone Achieved Excellent Hydrophilic and Hydrophobic Switching.

PubMed

Aoki, Daisuke; Ajiro, Hiroharu

2018-06-13

In order to prepare thermoresponsive polyurethane gels, a novel polyurethane bearing oligo(ethylene glycol) (OEG) as the side chain is successfully synthesized with hexamethylene diisocyanate and OEG tartrate ester. The aqueous solution of the polyurethane shows sharp and clear lower critical solution temperature behavior at 34 °C. Furthermore, a hydrogel based on the same polyurethane is also successfully prepared using glycerol as the crosslinker. This polyurethane hydrogel including 10 mol% of glycerol presents a large swelling ratio change between 4 °C and 37 °C from 250% to 40%. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

A multilayered polyurethane foam technique for skin graft immobilization.

PubMed

Nakamura, Motoki; Ito, Erika; Kato, Hiroshi; Watanabe, Shoichi; Morita, Akimichi

2012-02-01

Several techniques are applicable for skin graft immobilization. Although the sponge dressing is a popular technique, pressure failure near the center of the graft is a weakness of the technique that can result in engraftment failure. To evaluate the efficacy of a new skin graft immobilization technique using multilayered polyurethane foam in vivo and in vitro. Twenty-six patients underwent a full-thickness skin graft. Multiple layers of a hydrocellular polyurethane foam dressing were used for skin graft immobilization. In addition, we created an in vitro skin graft model that allowed us to estimate immobilization pressure at the center and edges of skin grafts of various sizes. Overall mean graft survival was 88.9%. In the head and neck region (19 patients), mean graft survival was 93.6%. Based on the in vitro outcomes, this technique supplies effective pressure (<30 mmHg) to the center region of the skin graft. This multilayered polyurethane foam dressing is simple, safe, and effective for skin graft immobilization. © 2011 by the American Society for Dermatologic Surgery, Inc. Published by Wiley Periodicals, Inc.

Isosorbide as the structural component of bio-based unsaturated polyesters for use as thermosetting resins.

PubMed

Sadler, Joshua M; Toulan, Faye R; Nguyen, Anh-Phuong T; Kayea, Ronald V; Ziaee, Saeed; Palmese, Giuseppe R; La Scala, John J

2014-01-16

In recent years, the development of renewable bio-based resins has gained interest as potential replacements for petroleum based resins. Modified carbohydrate-based derivatives have favorable structural features such as fused bicyclic rings that offer promising candidates for the development of novel renewable polymers with improved thermomechanical properties when compared to early bio-based resins. Isosorbide is one such compound and has been utilized as the stiffness component for the synthesis of novel unsaturated polyesters (UPE) resins. Resin blends of BioUPE systems with styrene were shown to possess viscosities (120-2200 cP) amenable to a variety of liquid molding techniques, and after cure had Tgs (53-107 °C) and storage moduli (430-1650 MPa) that are in the desired range for composite materials. These investigations show that BioUPEs containing isosorbide can be tailored during synthesis of the prepolymer to meet the needs of different property profiles. Copyright © 2013 Elsevier Ltd. All rights reserved.

[Analysis of anatomical pieces preservation with polyester resin for human anatomy study].

PubMed

de Oliveira, Ítalo Martins; Mindêllo, Marcela Maria Aguiar; Martins, Yasmin de Oliveira; da Silva Filho, Antônio Ribeiro

2013-01-01

To evaluate the use of polyester resin in preserving anatomical specimens for the study of human anatomy. We used 150 anatomical specimens, comprised of unfixed (fresh), fixed in 10% formalin and vascular casts of organs injected with vinyl acetate and polyester resin. The solution used consisted of polyester resin with the diluent styrene monomer and catalyst (peroxol). After embedding in this solution, models in transparent resin were obtained, allowing full observation of structures and conservation of the specimens used. upon evaluation of the specimens, we observed a high degree of transparency, which promoted a complete visualization of structures with perfect preservation of the anatomy. The average time for the completion of the embedding was 48 hours. Only 14 specimens (9.3%) were lost during the preparation. Polyester resin can be used for preserving anatomical specimens for teaching human anatomy in a practical, aesthetic and durable way.

Biodegradable polyester-based microcarriers with modified surface tailored for tissue engineering.

PubMed

Privalova, A; Markvicheva, E; Sevrin, Ch; Drozdova, M; Kottgen, C; Gilbert, B; Ortiz, M; Grandfils, Ch

2015-03-01

Microcarriers have been proposed in tissue engineering, namely for bone, cartilage, skin, vascular, and central nervous system. Although polyester-based microcarriers have been already used for this purpose, their surface properties should be improved to provide better cell growth. The goal of this study was to prepare microbeads based on poly(D,L-lactide) acid, poly(L-lactide) acid, and to study cell behavior (adhesion, spreading, growth, and proliferation) in function of microbead topography and surface chemistry. To improve L-929 fibroblasts adhesion, microbead surface has been modified with three polycations: chitosan, poly(2-dimethylamino ethylmethacrylate) (PDMAEMA), or chitosan-g-oligolactide copolymer (chit-g-OLA). Although modification of the microbead surface with chitosan and PDMAEMA was performed through physical adsorption on the previously prepared microbeads, chit-g-OLA copolymer was introduced directly during microbead processing. This simple approach (1) bypass the use of an emulsifier (polyvinyl alcohol, PVA); (2) avoid surface "contamination" with PVA molecules limiting a control of the surface characteristics. In vitro study of the growth of mouse fibroblasts on the microbeads showed that both surface topography and chemistry affected cell attachment, spreading, and proliferation. Cultivation of L-929 fibroblasts for 7 days resulted in the formation of a 3D cell-scaffold network. © 2014 Wiley Periodicals, Inc.

Patients’ satisfaction with anatomic polyurethane implants

PubMed Central

2017-01-01

This paper presents patients satisfaction using anatomical polyurethane breast implants. We performed surgery on 525 patients, 370 of which were primary and 155 were secondary to various causes such as capsular contracture, ruptured implants, volume changes, and incorrect positioning of the implant. The advantages of silicone polyurethane covers shown high level of patient satisfaction, low incidence of capsular contracture, and absence of implant rotation, and late seroma. PMID:28497022

77 FR 6783 - Certain Polyester Staple Fiber From the People's Republic of China: Extension of Preliminary...

Federal Register 2010, 2011, 2012, 2013, 2014

2012-02-09

... DEPARTMENT OF COMMERCE International Trade Administration [A-570-905] Certain Polyester Staple... results of the administrative review of certain polyester staple fiber from the People's Republic of China... polyester staple fiber from the PRC. See Initiation of Antidumping and Countervailing Duty Administrative...

Hydrolyzable polyester resins, varnishes and coating compositions containing the same

DOEpatents

Yamamori, Naoki; Yokoi, Junji; Yoshikawa, Motoyoshi

1984-01-01

Preparation of hydrolyzable polyester resin comprising reacting polycarboxylic acid and polyhydric alcohol components, which is characterized by using, as at least part of said polyhydric alcohol component, a metallic salt of hydroxy carboxylic acid of the formula defined and effecting the polycondensation at a temperature which is no more than the decomposition temperature of said metallic salt. The polyester resins are useful as resinous vehicle of varnishes and antifouling paints.

Nerve regeneration using tubular scaffolds from biodegradable polyurethane.

PubMed

Hausner, T; Schmidhammer, R; Zandieh, S; Hopf, R; Schultz, A; Gogolewski, S; Hertz, H; Redl, H

2007-01-01

In severe nerve lesion, nerve defects and in brachial plexus reconstruction, autologous nerve grafting is the golden standard. Although, nerve grafting technique is the best available approach a major disadvantages exists: there is a limited source of autologous nerve grafts. This study presents data on the use of tubular scaffolds with uniaxial pore orientation from experimental biodegradable polyurethanes coated with fibrin sealant to regenerate a 8 mm resected segment of rat sciatic nerve. Tubular scaffolds: prepared by extrusion of the polymer solution in DMF into water coagulation bath. The polymer used for the preparation of tubular scaffolds was a biodegradable polyurethane based on hexamethylene diisocyanate, poly(epsilon-caprolactone) and dianhydro-D-sorbitol. EXPERIMENTAL MODEL: Eighteen Sprague Dawley rats underwent mid-thigh sciatic nerve transection and were randomly assigned to two experimental groups with immediate repair: (1) tubular scaffold, (2) 180 degrees rotated sciatic nerve segment (control). Serial functional measurements (toe spread test, placing tests) were performed weekly from 3rd to 12th week after nerve repair. On week 12, electrophysiological assessment was performed. Sciatic nerve and scaffold/nerve grafts were harvested for histomorphometric analysis. Collagenic connective tissue, Schwann cells and axons were evaluated in the proximal nerve stump, the scaffold/nerve graft and the distal nerve stump. The implants have uniaxially-oriented pore structure with a pore size in the range of 2 micorm (the pore wall) and 75 x 700 microm (elongated pores in the implant lumen). The skin of the tubular implants was nonporous. Animals which underwent repair with tubular scaffolds of biodegradable polyurethanes coated with diluted fibrin sealant had no significant functional differences compared with the nerve graft group. Control group resulted in a trend-wise better electrophysiological recovery but did not show statistically significant

Characterization of Polyester Matrix Reinforced with Banana Fibers Thermal Properties by Photoacoustic Technique

NASA Astrophysics Data System (ADS)

de Assis, Foluke S.; Netto, Pedro A.; Margem, Frederico M.; Monteiro, Artur R. P. Junior Sergio N.

Synthetic fibers are being replaced gradually by natural materials such as lignocellulosic fibers. Compared to synthetic fibers, natural fibers have shown advantages in technical aspects such as environmental and economic. So there is a growing international interest in the use of those fibers. The banana fiber presents significant properties to be studied, but until now few thermal properties on banana fiber as reinforcement of polyester matrix were performed. The present work had as its objective to investigate, by photoacoustic spectroscopy and photothermal techniques the thermal properties of diffusivity, specific heat capacity and conductivity for polyester composites reinforced with banana fibers. In the polyester matrix will be added up to 30% in volume of continuous and aligned banana fibers. These values show that the incorporation of banana fibers in the polyester matrix changes its thermal properties.

75 FR 30373 - Certain Polyester Staple Fiber From the People's Republic of China: Extension of Preliminary...

Federal Register 2010, 2011, 2012, 2013, 2014

2010-06-01

... DEPARTMENT OF COMMERCE International Trade Administration [A-570-905] Certain Polyester Staple... results of the administrative review of certain polyester staple fiber from the People's Republic of China... administrative review of the antidumping duty order on certain polyester staple fiber from the PRC. See...

78 FR 38938 - Polyester Staple Fiber From Taiwan: Final Results of Antidumping Duty Administrative Review; 2011...

Federal Register 2010, 2011, 2012, 2013, 2014

2013-06-28

... DEPARTMENT OF COMMERCE International Trade Administration [A-583-833] Polyester Staple Fiber From... duty order on polyester staple fiber (PSF) from Taiwan. The period of review is May 1, 2011, through... Results. None were received. \\1\\ See Polyester Staple Fiber From Taiwan: Preliminary Results of...

75 FR 6352 - Certain Polyester Staple Fiber from the People's Republic of China: Extension of Preliminary...

Federal Register 2010, 2011, 2012, 2013, 2014

2010-02-09

... DEPARTMENT OF COMMERCE International Trade Administration [A-570-905] Certain Polyester Staple... results of the administrative review of certain polyester staple fiber from the People's Republic of China... administrative review of the antidumping duty order on certain polyester staple fiber from the PRC. See...

77 FR 62217 - Certain Polyester Staple Fiber From the People's Republic of China: Continuation of Antidumping...

Federal Register 2010, 2011, 2012, 2013, 2014

2012-10-12

... DEPARTMENT OF COMMERCE International Trade Administration [A-570-905] Certain Polyester Staple... International Trade Commission (``ITC'') that revocation of the antidumping duty order on certain polyester... antidumping duty order on certain polyester staple fiber from the PRC pursuant to section 751(c)(2) of the...

76 FR 7532 - Certain Polyester Staple Fiber From the People's Republic of China: Extension of Preliminary...

Federal Register 2010, 2011, 2012, 2013, 2014

2011-02-10

... DEPARTMENT OF COMMERCE International Trade Administration [A-570-905] Certain Polyester Staple... results of the administrative review of certain polyester staple fiber from the People's Republic of China... initiation of the administrative review of the antidumping duty order on certain polyester staple fiber from...

77 FR 19619 - Certain Polyester Staple Fiber from the People's Republic of China: Extension of Preliminary...

Federal Register 2010, 2011, 2012, 2013, 2014

2012-04-02

... DEPARTMENT OF COMMERCE International Trade Administration [A-570-905] Certain Polyester Staple... results of the administrative review of certain polyester staple fiber from the People's Republic of China... polyester staple fiber from the PRC.\\1\\ On February 9, 2012 the Department partially extended the deadline...

76 FR 37830 - Polyester Staple Fiber From Korea and Taiwan; Scheduling of Expedited Five-Year Reviews...

Federal Register 2010, 2011, 2012, 2013, 2014

2011-06-28

... INTERNATIONAL TRADE COMMISSION [Investigation Nos. 731-TA-825 and 826 (Second Review)] Polyester... Duty Orders on Polyester Staple Fiber From Korea and Taiwan AGENCY: United States International Trade... determine whether revocation of the antidumping duty orders on polyester staple fiber from Korea and Taiwan...

Flexible camphor diamond-like carbon coating on polyurethane to prevent Candida albicans biofilm growth.

PubMed

Santos, Thaisa B; Vieira, Angela A; Paula, Luciana O; Santos, Everton D; Radi, Polyana A; Khouri, Sônia; Maciel, Homero S; Pessoa, Rodrigo S; Vieira, Lucia

2017-04-01

Camphor was incorporated in diamond-like carbon (DLC) films to prevent the Candida albicans yeasts fouling on polyurethane substrates, which is a material commonly used for catheter manufacturing. The camphor:DLC and DLC film for this investigation was produced by plasma enhanced chemical vapor deposition (PECVD), using an apparatus based on the flash evaporation of organic liquid (hexane) containing diluted camphor for camphor:DLC and hexane/methane, mixture for DLC films. The film was deposited at a low temperature of less than 25°C. We obtained very adherent camphor:DLC and DLC films that accompanied the substrate flexibility without delamination. The adherence of camphor:DLC and DLC films on polyurethane segments were evaluated by scratching test and bending polyurethane segments at 180°. The polyurethane samples, with and without camphor:DLC and DLC films were characterized by Raman spectroscopy, scanning electron microscopy, atomic force microscopy, and optical profilometry. Candida albicans biofilm formation on polyurethane, with and without camphor:DLC and DLC, was assessed. The camphor:DLC and DLC films reduced the biofilm growth by 99.0% and 91.0% of Candida albicans, respectively, compared to bare polyurethane. These results open the doors to studies of functionalized DLC coatings with biofilm inhibition properties used in the production of catheters or other biomedical applications. Copyright © 2017 Elsevier Ltd. All rights reserved.

Microwave-assisted synthesis of cyclodextrin polyurethanes.

PubMed

Biswas, Atanu; Appell, Michael; Liu, Zengshe; Cheng, H N

2015-11-20

Cyclodextrin (CD) has often been incorporated into polyurethanes in order to facilitate its use in encapsulation or removal of organic species for various applications. In this work a microwave-assisted method has been developed to produce polyurethanes consisting of α-, β-, and γ-CD and three common diisocyanates. As compared to conventional heating, this new synthetic method saves energy, significantly reduces reaction time, and gets similar or improved yield. The reaction products have been fully characterized with (13)C, (1)H, and two-dimensional NMR spectroscopy. With suitable stoichiometry of starting CD and diisocyanate, the resulting CD polyurethane is organic-soluble and water-insoluble and is shown to remove Nile red dye and phenol from water. Possible applications include the removal of undesirable materials from process streams, toxic compounds from the environment, and encapsulation of color or fragrance molecules. Published by Elsevier Ltd.

Design and development of low cost polyurethane biopolymer based on castor oil and glycerol for biomedical applications.

PubMed

Tan, A C W; Polo-Cambronell, B J; Provaggi, E; Ardila-Suárez, C; Ramirez-Caballero, G E; Baldovino-Medrano, V G; Kalaskar, D M

2018-02-01

In the current study, we present the synthesis of novel low cost bio-polyurethane compositions with variable mechanical properties based on castor oil and glycerol for biomedical applications. A detailed investigation of the physicochemical properties of the polymer was carried out by using mechanical testing, ATR-FTIR, and X-ray photoelectron spectroscopy (XPS). Polymers were also tested in short term in-vitro cell culture with human mesenchymal stem cells to evaluate their biocompatibility for potential applications as biomaterial. FTIR analysis confirmed the synthesis of castor oil and glycerol based PU polymers. FTIR also showed that the addition of glycerol as co-polyol increases crosslinking within the polymer backbone hence enhancing the bulk mechanical properties of the polymer. XPS data showed that glycerol incorporation leads to an enrichment of oxidized organic species on the surface of the polymers. Preliminary investigation into in vitro biocompatibility showed that serum protein adsorption can be controlled by varying the glycerol content with polymer backbone. An alamar blue assay looking at the metabolic activity of the cells indicated that castor oil based PU and its variants containing glycerol are non-toxic to the cells. This study opens an avenue for using low cost bio-polyurethane based on castor oil and glycerol for biomedical applications. © 2017 The Authors Biopolymers Published by Wiley Periodicals, Inc.

Static properties and moisture content properties of polyester fabrics modified by plasma treatment and chemical finishing

NASA Astrophysics Data System (ADS)

Kan, C. W.; Yuen, C. W. M.

2008-01-01

Low temperature plasma treatment has been conducted in textile industry and has some success in the dyeing and finishing processes. In this paper, an attempt was made to apply low temperature plasma treatment to improve the anti-static property of polyester fabric. The polyester fabrics were treated under different conditions using low temperature plasma. An Orthogonal Array Testing Strategy was employed to determine the optimum treatment condition. After low temperature plasma treatment, the polyester fabrics were evaluated with different characterisation methods. Under the observation of scanning electron microscope, the surface structure of low temperature plasma-treated polyester fabric was seriously altered. This provided more capacity for polyester to capture moisture and hence increase the dissipation of static charges. The relationship between moisture content and half-life decay time for static charges was studied and the results showed that the increment of moisture content would result in shortening the time for the dissipation of static charges. Moreover, there was a great improvement in the anti-static property of the low temperature plasma-treated polyester fabric after comparing with that of the polyester fabric treated with commercial anti-static finishing agent.

40 CFR 63.1293 - Standards for slabstock flexible polyurethane foam production.

Code of Federal Regulations, 2014 CFR

2014-07-01

... polyurethane foam production. 63.1293 Section 63.1293 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY... CATEGORIES (CONTINUED) National Emission Standards for Hazardous Air Pollutants for Flexible Polyurethane Foam Production § 63.1293 Standards for slabstock flexible polyurethane foam production. Each owner or...

40 CFR 63.1293 - Standards for slabstock flexible polyurethane foam production.

Code of Federal Regulations, 2013 CFR

2013-07-01

... polyurethane foam production. 63.1293 Section 63.1293 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY... CATEGORIES (CONTINUED) National Emission Standards for Hazardous Air Pollutants for Flexible Polyurethane Foam Production § 63.1293 Standards for slabstock flexible polyurethane foam production. Each owner or...

75 FR 51442 - Polyester Staple Fiber from Taiwan: Rescission of Antidumping Duty Administrative Review in Part

Federal Register 2010, 2011, 2012, 2013, 2014

2010-08-20

... DEPARTMENT OF COMMERCE International Trade Administration [A-583-833] Polyester Staple Fiber from... antidumping duty order on polyester staple fiber from Taiwan. The period of review is May 1, 2009, through... duty order on polyester staple fiber from Taiwan with respect to respondents Nan Ya Plastics...

Recovery behaviour of shape memory polyurethane based laminates after thermoforming

NASA Astrophysics Data System (ADS)

Wu, Shuiliang; Xu, Wensen; Prasath Balamurugan, G.; Thompson, Michael R.; Nielsen, Kent E.; Brandys, Frank A.

2017-11-01

Shape memory polymers (SMPs) can be used to produce a new class of decorative films capable of improved formability and shape recovery in polymer laminates, which are increasingly being used for automotive, aerospace, construction and commercial applications. As a relatively new field there is little knowledge on the shape recovery behaviour of laminates with a SMP film and few methods of quantify that behaviour. The influences of different variables that affect the recovery behaviour of thermoplastic shape memory polyurethanes based laminates including ambient temperature (45 °C and 65 °C), material modulus, and adhesive strength were investigated after thermoforming, through both experimental and modelling methods. The empirical model assisted in identifying the contributions of the adhesive to transfer stresses, which dampened the recovery of the laminate with lower shear strength adhesives. Increasing ambient temperature and the film modulus increased both the final angle recovery ratios and recovery rates.

A simple approach for morphology tailoring of alginate particles by manipulation ionic nature of polyurethanes.

PubMed

Daemi, Hamed; Barikani, Mehdi; Barmar, Mohammad

2014-05-01

A number of different ionic aqueous polyurethane dispersions (PUDs) were synthesized based on NCO-terminated prepolymers. Two different anionic and cationic polyurethane samples were synthesized using dimethylol propionic acid and N-methyldiethanolamine emulsifiers, respectively. Then, proper amounts of PUDs and sodium alginate were mixed to obtain a number of aqueous polyurethane dispersions-sodium alginate (PUD/SA) elastomers. The chemical structure, thermal, morphological, thermo-mechanical and mechanical properties, and hydrophilicity content of the prepared samples were studied by FTIR, EDX, DSC, TGA, SEM, DMTA, tensile testing and contact angle techniques. The cationic polyurethanes and their blends with sodium alginate showed excellent miscibility and highly stretchable properties, while the samples containing anionic polyurethanes and alginate illustrated a poor compatibility and no significant miscibility. The morphology of alginate particles shifted from nanoparticles to microparticles by changing the nature of PUDs from cationic to anionic types. The final cationic elastomers not only showed better mechanical properties but also were formulated easier than anionic samples. Copyright © 2014 Elsevier B.V. All rights reserved.

Manufacturing of biodegradable polyurethane scaffolds based on polycaprolactone using a phase separation method: physical properties and in vitro assay

PubMed Central

Asefnejad, Azadeh; Khorasani, Mohammad Taghi; Behnamghader, Aliasghar; Farsadzadeh, Babak; Bonakdar, Shahin

2011-01-01

Background Biodegradable polyurethanes have found widespread use in soft tissue engineering due to their suitable mechanical properties and biocompatibility. Methods In this study, polyurethane samples were synthesized from polycaprolactone, hexamethylene diisocyanate, and a copolymer of 1,4-butanediol as a chain extender. Polyurethane scaffolds were fabricated by a combination of liquid–liquid phase separation and salt leaching techniques. The effect of the NCO:OH ratio on porosity content and pore morphology was investigated. Results Scanning electron micrographs demonstrated that the scaffolds had a regular distribution of interconnected pores, with pore diameters of 50–300 μm, and porosities of 64%–83%. It was observed that, by increasing the NCO:OH ratio, the average pore size, compressive strength, and compressive modulus increased. L929 fibroblast and chondrocytes were cultured on the scaffolds, and all samples exhibited suitable cell attachment and growth, with a high level of biocompatibility. Conclusion These biodegradable polyurethane scaffolds demonstrate potential for soft tissue engineering applications. PMID:22072874

Polyester composites reinforced with corona-treated fibers from pine, eucalyptus and sugarcane bagasse

USDA-ARS?s Scientific Manuscript database

This study aims to evaluate plant fibers that were surface activated with NaOH and corona discharge before incorporating in ortho unsaturated polyester-based fiber composites. It demonstrates the potential use of lignocellulosic particles, especially eucalyptus that presented the higher values for a...

40 CFR 63.1293 - Standards for slabstock flexible polyurethane foam production.

Code of Federal Regulations, 2010 CFR

2010-07-01

... polyurethane foam production. 63.1293 Section 63.1293 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY... CATEGORIES National Emission Standards for Hazardous Air Pollutants for Flexible Polyurethane Foam Production § 63.1293 Standards for slabstock flexible polyurethane foam production. Each owner or operator of a...

40 CFR 63.1293 - Standards for slabstock flexible polyurethane foam production.

Code of Federal Regulations, 2012 CFR

2012-07-01

... polyurethane foam production. 63.1293 Section 63.1293 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY... CATEGORIES National Emission Standards for Hazardous Air Pollutants for Flexible Polyurethane Foam Production § 63.1293 Standards for slabstock flexible polyurethane foam production. Each owner or operator of a...

40 CFR 63.1293 - Standards for slabstock flexible polyurethane foam production.

Code of Federal Regulations, 2011 CFR

2011-07-01

... polyurethane foam production. 63.1293 Section 63.1293 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY... CATEGORIES National Emission Standards for Hazardous Air Pollutants for Flexible Polyurethane Foam Production § 63.1293 Standards for slabstock flexible polyurethane foam production. Each owner or operator of a...

Optical properties of three-dimensional P(St-MAA) photonic crystals on polyester fabrics

NASA Astrophysics Data System (ADS)

Liu, Guojin; Zhou, Lan; Wu, Yujiang; Wang, Cuicui; Fan, Qinguo; Shao, Jianzhong

2015-04-01

The three-dimensional (3D) photonic crystals with face-centered cubic (fcc) structure was fabricated on polyester fabrics, a kind of soft textile materials quite different from the conventional solid substrates, by gravitational sedimentation self-assembly of monodisperse P(St-MAA) colloidal microspheres. The optical properties of structural colors on polyester fabrics were investigated and the position of photonic band gap was characterized. The results showed that the color-tuning ways of the structural colors from photonic crystals were in accordance with Bragg's law and could be modulated by the size of P(St-MAA) colloidal microspheres and the viewing angles. The L∗a∗b∗ values of the structural colors generated from the assembled polyester fabrics were in agreement with their reflectance spectra. The photonic band gap position of photonic crystals on polyester fabrics could be consistently confirmed by reflectance and transmittance spectra.

