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1

Constitutive modeling of fused deposition modeling acrylonitrile butadiene styrene (ABS)  

E-print Network

Fused deposition modeling is a rapid prototyping process that is widely used to create prototypes. Acrylonitrile butadiene styrene is the most widely used material for fused deposition modeling. The parts are fabricated in a layer by layer fashion...

Mamadapur, Monish Shivappa

2009-05-15

2

Denitrification with acrylonitrile as a substrate using pure bacteria cultures isolated from acrylonitrile–butadiene–styrene wastewater  

Microsoft Academic Search

This study attempted to isolate and identify the denitrifying bacteria that utilize acrylonitrile as a substrate from acrylonitrile–butadiene–styrene (ABS) resin wastewater. The performance of the denitrifying bacteria for treating different initial acrylonitrile concentrations was also investigated under anoxic conditions. The results showed that seven strains of denitrifying bacteria that can use acrylonitrile or acrylic acid as a substrate were isolated

Chun Chin Wang; Chi Mei Lee

2001-01-01

3

The thermal degradation of acrylonitrile-butadiene-styrene terpolymei as studied by TGA\\/FTIR  

Microsoft Academic Search

The thermal degradation of acrylonitrile-butadiene-styrene (ABS) terpolymer has been studied by TGA\\/FTIR. The degradation of ABS is compared with that of polystyrene, polybutadiene, polyacrylonitrile (PAN), and styreneacrylonitrile (SAN) copolymer. A small amount of acrylonitrile monomer is eliminated from PAN, SAN, and ABS. The grafting of butadiene on to SAN stabilizes the butadiene structure, since the evolution of butadiene begins 50

Masanori Suzuki; Charles A. Wilkie

1995-01-01

4

Poly(acrylonitrile-butadiene-styrene) Modified Epoxy–Amine Systems Analyzed by FTIR and Modulated DSC  

Microsoft Academic Search

Epoxy networks based on diglycidyl ether of bisphenol A (DGEBA) and diamino diphenyl sulfone (DDS) as curing agent were prepared in the presence of poly(acrylonitrile-butadiene-styrene) (ABS). Blends containing 3.6, 6.9, 10, and 12.9 wt% ABS were obtained by a melt mixing technique. Infrared spectroscopy was employed to follow the curing progress by determining the decrease of the band intensity caused

P. Jyotishkumar; J. Pionteck; L. Häußler; G. Adam; S. Thomas

2012-01-01

5

DC conductivity study of polyaniline and poly(acrylonitrile-butadiene-styrene) blends  

Microsoft Academic Search

In this study, conducting blends of poly(acrylonitrile-butadiene-styrene) and polyaniline doped with dodecylbenzene sulfonic acid were prepared by solution blending. In order to understand the electrical conduction mechanism of the samples, DC electrical conductivity measurements of the blends were carried out in the temperature range of 80–320K. The experimental results fit well with Mott's model of three-dimensional variable range hopping conduction.

Fernando H. Cristovan; Fernando R. de Paula; Sherlan G. Lemos; Adilson J. A. De Oliveira; Ernesto C. Pereira

2009-01-01

6

Poly(acrylonitrile-butadiene-styrene) Modified Epoxy–Amine Systems Analyzed by FTIR and Modulated DSC  

Microsoft Academic Search

Epoxy networks based on diglycidyl ether of bisphenol A (DGEBA) and diamino diphenyl sulfone (DDS) as curing agent were prepared in the presence of poly(acrylonitrile-butadiene-styrene) (ABS). Blends containing 3.6, 6.9, 10, and 12.9 wt% ABS were obtained by a melt mixing technique. Infrared spectroscopy was employed to follow the curing progress by determining the decrease of the band intensity caused

P. JYOTISHKUMAR; J. PIONTECK; L. HÄUßLER; G. ADAM; S. THOMAS

2011-01-01

7

GRAFT POLYMERIZATION OF STYRENE MONOMER AND MIXED MONOMER OF STYRENE AND ACRYLONITRILE ON TO ACRYLONITRILE-BUTADIENE COPOLYMER  

Microsoft Academic Search

Graft polymerization of styrene monomer and a mixed monomer of styrene ; and acrylonitrile onto an actylonitrilebuthdiene copolymer was conducted by both ; radiation and a chemical catalyst method. In the experiments, the radiation ; method used a direct process by which gamma radation was applied to a uniform ; solution, and the catalyst method adopted a solution polymerization process

A. Takahashi; S. Kobayashi

1963-01-01

8

Studies on thermal degradation of acrylonitrile–butadiene–styrene copolymer (ABS-Br) containing brominated flame retardant  

Microsoft Academic Search

The thermal degradation of acrylonitrile-butadiene-styrene copolymer (ABS-Br; 10 g) containing brominated flame retardant (Br: 9.59 wt.%) was carried out at 450°C using a semi batch operation using two different temperature programs. The heating rate was found to affect the quality of the degradation oil and yield of products (liquid, gas and residue). Data on the effect of the temperature program

Thallada Bhaskar; Kazuya Murai; Toshiki Matsui; Mihai Adrian Brebu; Akinori Muto; Yusaku Sakata; Katsuhide Murata

2003-01-01

9

Acrylonitrile Butadiene Styrene (ABS) plastic based low cost tissue equivalent phantom for verification dosimetry in IMRT.  

PubMed

A novel IMRT phantom was designed and fabricated using Acrylonitrile Butadiene Styrene (ABS) plastic. Physical properties of ABS plastic related to radiation interaction and dosimetry were compared with commonly available phantom materials for dose measurements in radiotherapy. The ABS IMRT phantom has provisions to hold various types of detectors such as ion chambers, radiographic/radiochromic films, TLDs, MOSFETs, and gel dosimeters. The measurements related to pre-treatment dose verification in IMRT of carcinoma prostate were carried out using ABS and Scanditronics-Wellhoffer RW3 IMRT phantoms for five different cases. Point dose data were acquired using ionization chamber and TLD discs while Gafchromic EBT and radiographic EDR2 films were used for generating 2-D dose distributions. Treatment planning system (TPS) calculated and measured doses in ABS plastic and RW3 IMRT phantom were in agreement within +/-2%. The dose values at a point in a given patient acquired using ABS and RW3 phantoms were found comparable within 1%. Fluence maps and dose distributions of these patients generated by TPS and measured in ABS IMRT phantom were also found comparable both numerically and spatially. This study indicates that ABS plastic IMRT phantom is a tissue equivalent phantom and dosimetrically it is similar to solid/plastic water IMRT phantoms. Though this material is demonstrated for IMRT dose verification but it can be used as a tissue equivalent phantom material for other dosimetry purposes in radiotherapy. PMID:20160681

Kumar, Rajesh; Sharma, S D; Deshpande, Sudesh; Ghadi, Yogesh; Shaiju, V S; Amols, H I; Mayya, Y S

2010-01-01

10

Carbon nanotube buckypaper reinforced acrylonitrile-butadiene-styrene composites for electronic applications.  

PubMed

Novel acrylonitrile-butadiene-styrene (ABS) nanocomposites reinforced with pristine or functionalized single- or multiwalled carbon nanotube buckypaper (BP) sheets were manufactured via hot-compression and vacuum infiltration. Their morphology, thermal, mechanical, and electrical properties were comparatively investigated. Scanning electron microscopy and thermogravimetric analysis showed that the infiltration process leads to better BP impregnation than the hot-press technique. BPs made from functionalized or short nanotubes form compact networks that hamper the penetration of the matrix chains, whereas those composed of pristine tubes possess large pores that facilitate the polymer flow, resulting in composites with low degree of porosity and improved mechanical performance. Enhanced thermal and electrical properties are found for samples incorporating functionalized BPs since dense networks lead to more conductive pathways, and a stronger barrier effect to the diffusion of degradation products, thus better thermal stability. According to dynamic mechanical analysis these composites exhibit the highest glass transition temperatures, suggesting enhanced filler-matrix interactions as corroborated by the Raman spectra. The results presented herein demonstrate that the composite performance can be tailored by controlling the BP architecture and offer useful insights into the structure-property relationships of these materials to be used in electronic applications, particularly for EMI shielding and packaging of integrated circuits. PMID:24171494

Díez-Pascual, Ana M; Gascón, David

2013-11-27

11

Design and testing of digitally manufactured paraffin Acrylonitrile-butadiene-styrene hybrid rocket motors  

NASA Astrophysics Data System (ADS)