Improved lignin polyurethane properties with Lewis acid treatment.

PubMed

Chung, Hoyong; Washburn, Newell R

2012-06-27

Chemical modification strategies to improve the mechanical properties of lignin-based polyurethanes are presented. We hypothesized that treatment of lignin with Lewis acids would increase the concentration of hydroxyl groups available to react with diisocyanate monomers. Under the conditions used, hydrogen bromide-catalyzed modification resulted in a 28% increase in hydroxyl group content. Associated increases in hydrophilicity of solvent-cast thin films were also recorded as evidenced by decreases in water contact angle. Polyurethanes were then prepared by first preparing a prepolymer based on mixtures of toluene-2,4-diisocyanate (TDI) and unmodified or modified lignin, then polymerization was completed through addition of polyethylene glycol (PEG), resulting in mass ratios of TDI:lignin:PEG of 43:17:40 in the compositions investigated here. The mixture of TDI and unmodified lignin resulted in a lignin powder at the bottom of the liquid, suggesting it did not react directly with TDI. However, a homogeneous solution resulted when TDI and the hydrogen bromide-treated lignin were mixed, suggesting demethylation indeed increased reactivity and resulted in better integration of lignin into the urethane network. Significant improvements in mechanical properties of modified lignin polyurethanes were observed, with a 6.5-fold increase in modulus, which were attributed to better integration of the modified lignin into the covalent polymer network due to the higher concentration of hydroxyl groups. This research indicates that chemical modification strategies can lead to significant improvements in the properties of lignin-based polymeric materials using a higher fraction of an inexpensive lignin monomer from renewable resources and a lower fraction an expensive, petroleum-derived isocyanate monomer to achieve the required material properties.

Polyester Wax: A New Embedding Medium for the Histopathologic Study of Human Temporal Bones

PubMed Central

Merchant, Saumil N.; Burgess, Barbara; O'Malley, Jennifer; Jones, Diane; Adams, Joe C.

2007-01-01

bones offers the advantage of good preservation of morphology and ease of immunostaining. We anticipate that in the future, polyester wax embedding will also permit other molecular biologic assays on temporal bone sections such as the retrieval of nucleic acids and the study of proteins using mass spectrometry–based proteomic analysis. PMID:16467713

40 CFR 63.1300 - Standards for molded flexible polyurethane foam production.

Code of Federal Regulations, 2010 CFR

2010-07-01

... polyurethane foam production. 63.1300 Section 63.1300 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY... CATEGORIES National Emission Standards for Hazardous Air Pollutants for Flexible Polyurethane Foam Production § 63.1300 Standards for molded flexible polyurethane foam production. Each owner or operator of a new...

40 CFR 63.1300 - Standards for molded flexible polyurethane foam production.

Code of Federal Regulations, 2013 CFR

2013-07-01

... polyurethane foam production. 63.1300 Section 63.1300 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY... Foam Production § 63.1300 Standards for molded flexible polyurethane foam production. Each owner or... polyurethane foam process, with the following exception. Diisocyanates may be used to flush the mixhead and...

40 CFR 63.1300 - Standards for molded flexible polyurethane foam production.

Code of Federal Regulations, 2011 CFR

2011-07-01

... polyurethane foam production. 63.1300 Section 63.1300 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY... CATEGORIES National Emission Standards for Hazardous Air Pollutants for Flexible Polyurethane Foam Production § 63.1300 Standards for molded flexible polyurethane foam production. Each owner or operator of a new...

40 CFR 63.1300 - Standards for molded flexible polyurethane foam production.

Code of Federal Regulations, 2012 CFR

2012-07-01

... polyurethane foam production. 63.1300 Section 63.1300 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY... CATEGORIES National Emission Standards for Hazardous Air Pollutants for Flexible Polyurethane Foam Production § 63.1300 Standards for molded flexible polyurethane foam production. Each owner or operator of a new...

40 CFR 63.1300 - Standards for molded flexible polyurethane foam production.

Code of Federal Regulations, 2014 CFR

2014-07-01

... polyurethane foam production. 63.1300 Section 63.1300 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY... Foam Production § 63.1300 Standards for molded flexible polyurethane foam production. Each owner or... polyurethane foam process, with the following exception. Diisocyanates may be used to flush the mixhead and...

40 CFR 721.8079 - Isophorone diisocyanate neopentyl glycol adipate polyurethane prepolymer.

Code of Federal Regulations, 2010 CFR

2010-07-01

... glycol adipate polyurethane prepolymer. 721.8079 Section 721.8079 Protection of Environment ENVIRONMENTAL... adipate polyurethane prepolymer. (a) Chemical substance and significant new uses subject to reporting. (1... polyurethane prepolymer (PMN P-94-1743) is subject to reporting under this section for the significant new uses...

Cryogenic line insulation made from prefabricated polyurethane shells

NASA Technical Reports Server (NTRS)

Lerma, G.

1975-01-01

Prefabricated polyurethane foam insulation is inexpensive and easily installed on cryogenic lines. Insulation sections are semicircular half shells. Pair of half shells is placed to surround cryogenic line. Cylindrically-shaped knit sock is pulled over insulation then covered with polyurethane resin to seal system.

3D printing of new biobased unsaturated polyesters by microstereo-thermallithography.

PubMed

Gonçalves, Filipa A M M; Costa, Cátia S M F; Fabela, Inês G P; Farinha, Dina; Faneca, Henrique; Simões, Pedro N; Serra, Arménio C; Bártolo, Paulo J; Coelho, Jorge F J

2014-09-01

New micro three-dimensional (3D) scaffolds using biobased unsaturated polyesters (UPs) were prepared by microstereo-thermal-lithography (μSTLG). This advanced processing technique offers indubitable advantages over traditional printing methods. The accuracy and roughness of the 3D structures were evaluated by scanning electron microscopy and infinite focus microscopy, revealing a suitable roughness for cell attachment. UPs were synthesized by bulk polycondensation between biobased aliphatic diacids (succinic, adipic and sebacic acid) and two different glycols (propylene glycol and diethylene glycol) using fumaric acid as the source of double bonds. The chemical structures of the new oligomers were confirmed by proton nuclear magnetic resonance spectra, attenuated total reflectance Fourier transform infrared spectroscopy and matrix assisted laser desorption/ionization-time of flight mass spectrometry. The thermal and mechanical properties of the UPs were evaluated to determine the influence of the diacid/glycol ratio and the type of diacid in the polyester's properties. In addition an extensive thermal characterization of the polyesters is reported. The data presented in this work opens the possibility for the use of biobased polyesters in additive manufacturing technologies as a route to prepare biodegradable tailor made scaffolds that have potential applications in a tissue engineering area.

A high-throughput assay for enzymatic polyester hydrolysis activity by fluorimetric detection.

PubMed

Wei, Ren; Oeser, Thorsten; Billig, Susan; Zimmermann, Wolfgang

2012-12-01

A fluorimetric assay for the fast determination of the activity of polyester-hydrolyzing enzymes in a large number of samples has been developed. Terephthalic acid (TPA) is a main product of the enzymatic hydrolysis of polyethylene terephthalate (PET), a synthetic polyester. Terephthalate has been quantified following its conversion to the fluorescent 2-hydroxyterephthalate by an iron autoxidation-mediated generation of free hydroxyl radicals. The assay proved to be robust at different buffer concentrations, reaction times, pH values, and in the presence of proteins. A validation of the assay was performed by analyzing TPA formation from PET films and nanoparticles catalyzed by a polyester hydrolase from Thermobifida fusca KW3 in a 96-well microplate format. The results showed a close correlation (R(2) = 0.99) with those obtained by a considerably more tedious and time-consuming HPLC method, suggesting the aptness of the fluorimetric assay for a high-throughput screening for polyester hydrolases. The method described in this paper will facilitate the detection and development of biocatalysts for the modification and degradation of synthetic polymers. The fluorimetric assay can be used to quantify the amount of TPA obtained as the final degradation product of the enzymatic hydrolysis of PET. In a microplate format, this assay can be applied for the high-throughput screening of polyester hydrolases. Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Exploring the potential of polyurethane-based soft foam as cell-free scaffold for soft tissue regeneration.

PubMed

Gerges, Irini; Tamplenizza, Margherita; Martello, Federico; Recordati, Camilla; Martelli, Cristina; Ottobrini, Luisa; Tamplenizza, Mariacaterina; Guelcher, Scott A; Tocchio, Alessandro; Lenardi, Cristina

2018-06-01

Reconstructive treatment after trauma and tumor resection would greatly benefit from an effective soft tissue regeneration. The use of cell-free scaffolds for adipose tissue regeneration in vivo is emerging as an attractive alternative to tissue-engineered constructs, since this approach avoids complications due to cell manipulation and lack of synchronous vascularization. In this study, we developed a biodegradable polyurethane-based scaffold for soft tissue regeneration, characterized by an exceptional combination between softness and resilience. Exploring the potential as a cell-free scaffold required profound understanding of the impact of its intrinsic physico-chemical properties on the biological performance in vivo. We investigated the effect of the scaffold's hydrophilic character, degradation kinetics, and internal morphology on (i) the local inflammatory response and activation of MGCs (foreign body response); (ii) its ability to promote rapid vascularisation, cell infiltration and migration through the scaffold over time; and (iii) the grade of maturation of the newly formed tissue into vascularized soft tissue in a murine model. The study revealed that soft tissue regeneration in vivo proceeded by gradual infiltration of undifferentiated mesenchymal cells though the periphery toward the center of the scaffold, where the rapid formation of a functional and well-formed vascular network supported cell viability overtime. Exploring the potential of polyurethane-based soft foam as cell-free scaffold for soft tissue regeneration. In this work, we address the unmet need for synthetic functional soft tissue substitutes that provide adequate biological and mechanical support to soft tissue. We developed a series of flexible cross-linked polyurethane copolymer scaffolds with remarkable fatigue-resistance and tunable physico-chemical properties for soft tissue regeneration in vivo. Accordingly, we could extend the potential of this class of biomaterials, which was

Scaffolds from block polyurethanes based on poly(ɛ-caprolactone) (PCL) and poly(ethylene glycol) (PEG) for peripheral nerve regeneration.

PubMed

Niu, Yuqing; Chen, Kevin C; He, Tao; Yu, Wenying; Huang, Shuiwen; Xu, Kaitian

2014-05-01

Nerve guide scaffolds from block polyurethanes without any additional growth factors or protein were prepared using a particle leaching method. The scaffolds of block polyurethanes (abbreviated as PUCL-ran-EG) based on poly(ɛ-caprolactone) (PCL-diol) and poly(ethylene glycol) (PEG) possess highly surface-area porous for cell attachment, and can provide biochemical and topographic cues to enhance tissue regeneration. The nerve guide scaffolds have pore size 1-5 μm and porosity 88%. Mechanical tests showed that the polyurethane nerve guide scaffolds have maximum loads of 4.98 ± 0.35 N and maximum stresses of 6.372 ± 0.5 MPa. The histocompatibility efficacy of these nerve guide scaffolds was tested in a rat model for peripheral nerve injury treatment. Four types of guides including PUCL-ran-EG scaffolds, autograft, PCL scaffolds and silicone tubes were compared in the rat model. After 14 weeks, bridging of a 10 mm defect gap by the regenerated nerve was observed in all rats. The nerve regeneration was systematically characterized by sciatic function index (SFI), histological assessment including HE staining, immunohistochemistry, ammonia silver staining, Masson's trichrome staining and TEM observation. Results revealed that polyurethane nerve guide scaffolds exhibit much better regeneration behavior than PCL, silicone tube groups and comparable to autograft. Electrophysiological recovery was also seen in 36%, 76%, and 87% of rats in the PCL, PUCL-ran-EG, and autograft groups respectively, whilst 29.8% was observed in the silicone tube groups. Biodegradation in vitro and in vivo show proper degradation of the PUCL-ran-EG nerve guide scaffolds. This study has demonstrated that without further modification, plain PUCL-ran-EG nerve guide scaffolds can help peripheral nerve regeneration excellently. Copyright © 2014 Elsevier Ltd. All rights reserved.

Inert Reassessment Document for Trimethylolpropane - CAS No. 77-99-6

EPA Pesticide Factsheets

Trimethylolpropane is used in a large variety of commercial applications, including in the manufacturer of varnishes, resins; polyesters for polyurethane foams, textile finishes, plastictzers, and cross-linking agents for spandex fibers.

[In Situ Polymerization and Characterization of Hydroxyapatite/polyurethane Implanted Material].

PubMed

Gu, Muqing; Xiao, Fengjuan; Liang, Ye; Yue, Lin; Li, Song; Li, Lanlan; Feng, Feifei

2015-08-01

In order to improve the interfacial bonding strength of hydroxyapatite/polyurethane implanted material and dispersion of hydroxyapatite in the polyurethane matrix, we in the present study synthesized nano-hydroxyapatite/polyurethane composites by in situ polymerization. We then characterized and analyzed the fracture morphology, thermal stability, glass transition temperature and mechanical properties. We seeded MG63 cells on composites to evaluate the cytocompatibility of the composites. In situ polymerization could improve the interfacial bonding strength, ameliorate dispersion of hydroxyapatite in the properties of the composites. After adding 20 wt% hydroxyapatite into the polyurethane, the thermal stability was improved and the glass transition temperatures were increased. The tensile strength and maximum elongation were 6.83 MPa and 861.17%, respectively. Compared with those of pure polyurethane the tensile strength and maximum elongation increased by 236.45% and 143.30%, respectively. The composites were helpful for cell adhesion and proliferation in cultivation.

Open-pore polyurethane product

DOEpatents

Jefferson, R.T.; Salyer, I.O.

1974-02-17

The method is described of producing an open-pore polyurethane foam having a porosity of at least 50% and a density of 0.1 to 0.5 g per cu cm, and which consists of coherent spherical particles of less than 10 mu diam separated by interconnected interstices. It is useful as a filter and oil absorbent. The product is admirably adapted to scavenging of crude oil from the surface of seawater by preferential wicking. The oil-soaked product may then be compressed to recover the oil or burned for disposal. The crosslinked polyurethane structures are remarkably solvent and heat-resistance as compared with known thermoplastic structures. Because of their relative inertness, they are useful filters for gasoline and other hydrocarbon compounds. (7 claims)

76 FR 2886 - Certain Polyester Staple Fiber From the People's Republic of China: Final Results and Partial...

Federal Register 2010, 2011, 2012, 2013, 2014

2011-01-18

... DEPARTMENT OF COMMERCE International Trade Administration [A-570-905] Certain Polyester Staple... duty order on certain polyester staple fiber (``PSF'') from the People's Republic of China (``PRC''). See Certain Polyester Staple Fiber From the People's Republic of China: Notice of Preliminary Results...

75 FR 34097 - Certain Polyester Staple Fiber From Taiwan: Extension of the Final Results of Antidumping Duty...

Federal Register 2010, 2011, 2012, 2013, 2014

2010-06-16

... DEPARTMENT OF COMMERCE International Trade Administration [A-583-833] Certain Polyester Staple... administrative review of the antidumping duty order on certain polyester staple fiber from Taiwan. See Certain Polyester Staple Fiber from Taiwan: Preliminary Results of Antidumping Duty Administrative Review, 75 FR...

75 FR 38463 - Greige Polyester Cotton Printcloth From the People's Republic of China: Final Results of Sunset...

Federal Register 2010, 2011, 2012, 2013, 2014

2010-07-02

... DEPARTMENT OF COMMERCE International Trade Administration [A-570-101] Greige Polyester Cotton... duty order on greige polyester cotton printcloth from the People's Republic of China (``PRC''). Because..., 1983, the Department issued an antidumping duty order on greige polyester cotton printcloth from the...

Electrospun nanofibrous scaffolds of segmented polyurethanes based on PEG, PLLA and PTMC blocks: Physico-chemical properties and morphology.

PubMed

Trinca, Rafael Bergamo; Abraham, Gustavo A; Felisberti, Maria Isabel

2015-11-01

Biocompatible polymeric scaffolds are crucial for successful tissue engineering. Biomedical segmented polyurethanes (SPUs) are an important and versatile class of polymers characterized by a broad spectrum of compositions, molecular architectures, properties and applications. Although SPUs are versatile materials that can be designed by different routes to cover a wide range of properties, they have been infrequently used for the preparation of electrospun nanofibrous scaffolds. This study reports the preparation of new electrospun polyurethane scaffolds. The segmented polyurethanes were synthesized using low molar masses macrodyols (poly(ethylene glycol), poly(l-lactide) and poly(trimethylene carbonate)) and 1,6-hexane diisocyanate and 1,4-butanodiol as isocyanate and chain extensor, respectively. Different electrospinning parameters such as solution properties and processing conditions were evaluated to achieve smooth, uniform bead-free fibers. Electrospun micro/nanofibrous structures with mean fiber diameters ranging from 600nm to 770nm were obtained by varying the processing conditions. They were characterized in terms of thermal and dynamical mechanical properties, swelling degree and morphology. The elastomeric polyurethane scaffolds exhibit interesting properties that could be appropriate as biomimetic matrices for soft tissue engineering applications. Copyright © 2015 Elsevier B.V. All rights reserved.

Polyester: simulating RNA-seq datasets with differential transcript expression.

PubMed

Frazee, Alyssa C; Jaffe, Andrew E; Langmead, Ben; Leek, Jeffrey T

2015-09-01

Statistical methods development for differential expression analysis of RNA sequencing (RNA-seq) requires software tools to assess accuracy and error rate control. Since true differential expression status is often unknown in experimental datasets, artificially constructed datasets must be utilized, either by generating costly spike-in experiments or by simulating RNA-seq data. Polyester is an R package designed to simulate RNA-seq data, beginning with an experimental design and ending with collections of RNA-seq reads. Its main advantage is the ability to simulate reads indicating isoform-level differential expression across biological replicates for a variety of experimental designs. Data generated by Polyester is a reasonable approximation to real RNA-seq data and standard differential expression workflows can recover differential expression set in the simulation by the user. Polyester is freely available from Bioconductor (http://bioconductor.org/). jtleek@gmail.com Supplementary data are available at Bioinformatics online. © The Author 2015. Published by Oxford University Press. All rights reserved. For Permissions, please e-mail: journals.permissions@oup.com.

The influence of chemical structure on thermal properties and surface morphology of polyurethane materials.

PubMed

Brzeska, Joanna; Morawska, Magda; Heimowska, Aleksandra; Sikorska, Wanda; Wałach, Wojciech; Hercog, Anna; Kowalczuk, Marek; Rutkowska, Maria

2018-01-01

The surface morphology and thermal properties of polyurethanes can be correlated to their chemical composition. The hydrophilicity, surface morphology, and thermal properties of polyurethanes (differed in soft segments and in linear/cross-linked structure) were investigated. The influence of poly([ R , S ]-3-hydroxybutyrate) presence in soft segments and blending of polyurethane with polylactide on surface topography were also estimated. The linear polyurethanes (partially crystalline) had the granular surface, whereas the surface of cross-linked polyurethanes (almost amorphous) was smooth. Round aggregates of polylactide un-uniformly distributed in matrix of polyurethane were clearly visible. It was concluded that some modification of soft segment (by mixing of poly([ R , S ]-3-hydroxybutyrate) with different polydiols and polytriol) and blending of polyurethanes with small amount of polylactide influence on crystallinity and surface topography of obtained polyurethanes.

Synthesis and Thermal Analysis of Nano-Aluminum/Fluorinated Polyurethane Elastomeric Composites for Structural Energetics.

PubMed

Zhang, Xianyu; Kim, Jin Seuk; Kwon, Younghwan

2017-04-01

Here we describe the synthesis of polyurethane (PU)-based energetic nanocomposites loaded with nano-aluminum (n-Al) particles. The energetic nanocomposite was prepared by polyurethane reaction of poly(glycidyl azide-co-tetramethylene glycol) (PGT) prepolymers and IPDI/N-100 isocyanates with simultaneous catalyst-free azide-alkyne Click reaction in the presence of n-Al. Initial study carried out with various n-Al/fluorinated PGT blends and demonstrated the potential of fluorinated PGT prepolymer for an energetic PU matrix. Thermal analysis of n-Al/fluorinated PGT-based PU energetic nanocomposite was performed using DSC and TGA.

A semi-phenomenological model to predict the acoustic behavior of fully and partially reticulated polyurethane foams

NASA Astrophysics Data System (ADS)

Doutres, Olivier; Atalla, Noureddine; Dong, Kevin

2013-02-01

This paper proposes simple semi-phenomenological models to predict the sound absorption efficiency of highly porous polyurethane foams from microstructure characterization. In a previous paper [J. Appl. Phys. 110, 064901 (2011)], the authors presented a 3-parameter semi-phenomenological model linking the microstructure properties of fully and partially reticulated isotropic polyurethane foams (i.e., strut length l, strut thickness t, and reticulation rate Rw) to the macroscopic non-acoustic parameters involved in the classical Johnson-Champoux-Allard model (i.e., porosity ϕ, airflow resistivity σ, tortuosity α∝, viscous Λ, and thermal Λ' characteristic lengths). The model was based on existing scaling laws, validated for fully reticulated polyurethane foams, and improved using both geometrical and empirical approaches to account for the presence of membrane closing the pores. This 3-parameter model is applied to six polyurethane foams in this paper and is found highly sensitive to the microstructure characterization; particularly to strut's dimensions. A simplified micro-/macro model is then presented. It is based on the cell size Cs and reticulation rate Rw only, assuming that the geometric ratio between strut length l and strut thickness t is known. This simplified model, called the 2-parameter model, considerably simplifies the microstructure characterization procedure. A comparison of the two proposed semi-phenomenological models is presented using six polyurethane foams being either fully or partially reticulated, isotropic or anisotropic. It is shown that the 2-parameter model is less sensitive to measurement uncertainties compared to the original model and allows a better estimation of polyurethane foams sound absorption behavior.

Storage-stable foamable polyurethane is activated by heat

NASA Technical Reports Server (NTRS)

1966-01-01

Polyurethane foamable mixture remains inert in storage unit activated to produce a rapid foaming reaction. The storage-stable foamable composition is spread as a paste on the surface of an expandable structure and, when heated, yields a rigid open-cell polyurethane foam that is self-bondable to the substrate.

Tests Of Polyurethane And Dichromate Coats On Aluminum

NASA Technical Reports Server (NTRS)

Danford, M. D.

1992-01-01

Report describes experiments to determine relative effectiveness of new polyurethane and more-conventional dichromate coat in helping to retard corrosion of anodized 6061-T6 aluminum. Concludes by suggesting greater protection against corrosion achieved by combining polyurethane-sealing method with hard-anodizing method and by increasing thickness of coat.

77 FR 21733 - Certain Polyester Staple Fiber From Taiwan: Extension of Time Limit for Preliminary Results of...

Federal Register 2010, 2011, 2012, 2013, 2014

2012-04-11

... DEPARTMENT OF COMMERCE International Trade Administration [A-583-833] Certain Polyester Staple... Department) initiated an administrative review of the antidumping duty order on certain polyester staple fiber from Taiwan for the period May 1, 2010, through April 30, 2011.\\1\\ In Certain Polyester Staple...

78 FR 38939 - Certain Polyester Staple Fiber From the People's Republic of China: Final Results of Antidumping...

Federal Register 2010, 2011, 2012, 2013, 2014

2013-06-28

... DEPARTMENT OF COMMERCE International Trade Administration [A-570-905] Certain Polyester Staple... Preliminary Results of the 2011-2012 administrative review of the antidumping duty order on certain polyester... dumping margin is listed in the ``Final Results of Review'' section below. \\1\\ See Certain Polyester...

76 FR 28420 - Certain Polyester Staple Fiber From the People's Republic of China: Full Extension of Preliminary...

Federal Register 2010, 2011, 2012, 2013, 2014

2011-05-17

... DEPARTMENT OF COMMERCE International Trade Administration [A-570-905] Certain Polyester Staple... results of the administrative review of certain polyester staple fiber from the People's Republic of China... administrative review of the antidumping duty order on certain polyester staple fiber from the PRC. See...

Conducting polymer actuator based on chemically deposited polypyrrole and polyurethane-based solid polymer electrolyte working in air

NASA Astrophysics Data System (ADS)

Choi, Hwa-Jeong; Song, Young-Min; Chung, Ildoo; Ryu, Kwang-Sun; Jo, Nam-Ju

2009-02-01

Conducting polymers (CPs), such as polypyrrole, polythiophene, and polyaniline, are unique in that they have switchable properties due to their two or more mechanically stable oxidation states. Thus, their films or coatings can be easily switched by the application of a small voltage and current to change their volume during electrochemical redox processes. In particular, polypyrrole (PPy) has been studied most extensively because of its high electrical conductivity and good environmental stability under ambient conditions. In this work, we have studied a new CP actuator, fully polymeric, assembled with two PPy film electrodes and a solid polymer electrolyte (SPE), polyurethane/Mg(ClO4)2. Polyurethanes (PUs) were synthesized from 4,4'-diphenylmethane diisocyanate (MDI), 1,4-butanediol (1,4-BD) and three types of polyol: poly(ethylene glycol) (PEG), poly(propylene glycol) (PPG), and PPG-block-PEG-block-PPG (PPG-co-PEG). The chemical polymerization of PPy by immersion in Py monomer aqueous solution and oxidant aqueous solution is an adequate method to prepare PU/PPy composite film as an actuator. To find the proper thickness of the PPy coating layer for actuation, we measured the displacements of the actuators according to the thickness of the PPy coating layer. The displacement of all actuators is discussed in connection with the properties of the SPE and PPy. All the results obtained in this work show the feasibility of electrochemomechanical devices based on PPy and SPE film being able to work in air.