This research investigates the application of additive manufacturing techniques for fabricating hybrid rocket fuel grains composed of porous Acrylonitrile-butadiene-styrene impregnated with paraffin wax. The digitally manufactured ABS substrate provides mechanical support for the paraffin fuel material and serves as an additional fuel component. The embedded paraffin provides an enhanced fuel regression rate while having no detrimental effect on the thermodynamic burn properties of the fuel grain. Multiple fuel grains with various ABS-to-Paraffin mass ratios were fabricated and burned with nitrous oxide. Analytical predictions for end-to-end motor performance and fuel regression are compared against static test results. Baseline fuel grain regression calculations use an enthalpy balance energy analysis with the material and thermodynamic properties based on the mean paraffin/ABS mass fractions within the fuel grain. In support of these analytical comparisons, a novel method for propagating the fuel port burn surface was developed. In this modeling approach the fuel cross section grid is modeled as an image with white pixels representing the fuel and black pixels representing empty or burned grid cells.

McCulley, Jonathan M.

12

Method for the separation of high impact polystyrene (HIPS) and acrylonitrile butadiene styrene (ABS) plastics  

DOEpatents

An improved method is provided for separating acrylonitrile butadiene styrene (ABS) and high impact polystyrene (HIPS) plastics from each other. The ABS and HIPS plastics are shredded to provide a selected particle size. The shredded particles of the ABS and HIPS plastics are applied to a solution having a solution density in a predefined range between 1.055 gm/cm.sup.3 and 1.07 gm/cm.sup.3, a predefined surface tension in a range between 22 dynes/cm to 40 dynes/cm and a pH in the range of 1.77 and 2.05. In accordance with a feature of the invention, the novel method is provided for separating ABS and HIPS, two solid thermoplastics which have similar densities by selectively modifying the effective density of the HIPS using a binary solution with the appropriate properties, such as pH, density and surface tension, such as a solution of acetic acid and water or a quaternary solution having the appropriate density, surface tension, and pH.

Jody, Bassam J. (Chicago, IL); Arman, Bayram (Amherst, NY); Karvelas, Dimitrios E. (Downers Grove, IL); Pomykala, Jr., Joseph A. (Crest Hill, IL); Daniels, Edward J. (Oak Lawn, IL)

1997-01-01

13

Environmentally benign electroless nickel plating using supercritical carbon-dioxide on hydrophilically modified acrylonitrile-butadiene-styrene  

NASA Astrophysics Data System (ADS)

Electroless Ni-P plating using supercritical carbon dioxide (scCO2) in conjunction with copolymer-based hydrophilic modification was applied to an acrylonitrile-butadiene-styrene (ABS) substrate. The surface of ABS substrate was hydrophilically modified by blending with a multi-block copolymer, poly(ether-ester-amide)s (PEEA), in injection molding process. The substrate was then impregnated with Pd(II)-hexafluoroacetylacetonate, Pd(hfa)2, using scCO2, followed by the electroless plating reaction. ABS/PEEA substrates with different PEEA to ABS blend ratios and different volume ratios of butadiene to the styrene-acrylonitrile copolymer (SAN) matrix were prepared to investigate how the dispersed PEEA and butadiene domains affected the blend morphology and the adhesive strength of the plating metal-to-polymer contact. Increasing the PEEA copolymer to ABS blend ratio increased the mass transfer rate of the plating solution in the ABS substrate. Consequently, the metal-polymer composite layer became thicker, which increased the adhesive strength of the metal-to-polymer contact because of the anchoring effect. The butadiene domains appeared to attract the Pd catalyst precursor, and thus, the proportion of butadiene in the ABS matrix also affected the adhesive strength of the contact between the metal layer and the substrate. The ABS substrate was successfully plated with a Ni-P metal layer with an average adhesive strength of 9.1 ± 0.5 N cm-1 by choosing appropriate ABS/PEEA blend ratios and a Pd(hfa)2 concentration.

Tengsuwan, Siwach; Ohshima, Masahiro

2014-08-01

14

The individual and cumulative effect of brominated flame retardant and polyvinylchloride (PVC) on thermal degradation of acrylonitrile–butadiene–styrene (ABS) copolymer  

Microsoft Academic Search

Acrylonitrile–butadiene–styrene (ABS) copolymers without and with a polybrominated epoxy type flame retardant were thermally degraded at 450 °C alone (10 g) and mixed with polyvinylchloride (PVC) (8 g\\/2 g). Gaseous and liquid products of degradation were analysed by various gas chromatographic methods (GC with TCD, FID, AED, MSD) in order to determine the individual and cumulative effect of bromine and

Mihai Brebu; Thallada Bhaskar; Kazuya Murai; Akinori Muto; Yusaku Sakata

2004-01-01

15

Surface discharge and tracking phenomena induced on acrylonitrile-butadiene-styrene polymer dielectric material by acid rain  

NASA Astrophysics Data System (ADS)

The discharge and tracking phenomena induced on the polymer dielectric materials by acid rain are investigated by the accelerated aging of acrylonitrile-butadiene-styrene copolymer in artificial rainwater in this article. Based on the investigation of acid rain, the artificial rainwater is chosen to agree well with the actual ingredients of precipitation. The influence of hydrophobicity degradation on the surface discharge and tracking is studied. The relations among the surface discharge, tracking, hydrophobicity, and microchemical structure and physical morphology of material are furthermore discussed. Experimental results show that the polymer dielectric materials suffer a large attack and degradation from acid rain. The dielectric surface degrades and becomes rough, and the hydrophobicity decreases so that the surface discharge and tracking may occur on them.

Wang, X.; Yoshimura, N.

1999-05-01

16

Separation of polycarbonate and acrylonitrile-butadiene-styrene waste plastics by froth flotation combined with ammonia pretreatment.  

PubMed

The objective of this research is flotation separation of polycarbonate (PC) and acrylonitrile-butadiene-styrene (ABS) waste plastics combined with ammonia pretreatment. The PC and ABS plastics show similar hydrophobicity, and ammonia treatment changes selectively floatability of PC plastic while ABS is insensitive to ammonia treatment. The contact angle measurement indicates the dropping of flotation recovery of PC is ascribed to a decline of contact angle. X-ray photoelectron spectroscopy demonstrates reactions occur on PC surface, which makes PC surface more hydrophilic. Separation of PC and ABS waste plastics was conducted based on the flotation behavior of single plastic. At different temperatures, PC and ABS mixtures were separated efficiently through froth flotation with ammonia pretreatment for different time (13min at 23°C, 18min at 18°C and 30min at 23°C). For both PC and ABS, the purity and recovery is more than 95.31% and 95.35%, respectively; the purity of PC and ABS is up to 99.72% and 99.23%, respectively. PC and ABS mixtures with different particle sizes were separated effectively, implying that ammonia treatment possesses superior applicability. PMID:25266156

Wang, Chong-Qing; Wang, Hui; Liu, Qun; Fu, Jian-Gang; Liu, You-Nian

2014-12-01

17

Synchrotron-based FTIR microspectroscopy for the mapping of photo-oxidation and additives in acrylonitrile-butadiene-styrene model samples and historical objects.  

PubMed

Synchrotron-based Fourier transform infrared micro-spectroscopy (SR-?FTIR) was used to map photo-oxidative degradation of acrylonitrile-butadiene-styrene (ABS) and to investigate the presence and the migration of additives in historical samples from important Italian design objects. High resolution (3×3 ?m(2)) molecular maps were obtained by FTIR microspectroscopy in transmission mode, using a new method for the preparation of polymer thin sections. The depth of photo-oxidation in samples was evaluated and accompanied by the formation of ketones, aldehydes, esters, and unsaturated carbonyl compounds. This study demonstrates selective surface oxidation and a probable passivation of material against further degradation. In polymer fragments from design objects made of ABS from the 1960s, UV-stabilizers were detected and mapped, and microscopic inclusions of proteinaceous material were identified and mapped for the first time. PMID:25150697

Saviello, Daniela; Pouyet, Emeline; Toniolo, Lucia; Cotte, Marine; Nevin, Austin

2014-09-16

18

Three-dimensional printed acrylonitrile butadiene styrene framework coated with Cu-BTC metal-organic frameworks for the removal of methylene blue.  

PubMed

Three-dimensional (3D) printing was applied for the fabrication of acrylonitrile butadiene styrene (ABS) framework. Functionalization of the ABS framework was then performed by coating of porous Cu-BTC (BTC = benzene tricarboxylic acid) metal-organic frameworks on it using a step-by-step in-situ growth. The size of the Cu-BTC particles on ABS was ranged from 200 nm to 900 nm. The Cu-BTC/ABS framework can take up most of the space of the tubular reactor that makes the adsorption effective with no need of stirring. Methylene blue (MB) can be readily removed from aqueous solution by this Cu-BTC/ABS framework. The MB removal efficiency for solutions with concentrations of 10 and 5 mg/L was 93.3% and 98.3%, respectively, within 10 min. After MB adsorption, the Cu-BTC/ABS composite can easily be recovered without the need for centrifugation or filtration and the composite is reusable. In addition the ABS framework can be recovered for subsequent reuse. A significant advantage of 3D-printed frameworks is that different frameworks can be easily fabricated to meet the needs of different applications. This is a promising strategy to synthesize new frameworks using MOFs and polymers to develop materials for applications beyond adsorption. PMID:25089616