Synthesis of Polyurethanes Membranes from Rubber Seed Oil and Methylene Diphenyl Diisocyanates (MDI)

NASA Astrophysics Data System (ADS)

Marlina; Nurman, S.; Saleha, S.; Fitriani; Thanthawi, I.

2017-03-01

Rubber seed oil and methylene diphenyl diisocyanates (MDI) based polyurethane membrane has been prepared in this study. The main objective of this research is manufacture of polyurethane membranes from avocado seed oil, as a filter of this membrane use as a filter of metals from water such as mercury (Hg). In this study, the polyurethane membrane had been synthesized by varying compositions of rubber seed oil and MDI, with ratios of 10:0.2; 10:0.4; 10:0.6; 10:0.8; 10:1.0; 10:1.2; 10:1.4; 10:1.6; 10:1.8 and 10:2.0 (v/w) at 80°C and 170°C as polymerization and curing temperatures, respectively. Optimum polyurethane membrane was obtained at rubber seed oil: MDI 10: 0.8 v/w, it was dry, non-sticky, smooth and blackish brown. The membrane flux was 5,8307 L / m2.h.bar and rejection factor was 35,3015 %. The results of characterization indicated the formation of urethane bonds (NH at 3480 cm-1, C=O at 1620 cm-1, CN at 1374 cm-1, -OC-NH- at 1096 cm-1 and no -NCO at 2270 cm-1), the value of Tg was 55°C. The polyurethane membrane which treated at the optimum treatment conditions were used to the filter of metals from water such as mercury (Hg).

Mechanical performance of hybrid polyester composites reinforced Cloisite 30B and kenaf fibre

NASA Astrophysics Data System (ADS)

Bonnia, N. N.; Surip, S. N.; Ratim, S.; Mahat, M. M.

2012-06-01

Hybridization of rubber toughened polyester-kenaf nanocomposite was prepared by adding various percentage of kenaf fiber with 4% Cloisite 30B in unsaturated polyester resin. Composite were prepared by adding filler to modified polyester resin subsequently cross-linked using methyl ethyl ketone peroxide and the accelerator cobalt octanoate 1%. Three per hundred rubbers (phr) of liquid natural rubber (LNR) were added in producing this composite. This composite expected to be applied in the interior of passenger cars and truck cabins. This is a quality local product from a combination of good properties polyester and high performance natural fiber, kenaf that is suitable for many applications such as in automotive sector and construction sector. The mechanical and thermal properties of composite were characterized using Durometer Shore-D hardness test, Izod impact test, Scanning electron microscopy, thermogravimetry (TGA) and differential scanning calorimetry (DSC). Result shows that addition of LNR give good properties on impact, flexural and hardness compare to without LNR composite. DSC curve shows that all composition of composites is fully cured and good in thermal properties. Addition of higher percentage of kenaf will lead the composite to elastic behavior and decrease the toughened properties of the composite. Hybrid system composite showed the flexural properties within the flexural properties of kenaf - polyester and Cloisite 30B.

76 FR 60802 - Certain Polyester Staple Fiber From the Republic of Korea and Taiwan: Continuation of Antidumping...

Federal Register 2010, 2011, 2012, 2013, 2014

2011-09-30

... DEPARTMENT OF COMMERCE International Trade Administration [A-580-839, A-583-833] Certain Polyester... Commission (ITC) that revocation of the antidumping duty orders on certain polyester staple fiber from the... and the ITC instituted sunset reviews of the antidumping duty orders on polyester staple fiber from...

Sorption of Triangular Silver Nanoplates on Polyurethane Foam

NASA Astrophysics Data System (ADS)

Furletov, A. A.; Apyari, V. V.; Garshev, A. V.; Volkov, P. A.; Tolmacheva, V. V.; Dmitrienko, S. G.

2018-02-01

The sorption of triangular silver nanoplates on polyurethane foam is investigated as a procedure for creating a nanocomposite sensing material for subsequent use in optical means of chemical analysis. Triangular silver nanoplates are synthesized and characterized, and a simple sorption technique for the formation of a composite material based on these nanoplates is proposed.

Presence of Biofilms on Polyurethane-Coated Breast Implants: Preliminary Results.

PubMed

Rieger, Ulrich M; Djedovic, Gabriel; Pattiss, Alexander; Raschke, Gregor F; Frei, Reno; Pierer, Gerhard; Trampuz, Andrej

2016-01-01

Polyurethane-coated breast implants seem to be associated with lower medium- and long-term capsular contracture rates in comparison to textured or smooth implant surfaces. Although the etiology of capsular contracture is uncertain, bacterial biofilms have been suggested to trigger chronic peri-implant inflammation, eventually leading to capsular contracture. It is unknown whether polyurethane-coated implants are less prone to biofilm colonization than other implant surfaces. We extracted data from patient records included in a prospective cohort between 2008 and 2011. All patients who underwent removal of polyurethane-coated implants were included in this current study and screened for presence of biofilms by sonication. In addition, implant- and patient-related data were analyzed. Of the ten included polyurethane-coated breast implants, six had been inserted for reconstructive purposes and four for aesthetic reasons. The median implant indwelling time was 28.3 mo. Overall, sonication cultures were positive in 50% of implants. Propionibacterium acnes and coagulase-negative staphylococci were the predominant pathogens isolated from biofilm cultures. Like other implant surfaces, polyurethane-coated implants are prone to biofilm colonization. Further investigations are needed to determine why capsular contracture rates seem to be lower in polyurethane implants than in other implant surfaces. Notably, in this study, 40% of the implants were explanted from breasts with severe capsular contracture.

A study on effect of ATH on Euphorbia coagulum modified polyester banana fiber composite

NASA Astrophysics Data System (ADS)

Kumari, Sanju; Rai, Bhuvneshwar; Kumar, Gulshan

2018-02-01

Fiber reinforced polymer composites are used for building and structural applications due to their high strength. In conventional composites both the binder and the reinforcing fibers are synthetic or either one of the material is natural. In the present study coagulum of Euphorbia royleana has been used for replacing polyester resinas binder in polyester banana composite. Euphorbia coagulum (driedlatex) is rich in resinous mass (60-80%), which are terpenes and polyisoprene (10-20%). Effect of varying percentage of coagulum content on various physico-mechanical properties of polyester-banana composites has been studied. Since banana fiber is sensitive to water due to presence of polar group, banana composite undergoes delamination and deterioration under humid condition. Alkali treated banana fiber along with coagulum content has improved overall mechanical properties and reduction in water absorption. The best physico-mechanical properties have been achieved on replacing 40% of polyester resin by coagulum. An increase of 50% in bending strength, 30% bending modulus and 45% impact strength as well as 68% decrease in water absorption was observed. Incorporation of 20% ATH as flame retardant in coagulum modified banana polyester composite enhanced limiting oxygen index from 20.6 to 26.8% and smoke density reduced up to 40%. This study presents the possibility of utilization of renewable materials for environmental friendly composite development as well as to find out alternative feedstock for petroleum products. Developed Euphorbia latex modified banana polyester composites can have potential utility in hardboard, partition panel, plywood and automotive etc.

Difference between electrostriction kinetics, and mechanical response of segmented polyurethane-based EAP

NASA Astrophysics Data System (ADS)

Jomaa, M. H.; Seveyrat, L.; Perrin, V.; Lebrun, L.; Masenelli-Varlot, K.; Diguet, Gildas; Cavaille, J. Y.

2017-03-01

Among the key parameters, which must be taken into account for the choice of actuators used as electrical to mechanical energy converters, the response to a step function and/or the frequency dependence of this response is extremely important. For polymeric actuators and more generally for electroactive polymers, three mechanisms can be at the origin of energy losses, namely dielectric relaxations, viscoelastic relaxations and possible electrical conductivity. In a previous paper, we studied the electrical behavior of segmented polyurethanes with different weight fractions of hard (MDI-BDO) and soft (PTMO) segments. They were shown to exhibit three main mechanisms, namely, from the fastest to the slowest, a secondary or β-relaxation, the main or α-relaxation associated with the glass-rubber transition of the soft phase, and finally, their electrical conductivity. In the present work, we present the general viscoelastic response (as measured through mechanical spectrometry) of the same polyurethanes and their respective time dependent electrostriction responses, and compare it with the relaxation characteristic times of electrical and mechanical spectroscopy data.

Bio-based production of monomers and polymers by metabolically engineered microorganisms.

PubMed

Chung, Hannah; Yang, Jung Eun; Ha, Ji Yeon; Chae, Tong Un; Shin, Jae Ho; Gustavsson, Martin; Lee, Sang Yup

2015-12-01

Recent metabolic engineering strategies for bio-based production of monomers and polymers are reviewed. In the case of monomers, we describe strategies for producing polyamide precursors, namely diamines (putrescine, cadaverine, 1,6-diaminohexane), dicarboxylic acids (succinic, glutaric, adipic, and sebacic acids), and ω-amino acids (γ-aminobutyric, 5-aminovaleric, and 6-aminocaproic acids). Also, strategies for producing diols (monoethylene glycol, 1,3-propanediol, and 1,4-butanediol) and hydroxy acids (3-hydroxypropionic and 4-hydroxybutyric acids) used for polyesters are reviewed. Furthermore, we review strategies for producing aromatic monomers, including styrene, p-hydroxystyrene, p-hydroxybenzoic acid, and phenol, and propose pathways to aromatic polyurethane precursors. Finally, in vivo production of polyhydroxyalkanoates and recombinant structural proteins having interesting applications are showcased. Copyright © 2015 Elsevier Ltd. All rights reserved.

Degradation of pentachlorophenol by polyurethane-immobilized Flavobacterium cells.

PubMed Central

O'Reilly, K T; Crawford, R L

1989-01-01

Polyurethane-immobilized Flavobacterium cells (ATCC 39723) degraded pentachlorophenol (PCP) at initial concentrations as high as 300 mg liter-1. The reversible binding of PCP to the polyurethane was shown to be important in the protection of the cells from inhibition of PCP degradation. The degradation activity of the bacteria was monitored for 150 days in semicontinuous batch reactors. The degradation rate dropped by about 0.6% per day. PCP was degraded in a continuous-culture bioreactor at a rate of 3.5 to 4 mg g of foam-1 day-1 for 25 days. Electron micrographs of the polyurethane suggested that the cells were entrapped within 50- to 500-microns-diameter pockets in the foam. PMID:2508552

Organic/inorganic hybrid coatings for anticorrosion

NASA Astrophysics Data System (ADS)

He, Zhouying

Compared to organic coatings, organic-inorganic hybrid coatings can potentially improve the anticorrosion performance. The organic phase provides the excellent mechaincal and barrier properties while the inorganic phase acts as an adhesion promoter and corrosion inhibitor. Despite that many studies on alkoxylsilane-based hybrid coatings have been developed and studied, their weatherability and anticorrosion performance has been rarely evaluated. On the other hand, organic-inorganic hybrid coatings based on mixed sol-gel precursors have received much less attention compared to alkoxylsilane-based hybrid coatings. In the first part, polyurethane hybrid coatings with a unique hybrid crosslinked structure as an improved unicoat were successfully prepared. The effect of polyesters on physical properties of the hybrid coatings was studied. Polyurethane coatings derived from cycloaliphatic polyester show comparable properties than those derived from the commercially viable aromatic polyester. Introducing the polysiloxane part into the polyurethane coatings enhanced the crosslinking density, Tg, mechanical properties, and general coating properties. The increased adhesion between the hybrid coating and the substrate make the hybrid coating a good candidate for anticorrosion application, which is shown by electrochemical impedance spectroscopy (EIS). The degradation mechanism of the polyurethane/polysiloxane hybrid coatings under various weathering conditions was shown to be the scission of the urethane and ester groups in the organic phase along with reorganizing and rearranging of the inorganic phase. The anticorrosion performance of the cycloaliphatic hybrid was much better than that of aromatic based hybrid under outdoor weathering based on visual observation and EIS analysis. Acid undercutting is an issue for TEOS based hybrid coating. In the second part, design of experiments (DOEs) was used to statistically investigate on the effect of sol-gel precursors. The

75 FR 76954 - Certain Polyester Staple Fiber From the People's Republic of China: Extension of Time Limit for...

Federal Register 2010, 2011, 2012, 2013, 2014

2010-12-10

... DEPARTMENT OF COMMERCE International Trade Administration [A-570-905] Certain Polyester Staple... administrative review of certain polyester staple fiber (``PSF'') from the People's Republic of China (``PRC''), covering the period June 1, 2008--May 31, 2009. See Certain Polyester Staple Fiber From the People's...

Sub-Surface and Bulk Creep Behaviour of Polyurethane/Clay Nanocomposites.

PubMed

Jin, J; Yusoh, K; Zhang, H X; Song, M

2016-03-01

A series of exfoliated and intercalated polyurethane organoclay nanocomposites were prepared by in situ polymerization of polyol/organoclay mixture, chain extender and diisocyanate. The creep behaviour of subsurface and bulk of the polyurethane coatings was investigated by nanoindentation technique and uniaxial conventional creep testing method, respectively. The results showed that the creep resistance of the nanocomposites was significantly improved by incorporation of organoclay. The enhancement of creep resistance was dependent on clay content as well as organoclay structure (exfoliation or intercalation) in the polymer matrix. With 1 wt% organoclay, the creep resistance increased by about 50% for the intercalated organoclay and 6% for the exfoliated organoclay systems, respectively, compared to the pristine polyurethane. Viscoelastic model was employed to investigate the effect of organoclay loadings on the creep performance of the polyurethane. Results showed the model was in good agreement with the experimental data. Incorporation of clay leads to an increase in elastic deformation especially in exfoliated polyurethane nanocomposites and induces a higher initial displacement at the early stage of creep.

Rigid palm oil-based polyurethane foam reinforced with diamine-modified montmorillonite nanoclay

NASA Astrophysics Data System (ADS)

Haziq Dzulkifli, Mohd; Yazid Yahya, Mohd; Majid, Rohah A.

2017-05-01

This paper presents work on organically-modified montmorillonite (MMT) nanoclay embedded in rigid palm oil-based polyurethane (PU) foam. MMT was modified with organic surfactant diamino propane (DAP). PU foam was fabricated in closed mold, and the amount of DAP-MMT was varied in each foam formulation. The obtained foam was tested for its microstructure and morphology. Appearance of peaks from infra-red spectra corresponding to N-H, C=O, and C-N confirms the formation of PU networks. Scanning electron microscopy (SEM) revealed fine, closed-cellular structure at low clay loading; increasing DAP-MMT content induced larger cell sizes with blowholes. X-ray diffraction (XRD) indicates fully-exfoliated clays at 1 wt. % and partial-exfoliation at 3 wt. % clay loading, suggesting clumping of clays as DAP-MMT content increased.

Polyurethane-Based Ionogels Exhibiting Durable Thermoresponsive Optical Behavior Under High-Temperature Conditions.

PubMed

Sato, Tomoya; England, Matt W; Wang, Liming; Urata, Chihiro; Kakiuchida, Hiroshi; Hozumi, Atsushi

2018-01-01

Polyurethane (PU)-based transparent and flexible ionogels, showing unusual thermo-responsive optical properties, were successfully prepared by mixing PU-precursor and a hydrophobic ionic liquid, 1-ethyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide (EMIM-TFSI). Although the initial ionogels were transparent at room temperature, significant increases in opacity were observed with increasing temperature up to 120°C, because of macroscopic phase separation of the PU-matrix and hydrophobic EMIM-TFSI. In addition, the optical transition temperature could be arbitrarily controlled simply by varying the mixing ratio of EMIM-TFSI within the PU-matrix. As confirmed by UV-Vis spectra acquired at different temperatures, this thermo-responsive optical behavior was found to be reversible, repeatable and durable even after 30 cycles of a thermal-stress testing between 30 and 100°C.

The Effect of Postmastectomy Radiation Therapy on Breast Implants: Material Analysis on Silicone and Polyurethane Prosthesis.

PubMed

Lo Torto, Federico; Relucenti, Michela; Familiari, Giuseppe; Vaia, Nicola; Casella, Donato; Matassa, Roberto; Miglietta, Selenia; Marinozzi, Franco; Bini, Fabiano; Fratoddi, Ilaria; Sciubba, Fabio; Cassese, Raffaele; Tombolini, Vincenzo; Ribuffo, Diego

2018-05-17

The pathogenic mechanism underlying capsular contracture is still unknown. It is certainly a multifactorial process, resulting from human body reaction, biofilm activation, bacteremic seeding, or silicone exposure. The scope of the present article is to investigate the effect of hypofractionated radiotherapy protocol (2.66 Gy × 16 sessions) both on silicone and polyurethane breast implants. Silicone implants and polyurethane underwent irradiation according to a hypofractionated radiotherapy protocol for the treatment of breast cancer. After irradiation implant shells underwent mechanical, chemical, and microstructural evaluation by means of tensile testing, infrared spectra in attenuated total reflectance mode, nuclear magnetic resonance, and field emission scanning electron microscopy. At superficial analysis, irradiated silicone samples show several visible secondary and tertiary blebs. Polyurethane implants showed an open cell structure, which closely resembles a sponge. Morphological observation of struts from treated polyurethane sample shows a more compact structure, with significantly shorter and thicker struts compared with untreated sample. The infrared spectra in attenuated total reflectance mode spectra of irradiated and control samples were compared either for silicon and polyurethane samples. In the case of silicone-based membranes, treated and control specimens showed similar bands, with little differences in the treated one. Nuclear magnetic resonance spectra on the fraction soluble in CDCl3 support these observations. Tensile tests on silicone samples showed a softer behavior of the treated ones. Tensile tests on Polyurethane samples showed no significant differences. Polyurethane implants seem to be more resistant to radiotherapy damage, whereas silicone prosthesis showed more structural, mechanical, and chemical modifications.

Soybean-oil-based waterborne polyurethane dispersions: effects of polyol functionality and hard segment content on properties.

PubMed

Lu, Yongshang; Larock, Richard C

2008-11-01

The environmentally friendly vegetable-oil-based waterborne polyurethane dispersions with very promising properties have been successfully synthesized without difficulty from a series of methoxylated soybean oil polyols (MSOLs) with different hydroxyl functionalities ranging from 2.4 to as high as 4.0. The resulting soybean-oil-based waterborne polyurethane (SPU) dispersions exhibit a uniform particle size, which increases from about 12 to 130 nm diameter with an increase in the OH functionality of the MSOL from 2.4 to 4.0 and decreases with increasing content of the hard segments. The structure and thermophysical and mechanical properties of the resulting SPU films, which contain 50-60 wt % MSOL as renewable resources, have been studied by Fourier transform infrared spectroscopy, differential scanning calorimetry, dynamic mechanical analysis, thermogravimetric analysis, transmission electron microscopy, and mechanical testing. The experimental results reveal that the functionality of the MSOLs and the hard segment content play a key role in controlling the structure and the thermophysical and mechanical properties of the SPU films. These novel films exhibit tensile stress-strain behavior ranging from elastomeric polymers to rigid plastics and possess Young's moduli ranging from 8 to 720 MPa, ultimate tensile strengths ranging from 4.2 to 21.5 MPa, and percent elongation at break values ranging from 16 to 280%. This work has addressed concerns regarding gelation and higher cross-linking caused by the high functionality of vegetable-oil-based polyols. This article reports novel environmentally friendly biobased SPU materials with promising applications as decorative and protective coatings.

The identification of cutin synthase: formation of the plant polyester cutin.

PubMed

Yeats, Trevor H; Martin, Laetitia B B; Viart, Hélène M-F; Isaacson, Tal; He, Yonghua; Zhao, Lingxia; Matas, Antonio J; Buda, Gregory J; Domozych, David S; Clausen, Mads H; Rose, Jocelyn K C

2012-07-01

A hydrophobic cuticle consisting of waxes and the polyester cutin covers the aerial epidermis of all land plants, providing essential protection from desiccation and other stresses. We have determined the enzymatic basis of cutin polymerization through characterization of a tomato extracellular acyltransferase, CD1, and its substrate, 2-mono(10,16-dihydroxyhexadecanoyl)glycerol. CD1 has in vitro polyester synthesis activity and is required for cutin accumulation in vivo, indicating that it is a cutin synthase.

Reduced toxicity polyester resins and microvascular pre-preg tapes for advanced composites manufacturing

NASA Astrophysics Data System (ADS)

Poillucci, Richard

Advanced composites manufacturing broadly encapsulates topics ranging from matrix chemistries to automated machines that lay-up fiber-reinforced materials. Environmental regulations are stimulating research to reduce matrix resin formulation toxicity. At present, composites fabricated with polyester resins expose workers to the risk of contact with and inhalation of styrene monomer, which is a potential carcinogen, neurotoxin, and respiratory irritant. The first primary goal of this thesis is to reduce the toxicity associated with polyester resins by: (1) identification of potential monomers to replace styrene, (2) determination of monomer solubility within the polyester, and (3) investigation of approaches to rapidly screen a large resin composition parameter space. Monomers are identified based on their ability to react with polyester and their toxicity as determined by the Globally Harmonized System (GHS) and a green screen method. Solubilities were determined by the Hoftyzer -- Van Krevelen method, Hansen solubility parameter database, and experimental mixing of monomers. A combinatorial microfluidic mixing device is designed and tested to obtain distinct resin compositions from two input chemistries. The push for safer materials is complemented by a thrust for multifunctional composites. The second primary goal of this thesis is to design and implement the manufacture of sacrificial fiber materials suitable for use in automated fiber placement of microvascaular multifunctional composites. Two key advancements are required to achieve this goal: (1) development of a roll-to-roll method to place sacrificial fibers onto carbon fiber pre-preg tape; and (2) demonstration of feasible manufacture of microvascular carbon fiber plates with automated fiber placement. An automated method for placing sacrificial fibers onto carbon fiber tapes is designed and a prototype implemented. Carbon fiber tows with manual placement of sacrificial fibers is implemented within an

N-halamine-based rechargeable antimicrobial and biofilm-controlling polyurethane

PubMed Central

Sun, Xinbo; Cao, Zhengbing; Porteous, Nuala; Sun, Yuyu

2012-01-01

An N-halamine precursor, 5, 5-dimethyl hydantoin (DMH), was covalently linked to the surface of polyurethane (PU) with 1,6-hexamethylene diisocyanate (HDI) as a coupling agent. The reaction pathways were investigated using propyl isocyanate (PI) as a model compound, and the results suggested that the imide and amide groups of DMH had very similar reactivity toward the isocyanate groups on PU surfaces activated with HDI. After bleach treatment, the covalently bound DMH moieties were transformed into N-halamines. The new N-halmaine-based PU provided potent antimicrobial effects against Staphylococcus aureus (S. aureus, Gram-positive), Escherichia coli (E. coli, Gram-negative), methicillin-resistant staphylococcus aureus (MRSA, drug resistant Gram-positive bacteria), vancomycin-resistant enterococcus (VRE, drug resistant Gram-positive bacteria), and Candida albicans (C. ablicans, fungi), and successfully prevented bacterial and fungal biofilm formation. The antimicrobial and biofilm-controlling effects were stable for longer than 6 months under normal storage in open air. Furthermore, if the functions were lost due to prolonged use, they could be recharged by another chlorination treatment. The recharging could be repeated as needed to achieve long-term protection against microbial contamination and biofilm-formation. PMID:22244984

Friction and morphology of magnetic tapes in sliding contact with nickel-zinc ferrite

NASA Technical Reports Server (NTRS)

Miyoshi, K.; Buckley, D. H.; Bhushan, B.

1984-01-01

Friction and morphological studies were conducted with magnetic tapes containing a Ni-Zn ferrite hemispherical pin in laboratory air at a relative humidity of 40 percent and at 23 C. The results indicate that the binder plays a significant role in the friction properties, morphology, and microstructure of the tape. Comparisons were made with four binders: nitrocellulose; poly (vinyledene) chloride; cellulose acetate; and hydroxyl-terminated, low molecular weight polyester added to the base polymer, polyester-polyurethane. The coefficient of friction was lowest for the tape with the nitrocellulose binder and increased in the order hydroxylterminated, low molecular weight polyester resin; poly (vinyledene) chloride; and cellulose acetate. The degree of enclosure of the oxide particles by the binder was highest for hydroxyl-terminated, low molecular weight polyester and decreased in the order cellulose acetate, poly (vinyledene) chloride, and nitrocellulose. The nature of deformation of the tape was a factor in controlling friction. The coefficient of friction under elastic contact conditions was considerably lower than under conditions that produced plastic contacts.

Encapsulation of β-Sitosterol in Polyurethane by Sol-Gel Electrospinning.

PubMed

Amina, Musarat; Amna, Touseef; Al-Musayeib, Nawal; Zabin, Sami A; Hassan, M Shamshi; Khil, Myung-Seob

2017-06-01

Pristine β-sitosterol or in combination with other phytosterols is utilized in an array of enriched commercial foods. Considering the presence of β-sitosterol in different functional foods and its potential role in prevention and cure of neurodegenerative diseases, the aims of our investigation were to encapsulate β-sitosterol in nanofibers and to estimate influence of β-sitosterol on proliferation of fibroblasts. Electrospun nanofibers have widely been used as scaffolds to mimic natural extracellular matrix. Herein, our group for the first time establishes an innovative scaffold based on β-sitosterol and polyurethane using electrospinning. β-Sitosterol promotes epithelialization and possesses anti-oxidant and anti-inflammatory activities, whereas polyurethane, besides possessing biomedical uses, also enhances epithelial growth. We optimized the concentration (5%) of β-sitosterol in polyurethane to obtain homogenous solution, which can be spun without difficulty for the synthesis of β-sitosterol amalgamated scaffold. The resulted twisted nanofibers have been characterized via scanning electron microscopy and Fourier transform infrared spectroscopy. The viability of cells on twisted scaffold was examined using NIH 3T3 fibroblasts as model cell line. Incorporation of β-sitosterol in polyurethane changed the structure and size of nanofibers, and the twisted scaffolds were non-cytotoxic. Thus, the twisted nanoribbons, which contain anti-inflammatory β-sitosterol, can be utilized as a promising future material, which will help to ease inflammation and also aid in wound healing. In conclusion, the outcome of the preliminary research evidently points out the potential of twisted scaffold in biomedical applications.