Wang, Zongyuan; Wang, Jiajun; Li, Minyue; Sun, Kaihang; Liu, Chang-jun

2014-01-01

19

Three-dimensional Printed Acrylonitrile Butadiene Styrene Framework Coated with Cu-BTC Metal-organic Frameworks for the Removal of Methylene Blue  

NASA Astrophysics Data System (ADS)

Three-dimensional (3D) printing was applied for the fabrication of acrylonitrile butadiene styrene (ABS) framework. Functionalization of the ABS framework was then performed by coating of porous Cu-BTC (BTC = benzene tricarboxylic acid) metal-organic frameworks on it using a step-by-step in-situ growth. The size of the Cu-BTC particles on ABS was ranged from 200 nm to 900 nm. The Cu-BTC/ABS framework can take up most of the space of the tubular reactor that makes the adsorption effective with no need of stirring. Methylene blue (MB) can be readily removed from aqueous solution by this Cu-BTC/ABS framework. The MB removal efficiency for solutions with concentrations of 10 and 5 mg/L was 93.3% and 98.3%, respectively, within 10 min. After MB adsorption, the Cu-BTC/ABS composite can easily be recovered without the need for centrifugation or filtration and the composite is reusable. In addition the ABS framework can be recovered for subsequent reuse. A significant advantage of 3D-printed frameworks is that different frameworks can be easily fabricated to meet the needs of different applications. This is a promising strategy to synthesize new frameworks using MOFs and polymers to develop materials for applications beyond adsorption.

Wang, Zongyuan; Wang, Jiajun; Li, Minyue; Sun, Kaihang; Liu, Chang-Jun

2014-08-01

20

Three-dimensional Printed Acrylonitrile Butadiene Styrene Framework Coated with Cu-BTC Metal-organic Frameworks for the Removal of Methylene Blue  

PubMed Central

Three-dimensional (3D) printing was applied for the fabrication of acrylonitrile butadiene styrene (ABS) framework. Functionalization of the ABS framework was then performed by coating of porous Cu-BTC (BTC = benzene tricarboxylic acid) metal-organic frameworks on it using a step-by-step in-situ growth. The size of the Cu-BTC particles on ABS was ranged from 200?nm to 900?nm. The Cu-BTC/ABS framework can take up most of the space of the tubular reactor that makes the adsorption effective with no need of stirring. Methylene blue (MB) can be readily removed from aqueous solution by this Cu-BTC/ABS framework. The MB removal efficiency for solutions with concentrations of 10 and 5?mg/L was 93.3% and 98.3%, respectively, within 10?min. After MB adsorption, the Cu-BTC/ABS composite can easily be recovered without the need for centrifugation or filtration and the composite is reusable. In addition the ABS framework can be recovered for subsequent reuse. A significant advantage of 3D-printed frameworks is that different frameworks can be easily fabricated to meet the needs of different applications. This is a promising strategy to synthesize new frameworks using MOFs and polymers to develop materials for applications beyond adsorption. PMID:25089616

Wang, Zongyuan; Wang, Jiajun; Li, Minyue; Sun, Kaihang; Liu, Chang-jun

2014-01-01

21

Butadiene-acrylonitrile elastomers as PVC modifiers  

Microsoft Academic Search

Purpose: The purpose of the paper is to present the results of research programme on influence of acrylonitrile- butadiene copolymers on plasticized polyvinylchloride compounds used as window gasket material. Design\\/methodology\\/approach: Short review concerning application of modified plasticized PVC compounds as gasket material was presented. In experimental part two types of acrylonitrile-butadiene copolymers were used as elastomeric plasticizers for PVC. Formulations

M. Rojek; J. Stabik

22

Improvement in the etching performance of the acrylonitrile-butadiene-styrene resin by MnO2-H3PO4-H2SO4 colloid.  