76 FR 38612 - Certain Polyester Staple Fiber From the Republic of Korea and Taiwan: Final Results of the...

Federal Register 2010, 2011, 2012, 2013, 2014

2011-07-01

... DEPARTMENT OF COMMERCE International Trade Administration [A-580-839, A-583-833] Certain Polyester... sunset reviews of the antidumping duty orders on polyester staple fiber (PSF) from the Republic of Korea... polyesters measuring 3.3 decitex (3 denier, inclusive) or more in diameter. This merchandise is cut to...

Adhesion of Blood Plasma Proteins and Platelet-rich Plasma on l-Valine-Based Poly(ester urea).

PubMed

Childers, Erin P; Peterson, Gregory I; Ellenberger, Alex B; Domino, Karen; Seifert, Gabrielle V; Becker, Matthew L

2016-10-10

The competitive absorption of blood plasma components including fibrinogen (FG), bovine serum albumin (BSA), and platelet-rich plasma (PRP) on l-valine-based poly(ester urea) (PEU) surfaces were investigated. Using four different PEU polymers, possessing compositionally dependent trends in thermal, mechanical, and critical surface tension measurements, water uptake studies were carried out to determine in vitro behavior of the materials. Quartz crystal microbalance (QCM) measurements were used to quantify the adsorption characteristics of PRP onto PEU thin films by coating the surfaces initially with FG or BSA. Pretreatment of the PEU surfaces with FG inhibited the adsorption of PRP and BSA decreased the absorption 4-fold. In vitro studies demonstrated that cells cultured on l-valine-based PEU thin films allowed attachment and spreading of rat aortic cells. These measurements will be critical toward efforts to use this new class of materials in blood-contacting biomaterials applications.

Poly(ester amide)s based on (L)-lactic acid oligomers and α-amino acids: influence of the α-amino acid side chain in the poly(ester amide)s properties.

PubMed

Fonseca, Ana C; Coelho, Jorge F J; Valente, Joana F A; Correia, Tiago R; Correia, Ilídio J; Gil, Maria H; Simões, Pedro N

2013-01-01

Novel biodegradable and low cytotoxic poly(ester amide)s (PEAs) based on α-amino acids and (L)-lactic acid (L-LA) oligomers were successfully synthesized by interfacial polymerization. The chemical structure of the new polymers was confirmed by spectroscopic analyses. Further characterization suggests that the α-amino acid plays a critical role on the final properties of the PEA. L-phenylalanine provides PEAs with higher glass transition temperature, whereas glycine enhances the crystallinity. The hydrolytic degradation in PBS (pH = 7.4) at 37 °C also depends on the α-amino acid, being faster for glycine-based PEAs. The cytotoxic profiles using fibroblast human cells indicate that the PEAs did not elicit an acute cytotoxic effect. The strategy presented in this work opens the possibility of synthesizing biodegradable PEAs with low citotoxicity by an easy and fast method. It is worth to mention also that the properties of these materials can be fine-tuned only by changing the α-amino acid.

The identification of cutin synthase: formation of the plant polyester cutin

PubMed Central

Yeats, Trevor H.; Martin, Laetitia B. B.; Viart, Hélène M.-F.; Isaacson, Tal; He, Yonghua; Zhao, Lingxia; Matas, Antonio J.; Buda, Gregory J.; Domozych, David S.; Clausen, Mads H.; Rose, Jocelyn K. C.

2012-01-01

A hydrophobic cuticle consisting of waxes and the polyester cutin covers the aerial epidermis of all land plants, providing essential protection from desiccation and other stresses. We have determined the enzymatic basis of cutin polymerization through characterization of a tomato extracellular acyltransferase, CD1, and its substrate, 2-mono(10,16-dihydroxyhexadecanoyl)glycerol (2-MHG). CD1 has in vitro polyester synthesis activity and is required for cutin accumulation in vivo, indicating that it is a cutin synthase. PMID:22610035

The influence of solvent processing on polyester bioabsorbable polymers.

PubMed

Manson, Joanne; Dixon, Dorian

2012-01-01

Solvent-based methods are commonly employed for the production of polyester-based samples and coatings in both medical device production and research. The influence of solvent casting and subsequent drying time was studied using thermal analysis, spectroscopy and weight measurement for four grades of 50 : 50 poly(lactic-co-glycolic acid) (PLGA) produced by using chloroform, dichloromethane, and acetone. The results demonstrate that solvent choice and PLGA molecular weight are critical factors in terms of solvent removal rate and maintaining sample integrity, respectively. The protocols widely employed result in high levels of residual solvent and a new protocol is presented together with solutions to commonly encountered problems.

40 CFR 63.1294 - Standards for slabstock flexible polyurethane foam production-diisocyanate emissions.

Code of Federal Regulations, 2014 CFR

2014-07-01

... polyurethane foam production-diisocyanate emissions. 63.1294 Section 63.1294 Protection of Environment... Pollutants for Flexible Polyurethane Foam Production § 63.1294 Standards for slabstock flexible polyurethane foam production—diisocyanate emissions. Each new and existing slabstock affected source shall comply...

40 CFR 63.1294 - Standards for slabstock flexible polyurethane foam production-diisocyanate emissions.

Code of Federal Regulations, 2013 CFR

2013-07-01

... polyurethane foam production-diisocyanate emissions. 63.1294 Section 63.1294 Protection of Environment... Pollutants for Flexible Polyurethane Foam Production § 63.1294 Standards for slabstock flexible polyurethane foam production—diisocyanate emissions. Each new and existing slabstock affected source shall comply...

Effect of structural parameters on burning behavior of polyester fabrics having flame retardancy property

NASA Astrophysics Data System (ADS)

Çeven, E. K.; Günaydın, G. K.

2017-10-01

The aim of this study is filling the gap in the literature about investigating the effect of yarn and fabric structural parameters on burning behavior of polyester fabrics. According to the experimental design three different fabric types, three different weft densities and two different weave types were selected and a total of eighteen different polyester drapery fabrics were produced. All statistical procedures were conducted using the SPSS Statistical software package. The results of the Analysis of Variance (ANOVA) tests indicated that; there were statistically significant (5% significance level) differences between the mass loss ratios (%) in weft and mass loss ratios (%) in warp direction of different fabrics calculated after the flammability test. The Student-Newman-Keuls (SNK) results for mass loss ratios (%) both in weft and warp directions revealed that the mass loss ratios (%) of fabrics containing Trevira CS type polyester were lower than the mass loss ratios of polyester fabrics subjected to washing treatment and flame retardancy treatment.

Thermal behaviour and corrosion resistance of nano-ZnO/polyurethane film

NASA Astrophysics Data System (ADS)

Virgawati, E.; Soegijono, B.

2018-03-01

Hybrid materials Nano-ZnO/polyurethane film was prepared with different zinc oxide (ZnO) content in polyurethane as a matrix. The film was deposited on low carbon steel plate using high volume low pressure (HVLP) method. To observe thermal behaviour of the film, the sample was investigated using thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC). Fourier transform infrared spectroscopy (FTIR) was used to see whether any chemical reaction of ZnO in polyurethane occured. TGA and FTIR results showed that the decomposition temperature shifted to a higher point and the chemical reaction of zinc oxide in polyurethane occurred. The surface morphology changed and the corrosion resistance increased with an increase of ZnO content

Precision Aliphatic Polyesters with Alternating Microstructures via Cross-Metathesis Polymerization: An Event of Sequence Control.

PubMed

Li, Zi-Long; Zeng, Fu-Rong; Ma, Ji-Mei; Sun, Lin-Hao; Zeng, Zhen; Jiang, Hong

2017-06-01

Sequence-regulated polymerization is realized upon sequential cross-metathesis polymerization (CMP) and exhaustive hydrogenation to afford precision aliphatic polyesters with alternating sequences. This strategy is particularly suitable for the arrangement of well-known monomer units including glycolic acid, lactic acid, and caprolactic acid on polymer chain in a predetermined sequence. First of all, structurally asymmetric monomers bearing acrylate and α-olefin terminuses are generated in an efficient and straightforward fashion. Subsequently, cross-metathesis (co)polymerization of M1 and M2 using the Hoveyda-Grubbs second-generation catalyst (HG-II) furnishes P1-P3, respectively. Finally, hydrogenation yields the desired saturated polyesters HP1-HP3. It is noteworthy that the ε-caprolactone-derived unit is generated in situ rather than introduced to tailor-made monomers prior to CMP. NMR and matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF-MS) results verify the microstructural periodicity of these precision polyesters. Differential scanning calorimetry (DSC) results reflect that polyesters without methyl side groups exhibit crystallinity, and unsaturated polyester samples show higher glass transition temperatures than their hydrogenated counterparts owing to structural rigidity. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Open-celled polyurethane foam

NASA Technical Reports Server (NTRS)

Russell, L. W.

1970-01-01

Open-celled polyurethane foam has a density of 8.3 pounds per cubic foot and a compressive strength of 295 to 325 psi. It is useful as a porous spacer in layered insulation and as an insulation material in vacuum tight systems.

40 CFR 63.1294 - Standards for slabstock flexible polyurethane foam production-diisocyanate emissions.

Code of Federal Regulations, 2010 CFR

2010-07-01

... 40 Protection of Environment 11 2010-07-01 2010-07-01 true Standards for slabstock flexible polyurethane foam production-diisocyanate emissions. 63.1294 Section 63.1294 Protection of Environment... Flexible Polyurethane Foam Production § 63.1294 Standards for slabstock flexible polyurethane foam...

40 CFR 63.1294 - Standards for slabstock flexible polyurethane foam production-diisocyanate emissions.

Code of Federal Regulations, 2012 CFR

2012-07-01

... 40 Protection of Environment 12 2012-07-01 2011-07-01 true Standards for slabstock flexible polyurethane foam production-diisocyanate emissions. 63.1294 Section 63.1294 Protection of Environment... Flexible Polyurethane Foam Production § 63.1294 Standards for slabstock flexible polyurethane foam...

40 CFR 63.1294 - Standards for slabstock flexible polyurethane foam production-diisocyanate emissions.

Code of Federal Regulations, 2011 CFR

2011-07-01

... 40 Protection of Environment 11 2011-07-01 2011-07-01 false Standards for slabstock flexible polyurethane foam production-diisocyanate emissions. 63.1294 Section 63.1294 Protection of Environment... Flexible Polyurethane Foam Production § 63.1294 Standards for slabstock flexible polyurethane foam...

Antibacterial property of fabrics coated by magnesium-based brucites

NASA Astrophysics Data System (ADS)

Wang, Ying; Sha, Lin; Zhao, Jiao; Li, Qian; Zhu, Yimin; Wang, Ninghui

2017-04-01

A kind of environmental-friendly magnesium-based antibacterial agent was reported for the first time, which was composited by brucites with different particle sizes. The antibacterial fabrics were produced by coating the magnesium-based antibacterial agents on the 260T polyester pongee fabrics with waterborne polyurethane. The coating process was simple, low-cost, and harmless to human health and environment. Characteristics of the antibacterial agents and fabrics were studied by particulate size distribution analyzer (PSDA), X-ray diffraction (XRD), and scanning electron microscopy (SEM). The results demonstrated that the coating layer was covered tightly on the fabrics and compositing of different particles by a certain proportion made full filling of the coating layer. Meanwhile, compositing did not change the structure of brucites. The antibacterial fabrics presented strong antibacterial properties against Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus), with the reduction percentage of 96.6% and 100%, respectively, and the antibacterial fabrics attained excellent washing durability.

The effect of autoclave resterilisation on polyester vascular grafts.

PubMed

Riepe, G; Whiteley, M S; Wente, A; Rogge, A; Schröder, A; Galland, R B; Imig, H

1999-11-01

polyester grafts are expensive, single-use items. Some manufacturers of uncoated, woven grafts include instructions for autoclave resterilisation to be performed at the surgeon's own request. Others warn against such manipulation. Theoretically, the glass transition point of polyester at 70-80 degrees C and the possible acceleration of hydrolysis suggest that autoclave resterilisation at 135 degrees C might be a problem. a DeBakey Soft Woven Dacron Vascular Prosthesis (Bard) and a Woven Double Velour Dacron Graft (Meadox) were autoclave-resterilised 0 to 20 times, having been weighed before and after sterilisation. Tactile testing was performed. Mechanical properties were examined by probe puncture and single-filament testing, the surface was examined by scanning electron microscopy and the degree of hydrolysis by infra-red spectroscopy. tactile testing revealed a change of feeling with increasing cycles of resterilisation. Investigation of weight, textile strength, single-filament strength, electron microscopy of the surface and infra-red spectroscopy showed no change of the material. changes felt are presumably a surface phenomenon, not measurably affecting strength or chemistry of material after autoclave resterilisation. We therefore feel that it is safe to use once-autoclave-resterilised surplus uncoated polyester grafts, provided that sterility is guaranteed. Copyright 1999 Harcourt Publishers Ltd.

Designed drug-release systems having various breathable polyurethane film-backed hydrocolloid acrylated adhesive layers for moisture healing.

PubMed

Chang, Ching-Hsien; Liu, Hsia-Wei; Huang, Ching-Cheng

2014-01-01

A series of designed drug-release systems were prepared and established for clear moisture healing. These systems were designed to have an interpenetrating polymer network (IPN) structure, which contained a breathable polyurethane film, hydrocolloidlayer, and polyacrylate adhesive layer. Breathable polyurethane film (2000 g/m(2)/24 hr) with high moisture permeability was employed as a base for new drug-release systems or wound dressings. All drug-release systems having a polyurethane film-backed hydrocolloid acrylated adhesive layer showed an increase of water uptakes with increasing time. After 114 hours, high water uptakes of drug-release systems with 20% hydrocolloid components were observed in the values of 160, 1100, and 1870% for different additional hydrocolloid components of carboxymethylcellulose, sodium alginate, and carbomer U10, respectively. New drug-release systems of polyurethane film-backed hydrocolloid/adhesive layers could be designed and established for wound care managements.

Diamine curing agents for polyurethanes

NASA Technical Reports Server (NTRS)

Bell, V. L.; St. Clair, T. L.

1975-01-01

Three aromatic diamines have properties that make them promising candidates as curing agents for converting isocyanates to polyurethanes with higher adhesive strengths, higher softening temperatures, better toughness, and improved abrasion resistance.

BONE REGENERATION AFTER DEMINERALIZED BONE MATRIX AND CASTOR OIL (RICINUS COMMUNIS) POLYURETHANE IMPLANTATION

PubMed Central

Leite, Fábio Renato Manzolli; Ramalho, Lizeti Toledo de Oliveira

2008-01-01

Innocuous biocompatible materials have been searched to repair or reconstruct bone defects. Their goal is to restore the function of live or dead tissues. This study compared connective tissue and bone reaction when exposed to demineralized bovine bone matrix and a polyurethane resin derived from castor bean (Ricinus communis). Forty-five rats were assigned to 3 groups of 15 animals (control, bovine bone and polyurethane). A cylindrical defect was created on mandible base and filled with bovine bone matrix and the polyurethane. Control group received no treatment. Analyses were performed after 15, 45 and 60 days (5 animals each). Histological analysis revealed connective tissue tolerance to bovine bone with local inflammatory response similar to that of the control group. After 15 days, all groups demonstrated similar outcomes, with mild inflammatory reaction, probably due to the surgical procedure rather than to the material. In the polymer group, after 60 days, scarce multinucleated cells could still be observed. In general, all groups showed good stability and osteogenic connective tissue with blood vessels into the surgical area. The results suggest biocompatibility of both materials, seen by their integration into rat mandible. Moreover, the polyurethane seems to be an alternative in bone reconstruction and it is an inexhaustible source of biomaterial. PMID:19089203

Experimental Investigation on Thermal Physical Properties of an Advanced Polyester Material

NASA Astrophysics Data System (ADS)

Guangfa, Gao; Shujie, Yuan; Ruiyuan, Huang; Yongchi, Li

Polyester materials were applied widely in aircraft and space vehicles engineering. Aimed to an advanced polyester material, a series of experiments for thermal physical properties of this material were conducted, and the corresponding performance curves were obtained through statistic analyzing. The experimental results showed good consistency. And then the thermal physical parameters such as thermal expansion coefficient, engineering specific heat and sublimation heat were solved and calculated. This investigation provides an important foundation for the further research on the heat resistance and thermodynamic performance of this material.

Biobased composites from cross-linked soybean oil and thermoplastic polyurethane

USDA-ARS?s Scientific Manuscript database

Soybean oil is an important sustainable material. Crosslinked acrylated epoxidized soybean oil (AESO) is brittle and the incorporation of thermoplastic polyurethane improves its toughness. The hydrophilic functional groups from both oil and polyurethane contribute to the adhesion of the blend compon...

Enzyme-Catalyzed Synthesis of Unsaturated Aliphatic Polyesters Based on Green Monomers from Renewable Resources

PubMed Central

Jiang, Yi; Woortman, Albert J.J.; Alberda van Ekenstein, Gert O.R.; Loos, Katja

2013-01-01

Bio-based commercially available succinate, itaconate and 1,4-butanediol are enzymatically co-polymerized in solution via a two-stage method, using Candida antarctica Lipase B (CALB, in immobilized form as Novozyme® 435) as the biocatalyst. The chemical structures of the obtained products, poly(butylene succinate) (PBS) and poly(butylene succinate-co-itaconate) (PBSI), are confirmed by 1H- and 13C-NMR. The effects of the reaction conditions on the CALB-catalyzed synthesis of PBSI are fully investigated, and the optimal polymerization conditions are obtained. With the established method, PBSI with tunable compositions and satisfying reaction yields is produced. The 1H-NMR results confirm that carbon-carbon double bonds are well preserved in PBSI. The differential scanning calorimetry (DSC) and thermal gravimetric analysis (TGA) results indicate that the amount of itaconate in the co-polyesters has no obvious effects on the glass-transition temperature and the thermal stability of PBS and PBSI, but has significant effects on the melting temperature. PMID:24970176

Tracking composition of microbial communities for simultaneous nitrification and denitrification in polyurethane foam.

PubMed

Chen, Yuan; Wang, Li; Ma, Fang; Yang, Ji-xian; Qiu, Shan

2014-01-01

The process of simultaneous nitrification and denitrification (SND) of immobilized microorganisms in polyurethane form is discussed. The effect of different positions within the polyurethane carrier on microbial community response for the SND process is investigated by a combination of denaturing gradient gel electrophoresis profiles of the 16S rRNA gene V3 region and scanning electron microscopy. Results show that polyurethane, which consists of a unique porous structure, is an ideal platform for biofilm stratification of aerobe, anaerobe and facultative microorganisms in regard to the SND process. The community structure diversity response to different positions was distinct. The distributions of various functional microbes, detected from the surface aerobic stratification to the interior anaerobic stratification of polyurethane, were mainly nitrifying and denitrifying bacteria. Meanwhile aerobic denitrifying bacteria such as Paracoccus sp., Agrobacterium rubi and Ochrobactrum sp. were also adhered to the interior and surface of polyurethane. The SND process occurring on polyurethane foam was carried out by two independent processes: nitrogen removal and aerobic denitrification.

Surface modification of polyester fabrics by atmospheric-pressure air/He plasma for color strength and adhesion enhancement

NASA Astrophysics Data System (ADS)

Zhang, Chunming; Zhao, Meihua; Wang, Libing; Qu, Lijun; Men, Yajing

2017-04-01

Surface properties of water-based pigmented inks for ink-jet printed polyester fabrics were modified with atmospheric-pressure air/He plasma to improve the color strength and pigment adhesion of the treated surfaces. The influence of various parameters, including the surface morphology, chemical compositions, surface energy and dynamic contact angles of the control and plasma treated samples was studied. Color strength and edge definition were used to evaluate the ink-jet printing performance of fabrics. The change in pigment adhesion to polyester fibers was analyzed by SEM (scanning electron microscopy). AFM (Atomic force microscope) and XPS (X-ray photoelectron spectroscopy) analyses indicated the increase in surface roughness and the oxygen-containing polar groups(Cdbnd O, Csbnd OH and COOH) reinforced the fixation of pigments on the fiber surface. The result from this study suggested that the improved pigment color yield was clearly affected by alteration of pigment adhesion enhanced by plasma surface modification. Polyester fabrics exhibited better surface property and ink-jet printing performance after the air/He mixture plasma treatment comparing with those after air plasma treatment.

[Cost-effectiveness of a TLC-NOSF polyurethane foam dressing].

PubMed

Arroyo Ana, Abejón; Alvarez Vázquez, Juan Carlos; Blasco García, Carmen; Bermejo Martínez, Mariano; López Casanova, Pablo; Cuesta Cuesta, Juan José; De Haro Fernández, Francisco; Mateo Marín, Emilia; Segovia Gómez, Teresa; Villar Rojas, Antonio Erasto

2012-11-01

Chronic wounds represent a drain on the Spanish health system, nowdays is necessary an optimization of the resources used and that is for this that is necessary justify the use of the products over others through cost-effective studies for to show the economic benefit to professionals and the life quality of patient. This article compares the use of a new technology for format polyurethane foam, TLC-NOSF, with the most commonly used products for treating wounds. This comparison is made using a cost-effectiveness model (Markov Model). The results demonstrate that treatment with polyurethane foam dressing with TLC-NOSF are cost-effective versus treatments with polyurethane foams most commonly used in Spain.

Comparison of polyurethane with cyanoacrylate in hemostasis of vascular injury in guinea pigs.

PubMed

Kubrusly, Luiz Fernando; Formighieri, Marina Simões; Lago, José Vitor Martins; Graça, Yorgos Luiz Santos de Salles; Sobral, Ana Cristina Lira; Lago, Marianna Martins

2015-01-01

To evaluate the behavior of castor oil-derived polyurethane as a hemostatic agent and tissue response after abdominal aortic injury and to compare it with 2-octyl-cyanoacrylate. Twenty-four Guinea Pigs were randomly divided into three groups of eight animals (I, II, and III). The infrarenal abdominal aorta was dissected, clamped proximally and distally to the vascular puncture site. In group I (control), hemostasis was achieved with digital pressure; in group II (polyurethane) castor oil-derived polyurethane was applied, and in group III (cyanoacrylate), 2-octyl-cyanoacrylate was used. Group II was subdivided into IIA and IIB according to the time of preparation of the hemostatic agent. Mean blood loss in groups IIA, IIB and III was 0.002 grams (g), 0.008 g, and 0.170 g, with standard deviation of 0.005 g, 0.005 g, and 0.424 g, respectively (P=0.069). The drying time for cyanoacrylate averaged 81.5 seconds (s) (standard deviation: 51.5 seconds) and 126.1 s (standard deviation: 23.0 s) for polyurethane B (P=0.046). However, there was a trend (P=0.069) for cyanoacrylate to dry more slowly than polyurethane A (mean: 40.5 s; SD: 8.6 s). Furthermore, polyurethane A had a shorter drying time than polyurethane B (P=0.003), mean IIA of 40.5 s (standard deviation: 8.6 s). In group III, 100% of the animals had mild/severe fibrosis, while in group II only 12.5% showed this degree of fibrosis (P=0.001). Polyurethane derived from castor oil showed similar hemostatic behavior to octyl-2-cyanoacrylate. There was less perivascular tissue response with polyurethane when compared with cyanoacrylate.

A novel approach for synthesis of zwitterionic polyurethane coating with protein resistance.

PubMed

Wang, Chunhua; Ma, Chunfeng; Mu, Changdao; Lin, Wei

2014-11-04

We have developed a novel approach to introduce zwitterions into polyurethane for the preparation of antibiofouling coating. First, the thiol-ene click reaction between 2-(dimethylamino)ethyl methacrylate (DMAEMA) and 3-mercapto-1,2-propanediol (TPG) is used to synthesize dihydroxy-terminated DMAEMA (DMA(OH)2) under UV catalysis. The product has been proved by gel permeation chromatography (GPC), Fourier transform infrared spectrum (FT-IR), proton nuclear magnetic resonance ((1)H NMR), and high resolution mass spectrometry (HRMS). DMA(OH)2 is then incorporated into polyurethane as side groups by polyaddition with diisocyanate and further reacts with 1,3-propane sultone to obtain the zwitterionic polyurethanes. The presence of sulfobetaine zwitterions side groups has been demonstrated by FT-IR and X-ray photoelectron spectroscopy (XPS). Thermal analysis indicates that the thermal stability is decreased with the increasing content of zwitterionions. The antibiofouling property of polyurethanes has been investigated by the measurement of adsorption of fibrinogen, bovine serum albumin (BSA), and lysozyme on the polyurethanes surface using quartz crystal microbalance with dissipation (QCM-D). The results show that the polyurethane coatings exhibit effective nonspecific protein resistance at higher content of zwitterionic side groups.

Amphiphilic Polyurethane Hydrogels as Smart Carriers for Acidic Hydrophobic Drugs.

PubMed

Fonseca, Lucas P; Trinca, Rafael B; Isabel Felisberti, Maria

2018-05-14

Amphiphilic hydrogels are widely reported as systems with great potential for controlled drug release. Nevertheless, the majority of studies make use of functionalization or attachment of drugs to the polymer chains. In this study, we propose a strategy of combining amphiphilic polyurethanes with pH-responsive drugs to develop smart drug carriers. While the amphiphilic character of the polymer imparts an efficient load of hydrophobic and hydrophilic drugs, the drug's characteristics determine the selectivity of the medium delivery. Drug loading and release behavior as well as hydrolytic degradation of chemically crosslinked polyurethane hydrogels based on PEG and PCL-triol (PU (polyurethane) hydrogels) synthesized by an easy one-pot route were studied. PU hydrogels have been shown to successfully load the hydrophobic acidic drug sodium diclofenac, reaching a partition coefficient of 8 between the most hydrophobic PU and diclofenac/ethanol solutions. Moreover, an oral administration simulation was conducted by changing the environment from an acidic to a neutral medium. PU hydrogels release less than 5 % of the drug in an acidic medium; however, in a PBS pH 7.4 solution, diclofenac is delivered in a sustained fashion for up to 40 hours, achieving 80% of cumulative release. Copyright © 2018. Published by Elsevier B.V.

Surface hydrophobic modification of polyurethanes by diaryl carbene chemistry: Synthesis and characterization

NASA Astrophysics Data System (ADS)

Yang, Pengfei; Wang, Yongqing; Lu, Ling; Yu, Xi; Liu, Lian

2018-03-01

Dodecyl diaryl diazomethane was firstly synthesized from 4,4-dihydroxybenzophenone and 1-bromododecane by a series of reaction steps. Then water-borne polyurethane films with different amount of DMPA were prepared, as well as a type of solvent-borne polyurethane film for comparison. Finally, all these polyurethane films were modified by dodecyl diaryl diazomethane. The dodecyl diaryl carbene was generated from dodecyl diaryl diazomethane by strong solar light, which was very convenient to insert into the Xsbnd H bonds (X = C, N) on the surface of polyurethane films. The contact angle test was used to characterize these films and depict the surface property. DSC analysis and tensile test were used to investigate the physical properties of polyurethane films before and after modification. It was suggested that the hydrophobic modification protocol with carbene insertion was very useful and convenient to prepare water-proof coatings outdoors under direct solar-light exposure.

Synthesis of amphiphilic alternating polyesters with oligo(ethylene glycol) side chains and potential use for sustained release drug delivery.

PubMed

Wang, Wei; Ding, Jianxun; Xiao, Chunsheng; Tang, Zhaohui; Li, Di; Chen, Jie; Zhuang, Xiuli; Chen, Xuesi

2011-07-11

Novel amphiphilic alternating polyesters, poly((N-phthaloyl-l-glutamic anhydride)-co-(2-(2-(2-methoxyethoxy)ethoxy)methyl)oxirane) (P(PGA-co-ME(2)MO)), were synthesized by alternating copolymerization of PGA and ME(2)MO. The structures of the synthesized polyesters were characterized by (1)H NMR, (13)C NMR, FT-IR, and GPC analyses. Because of the presence of oligo(ethylene glycol) (OEG) side chains, the polyesters could self-assemble into thermosensitive micelles. Dynamic light scattering (DLS) showed that these micelles underwent thermoinduced size decrease without intermicellar aggregation. In vitro methyl thiazolyl tetrazolium (MTT) assay demonstrated that the polyesters were biocompatible to Henrietta Lacks (HeLa) cells, rendering their potential for drug delivery applications. Two hydrophobic drugs, rifampin and doxorubicin (DOX), were loaded into the polyester micelles and observed to be released in a zero-order sustained manner. The sustained release could be accelerated in lower pH or in the presence of proteinase K, due to the degradation of the polyester under these conditions. Remarkably, in vitro cell experiments showed that the polyester micelles accomplished fast release of DOX inside cells and higher anticancer efficacy as compared with the free DOX. With enhanced stability during circulation condition and accelerated drug release at the target sites (e.g., low pH or enzyme presence), these novel polyesters with amphiphilic structures are promising to be used in sustained release drug delivery systems.

Systematic review of the effectiveness of polyurethane-coated compared with textured silicone implants in breast surgery.

PubMed

Duxbury, Paula J; Harvey, James R

2016-04-01

Silicone gel implants are used worldwide for breast augmentation and breast reconstruction. Textured silicone implants are the most commonly placed implant, but polyurethane-coated implants are increasingly being used in an attempt to ameliorate the long-term complications associated with implant insertion. This systematic review was conducted according to the Preferred Reporting Items for Systematic Reviews and Meta-analyses guidelines. Electronic searches of MEDLINE, EMBASE, the Cochrane Library and www.ClinicalTrials.gov were undertaken in March 2014 using keywords. Following data extraction, 18 studies were included in the review, including four core studies of textured silicone implants and five studies reporting outcomes for polyurethane-coated silicone implants. There are no clear data reporting revision rates in patients treated with polyurethane implants. In the primary reconstructive setting, capsular contracture rates with silicone implants are 10-15% at 6 years, whilst studies of polyurethane implants report rates of 1.8-3.4%. In the primary augmentation setting, core studies show a capsular contracture rate of 2-15% at 6 years compared with 0.4-1% in polyurethane-coated implants; however, the polyurethane studies are limited by their design and poor follow-up. The use of polyurethane implants should be considered a safe alternative to textured silicone implants. It is likely that an implant surface does influence short- and long-term outcomes; however, the extent of any benefit cannot be determined from the available evidence base. Future implant studies should target the short- and long-term benefits of implant surfacing by procedure with defined outcome measures; a head-to-head comparison would help clarify outcomes. Copyright © 2016 British Association of Plastic, Reconstructive and Aesthetic Surgeons. Published by Elsevier Ltd. All rights reserved.

Renewable unsaturated polyesters from muconic acid

DOE PAGES

Rorrer, Nicholas A.; Dorgan, John R.; Vardon, Derek R.; ...

2016-09-27

cis,cis-Muconic acid is an unsaturated dicarboxylic acid that can be produced in high yields via biological conversion of sugars and lignin-derived aromatic compounds. Muconic acid is often targeted as an intermediate to direct replacement monomers such as adipic or terephthalic acid. However, the alkene groups in muconic acid provide incentive for its direct use in polymers, for example, in the synthesis of unsaturated polyester resins. Here, biologically derived muconic acid is incorporated into polyesters via condensation polymerization using the homologous series of poly(ethylene succinate), poly(propylene succinate), poly(butylene succinate), and poly(hexylene succinate). Additionally, dimethyl cis,cis-muconate is synthesized and subsequently incorporated intomore » poly(butylene succinate). NMR measurements demonstrate that alkene bonds are present in the polymer backbones. In all cases, the glass transition temperatures are increased whereas the melting and degradation temperatures are decreased. In the case of poly(butylene succinate), utilization of neat muconic acid yields substoichiometric incorporation consistent with a tapered copolymer structure, whereas the muconate diester exhibits stoichiometric incorporation and a random copolymer structure based on thermal and mechanical properties. Prototypical fiberglass panels were produced by infusing a mixture of low molecular weight poly(butylene succinate-co-muconate) and styrene into a woven glass mat and thermally initiating polymerization resulting in thermoset composites with shear moduli in excess of 30 GPa, a value typical of commercial composites. The increased glass transition temperatures with increasing mucconic incorporation leads to improved composites properties. We find that the molecular tunability of poly(butylene succinate-co-muconate) as a tapered or random copolymer enables the tunability of composite properties. Altogether, this study demonstrates the utility of muconic acid as a

Renewable unsaturated polyesters from muconic acid

DOE Office of Scientific and Technical Information (OSTI.GOV)

Rorrer, Nicholas A.; Dorgan, John R.; Vardon, Derek R.

cis,cis-Muconic acid is an unsaturated dicarboxylic acid that can be produced in high yields via biological conversion of sugars and lignin-derived aromatic compounds. Muconic acid is often targeted as an intermediate to direct replacement monomers such as adipic or terephthalic acid. However, the alkene groups in muconic acid provide incentive for its direct use in polymers, for example, in the synthesis of unsaturated polyester resins. Here, biologically derived muconic acid is incorporated into polyesters via condensation polymerization using the homologous series of poly(ethylene succinate), poly(propylene succinate), poly(butylene succinate), and poly(hexylene succinate). Additionally, dimethyl cis,cis-muconate is synthesized and subsequently incorporated intomore » poly(butylene succinate). NMR measurements demonstrate that alkene bonds are present in the polymer backbones. In all cases, the glass transition temperatures are increased whereas the melting and degradation temperatures are decreased. In the case of poly(butylene succinate), utilization of neat muconic acid yields substoichiometric incorporation consistent with a tapered copolymer structure, whereas the muconate diester exhibits stoichiometric incorporation and a random copolymer structure based on thermal and mechanical properties. Prototypical fiberglass panels were produced by infusing a mixture of low molecular weight poly(butylene succinate-co-muconate) and styrene into a woven glass mat and thermally initiating polymerization resulting in thermoset composites with shear moduli in excess of 30 GPa, a value typical of commercial composites. The increased glass transition temperatures with increasing mucconic incorporation leads to improved composites properties. We find that the molecular tunability of poly(butylene succinate-co-muconate) as a tapered or random copolymer enables the tunability of composite properties. Altogether, this study demonstrates the utility of muconic acid as a

Design and fabrication of an E-shaped wearable textile antenna on PVB-coated hydrophobic polyester fabric

NASA Astrophysics Data System (ADS)

Babu Roshni, Satheesh; Jayakrishnan, M. P.; Mohanan, P.; Peethambharan Surendran, Kuzhichalil

2017-10-01

In this paper, we investigated the simulation and fabrication of an E-shaped microstrip patch antenna realized on multilayered polyester fabric suitable for WiMAX (Worldwide Interoperability for Microwave Access) applications. The main challenges while designing a textile antenna were to provide adequate thickness, surface uniformity and water wettability to the textile substrate. Here, three layers of polyester fabric were stacked together in order to obtain sufficient thickness, and were subsequently dip coated with polyvinyl butyral (PVB) solution. The PVB-coated polyester fabric showed a hydrophobic nature with a contact angle of 91°. The RMS roughness of the uncoated and PVB-coated polyester fabric was about 341 nm and 15 nm respectively. The promising properties, such as their flexibility, light weight and cost effectiveness, enable effortless integration of the proposed antenna into clothes like polyester jackets. Simulated and measured results in terms of return loss as well as gain were showcased to confirm the usefulness of the fabricated prototype. The fabricated antenna successfully operates at 3.37 GHz with a return loss of 21 dB and a maximum measured gain of 3.6 dB.

Comparison of polyurethane with cyanoacrylate in hemostasis of vascular injury in guinea pigs

PubMed Central

Kubrusly, Luiz Fernando; Formighieri, Marina Simões; Lago, José Vitor Martins; Graça, Yorgos Luiz Santos de Salles; Sobral, Ana Cristina Lira; Lago, Marianna Martins

2015-01-01

Objective To evaluate the behavior of castor oil-derived polyurethane as a hemostatic agent and tissue response after abdominal aortic injury and to compare it with 2-octyl-cyanoacrylate. Methods Twenty-four Guinea Pigs were randomly divided into three groups of eight animals (I, II, and III). The infrarenal abdominal aorta was dissected, clamped proximally and distally to the vascular puncture site. In group I (control), hemostasis was achieved with digital pressure; in group II (polyurethane) castor oil-derived polyurethane was applied, and in group III (cyanoacrylate), 2-octyl-cyanoacrylate was used. Group II was subdivided into IIA and IIB according to the time of preparation of the hemostatic agent. Results Mean blood loss in groups IIA, IIB and III was 0.002 grams (g), 0.008 g, and 0.170 g, with standard deviation of 0.005 g, 0.005 g, and 0.424 g, respectively (P=0.069). The drying time for cyanoacrylate averaged 81.5 seconds (s) (standard deviation: 51.5 seconds) and 126.1 s (standard deviation: 23.0 s) for polyurethane B (P=0.046). However, there was a trend (P=0.069) for cyanoacrylate to dry more slowly than polyurethane A (mean: 40.5 s; SD: 8.6 s). Furthermore, polyurethane A had a shorter drying time than polyurethane B (P=0.003), mean IIA of 40.5 s (standard deviation: 8.6 s). In group III, 100% of the animals had mild/severe fibrosis, while in group II only 12.5% showed this degree of fibrosis (P=0.001). Conclusion Polyurethane derived from castor oil showed similar hemostatic behavior to octyl-2-cyanoacrylate. There was less perivascular tissue response with polyurethane when compared with cyanoacrylate. PMID:25859876

Release of polyester and cotton fibers from textiles in machine washings.

PubMed

Sillanpää, Markus; Sainio, Pirjo

2017-08-01

Microplastics are widely spread in the environment, which along with still increasing production have aroused concern of their impacts on environmental health. The objective of this study is to quantify the number and mass of two most common textile fibers discharged from sequential machine washings to sewers. The number and mass of microfibers released from polyester and cotton textiles in the first wash varied in the range 2.1 × 10 5 to 1.3 × 10 7 and 0.12 to 0.33% w/w, respectively. Amounts of released microfibers showed a decreasing trend in sequential washes. The annual emission of polyester and cotton microfibers from household washing machines was estimated to be 154,000 (1.0 × 10 14 ) and 411,000 kg (4.9 × 10 14 ) in Finland (population 5.5 × 10 6 ). Due to the high emission values and sorption capacities, the polyester and cotton microfibers may play an important role in the transport and fate of chemical pollutants in the aquatic environment.

Synthesis of palm-based polyurethane-LiClO{sub 4} via prepolymerization

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sien, Jason Wong Chee; School of Biosciences, Taylor’s University, Subang Jaya; Badri, Khairiah Haji

2015-09-25

Palm-based polyurethane (pPU) with varying lithium salt (LiClO{sub 4}) content was synthesized. Higher loading percentage of LiClO{sub 4} in the pPU led to the inhibition of prepolymerization process from taking place. Hydrogen bonded C=O was detected in the FTIR spectrum indicating the hydrogen bonding between the urethane bonds. Ordered complexed C=O was observed in the FTIR spectrum confirming the complex formation between urethane bond and Li{sup +} ion. DSC thermogram showed the increase in the LiClO{sub 4} content could increase the glass transition temperature. SEM micrographs exhibited that more bubbles were formed when the LiClO{sub 4} increased from 10 tomore » 30wt% indicating the reaction between free isocyanate groups with moisture presence in the salt due to the hygroscopic properties of LiClO{sub 4}.« less

[Synthesis and characterization of polylactide-based thermosetting polyurethanes with shape memory properties].

PubMed

Shi, Shuo; Gu, Lin; Yang, Yihu; Yu, Haibin; Chen, Rui; Xiao, Xianglian; Qiu, Jun

2016-06-25

A series of bio-based thermosetting polyurethanes (Bio-PUs) were synthesized by the crosslinking reaction of polylactide and its copolymers diols with hexamethylene diisocyanate (HDI) trimer. The obtained Bio-PUs were characterized by Fourier Transform Infrared Spectroscopy (FTIR), Differential Scanning Calorimetry (DSC), Thermal Gravimetric Analysis (TGA), universal tensile testing machine and cytotoxicity test. Results indicate that the PLA copolymer (P(LA-co-CL)) diols reduced the glass transition temperature (Tg) of Bio-PUs and improved their thermal stability, compared with PLA diols. The Bio-PUs synthesized from P (LA-co-CL) diols exhibit better mechanical performance and shape memory properties. Especially, Young modulus and elongation at break of the obtained Bio-PUs were 277.7 MPa and 230% respectively; the shape recovery time of the obtained Bio-PUs at body temperature was only 93 s. Furthermore, alamar blue assay results showed that the obtained Bio-PUs had no cell toxicity.

Optical, colloidal and biological properties of up-converting nanoparticles embedded in polyester nanocarriers

NASA Astrophysics Data System (ADS)

Wawrzyńczyk, Dominika; Kulbacka, Julita; Bazylińska, Urszula

2017-08-01

We have investigated the change in optical properties and biocompatibility of up-converting NaYF4 nanoparticles (NPs) upon encapsulation inside the polyester nanocarriers (NCs) stabilized by Crempophor RH40 (CRH40), poly(D,L-lactide) (PLA), Pluronic P123 (P123). NaYF4:Er3+,Yb3+ NPs showed intense green and red emission, and upon encapsulation the increase of red band in respect to green one was observed, with no luminescence lifetime shortening. Obtained NCs showed prolonged colloidal stability and protective effect of the polymer shell simultaneously preserving the high emission efficiency of nanoparticles embedded within the silicon oil (SO) core. Based on emission spectra, kinetic measurements and cytotoxicity studies upon human malignant melanoma Me45 cell line we have shown the advantages of using polyester NCs as containers for the up-converting NPs. Due to the possibility of co-encapsulation of photosensitizers the obtained nanocarriers showed potential for application in theranostics.

Development of volume-stable adipose tissue constructs using polycaprolactone-based polyurethane scaffolds and fibrin hydrogels.

PubMed

Wittmann, Katharina; Storck, Katharina; Muhr, Christian; Mayer, Helena; Regn, Sybille; Staudenmaier, Rainer; Wiese, Hinrich; Maier, Gerhard; Bauer-Kreisel, Petra; Blunk, Torsten

2016-10-01

Adipose tissue engineering aims at the restoration of soft tissue defects and the correction of contour deformities. It is therefore crucial to provide functional adipose tissue implants with appropriate volume stability. Here, we investigate two different fibrin formulations, alone or in combination with biodegradable polyurethane (PU) scaffolds as additional support structures, with regard to their suitability to generate volume-stable adipose tissue constructs. Human adipose-derived stem cells (ASCs) were incorporated in a commercially available fibrin sealant as well as a stable fibrin hydrogel previously developed by our group. The composite constructs made from the commercially available fibrin and porous poly(ε-caprolactone)-based polyurethane scaffolds exhibited increased volume stability as compared to fibrin gels alone; however, only constructs using the stable fibrin gels completely maintained their size and weight for 21 days. Adipogenesis of ASCs was not impaired by the additional PU scaffold. After induction with a common hormonal cocktail, for constructs with either fibrin formulation, strong adipogenic differentiation of ASCs was observed after 21 days in vitro. Furthermore, upregulation of adipogenic marker genes was demonstrated at mRNA (PPARγ, C/EBPα, GLUT4 and aP2; qRT-PCR) and protein (leptin; ELISA) levels. Stable fibrin/PU constructs were further evaluated in a pilot in vivo study, resulting in areas of well-vascularized adipose tissue within the implants after only 5 weeks. Copyright © 2013 John Wiley & Sons, Ltd. Copyright © 2013 John Wiley & Sons, Ltd.

Guiding the orientation of smooth muscle cells on random and aligned polyurethane/collagen nanofibers.

PubMed

Jia, Lin; Prabhakaran, Molamma P; Qin, Xiaohong; Ramakrishna, Seeram

2014-09-01

Fabricating scaffolds that can simulate the architecture and functionality of native extracellular matrix is a huge challenge in vascular tissue engineering. Various kinds of materials are engineered via nano-technological approaches to meet the current challenges in vascular tissue regeneration. During this study, nanofibers from pure polyurethane and hybrid polyurethane/collagen in two different morphologies (random and aligned) and in three different ratios of polyurethane:collagen (75:25; 50:50; 25:75) are fabricated by electrospinning. The fiber diameters of the nanofibrous scaffolds are in the range of 174-453 nm and 145-419 for random and aligned fibers, respectively, where they closely mimic the nanoscale dimensions of native extracellular matrix. The aligned polyurethane/collagen nanofibers expressed anisotropic wettability with mechanical properties which is suitable for regeneration of the artery. After 12 days of human aortic smooth muscle cells culture on different scaffolds, the proliferation of smooth muscle cells on hybrid polyurethane/collagen (3:1) nanofibers was 173% and 212% higher than on pure polyurethane scaffolds for random and aligned scaffolds, respectively. The results of cell morphology and protein staining showed that the aligned polyurethane/collagen (3:1) scaffold promote smooth muscle cells alignment through contact guidance, while the random polyurethane/collagen (3:1) also guided cell orientation most probably due to the inherent biochemical composition. Our studies demonstrate the potential of aligned and random polyurethane/collagen (3:1) as promising substrates for vascular tissue regeneration. © The Author(s) 2014 Reprints and permissions: sagepub.co.uk/journalsPermissions.nav.

40 CFR 63.1297 - Standards for slabstock flexible polyurethane foam production-HAP ABA emissions from the...

Code of Federal Regulations, 2012 CFR

2012-07-01

... polyurethane foam production-HAP ABA emissions from the production line. 63.1297 Section 63.1297 Protection of... Pollutants for Flexible Polyurethane Foam Production § 63.1297 Standards for slabstock flexible polyurethane... § 63.1293(a)(1) shall control HAP ABA emissions from the slabstock polyurethane foam production line in...

40 CFR 63.1297 - Standards for slabstock flexible polyurethane foam production-HAP ABA emissions from the...

Code of Federal Regulations, 2010 CFR

2010-07-01

... polyurethane foam production-HAP ABA emissions from the production line. 63.1297 Section 63.1297 Protection of... Pollutants for Flexible Polyurethane Foam Production § 63.1297 Standards for slabstock flexible polyurethane... § 63.1293(a)(1) shall control HAP ABA emissions from the slabstock polyurethane foam production line in...

40 CFR 63.1297 - Standards for slabstock flexible polyurethane foam production-HAP ABA emissions from the...

Code of Federal Regulations, 2011 CFR

2011-07-01

... polyurethane foam production-HAP ABA emissions from the production line. 63.1297 Section 63.1297 Protection of... Pollutants for Flexible Polyurethane Foam Production § 63.1297 Standards for slabstock flexible polyurethane... § 63.1293(a)(1) shall control HAP ABA emissions from the slabstock polyurethane foam production line in...

Durability of one-part polyurethane bonds to wood improved by HMR coupling agent

Treesearch

Charles B. Vick; E. Arnold Okkonen

2000-01-01

In a previous study on the strength and durability of a new class of wood adhesives called one-part polyurethanes, four commercial one-part polyurethanes, along with a resorcinol-formaldehyde adhesive representing a standard of performance, were compared in bonds to yellow birch and Douglas-fir in a series of industry-accepted tests (7). The polyurethanes all performed...

Water as foaming agent for open cell polyurethane structures.

PubMed

Haugen, H; Ried, V; Brunner, M; Will, J; Wintermantel, E

2004-04-01

The problem of moisture in polymer processing is known to any polymer engineer, as air bubbles may be formed. Hence granulates are generally dried prior to manufacturing. This study tried to develop a novel processing methods for scaffolds with controlled moisture content in thermoplastic polyurethane. The common foaming agents for polyurethane are organic solvents, whose residues remaining in the scaffold may be harmful to adherent cells, protein growth factors or nearby tissues. Water was used as a foaming agent and NaCl was used as porogens to achieve an open-cell structure. The polyether-polyurethane samples were processed in a heated press, and achieved a porosity of 64%. The pore size ranged between 50 and 500 microm. Human fibroblasts adhered and proliferate in the scaffold. A non-toxic production process was developed to manufacture a porous structure with a thermoplastic polyether-polyurethane. The process enables a mass-production of samples with adjustable pore size and porosity. In contrast to an existing method (solvent casting), the processing of the samples was not limited by its thickness. The process parameters, which attribute mostly to the pore building, were filling volume, temperature, NaCl-concentration and water-uptake rate.

Thermal behaviour properties and corrosion resistance of organoclay/polyurethane film

NASA Astrophysics Data System (ADS)

Kurniawan, O.; Soegijono, B.

2018-03-01

Organoclay/polyurethane film composite was prepared by adding organoclay with different content (1, 3, and 5 wt.%) in polyurethane as a matrix. TGA and DSC showed decomposition temperature shifted to a lower point as organoclay content change. FT-IR spectra showed chemical bonding of organoclay and polyurethane as a matrix, which means that the bonding between filler and matrix occured and the composite was stronger but less bonding occur in composite with 5 wt.% organoclay. The corrosion resistance overall increased with the increasing organoclay content. Composite with 5 wt.% organoclay had more thermal stability and corrosion resistance may probably due to exfoliation of organoclay.

Directionally Antagonistic Graphene Oxide-Polyurethane Hybrid Aerogel as a Sound Absorber.

PubMed

Oh, Jung-Hwan; Kim, Jieun; Lee, Hyeongrae; Kang, Yeonjune; Oh, Il-Kwon

2018-06-21

Innovative sound absorbers, the design of which is based on carbon nanotubes and graphene derivatives, could be used to make more efficient sound absorbing materials because of their excellent intrinsic mechanical and chemical properties. However, controlling the directional alignments of low-dimensional carbon nanomaterials, such as restacking, alignment, and dispersion, has been a challenging problem when developing sound absorbing forms. Herein, we present the directionally antagonistic graphene oxide-polyurethane hybrid aerogel we developed as a sound absorber, the physical properties of which differ according to the alignment of the microscopic graphene oxide sheets. This porous graphene sound absorber has a microporous hierarchical cellular structure with adjustable stiffness and improved sound absorption performance, thereby overcoming the restrictions of both geometric and function-orientated functions. Furthermore, by controlling the inner cell size and aligned structure of graphene oxide layers in this study, we achieved remarkable improvement of the sound absorption performance at low frequency. This improvement is attributed to multiple scattering of incident and reflection waves on the aligned porous surfaces, and air-viscous resistance damping inside interconnected structures between the urethane foam and the graphene oxide network. Two anisotropic sound absorbers based on the directionally antagonistic graphene oxide-polyurethane hybrid aerogels were fabricated. They show remarkable differences owing to the opposite alignment of graphene oxide layers inside the polyurethane foam and are expected to be appropriate for the engineering design of sound absorbers in consideration of the wave direction.

Thermoplastic Polyurethanes with Isosorbide Chain Extender

DOE Office of Scientific and Technical Information (OSTI.GOV)

Javni, Ivan; Bilic, Olivera; Bilic, Nikola

2015-12-15

Isosorbide, a renewable diol derived from starch, was used alone or in combination with butane diol (BD) as the chain extender in two series of thermoplastic polyurethanes (TPU) with 50 and 70% polytetramethylene ether glycol (PTMEG) soft segment concentration (SSC), respectively. In the synthesized TPUs, the hard segment composition was systematically varied in both series following BD/isosorbide molar ratios of 100 : 0; 75 : 25; 50 : 50; 25 : 75, and 0 : 100 to examine in detail the effect of chain extenders on properties of segmented polyurethane elastomers with different morphologies. We found that polyurethanes with 50%more » SSC were hard elastomers with Shore D hardness of around 50, which is consistent with assumed co-continuous morphology. Polymers with 70% SSC displayed lower Shore A hardness of 74–79 (Shore D around 25) as a result of globular hard domains dispersed in the soft matrix. Insertion of isosorbide increased rigidity, melting point and glass transition temperature of hard segments and tensile strength of elastomers with 50% SSC. These effects were weaker or non-existent in 70% SSC series due to the short hard segments and low content of isosorbide. We also found that the thermal stability was lowered by increasing isosorbide content in both series.« less

Localized gene delivery using antibody tethered adenovirus from polyurethane heart valve cusps and intra-aortic implants.

PubMed

Stachelek, S J; Song, C; Alferiev, I; Defelice, S; Cui, X; Connolly, J M; Bianco, R W; Levy, R J

2004-01-01

The present study investigated a novel approach for gene therapy of heart valve disease and vascular disorders. We formulated and characterized implantable polyurethane films that could also function as gene delivery systems through the surface attachment of replication defective adenoviruses using an anti-adenovirus antibody tethering mechanism. Our hypothesis was that we could achieve site-specific gene delivery to cells interacting with these polyurethane implants, and thereby demonstrate the potential for intravascular devices that could also function as gene delivery platforms for therapeutic vectors. Previous research by our group has demonstrated that polyurethane elastomers can be derivatized post-polymerization through a series of chemical reactions activating the hard segment amide groups with alkyl bromine residues, which can enable a wide variety of subsequent chemical modifications. Furthermore, prior research by our group investigating gene delivery intravascular stents has shown that collagen-coated balloon expandable stents can be configured with anti-adenovirus antibodies via thiol-based chemistry, and can then tether adenoviral vectors at doses that lead to high levels of localized arterial neointima expression, but with virtually no distal spread of vector. Thus, we sought to create two-device configurations for our investigations building on this previous research. (1) Polyurethane films coated with Type I collagen were thiol activated to permit covalent attachment of anti-adenovirus antibodies to enable gene delivery via vector tethering. (2) We also formulated polyurethane films with direct covalent attachment of anti-adenovirus antibodies to polyurethane hard segments derivatized with alkyl-thiol groups, thereby also enabling tethering of replication-defective adenoviruses. Both formulations demonstrated highly localized and efficient transduction in cell culture studies with rat arterial smooth muscle cells. In vivo experiments with collagen

Fiber glass prevents cracking of polyurethane foam insulation on cryogenic vessels

NASA Technical Reports Server (NTRS)

Forge, D. A.

1968-01-01

Fiber glass material, placed between polyurethane foam insulation and the outer surfaces of cryogenic vessels, retains its resilience at cryogenic temperatures and provides an expansion layer between the metal surfaces and the polyurethane foam, preventing cracking of the latter.

Radioluminescence of polyester resin modified with acrylic acid and its salts

NASA Astrophysics Data System (ADS)

Szalińska, H.; Wypych, M.; Pietrzak, M.; Szadkowska-Nicze, M.

Polimal-109 polyester resin and its compounds containing acrylic acid and its salts such as: sodium, potassium, magnesium, calcium, barium, iron, cobalt, copper and manganese acrylates were studied by the radioluminescence method, including isothermal luminescence (ITL) at a radiation temperature of 77 K, thermoluminescence (RTL) and spectral distributions of isothermal luminescence. Measurements of optical absorption at 77 K before and after irradiation of the investigated samples were also carried out. The results obtained have shown that metal ions play a significant part in the processes taking place in the polyester matrix under the influence of γ 60Co radiation.

Antifungal activity of fabrics knitted by metalized Silver/Polyester composite yarn

NASA Astrophysics Data System (ADS)

Özkan, İ.; Duru Baykal, P.

2017-10-01

In this study, antifungal properties of fabric knitted from metalized silver/polyester composite yarn were investigated. Intermingling is an alternative technique for yarn blending process. Yarns having different features can be combined by feeding the same intermingling jet. This process is defined as commingling. In the study, intermingling process was used to produce metalized silver/polyester composite yarn. Commingled yarns were knitted to single jersey fabrics by IPM brand sample type circular knitting machine. Antifungal activity test was applied to samples against Aspergillus Niger according to AATCC 30 test procedure. It has been identified that the application provides antifungal activity to fabric.

77 FR 54562 - Certain Polyester Staple Fiber From the Republic of Korea: Rescission of Antidumping Duty...

Federal Register 2010, 2011, 2012, 2013, 2014

2012-09-05

... DEPARTMENT OF COMMERCE International Trade Administration [A-580-839] Certain Polyester Staple Fiber From the Republic of Korea: Rescission of Antidumping Duty Administrative Review AGENCY: Import... antidumping duty order on certain polyester staple fiber from the Republic of Korea (``the Order''). The...

Modeling of skeletal members using polyurethane foam

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sena, J.M.F.; Weaver, R.W.

1983-11-01

At the request of the University of New Mexico's Maxwell Museum of Anthropology, members of the Plastic Section in the Process Development Division at SNLA undertook the special project of the Chaco Lady. The project consisted of polyurethane foam casting of a disinterred female skull considered to be approximately 1000 years old. Rubber latex molds, supplied by the UNM Anthropology Department, were used to produce the polymeric skull requested. The authors developed for the project a modified foaming process which will be used in future polyurethane castings of archaeological artifacts and contemporary skeletal members at the University.

Rheological and Thermal Properties of Bio-based Hyperbranched Polyesters

NASA Astrophysics Data System (ADS)

Bubeck, Robert; Dumitrascu, Adina; Zhang, Tracy; Smith, Patrick

Hyperbranched poly(ester)s (HBPEs) of designed molecular structures and targeted molecular weight can be prepared from a variety of multi-functional acids and alcohols. These polymers find application in the areas of coatings and rheology modifiers for coatings. These functional polymers can be synthesized in variety of architectures, possessing either hydroxyl or carboxyl reactive end-groups suitable for the attachment of active entities. The rheological characteristics as related to variation in molecular structure were determined using cone and plate or couette geometries. Viscosities of the HBPEs were found to be near Newtonian. HB polymers permit the control of Tg that is not as readily attained with linear polymers. Accordingly, Tg and viscosity are affected little as a function of Mw but vary dramatically with the nature of the end-groups, are highly dependent on hydrogen bonding of the hydroxyl end groups, and decrease dramatically with the incorporation of aliphatic end-caps. The thermal properties and the degradation characteristics of the HBPEs were determined. Thermal degradation of the hydroxyl-terminal HBPEs is initiated by dehydrative ether formation (crosslinking) while decarboxylation is the initial decomposition event for the carboxyl-terminal polymers. Midland, MI Campus.

New insights into polyurethane biodegradation and realistic prospects for the development of a sustainable waste recycling process.

PubMed

Cregut, Mickael; Bedas, M; Durand, M-J; Thouand, G

2013-12-01

Polyurethanes are polymeric plastics that were first used as substitutes for traditional polymers suspected to release volatile organic hazardous substances. The limitless conformations and formulations of polyurethanes enabled their use in a wide variety of applications. Because approximately 10 Mt of polyurethanes is produced each year, environmental concern over their considerable contribution to landfill waste accumulation appeared in the 1990s. To date, no recycling processes allow for the efficient reuse of polyurethane waste due to their high resistance to (a)biotic disturbances. To find alternatives to systematic accumulation or incineration of polyurethanes, a bibliographic analysis was performed on major scientific advances in the polyurethane (bio)degradation field to identify opportunities for the development of new technologies to recondition this material. Until polymers exhibiting oxo- or hydro-biodegradative traits are generated, conventional polyurethanes that are known to be only slightly biodegradable are of great concern. The research focused on polyurethane biodegradation highlights recent attempts to reprocess conventional industrial polyurethanes via microbial or enzymatic degradation. This review describes several wonderful opportunities for the establishment of new processes for polyurethane recycling. Meeting these new challenges could lead to the development of sustainable management processes involving polymer recycling or reuse as environmentally safe options for industries. The ability to upgrade polyurethane wastes to chemical compounds with a higher added value would be especially attractive. © 2013.

Fabrication of polyurethane and polyurethane based composite fibres by the electrospinning technique for soft tissue engineering of cardiovascular system.

PubMed

Kucinska-Lipka, J; Gubanska, I; Janik, H; Sienkiewicz, M

2015-01-01

Electrospinning is a unique technique, which provides forming of polymeric scaffolds for soft tissue engineering, which include tissue scaffolds for soft tissues of the cardiovascular system. Such artificial soft tissues of the cardiovascular system may possess mechanical properties comparable to native vascular tissues. Electrospinning technique gives the opportunity to form fibres with nm- to μm-scale in diameter. The arrangement of obtained fibres and their surface determine the biocompatibility of the scaffolds. Polyurethanes (PUs) are being commonly used as a prosthesis of cardiovascular soft tissues due to their excellent biocompatibility, non-toxicity, elasticity and mechanical properties. PUs also possess fine spinning properties. The combination of a variety of PU properties with an electrospinning technique, conducted at the well tailored conditions, gives unlimited possibilities of forming novel polyurethane materials suitable for soft tissue scaffolds applied in cardiovascular tissue engineering. This paper can help researches to gain more widespread and deeper understanding of designing electrospinable PU materials, which may be used as cardiovascular soft tissue scaffolds. In this paper we focus on reagents used in PU synthesis designed to increase PU biocompatibility (polyols) and biodegradability (isocyanates). We also describe suggested surface modifications of electrospun PUs, and the direct influence of surface wettability on providing enhanced biocompatibility of scaffolds. We indicate a great influence of electrospinning parameters (voltage, flow rate, working distance) and used solvents (mostly DMF, THF and HFIP) on fibre alignment and diameter - what impacts the biocompatibility and hemocompatibility of such electrospun PU scaffolds. Moreover, we present PU modifications with natural polymers with novel approach applied in electrospinning of PU scaffolds. This work may contribute with further developing of novel electrospun PUs, which may be

Biochemical and Structural Insights into Enzymatic Depolymerization of Polylactic Acid and Other Polyesters by Microbial Carboxylesterases.

PubMed

Hajighasemi, Mahbod; Nocek, Boguslaw P; Tchigvintsev, Anatoli; Brown, Greg; Flick, Robert; Xu, Xiaohui; Cui, Hong; Hai, Tran; Joachimiak, Andrzej; Golyshin, Peter N; Savchenko, Alexei; Edwards, Elizabeth A; Yakunin, Alexander F

2016-06-13

Polylactic acid (PLA) is a biodegradable polyester derived from renewable resources, which is a leading candidate for the replacement of traditional petroleum-based polymers. Since the global production of PLA is quickly growing, there is an urgent need for the development of efficient recycling technologies, which will produce lactic acid instead of CO2 as the final product. After screening 90 purified microbial α/β-hydrolases, we identified hydrolytic activity against emulsified PLA in two uncharacterized proteins, ABO2449 from Alcanivorax borkumensis and RPA1511 from Rhodopseudomonas palustris. Both enzymes were also active against emulsified polycaprolactone and other polyesters as well as against soluble α-naphthyl and p-nitrophenyl monoesters. In addition, both ABO2449 and RPA1511 catalyzed complete or extensive hydrolysis of solid PLA with the production of lactic acid monomers, dimers, and larger oligomers as products. The crystal structure of RPA1511 was determined at 2.2 Å resolution and revealed a classical α/β-hydrolase fold with a wide-open active site containing a molecule of polyethylene glycol bound near the catalytic triad Ser114-His270-Asp242. Site-directed mutagenesis of both proteins demonstrated that the catalytic triad residues are important for the hydrolysis of both monoester and polyester substrates. We also identified several residues in RPA1511 (Gln172, Leu212, Met215, Trp218, and Leu220) and ABO2449 (Phe38 and Leu152), which were not essential for activity against soluble monoesters but were found to be critical for the hydrolysis of PLA. Our results indicate that microbial carboxyl esterases can efficiently hydrolyze various polyesters making them attractive biocatalysts for plastics depolymerization and recycling.

Protoenzymes: the case of hyperbranched polyesters

NASA Astrophysics Data System (ADS)

Mamajanov, Irena; Cody, George D.

2017-11-01

Enzymes are biopolymeric complexes that catalyse biochemical reactions and shape metabolic pathways. Enzymes usually work with small molecule cofactors that actively participate in reaction mechanisms and complex, usually globular, polymeric structures capable of specific substrate binding, encapsulation and orientation. Moreover, the globular structures of enzymes possess cavities with modulated microenvironments, facilitating the progression of reaction(s). The globular structure is ensured by long folded protein or RNA strands. Synthesis of such elaborate complexes has proven difficult under prebiotically plausible conditions. We explore here that catalysis may have been performed by alternative polymeric structures, namely hyperbranched polymers. Hyperbranched polymers are relatively complex structures that can be synthesized under prebiotically plausible conditions; their globular structure is ensured by virtue of their architecture rather than folding. In this study, we probe the ability of tertiary amine-bearing hyperbranched polyesters to form hydrophobic pockets as a reaction-promoting medium for the Kemp elimination reaction. Our results show that polyesters formed upon reaction between glycerol, triethanolamine and organic acid containing hydrophobic groups, i.e. adipic and methylsuccinic acid, are capable of increasing the rate of Kemp elimination by a factor of up to 3 over monomeric triethanolamine. This article is part of the themed issue 'Reconceptualizing the origins of life'.

Final Report: Development of Renewable Microbial Polyesters for Cost Effective and Energy- Efficient Wood-Plastic Composites

DOE Office of Scientific and Technical Information (OSTI.GOV)

Thompson, David N.; Emerick, Robert W.; England, Alfred B.

In this project, we proposed to produce wood fiber reinforced thermoplastic composites (WFRTCs) using microbial thermoplastic polyesters in place of petroleum-derived plastic. WFRTCs are a rapidly growing product area, averaging a 38% growth rate since 1997. Their production is dependent on substantial quantities of petroleum based thermoplastics, increasing their overall energy costs by over 230% when compared to traditional Engineered Wood Products (EWP). Utilizing bio-based thermoplastics for these materials can reduce our dependence on foreign petroleum. We have demonstrated that biopolymers (polyhydroxyalkanoates, PHA) can be successfully produced from wood pulping waste streams and that viable wood fiber reinforced thermoplastic compositemore » products can be produced from these materials. The results show that microbial polyester (PHB in this study) can be extruded together with wastewater-derived cell mass and wood flour into deck products having performance properties comparable to existing commercial HDPE/WF composite products. This study has thus proven the underlying concept that the microbial polyesters produced from waste effluents can be used to make cost-effective and energy-efficient wood-plastic composites. The cost of purified microbial polyesters is about 5-20 times that of HDPE depending on the cost of crude oil, due to high purification (40%), carbon substrate (40%) and sterilized fermentation (20%) costs for the PHB. Hence, the ability to produce competitive and functional composites with unpurified PHA-biomass mixtures from waste carbon sources in unsterile systems—without cell debris removal—is a significant step forward in producing competitive value-added structural composites from forest products residuals using a biorefinery approach. As demonstrated in the energy and waste analysis for the project, significant energy savings and waste reductions can also be realized using this approach. We recommend that the next step for

Reactive modification of polyesters and their blends

NASA Astrophysics Data System (ADS)

Wan, Chen

2004-12-01

As part of a broader research effort to investigate the chemical modification of polyesters by reactive processing a low molecular weight (MW) unsaturated polyester (UP) and a higher MW saturated polyester, polyethylene terephthalate (PET), alone or blended with polypropylene (PP) were melt processed in a batch mixer and continuous twin screw extruders. Modification was monitored by on-line rheology and the products were characterized primarily by off-line rheology, morphology and thermal analysis. Efforts were made to establish processing/property relationships and provide an insight of the accompanying structural changes. The overall response of the reactively modified systems was found to be strongly dependent on the component characteristics, blend composition, type and concentrations of reactive additives and processing conditions. The work concluded that UP can be effectively modified through reactive melt processing. Its melt viscosity and MW can be increased through chemical reactions between organic peroxides (POX) and chain unsaturation or between MgO and carboxyl/hydroxyl end groups. Reactive blending of PP/UP blends through peroxide modification gave finer and more uniform morphology than unreacted blends and at a given PP/UP weight ratio more thermoplastic elastomers-like rheological behavior. This is due to the continuously decreasing viscosity ratio of PP/UP towards unity by the competing reactions between POX and the blend components and formation of PP-UP copolymers which serve as in-situ compatibilizers to promote better interfacial adhesion. Kinetics of the competing reactions were analyzed through a developed model. In addition to POX concentration and mixing efficiency, rheology and morphology of UP/PP bends were significantly affected by the addition of inorganic and organic coagents. Addition of coagents such as a difunctional maleimide, MgO and/or an anhydride functionalized PP during reactive blending offers effective means for tailoring

Improving the mechanical performance of wood fiber reinforced bio-based polyurethane foam

NASA Astrophysics Data System (ADS)

Chang, Li-Chi

Because of the environmental impact of fossil fuel consumption, soybean-based polyurethane (PU) foam has been developed as an alternative to be used as the core in structural insulated panels (SIPs). Wood fibers can be added to enhance the resistance of foam against bending and buckling in compression. The goal of this work is to study the effect of three modifications: fiber surface treatment, catalyst choice, and mixing method on the compression performance of wood fiber-reinforced PU foam. Foams were made with a free-rising process. The compression performance of the foams was measured and the foams were characterized using Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), and X-ray computed tomography (CT). The foam reinforced with alkali-treated fibers had improved compression performance. The foams made with various catalysts shared similar performance. The foam made using a mechanical stirrer contained well-dispersed fibers but the reinforcing capability of the fibers was reduced.

Cytotoxicity and mechanical behavior of chitin-bentonite clay based polyurethane bio-nanocomposites.

PubMed

Zia, Khalid Mahmood; Zuber, Mohammad; Barikani, Mehdi; Hussain, Rizwan; Jamil, Tahir; Anjum, Sohail

2011-12-01

Chitin based polyurethane bio-nanocomposites (PUBNC) were prepared using chitin, Delite HPS bentonite nanoclay enriched in montmorillonite (MMT), 4,4'-diphenylmethane diisocyanate (MDI) and polycaprolactone polyol CAPA 231 (3000 g/mol(-1)). The prepolymers having different concentration of Delite HPS bentonite nanoclay were extended with 2 moles of chitin. The structures of the resulted polymers were determined by FT-IR technique. The effect of nanoclay contents on mechanical properties and in vitro biocompatibility was investigated. The mechanical properties of the synthesized materials were improved with increase in the Delite HPS bentonite nanoclay contents. Optimum mechanical properties were obtained from the PU bio-nanocomposite samples having 4% Delite HPS bentonite nanoclay. The results revealed that the final PU bio-nanocomposite having 2% Delite HPS bentonite nanoclay contents is ideal contenders for surgical threads with on going investigations into their in vitro biocompatibility, non-toxicity, and mechanical properties. Copyright © 2011 Elsevier B.V. All rights reserved.

Shape Memory Polyurethane Materials Containing Ferromagnetic Iron Oxide and Graphene Nanoplatelets

PubMed Central

Urban, Magdalena

2017-01-01

Intelligent materials, such as memory shape polymers, have attracted considerable attention due to wide range of possible applications. Currently, intensive research is underway, in matters of obtaining memory shape materials that can be actuated via inductive methods, for example with help of magnetic field. In this work, an attempt was made to develop a new polymer composite—polyurethane modified with graphene nanoplates and ferromagnetic iron oxides—with improved mechanical properties and introduced magnetic and memory shape properties. Based on the conducted literature review, gathered data were compared to the results of similar materials. Obtained materials were tested for their thermal, rheological, mechanical and shape memory properties. Structure of both fillers and composites were also analyzed using various spectroscopic methods. The addition of fillers to the polyurethane matrix improved the mechanical and shape memory properties, without having a noticeable impact on thermal properties. As it was expected, the high content of fillers caused a significant change in viscosity of filled prepolymers (during the synthesis stage). Each of the studied composites showed better mechanical properties than the unmodified polyurethanes. The addition of magnetic particles introduced additional properties to the composite, which could significantly expand the functionality of the materials developed in this work. PMID:28906445

Shape Memory Polyurethane Materials Containing Ferromagnetic Iron Oxide and Graphene Nanoplatelets.

PubMed

Urban, Magdalena; Strankowski, Michał

2017-09-14

Intelligent materials, such as memory shape polymers, have attracted considerable attention due to wide range of possible applications. Currently, intensive research is underway, in matters of obtaining memory shape materials that can be actuated via inductive methods, for example with help of magnetic field. In this work, an attempt was made to develop a new polymer composite-polyurethane modified with graphene nanoplates and ferromagnetic iron oxides-with improved mechanical properties and introduced magnetic and memory shape properties. Based on the conducted literature review, gathered data were compared to the results of similar materials. Obtained materials were tested for their thermal, rheological, mechanical and shape memory properties. Structure of both fillers and composites were also analyzed using various spectroscopic methods. The addition of fillers to the polyurethane matrix improved the mechanical and shape memory properties, without having a noticeable impact on thermal properties. As it was expected, the high content of fillers caused a significant change in viscosity of filled prepolymers (during the synthesis stage). Each of the studied composites showed better mechanical properties than the unmodified polyurethanes. The addition of magnetic particles introduced additional properties to the composite, which could significantly expand the functionality of the materials developed in this work.

Influence of nanosize clay platelets on the mechanical properties of glass fiber reinforced polyester composites.

PubMed

Jawahar, P; Balasubramanian, M

2006-12-01

Glass fiber reinforced polyester composite and hybrid nanoclay-fiber reinforced composites were prepared by hand lay-up process. The mechanical behavior of these materials and the changes as a result of the incorporation of both nanosize clay and glass fibers were investigated. Composites were prepared with a glass fibre content of 25 vol%. The proportion of the nanosize clay platelets was varied from 0.5 to 2.5 vol%. Hybrid clay-fiber reinforced polyester composite posses better tensile, flexural, impact, and barrier properties. Hybrid clay-fiber reinforced polyester composites also posses better shear strength, storage modulus, and glass transition temperature. The optimum properties were found to be with the hybrid laminates containing 1.5 vol% nanosize clay.

Antiangiogenic activity of a bevacizumab-loaded polyurethane device in animal neovascularization models.

PubMed

Ferreira, A E R; Castro, B F M; Vieira, L C; Cassali, G D; Souza, C M; Fulgêncio, G O; Ayres, E; Oréfice, R L; Jorge, R; Silva-Cunha, A; Fialho, S L

2017-03-01

To evaluate the antiangiogenic activity of bevacizumab-loaded polyurethane using two animal models of neovascularization. The percentage of blood vessels was evaluated in a chicken chorioallantoic membrane model (n=42) and in the rabbit cornea (n=24) with neovascularization induced by alkali injury. In each model, the animals were randomly divided into the groups treated with the bevacizumab-loaded polyurethane device, phosphate-buffered-saline (negative control) and bevacizumab commercial solution (positive control). Clinical examination, as well as histopathological and immunohistochemical evaluation, were performed in the rabbit eyes. Microvascular density in hot spot areas was determined in semi-thin sections of corneal tissue by hematoxylin-eosin staining and factor VIII immunohistochemistry. Immunohistochemical analysis was also performed to evaluate VEGF expression. In the evaluated models, the use of bevacizumab (Avastin ® ) and the bevacizumab-loaded polyurethane device led to similar results with regard to inhibition of neovascularization. In the chorioallantoic membrane model, the bevacizumab-loaded polyurethane device reduced angiogenesis by 50.27% when compared to the negative control group. In the rabbit model of corneal neovascularization, the mean density of vessels/field was reduced by 46.87% on analysis of factor VIII immunohistochemistry photos in the bevacizumab-loaded polyurethane device group as compared to the negative control (PBS) sections. In both models, no significant difference could be identified between the bevacizumab-loaded polyurethane device and the positive control group, leading to similar results with regard to inhibition of neovascularization. The present study shows that the bevacizumab-loaded polyurethane device may release bevacizumab and inhibit neovascularization similarly to commercial bevacizumab solution in the short-term. Copyright © 2017 Elsevier Masson SAS. All rights reserved.

Investigation into reversion of polyurethane encapsulants

NASA Technical Reports Server (NTRS)

Lynch, C. R.

1973-01-01

The effect of high humidity (95% RH) at 60 C, 70 C, 85 C and 100 C on the solid-to-liquid reversion of polyurethane elastomers (used for potting electrical connectors and conformal coating printed circuit boards) was investigated. Hardness measurements were conducted on eleven elastomers to track reversion for a 101-day period. The primary purpose of the tests was to provide data to predict service life for the polyurethane elastomers. This was not accomplished as the hardness did not deteriorate rapidly enough at the lower test temperatures. The tests did determine that the potting and coating materials most widely used on the S-1C Program are susceptible to reversion but appear adequate for service in the S-1C environment.

Histopathological reaction over prosthesis surface covered with silicone and polyurethane foam implanted in rats.

PubMed

Wagenführ-Júnior, Jorge; Ribas Filho, Jurandir Marcondes; Nascimento, Marcelo Mazza do; Ribas, Fernanda Marcondes; Wanka, Marcus Vinícius; Godoi, Andressa de Lima

2012-12-01

To evaluate whether polyurethane foam leads more intense foreign-body reaction than silicone foam. To compare the vascularization of the capsules surrounding the foam implants. To investigate if the capsule of polyurethane foam implanted has greater amount of collagen than that of silicone foam. Sixty-four young male Wistar rats were allocated into two groups: polyurethane foam and silicone foam. Subcutaneous discs were implanted into the dorsum of the animals in both groups. The capsules were assessed 28 days, two months, three months and six months postoperatively. Microscopic analysis with H&E stain was performed to evaluate the acute and chronic inflammatory process, foreign-body reaction and neovascularization. The analysis with picrosirius red was performed using the ImageProPlus software, to measure the number of vessels and collagen types I and III. There were no statistical differences between the two groups regarding the acute and chronic inflammatory processes. All rats from the polyurethane group, in all times, exhibited moderate or intense foreign-body reaction, with statistic significant difference (p=0.046) when compared with the silicone group, in which the reaction was either mild or nonexistent at two months. Vascular proliferation was significantly different between the groups at 28 days (p=0.0002), with the polyurethane group displaying greater neovascularization with H&E stain. Similar results were obtained with picrosirius red, which revealed in the polyurethane group a much greater number of vessels than in the silicone group (p=0.001). The collagen area was larger in the polyurethane group, significantly at 28 days (p=0.001) and at two months (p=0.030). Polyurethane foam elicited more intense foreign-body reaction when compared with silicone foam. The number of vessels was higher in the capsules of the polyurethane foam implants 28 days after the operation. The capsule of the polyurethane foam implants showed a greater amount of collagen

The Effect of Structural Modifications on Ionic Conductivity in Newly-Designed Polyester Electrolytes

NASA Astrophysics Data System (ADS)

Pesko, Danielle; Jung, Yuki; Coates, Geoff; Balsara, Nitash

2015-03-01

Gaining a fundamental understanding of the relationship between molecular structure and ionic conductivity of polymer electrolytes is an essential step toward designing next generation materials for battery applications. In this study, we use a systematic set of newly-designed polyesters with varying side-chain lengths and oxygen functional groups to elucidate the effects of structural modifications on the conductive properties of the corresponding electrolytes. Mixtures of polyesters and lithium bis(trifluromethanesulfonyl)imide (LiTFSI) were characterized using ac impedance spectroscopy to measure the ionic conductivity at various temperatures and salt concentrations. The relative conductivities of these electrolytes in the dilute limit are directly comparable to results of molecular dynamics simulations performed using the same polymers. The simulations correspond well with the experimental results, and provide molecular level insight about the solvation environment of the lithium ions and how the ions transport through these polyesters.

40 CFR 63.1296 - Standards for slabstock flexible polyurethane foam production-HAP ABA equipment leaks.

Code of Federal Regulations, 2011 CFR

2011-07-01

... polyurethane foam production-HAP ABA equipment leaks. 63.1296 Section 63.1296 Protection of Environment... Flexible Polyurethane Foam Production § 63.1296 Standards for slabstock flexible polyurethane foam... emissions from leaks from transfer pumps, valves, connectors, pressure-relief valves, and open-ended lines...

40 CFR 63.1296 - Standards for slabstock flexible polyurethane foam production-HAP ABA equipment leaks.

Code of Federal Regulations, 2012 CFR

2012-07-01

... polyurethane foam production-HAP ABA equipment leaks. 63.1296 Section 63.1296 Protection of Environment... Flexible Polyurethane Foam Production § 63.1296 Standards for slabstock flexible polyurethane foam... emissions from leaks from transfer pumps, valves, connectors, pressure-relief valves, and open-ended lines...

40 CFR 63.1296 - Standards for slabstock flexible polyurethane foam production-HAP ABA equipment leaks.

Code of Federal Regulations, 2010 CFR

2010-07-01

... polyurethane foam production-HAP ABA equipment leaks. 63.1296 Section 63.1296 Protection of Environment... Flexible Polyurethane Foam Production § 63.1296 Standards for slabstock flexible polyurethane foam... emissions from leaks from transfer pumps, valves, connectors, pressure-relief valves, and open-ended lines...

Modelling of the mechanical behavior of a polyurethane finger interphalangeal joint endoprosthesis after surface modification by ion implantation

NASA Astrophysics Data System (ADS)

Beliaev, A.; Svistkov, A.; Iziumov, R.; Osorgina, I.; Kondyurin, A.; Bilek, M.; McKenzie, D.

2016-04-01

Production of biocompatible implants made of polyurethane treated with plasma is very perspective. During plasma treatment the surface of polyurethane acquires unique physic-chemical properties. However such treatment may change the mechanical properties of polyurethane which may adversely affect the deformation behaviour of the real implant. Therefore careful study of the mechanical properties of the plasma-modified polyurethane is needed. In this paper, experimental observations of the elastic characteristics of plasma treated polyurethane and modelling of the deformation behaviour of polyurethane bio-implants are reported.

Starch-based polyurethane/CuO nanocomposite foam: Antibacterial effects for infection control.

PubMed

Ashjari, Hamid Reza; Dorraji, Mir Saeed Seyed; Fakhrzadeh, Vahid; Eslami, Hosein; Rasoulifard, Mohammad Hossein; Rastgouy-Houjaghan, Mehrdad; Gholizadeh, Pourya; Kafil, Hossein Samadi

2018-05-01

In the present study, a new method for the synthesis of the open cell flexible polyurethane foams (PUFs) was developed by using starch powder and the modification of closed cell foam formulation. Starch is the second largest polymeric carbohydrate as a macromolecule on this planet with a large number of glucose units. Copper oxide nanoparticles (CuO NPs) were synthesized by thermal degradation method at different temperatures of 400, 600 and 800 °C as antimicrobial agents. The antimicrobial activity of CuO NPs and commercial CuO powder against the main causes of hospital infections were tested. CuO 600 was the most effective antimicrobial agent and enhanced polymer matrix tensile strength with starch powder as new polyurethane foams (PUFs) cell opener with high tensile strength. The effects of parameters on tensile strength were optimized using response surface methodology (RSM). CuO NPs and PUF had optimal conditions and were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), scanning electron microscopy (SEM) and Fourier transform infrared spectroscopy (FT-IR). Foam synthesized at the optimal conditions had an open cell structure with high tensile strength and efficient antimicrobial activity that made them suitable to be used as an antimicrobial hospital mattress to control hospital infections. Copyright © 2018 Elsevier B.V. All rights reserved.

IDENTIFICATION OF CFC AND HCFC SUBSTITUTES FOR BLOWING POLYURETHANE FOAM INSULATION PRODUCTS

EPA Science Inventory

The report gives results of a cooperative effort to identiry chlorofluorocarbons and hydrochlorofluorocarbon substitutes for blowing polyurethane foam insulation products. The substantial ongoing effort is identifying third-generation blowing agets for polyurethane foams to repla...

78 FR 14512 - Certain Polyester Staple Fiber From the People's Republic of China: Preliminary Results and...

Federal Register 2010, 2011, 2012, 2013, 2014

2013-03-06

... Fiber From the People's Republic of China: Preliminary Results and Rescission in Part of the 2011-2012... administrative review of the antidumping duty order on certain polyester staple fiber from the People's Republic... Industries (``Far Eastern'') and Huvis Sichuan Chemical Fiber Corp. and Huvis Sichuan Polyester Fiber Ltd...

75 FR 70906 - Certain Polyester Staple Fiber From the People's Republic of China: Partial Rescission of the...

Federal Register 2010, 2011, 2012, 2013, 2014

2010-11-19

... DEPARTMENT OF COMMERCE International Trade Administration [A-570-905] Certain Polyester Staple Fiber From the People's Republic of China: Partial Rescission of the Third Antidumping Duty... Request Administrative Review'' of the antidumping duty order on certain polyester staple fiber (``PSF...

76 FR 5331 - Certain Polyester Staple Fiber From Taiwan: Extension of Time Limit for Preliminary Results of...

Federal Register 2010, 2011, 2012, 2013, 2014

2011-01-31

... DEPARTMENT OF COMMERCE International Trade Administration [A-583-833] Certain Polyester Staple Fiber From Taiwan: Extension of Time Limit for Preliminary Results of Antidumping Duty Administrative...) initiated an administrative review of the antidumping duty order on certain polyester staple fiber from...

77 FR 4543 - Certain Polyester Staple Fiber From Taiwan: Extension of Time Limit for Preliminary Results of...

Federal Register 2010, 2011, 2012, 2013, 2014

2012-01-30

... DEPARTMENT OF COMMERCE International Trade Administration [A-583-833] Certain Polyester Staple Fiber From Taiwan: Extension of Time Limit for Preliminary Results of Antidumping Duty Administrative...) initiated an administrative review of the antidumping duty order on certain polyester staple fiber from...

77 FR 50530 - Polyester Staple Fiber From China; Scheduling of an Expedited Five-Year Review Concerning the...

Federal Register 2010, 2011, 2012, 2013, 2014

2012-08-21

... INTERNATIONAL TRADE COMMISSION [Investigation No. 731-TA-1104 (Review)] Polyester Staple Fiber... Polyester Staple Fiber From China AGENCY: United States International Trade Commission. ACTION: Notice... CONTACT: Joanna Lo (202-205-1888), Office of Investigations, U.S. International Trade Commission, 500 E...

Enhanced photocatalytic activity of Bi2WO6/TiO2 composite coated polyester fabric under visible light irradiation

NASA Astrophysics Data System (ADS)

Du, Zoufei; Cheng, Cheng; Tan, Lin; Lan, Jianwu; Jiang, Shouxiang; Zhao, Ludan; Guo, Ronghui

2018-03-01

In this study, a visible-light-driven photocatalyst Bi2WO6/TiO2 composite was reported using one-step hydrothermal method and then coated on the polyester fabric. The samples were systematically characterized by X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD), Brunauer-Emmett-Teller (BET) surface area, UV-vis diffuse reflection spectroscopy and photoluminescence spectroscopy (PL). The photocatalytic activity of Bi2WO6/TiO2 coated polyester fabric was evaluated by degradation of Rhodamine B (RhB) and Methylene blue (MB) under visible light irradiation. The self-cleaning property of the fabrics was assessed through removing red wine stain. The results reveal that the Bi2WO6/TiO2 composites with irregular shape are coated on the polyester fabric successfully. The UV-vis absorption spectra show a broad absorption band in the visible region, which extends the scope of absorption spectrum and helps to improve the photocatalytic degradation efficiency. Photocatalytic activities of the Bi2WO6/TiO2 composite polyester fabric are associated with the content of TiO2. Bi2WO6/15%TiO2 coated polyester fabric exhibits the degradation efficiency for RhB and MB up to 98% and 95.1%, respectively, which is much higher than that of pure Bi2WO6 and TiO2 coated polyester fabric. Moreover, Bi2WO6/15%TiO2 coated polyester fabric shows good cycle stability toward continuous three cycles of photocatalytic experiment for dyes degradation. In addition, the Bi2WO6/TiO2 coated polyester fabric shows good self-cleaning property. This work could be extended to design of other composite photocatalyst coating on the fabric for enhancing activity by coupling suitable wide and narrow band-gap semiconductors.

A study on the quality control of slow burning polyester

NASA Astrophysics Data System (ADS)

Chen, Bin; Wang, Yinglei; Yan, Zhengfeng; Yu, Tao

2018-04-01

In this paper, the influence of the alcohol/acid mole ratio, reaction temperature, warm-up mode, end-capping, vacuity to the quality of slow burning polyester was studied. The hydroxyl value will increase when the alcohol/acid mole ratio increase, but the acid value and molecular weight will decrease. The molecular weight and molecular weight distribution of the polyester consistent with the designed one can be obtained by stepped heating up. Monobasic alcohol end-capping can be used to control the molecular weight effectively and reduce acid value. Stripping process narrow the molecular weight distribution and reduce the hydroxyl value. Decompression is in favor of the decrease of acid value and increase of the reaction speed to get qualified production.

40 CFR 63.1295 - Standards for slabstock flexible polyurethane foam production-HAP ABA storage vessels.

Code of Federal Regulations, 2010 CFR

2010-07-01

... 40 Protection of Environment 11 2010-07-01 2010-07-01 true Standards for slabstock flexible polyurethane foam production-HAP ABA storage vessels. 63.1295 Section 63.1295 Protection of Environment... Flexible Polyurethane Foam Production § 63.1295 Standards for slabstock flexible polyurethane foam...

40 CFR 63.1299 - Standards for slabstock flexible polyurethane foam production-source-wide emission limitation.

Code of Federal Regulations, 2014 CFR

2014-07-01

... polyurethane foam production-source-wide emission limitation. 63.1299 Section 63.1299 Protection of Environment... Pollutants for Flexible Polyurethane Foam Production § 63.1299 Standards for slabstock flexible polyurethane foam production—source-wide emission limitation. Each owner or operator of a new or existing slabstock...

40 CFR 63.1295 - Standards for slabstock flexible polyurethane foam production-HAP ABA storage vessels.

Code of Federal Regulations, 2011 CFR

2011-07-01

... 40 Protection of Environment 11 2011-07-01 2011-07-01 false Standards for slabstock flexible polyurethane foam production-HAP ABA storage vessels. 63.1295 Section 63.1295 Protection of Environment... Flexible Polyurethane Foam Production § 63.1295 Standards for slabstock flexible polyurethane foam...

40 CFR 63.1295 - Standards for slabstock flexible polyurethane foam production-HAP ABA storage vessels.

Code of Federal Regulations, 2012 CFR

2012-07-01

... 40 Protection of Environment 12 2012-07-01 2011-07-01 true Standards for slabstock flexible polyurethane foam production-HAP ABA storage vessels. 63.1295 Section 63.1295 Protection of Environment... Flexible Polyurethane Foam Production § 63.1295 Standards for slabstock flexible polyurethane foam...

40 CFR 63.1299 - Standards for slabstock flexible polyurethane foam production-source-wide emission limitation.

Code of Federal Regulations, 2013 CFR

2013-07-01

... polyurethane foam production-source-wide emission limitation. 63.1299 Section 63.1299 Protection of Environment... Pollutants for Flexible Polyurethane Foam Production § 63.1299 Standards for slabstock flexible polyurethane foam production—source-wide emission limitation. Each owner or operator of a new or existing slabstock...

Limitations of predicting in vivo biostability of multiphase polyurethane elastomers using temperature-accelerated degradation testing.

PubMed

Padsalgikar, Ajay; Cosgriff-Hernandez, Elizabeth; Gallagher, Genevieve; Touchet, Tyler; Iacob, Ciprian; Mellin, Lisa; Norlin-Weissenrieder, Anna; Runt, James

2015-01-01

Polyurethane biostability has been the subject of intense research since the failure of polyether polyurethane pacemaker leads in the 1980s. Accelerated in vitro testing has been used to isolate degradation mechanisms and predict clinical performance of biomaterials. However, validation that in vitro methods reproduce in vivo degradation is critical to the selection of appropriate tests. High temperature has been proposed as a method to accelerate degradation. However, correlation of such data to in vivo performance is poor for polyurethanes due to the impact of temperature on microstructure. In this study, we characterize the lack of correlation between hydrolytic degradation predicted using a high temperature aging model of a polydimethylsiloxane-based polyurethane and its in vivo performance. Most notably, the predicted molecular weight and tensile property changes from the accelerated aging study did not correlate with clinical explants subjected to human biological stresses in real time through 5 years. Further, DMTA, ATR-FTIR, and SAXS experiments on samples aged for 2 weeks in PBS indicated greater phase separation in samples aged at 85°C compared to those aged at 37°C and unaged controls. These results confirm that microstructural changes occur at high temperatures that do not occur at in vivo temperatures. In addition, water absorption studies demonstrated that water saturation levels increased significantly with temperature. This study highlights that the multiphase morphology of polyurethane precludes the use of temperature accelerated biodegradation for the prediction of clinical performance and provides critical information in designing appropriate in vitro tests for this class of materials. © 2014 Wiley Periodicals, Inc.

Mechanical and Physical Properties of Polyester Polymer Concrete Using Recycled Aggregates from Concrete Sleepers

PubMed Central

Carrión, Francisco; Montalbán, Laura; Real, Julia I.

2014-01-01

Currently, reuse of solid waste from disused infrastructures is an important environmental issue to study. In this research, polymer concrete was developed by mixing orthophthalic unsaturated polyester resin, artificial microfillers (calcium carbonate), and waste aggregates (basalt and limestone) coming from the recycling process of concrete sleepers. The variation of the mechanical and physical properties of the polymer concrete (compressive strength, flexural strength, modulus of elasticity, density, and water absorption) was analyzed based on the modification of different variables: nature of the recycled aggregates, resin contents (11 wt%, 12 wt%, and 13 wt%), and particle-size distributions of microfillers used. The results show the influence of these variables on mechanical performance of polymer concrete. Compressive and flexural strength of recycled polymer concrete were improved by increasing amount of polyester resin and by optimizing the particle-size distribution of the microfillers. Besides, the results show the feasibility of developing a polymer concrete with excellent mechanical behavior. PMID:25243213

Mechanical and physical properties of polyester polymer concrete using recycled aggregates from concrete sleepers.

PubMed

Carrión, Francisco; Montalbán, Laura; Real, Julia I; Real, Teresa

2014-01-01

Currently, reuse of solid waste from disused infrastructures is an important environmental issue to study. In this research, polymer concrete was developed by mixing orthophthalic unsaturated polyester resin, artificial microfillers (calcium carbonate), and waste aggregates (basalt and limestone) coming from the recycling process of concrete sleepers. The variation of the mechanical and physical properties of the polymer concrete (compressive strength, flexural strength, modulus of elasticity, density, and water absorption) was analyzed based on the modification of different variables: nature of the recycled aggregates, resin contents (11 wt%, 12 wt%, and 13 wt%), and particle-size distributions of microfillers used. The results show the influence of these variables on mechanical performance of polymer concrete. Compressive and flexural strength of recycled polymer concrete were improved by increasing amount of polyester resin and by optimizing the particle-size distribution of the microfillers. Besides, the results show the feasibility of developing a polymer concrete with excellent mechanical behavior.

46 CFR 160.035-1 - Applicable specifications.

Code of Federal Regulations, 2010 CFR

2010-10-01

... Laminates, Fibrous Glass Reinforced, Marine Structural. MIL-P-19644—Plastic Foam, Molded Polystyrene..., Polyester, Low Pressure Laminating, Fire Retardant. MIL-P-21929—Plastic Material, Cellular Polyurethane, Rigid, Foam-In-Place, Low Density. (3) Federal specifications: TT-P-59—Paint, Ready-Mixed, International...

46 CFR 160.035-1 - Applicable specifications.

Code of Federal Regulations, 2011 CFR

2011-10-01

... Laminates, Fibrous Glass Reinforced, Marine Structural. MIL-P-19644—Plastic Foam, Molded Polystyrene..., Polyester, Low Pressure Laminating, Fire Retardant. MIL-P-21929—Plastic Material, Cellular Polyurethane, Rigid, Foam-In-Place, Low Density. (3) Federal specifications: TT-P-59—Paint, Ready-Mixed, International...

Thread angle dependency on flame spread shape over kenaf/polyester combined fabric

NASA Astrophysics Data System (ADS)

Azahari Razali, Mohd; Sapit, Azwan; Nizam Mohammed, Akmal; Nor Anuar Mohamad, Md; Nordin, Normayati; Sadikin, Azmahani; Faisal Hushim, Mohd; Jaat, Norrizam; Khalid, Amir

2017-09-01

Understanding flame spread behavior is crucial to Fire Safety Engineering. It is noted that the natural fiber exhibits different flame spread behavior than the one of the synthetic fiber. This different may influences the flame spread behavior over combined fabric. There is a research has been done to examined the flame spread behavior over kenaf/polyester fabric. It is seen that the flame spread shape is dependent on the thread angle dependency. However, the explanation of this phenomenon is not described in detail in that research. In this study, explanation about this phenomenon is given in detail. Results show that the flame spread shape is dependent on the position of synthetic thread. For thread angle, θ = 0°, the polyester thread is breaking when the flame approach to the thread and the kenaf thread tends to move to the breaking direction. This behavior produces flame to be ‘V’ shape. However, for thread angle, θ = 90°, the polyester thread melts while the kenaf thread decomposed and burned. At this angle, the distance between kenaf threads remains constant as flame approaches.

Soil-release behaviour of polyester fabrics after chemical modification with polyethylene glycol

NASA Astrophysics Data System (ADS)

Miranda, T. M. R.; Santos, J.; Soares, G. M. B.

2017-10-01

The fibres cleanability depends, among other characteristics, on their hydrophilicity. Hydrophilic fibres are easy-wash materials but hydrophobic fibres are difficult to clean due to their higher water-repellent surfaces. This type of surfaces, like polyester (PET), produce an accumulation of electrostatic charges, which favors adsorption and retention of dirt. Thus, the polyester soil-release properties can be increased by finishing processes that improve fiber hydrophilicity. In present study, PET fabric modification was described by using poly(ethylene glycol) (PEG) and N,N´-dimethylol-4,5-dihydroxyethylene urea (DMDHEU) chemically modified resin. Briefly, the modification process was carried out in two steps, one to hydrolyse the polyester and create hydroxyl and carboxylic acid groups on the surface and other to crosslink the PEG chains. The resulting materials were characterized by contact angle, DSC and FTIR-ATR methods. Additionally, the soil release behavior and the mechanical properties of modified PET were evaluated. For the best process conditions, the treated PET presented 0° contact angle, grade 5 stain release and acceptable mechanical performance.

40 CFR 63.1296 - Standards for slabstock flexible polyurethane foam production-HAP ABA equipment leaks.

Code of Federal Regulations, 2013 CFR

2013-07-01

... polyurethane foam production-HAP ABA equipment leaks. 63.1296 Section 63.1296 Protection of Environment... Pollutants for Flexible Polyurethane Foam Production § 63.1296 Standards for slabstock flexible polyurethane foam production—HAP ABA equipment leaks. Each owner or operator of a new or existing slabstock affected...

40 CFR 63.1296 - Standards for slabstock flexible polyurethane foam production-HAP ABA equipment leaks.

Code of Federal Regulations, 2014 CFR

2014-07-01

... polyurethane foam production-HAP ABA equipment leaks. 63.1296 Section 63.1296 Protection of Environment... Pollutants for Flexible Polyurethane Foam Production § 63.1296 Standards for slabstock flexible polyurethane foam production—HAP ABA equipment leaks. Each owner or operator of a new or existing slabstock affected...

40 CFR 63.1295 - Standards for slabstock flexible polyurethane foam production-HAP ABA storage vessels.

Code of Federal Regulations, 2014 CFR

2014-07-01

... polyurethane foam production-HAP ABA storage vessels. 63.1295 Section 63.1295 Protection of Environment... Pollutants for Flexible Polyurethane Foam Production § 63.1295 Standards for slabstock flexible polyurethane foam production—HAP ABA storage vessels. Each owner or operator of a new or existing slabstock affected...

40 CFR 63.1299 - Standards for slabstock flexible polyurethane foam production-source-wide emission limitation.

Code of Federal Regulations, 2010 CFR

2010-07-01

... polyurethane foam production-source-wide emission limitation. 63.1299 Section 63.1299 Protection of Environment... Flexible Polyurethane Foam Production § 63.1299 Standards for slabstock flexible polyurethane foam... procedures in paragraphs (c)(1) through (4) of this section, unless a recovery device is used. Slabstock foam...

40 CFR 63.1299 - Standards for slabstock flexible polyurethane foam production-source-wide emission limitation.

Code of Federal Regulations, 2012 CFR

2012-07-01

... polyurethane foam production-source-wide emission limitation. 63.1299 Section 63.1299 Protection of Environment... Flexible Polyurethane Foam Production § 63.1299 Standards for slabstock flexible polyurethane foam... procedures in paragraphs (c)(1) through (4) of this section, unless a recovery device is used. Slabstock foam...

40 CFR 63.1295 - Standards for slabstock flexible polyurethane foam production-HAP ABA storage vessels.

Code of Federal Regulations, 2013 CFR

2013-07-01

... polyurethane foam production-HAP ABA storage vessels. 63.1295 Section 63.1295 Protection of Environment... Pollutants for Flexible Polyurethane Foam Production § 63.1295 Standards for slabstock flexible polyurethane foam production—HAP ABA storage vessels. Each owner or operator of a new or existing slabstock affected...

40 CFR 63.1299 - Standards for slabstock flexible polyurethane foam production-source-wide emission limitation.

Code of Federal Regulations, 2011 CFR

2011-07-01

... polyurethane foam production-source-wide emission limitation. 63.1299 Section 63.1299 Protection of Environment... Flexible Polyurethane Foam Production § 63.1299 Standards for slabstock flexible polyurethane foam... procedures in paragraphs (c)(1) through (4) of this section, unless a recovery device is used. Slabstock foam...

Synthesis and Characterization of High-Dielectric-Constant Nanographite-Polyurethane Composite

NASA Astrophysics Data System (ADS)

Mishra, Praveen; Bhat, Badekai Ramachandra; Bhattacharya, B.; Mehra, R. M.

2018-05-01

In the face of ever-growing demand for capacitors and energy storage devices, development of high-dielectric-constant materials is of paramount importance. Among various dielectric materials available, polymer dielectrics are preferred for their good processability. We report herein synthesis and characterization of nanographite-polyurethane composite with high dielectric constant. Nanographite showed good dispersibility in the polyurethane matrix. The thermosetting nature of polyurethane gives the composite the ability to withstand higher temperature without melting. The resultant composite was studied for its dielectric constant (ɛ) as a function of frequency. The composite exhibited logarithmic variation of ɛ from 3000 at 100 Hz to 225 at 60 kHz. The material also exhibited stable dissipation factor (tan δ) across the applied frequencies, suggesting its ability to resist current leakage.

Poly(Neopentyl Glycol Furanoate): A Member of the Furan-Based Polyester Family with Smart Barrier Performances for Sustainable Food Packaging Applications

PubMed Central

Munari, Andrea

2017-01-01

In the last decade, there has been an increased interest from the food packaging industry toward the development and application of bioplastics, to contribute to the sustainable economy and to reduce the huge environmental problem afflicting the planet. In the present work, we focus on a new furan-based polyester, poly(neopentyl glycol 2,5-furanoate) (PNF) to be used for sustainable food packaging applications. The aromatic polyester was successfully synthesized with high molecular weight, through a solvent-free process, starting directly from 2,5-furandicarboxylic acid. PNF was revealed to be a material with good thermal stability, characterized by a higher Tg and Tm and a lower RAF fraction compared to poly(propylene 2,5-furanoate) (PPF), ascribable to the two methyl side groups present in PNF glycol-sub-unit. PNF’s mechanical characteristics, i.e., very high elastic modulus and brittle fracture, were found to be similar to those of PPF and PEF. Barrier properties to different gases, temperatures and relative humidity were evaluated. From the results obtained, PNF was showed to be a material with very smart barrier performances, significantly superior with respect to PEF’s ones. Lastly, PNF’s permeability behavior did not appreciably change after contact with food simulants, whereas it got worse with increasing RH, due to the polar nature of furan ring. PMID:28869555

Poly(Neopentyl Glycol Furanoate): A Member of the Furan-Based Polyester Family with Smart Barrier Performances for Sustainable Food Packaging Applications.

PubMed

Genovese, Laura; Lotti, Nadia; Siracusa, Valentina; Munari, Andrea

2017-09-04

In the last decade, there has been an increased interest from the food packaging industry toward the development and application of bioplastics, to contribute to the sustainable economy and to reduce the huge environmental problem afflicting the planet. In the present work, we focus on a new furan-based polyester, poly(neopentyl glycol 2,5-furanoate) (PNF) to be used for sustainable food packaging applications. The aromatic polyester was successfully synthesized with high molecular weight, through a solvent-free process, starting directly from 2,5-furandicarboxylic acid. PNF was revealed to be a material with good thermal stability, characterized by a higher T g and T m and a lower RAF fraction compared to poly(propylene 2,5-furanoate) (PPF), ascribable to the two methyl side groups present in PNF glycol-sub-unit. PNF's mechanical characteristics, i.e., very high elastic modulus and brittle fracture, were found to be similar to those of PPF and PEF. Barrier properties to different gases, temperatures and relative humidity were evaluated. From the results obtained, PNF was showed to be a material with very smart barrier performances, significantly superior with respect to PEF's ones. Lastly, PNF's permeability behavior did not appreciably change after contact with food simulants, whereas it got worse with increasing RH, due to the polar nature of furan ring.

Cost-Benefit Analysis for Alternatives to Aliphatic Isocyanate Polyurethanes

NASA Technical Reports Server (NTRS)

Lewis, Pattie

2007-01-01

NASA and Air Force Space Command (AFSPC) have similar missions and therefore similar facilities and structures in similar environments. The standard practice for protecting metallic substrates in atmospheric environments is the application of an applied coating system. The most common topcoats used in coating systems are polyurethanes that contain isocyanates. Isocyanates are classified as potential human carcinogens and are known to cause cancer in animals. The primary objective of this effort was to demonstrate and validate alternatives to aliphatic isocyanate polyurethanes resulting in one or more isocyanate-free coatings qualified for use at AFSPC and NASA installations participating in this project. This Cost-Benefit Analysis (CBA) quantifies the estimated capital and process costs of coating alternatives and cost savings relative to the current coatings. The estimates in this CBA are to be used for assessing the relative merits of the selected alternatives. The actual economic effects at any specific facility will depend on the alternative material or technology implemented, the number of actual applications converted, future workloads, and other factors . The participants initially considered eighteen (18) alternative coatings as described in the Potential Alternatives Report entitled Potential Alternatives Report for Validation of Alternatives to Aliphatic Isocyanate Polyurethanes, prepared by ITB. Of those, 8 alternatives were selected for testing in accordance with the Joint Test Protocol entitled Joint Test Protocol for Validation of Alternatives to Aliphatic Isocyanate Polyurethanes, and the Field Test Plan entitled Field Evaluations Test Plan for Validation of Alternatives 10 Aliphatic Isocyanate Polyurethanes, both of which were prepared by ITB. A joint Test Report entitled Joint Test Report for Validation of Alternatives to Aliphatic Isocyanate Polyurethanes, prepared by ITB, documents the results of the laboratory and field testing, as well as any

Preparation of highly fluorinated polyurethanes

NASA Technical Reports Server (NTRS)

Rochow, S. E.; Stump, E. C., Jr.

1971-01-01

New polyurethanes, formed from a reaction of a prepolymer diol and a perfluorinated diisocyanate, are nonflammable and possess high corrosion resistance and good low temperature flexibility. Polymer hardness increases rapidly with increasing ratio of diisocaynate to diol, but its glass transition temperature is not adversely affected.

Corrosion and degradation of a polyurethane/Co-Ni-Cr-Mo pacemaker lead

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sung, P.; Fraker, A.C.

1987-12-01

An investigation to study changes in the metal surfaces and the polyurethane insulation of heart pacemaker leads under controlled in vitro conditions was conducted. A polyurethane (Pellethane 2363-80A)/Co-Ni-Cr-Mo (MP35N) wire lead was exposed in Hanks' physiological saline solution for 14 months and then analyzed using scanning electron microscopy, x-ray energy dispersive analysis, and small angle x-ray scattering. Results showed that some leakage of solution into the lead had occurred and changes were present on both the metal and the polyurethane surfaces.

Engineered soy oils for new value added applications

NASA Astrophysics Data System (ADS)

Tran, Phuong T.

Soybean oil is an abundant annually renewable resource. It is composed of triglycerides with long chain saturated and unsaturated fatty acids. The presence of unsaturated fatty acids allows for chemical modification to introduce new functionalities to soybean oil. A portfolio of chemically modified soy oil with suitable functional groups has been designed and engineered to serve as the starting material in applications such as polyamides, polyesters, polyurethanes, composites, and lubricants. Anhydride, hydroxyl, and silicone functionalities were introduced to soy oil. Anhydride functionality was introduced using a single-step free radical initiated process, and the chemically modified soy oils were evaluated for potential applications as a composite and lubricant. Hydroxyl functionalities were introduced in a single-step catalytic ozonolysis process recently developed in our labs, which proceeds rapidly and efficiently at room temperature without solvent. The transformed soy oil was used to successfully prepare bio-lubricants with good thermal/oxidative stability and bio-plastics such as polyamides, polyesters, and polyurethanes. A new class of organic-inorganic hybrid materials was prepared by curing vinyltrimethoxysilane functionalized soy oil. This hybrid material could have potential as biobased sealant through a moisture initiated room temperature cure. These new classes of soy-based materials are competitive both in cost and performance to petroleum based materials, but offer the advantage of being biobased.

Synthesis and characterization of polyurethane/CdS-SiO 2 nanocomposites via ultrasonic process

NASA Astrophysics Data System (ADS)

Chen, Jing; Zhou, Yu-Ming; Nan, Qiu-Li; Ye, Xiao-Yun; Sun, Yan-Qing; Wang, Zhi-Qiang; Zhang, Shi-Ming

2008-12-01

In this study, the high-intensity ultrasound was applied in the preparation of chiral polyurethane/CdS-SiO 2 nanocomposites. The polyurethane/CdS-SiO 2 nanocomposites were analyzed by powder X-ray diffraction, thermogravimetric analysis (TGA), TEM and SEM. The results indicated that the heat stability of the nanocomposites was improved in the presence of CdS-SiO 2 core-shell nanoparticles. The infrared emissivity (8-14 μm) study revealed that the nanocomposites possessed much lower infrared values compared with those of the neat polymers and nanoparticles, respectively. A possible mechanism of ultrasonic induced composite reaction was proposed based on the experimental results.

75 FR 5763 - Notice of Correction to the First Administrative Review of Certain Polyester Staple Fiber From...

Federal Register 2010, 2011, 2012, 2013, 2014

2010-02-04

... First Administrative Review of Certain Polyester Staple Fiber From the People's Republic of China: Final... the People's Republic of China (``PRC''). See First Administrative Review of Certain Polyester Staple Fiber From the People's Republic of China: Final Results of Antidumping Duty Administrative Review, 75...

75 FR 1336 - First Administrative Review of Certain Polyester Staple Fiber From the People's Republic of China...

Federal Register 2010, 2011, 2012, 2013, 2014

2010-01-11

... System. Jianxin Fuda Chemical Fibre Factory. Comment 6: Correction of Name in Federal Register Notice... of Certain Polyester Staple Fiber From the People's Republic of China: Final Results of Antidumping... duty order on certain polyester staple fiber (``PSF'') from the People's Republic of China (``PRC...

77 FR 39990 - Certain Polyester Staple Fiber From the People's Republic of China: Preliminary Results of the...

Federal Register 2010, 2011, 2012, 2013, 2014

2012-07-06

... calls into question the reliability of this information. \\27\\ See Polyester Staple Fiber Final... Fiber From the People's Republic of China: Preliminary Results of the Antidumping Duty Administrative... duty order on certain polyester staple fiber from the People's Republic of China (``PRC'') for the...

Effect OF NaOH Treatment on Bending Strength Of The Polyester Composite Reinforce By Sugar Palm Fibers

NASA Astrophysics Data System (ADS)

Arif Irfai, Mochamad; Wulandari, Diah; Sutriyono; Marsyahyo, Eko

2018-04-01

The objective of this research is to investigate the effect of NaOH treatment on bending strength of lamina composite reinforced by sugar palm fiber. To know of mechanism fracture can be done with visual inspection of the fracture surface. The Materials used are random sugar palm fibers that have been in the treatment of NaOH, polyester resin and hardener. Sugar palm fibers after washed and dried then soaked NaOH with a long time soaking 0, 2, 4, 6 and 8 hours. The bending test specimens were produced according to ASTM D 790. All specimens were post cured at 62°C for 4 hours. The Bending test was carried out on a universal testing machine. The SEM analysis has conducted to provide the analysis on interface adhesion between the surfaces of fiber with the matrix. The result shows that polyester composite reinforced by sugar palm fiber has highest bending stress 176.77 N/mm2 for 2 hours of a long time soaking NaOH, the highest flexural strain 0.27 mm for 2 hours of a long time soaking NaOH, elongation 24.05% for 2 hours of a long time soaking NaOH and the highest bending modulus 1.267 GPa for 2 hours of a long time soaking NaOH. Based on the results, it can be concluded that the polyester composite reinforced by sugar palm fiber has the optimum bending properties for a long time soaking 2 hours. The fracture surface shows that the polyester composite reinforced by sugar palm fiber pull out that indicate weakens the bond between fiber and matrix.

Development of a smart, anti-water polyurethane polymer hair coating for style setting.

PubMed

Liu, Y; Liu, Y J; Hu, J; Ji, F L; Lv, J; Chen, S J; Zhu, Y

2016-06-01

The goal of this work was to develop a novel polyurethane polymer coating for the surface of the hair that could be used for style setting via the shape memory effect (SME). The features of the films are in accordance with conventional hair styling methods used in the laboratory. In this study, a new polyurethane polymer was synthesized; the morphology and mechanical behaviour of the coated hair were systematically investigated using a scanning electron microscope (SEM) and an Instron 5566 (with a temperature oven). The SME of the hair was tested using a 35-g weight and over five washing and drying cycles. The experimental result shows that the polyurethane polymer has effects on the mechanical behaviour of the hair. It indicates that the fixed shape (at 22°C) and recover rate (at 60°C) of different casted thickness films are similar. And the stress of the film becomes larger with increasing film thickness. Furthermore, the shape memory ability could be endowed with the hair styling using this polymer; the hair fibre could recover to the 65% of its original shape after five cycle deformation by 35 g mass under the heat-treated condition; it could recover its original setting styling even after 5th water washing and drying. The SEM results indicated that the microsurface of the hair is coated with the polymer membrane; it contributes to the shape memory ability of the coated hair to keep and recover to the original setting styling. The styling hair can return to the original hair because the polyurethane polymer can be washed out by water with suitable strength and shampoo totally which does not leave any flake. The polyurethane polymer-based hair setting agent has been developed successfully, and it could be coated evenly on the human hair with good hand feeling and SMEs. The SME is highly related to the quantity of polyurethane polymer solution, and the effect could be improved by increasing the solution quantity. The maximum deformation of the coated hair could

Synthesis of silver nanoparticles in melts of amphiphilic polyesters

NASA Astrophysics Data System (ADS)

Vasylyev, S.; Damm, C.; Segets, D.; Hanisch, M.; Taccardi, N.; Wasserscheid, P.; Peukert, W.

2013-03-01

The current work presents a one-step procedure for the synthesis of amphiphilic silver nanoparticles suitable for production of silver-filled polymeric materials. This solvent free synthesis via reduction of Tollens’ reagent as silver precursor in melts of amphiphilic polyesters consisting of hydrophilic poly(ethylene glycol) blocks and hydrophobic alkyl chains allows the production of silver nanoparticles without any by-product formation. This makes them especially interesting for the production of medical devices with antimicrobial properties. In this article the influences of the chain length of the hydrophobic block in the amphiphilic polyesters and the process temperature on the particle size distribution (PSD) and the stability of the particles against agglomeration are discussed. According to the results of spectroscopic and viscosimetric investigations the silver precursor is reduced to elemental silver nanoparticles by a single electron transfer process from the poly(ethylene glycol) chain to the silver ion.

Synthesis of Nitric Oxide-Releasing Polyurethanes with S-Nitrosothiol-Containing Hard and Soft Segments

PubMed Central

Coneski, Peter N.

2013-01-01

Nitric oxide (NO)-releasing polyurethanes capable of releasing up to 0.20 μmol NO cm−2 were synthesized by incorporating active S-nitrosothiol functionalities into hard and soft segment domains using thiol group protection and post-polymerization modifications, respectively. The nitrosothiol position within the hard and soft segment domains of the polyurethanes impacted both the total NO release and NO release kinetics. The NO storage and release properties were correlated to both chain extender modification and ensuing phase miscibility of the polyurethanes. Thorough material characterization is provided to examine the effects of hard and soft segment modifications on the resultant polyurethane properties. PMID:23418409

Impact of Medium and Substrate on Growth of Pseudomonas Fluorescens Biofilms on Polyurethane Paint

DTIC Science & Technology

2011-02-01

biofilm formation on polyurethane (PU) coatings, and to define how those parameters contribute to polyurethane biodegradation. We used a batch flow system...determine which factors best support the growth and persistence of Pseudomonas fluorescens biofilms . Factors that enhance biofilm formation and...AFRL-RX-WP-TP-2011-4131 IMPACT OF MEDIUM AND SUBSTRATE ON GROWTH OF PSEUDOMONAS FLUORESCENS BIOFILMS ON POLYURETHANE PAINT Wendy L. Goodson

Airway symptoms and lung function in pipelayers exposed to thermal degradation products from MDI-based polyurethane.

PubMed Central

Jakobsson, K; Kronholm-Diab, K; Rylander, L; Hagmar, L

1997-01-01

OBJECTIVES: To study the prevalence of symptoms from the eyes and the upper and lower respiratory tract, lung function, and immunological sensitisation towards isocyanates in pipelayers exposed to thermal degradation products from methylene diphenyl diisocyanate (MDI)-based polyurethane (PUR). MATERIAL AND METHODS: 50 presently active and 113 formerly active pipelayers were examined. Also, 65 unexposed workers were investigated for comparison. The one year prevalence of symptoms and smoking history (questionnaire data), lung function (vital capacity (VC) and forced expiratory volume in one second (FEV1), and atopy (positive skin prick tests towards standard allergens) were assessed among pipelayers and controls. For the pipelayers, the presence of work related symptoms and estimates of isocyanate and welding exposure were obtained from an interview. Skin prick tests towards specific isocyanate antigens and determinations of IgE-MDI and IgG-MDI in serum were also performed. RESULTS: The prevalence of episodes (more than once a month) of irritative eye symptoms, congestion of the nose, and soreness or dryness in the throat was much higher among the PUR pipelayers than among the controls. Most of the pipelayers with symptoms reported that these had started and occurred in relation to the PUR welding tasks. Presently active pipelayers with recent high PUR exposure showed a significant reduction of FEV1 compared with the controls. The estimated reduction, adjusted for smoking, was -0.3 l (P = 0.04). There was no confounding effect of ordinary welding. None of the pipelayers showed positive skin prick reactions against the specific isocyanate antigens used, or positive IgE-MDI, and only two had increased IgG-MDI. CONCLUSIONS: The findings indicate that exposure to thermal degradation products from MDI-based polyurethane has adverse effects on the mucous membranes and airways. PMID:9470895

Nano-engineered polyurethane resin-modified concrete.

DOT National Transportation Integrated Search

2014-04-01

The goal of the proposed work is to investigate the application of nano-engineered polyurethane (NEPU) emulsions for latex modified : concrete (LMC). NEPU emulsions are non-toxic, environment friendly, durable over a wide temperature range, provide b...

Microcellular processing of polylactide-hyperbranched polyester-nanoclay composites

Treesearch

Srikanth Pilla; Adam Kramschuster; Jungjoo Lee; Craig Clemons; Shaoqin Gong; Lih-Sheng Turng

2010-01-01

The effects of addition of hyperbranched polyesters (HBPs) and nanoclay on the material properties of both solid and microcellular polylactide (PLA) produced via a conventional and microcellular injection-molding process, respectively, were investigated. The effects of two different types of HBPs (i.e., Boltorn H2004® and Boltorn H20®) at the same...

Stretching-induced nanostructures on shape memory polyurethane films and their regulation to osteoblasts morphology.

PubMed

Xing, Juan; Ma, Yufei; Lin, Manping; Wang, Yuanliang; Pan, Haobo; Ruan, Changshun; Luo, Yanfeng

2016-10-01

Programming such as stretching, compression and bending is indispensible to endow polyurethanes with shape memory effects. Despite extensive investigations on the contributions of programming processes to the shape memory effects of polyurethane, less attention has been paid to the nanostructures of shape memory polyurethanes surface during the programming process. Here we found that stretching could induce the reassembly of hard domains and thereby change the nanostructures on the film surfaces with dependence on the stretching ratios (0%, 50%, 100%, and 200%). In as-cast polyurethane films, hard segments sequentially assembled into nano-scale hard domains, round or fibrillar islands, and fibrillar apophyses. Upon stretching, the islands packed along the stretching axis to form reoriented fibrillar apophyses along the stretching direction. Stretching only changed the chemical patterns on polyurethane films without significantly altering surface roughness, with the primary composition of fibrillar apophyses being hydrophilic hard domains. Further analysis of osteoblasts morphology revealed that the focal adhesion formation and osteoblasts orientation were in accordance with the chemical patterns of the underlying stretched films, which corroborates the vital roles of stretching-induced nanostructures in regulating osteoblasts morphology. These novel findings suggest that programming might hold great potential for patterning polyurethane surfaces so as to direct cellular behavior. In addition, this work lays groundwork for guiding the programming of shape memory polyurethanes to produce appropriate nanostructures for predetermined medical applications. Copyright © 2016 Elsevier B.V. All rights reserved.

Electropositive bivalent metallic ion unsaturated polyester complexed polymer concrete

DOEpatents

Sugama, Toshifumi; Kukacka, Lawrence E.; Horn, William H.

1985-01-01

Quick setting polymer concrete compositions with excellent structural properties are disclosed; these polymer concrete compositions are mixtures of unsaturated polyesters and crosslinking monomers together with appropriate initiators and promoters in association with aggregate, which may be wet, and with a source of bivalent metallic ions.

Electropositive bivalent metallic ion unsaturated polyester complexed polymer concrete

DOEpatents

Sugama, T.; Kukacka, L.E.; Horn, W.H.

1981-11-04

Quick setting polymer concrete compositions which are mixtures of unsaturated polyesters and crosslinking monomers together with appropriate initiators and promoters in association with aggregate which may be wet and a source of bivalent metallic ions which will set to polymer concrete with excellent structural properties.

Randomized intubation with polyurethane or conical cuffs to prevent pneumonia in ventilated patients.

PubMed

Philippart, François; Gaudry, Stéphane; Quinquis, Laurent; Lau, Nicolas; Ouanes, Islem; Touati, Samia; Nguyen, Jean Claude; Branger, Catherine; Faibis, Frédéric; Mastouri, Maha; Forceville, Xavier; Abroug, Fekri; Ricard, Jean Damien; Grabar, Sophie; Misset, Benoît

2015-03-15

The occurrence of ventilator-associated pneumonia (VAP) is linked to the aspiration of contaminated pharyngeal secretions around the endotracheal tube. Tubes with cuffs made of polyurethane rather than polyvinyl chloride or with a conical rather than a cylindrical shape increase tracheal sealing. To test whether using polyurethane and/or conical cuffs reduces tracheal colonization and VAP in patients with acute respiratory failure. We conducted a multicenter, prospective, open-label, randomized study in four parallel groups in four intensive care units between 2010 and 2012. A cohort of 621 patients with expected ventilation longer than 2 days was included at intubation with a cuff composed of cylindrical polyvinyl chloride (n = 148), cylindrical polyurethane (n = 143), conical polyvinyl chloride (n = 150), or conical polyurethane (n = 162). We used Kaplan-Meier estimates and log-rank tests to compare times to events. After excluding 17 patients who secondarily refused participation or had met an exclusion criterion, 604 were included in the intention-to-treat analysis. Cumulative tracheal colonization greater than 10(3) cfu/ml at Day 2 was as follows (median [interquartile range]): cylindrical polyvinyl chloride, 0.66 (0.58-0.74); cylindrical polyurethane, 0.61 (0.53-0.70); conical polyvinyl chloride, 0.67 (0.60-0.76); and conical polyurethane, 0.62 (0.55-0.70) (P = 0.55). VAP developed in 77 patients (14.4%), and postextubational stridor developed in 28 patients (6.4%) (P = 0.20 and 0.28 between groups, respectively). Among patients requiring mechanical ventilation, polyurethane and/or conically shaped cuffs were not superior to conventional cuffs in preventing tracheal colonization and VAP. Clinical trial registered with clinicaltrials.gov (NCT01114022).

Novel polymer electrolytes based on cationic polyurethane with different alkyl chain length

NASA Astrophysics Data System (ADS)

Liu, Libin; Wu, Xiwen; Li, Tianduo

2014-03-01

A series of comb-like cationic polyurethanes (PUs) were synthesized by quaternizing different bromoalkane (C2H5Br, C8H17Br, and C14H29Br) with polyurethane. Solid polymer electrolytes were prepared by complexes cationic PUs with different content of LiClO4. All the solid polymer electrolytes had sufficient thermal stability as confirmed by TGA and exhibited a single-phase behavior evidenced by DSC results. For these electrolytes, FT-IR spectra indicated the formation of polymer-ion complexes. The ac impedance spectra show that the conductivity of the electrolytes follow the Arrhenius behavior, and ionic conductivity is associated with both the charge migration of ions between coordination sites and transmission between aggregates, as confirmed by FT-IR and SEM. Alkyl quaternary ammonium salts in the polymer backbone are recognized as inherent plasticizers, which make the electrolytes exhibit liquid-like behavior. The plasticizing effect of PU-C8 and PU-C14 electrolytes are more effective than that of PU-C2 electrolyte. Maximum ionic conductivity at room temperature for PU-C8 electrolytes containing 50 wt% LiClO4 reached 1.1 × 10-4 S cm-1. This work provides a new research clue that alkyl quaternary ammonium salts could be used as inherent plasticizers and hence make the system behave like a liquid with high ionic conductivity, while preserving the dimensional stability of the solids.

77 FR 54898 - Certain Polyester Staple Fiber From the People's Republic of China: Final Results of Expedited...

Federal Register 2010, 2011, 2012, 2013, 2014

2012-09-06

... Fiber From the People's Republic of China: Final Results of Expedited Sunset Review of the Antidumping... (``sunset'') review of the antidumping duty order on certain polyester staple fiber from the People's... Department finds that revocation of the antidumping duty order on certain polyester staple fiber from the PRC...

Treatment of concentrated industrial wastewaters originating from oil shale and the like by electrolysis polyurethane foam interaction

DOEpatents

Tiernan, Joan E.

1990-01-01

Highly concentrated and toxic petroleum-based and synthetic fuels wastewaters such as oil shale retort water are treated in a unit treatment process by electrolysis in a reactor containing oleophilic, ionized, open-celled polyurethane foams and subjected to mixing and laminar flow conditions at an average detention time of six hours. Both the polyurethane foams and the foam regenerate solution are re-used. The treatment is a cost-effective process for waste-waters which are not treatable, or are not cost-effectively treatable, by conventional process series.

Washing Off Polyurethane Foam Insulation

NASA Technical Reports Server (NTRS)

Burley, Richard K.; Fogel, Irving

1990-01-01

Jet of hot water removes material quickly and safely. Simple, environmentally sound technique found to remove polyurethane foam insulation from metal parts. Developed for (but not limited to) use during rebuilding of fuel system of Space Shuttle main engine, during which insulation must be removed for penetrant inspection of metal parts.

40 CFR 63.1298 - Standards for slabstock flexible polyurethane foam production-HAP emissions from equipment cleaning.

Code of Federal Regulations, 2014 CFR

2014-07-01

... polyurethane foam production-HAP emissions from equipment cleaning. 63.1298 Section 63.1298 Protection of... Hazardous Air Pollutants for Flexible Polyurethane Foam Production § 63.1298 Standards for slabstock flexible polyurethane foam production—HAP emissions from equipment cleaning. Each owner or operator of a...

40 CFR 63.1298 - Standards for slabstock flexible polyurethane foam production-HAP emissions from equipment cleaning.

Code of Federal Regulations, 2010 CFR

2010-07-01

... polyurethane foam production-HAP emissions from equipment cleaning. 63.1298 Section 63.1298 Protection of... Pollutants for Flexible Polyurethane Foam Production § 63.1298 Standards for slabstock flexible polyurethane foam production—HAP emissions from equipment cleaning. Each owner or operator of a new or existing...