PubMed

The present study aimed to evaluate the surface etching of the acrylonitrile-butadiene-styrene (ABS) resin in the MnO2-H3PO4-H2SO4 colloid. To enhance the soluble Mn(IV) ion concentration and improve the etching performance of ABS resin, H3PO4 was added as a complexing agent into the MnO2-H2SO4 etching system. The effects of the H2SO4 concentration and etching time on the surface topography, surface roughness, adhesion strength, and the surface chemistry of the ABS substrates were investigated. The optimal oxidation potentials of MnO2 in the colloids decreased from 1.426 to 1.369 V with the addition of H3PO4. Though the etching conditions changed from 70 °C for 20 min to 60 °C for 10 min, the adhesion strength between the ABS substrates and electroless copper film increased from 1.19 to 1.33 KN/m after etching treatment. This could be attributed to the significant increase of the soluble Mn(IV) ion concentration in the MnO2-H3PO4-H2SO4 colloid. The surface chemistry results demonstrated that the oxidation reaction of -C?C- bonds in the polybutadiene phase was accelerated in the etching process by the addition of H3PO4, and the abundant -COOH and -OH groups were formed rapidly on the ABS surface with the etching treatment. These results were in agreement with the results of surface scanning electron microscopic observations and adhesion strength measurement. The results suggested that the MnO2-H3PO4-H2SO4 colloid was an effective surface etching system for the ABS surface roughness. PMID:23611532

Zhao, Wenxia; Ding, Jie; Wang, Zenglin

2013-05-21

23

Complex phase separation in poly(acrylonitrile-butadiene-styrene)-modified epoxy/4,4'-diaminodiphenyl sulfone blends: generation of new micro- and nanosubstructures.  

PubMed

The epoxy system containing diglycidyl ether of bisphenol A and 4,4'-diaminodiphenyl sulfone is modified with poly(acrylonitrile-butadiene-styrene) (ABS) to explore the effects of the ABS content on the phase morphology, mechanism of phase separation, and viscoelastic properties. The amount of ABS in the blends was 5, 10, 15, and 20 parts per hundred of epoxy resin (phr). Transmission electron microscopy (TEM) and scanning electron microscopy (SEM) were employed to investigate the final morphology of ABS-modified epoxy blends. Scanning electron microscopic studies of 15 phr ABS-modified epoxy blends reveal a bicontinuous structure in which both epoxy and ABS are continuous, with substructures of the ABS phase dispersed in the continuous epoxy phase and substructures of the epoxy phase dispersed in the continuous ABS phase. TEM micrographs of 15 phr ABS-modified epoxy blends confirm the results observed by SEM. TEM micrographs reveal the existence of nanosubstructures of ABS in 20 phr ABS-modified epoxy blends. To the best of our knowledge, to date, nanosubstructures have never been reported in any epoxy/thermoplastic blends. The influence of the concentration of the thermoplastic on the generated morphology as analyzed by SEM and TEM was explained in detail. The evolution and mechanism of phase separation was investigated in detail by optical microscopy (OM) and small-angle laser light scattering (SALLS). At concentrations lower than 10 phr the system phase separates through nucleation and growth (NG). However, at higher concentrations, 15 and 20 phr, the blends phase separate through both NG and spinodal decomposition mechanisms. On the basis of OM and SALLS, we conclude that the phenomenon of complex substructure formation in dynamic asymmetric blends is due to the combined effect of hydrodynamics and viscoelasticity. Additionally, dynamic mechanical analysis was carried out to evaluate the viscoelastic behavior of the cross-linked epoxy/ABS blends. Finally, apparent weight fractions of epoxy and ABS components in epoxy- and ABS-rich phases were evaluated from T(g) analysis. PMID:19331324

Jyotishkumar, P; Koetz, Joachim; Tiersch, Brigitte; Strehmel, Veronika; Ozdilek, Ceren; Moldenaers, Paula; Hässler, Rudiger; Thomas, Sabu

2009-04-23

24

Crude butadiene to styrene process  

SciTech Connect

One of the natural by-products of ethylene manufacture is a mixture of C4`s containing butadiene, butenes and butane. This C4 stream is the predominant feed stock for producing pure butadiene by an extraction process. The demand growth for ethylene far exceeds that for butadiene resulting in a world wide surplus of butadiene. The ethylene producer has a number of options available to process the crude C4 stream if the market price does not justify isolation of the pure butadiene. The first option is recycle the crude C4 stream back to the ethylene cracker and co-crack with fresh feed. A second option that has become popular in the last few years has been the partial or complete hydrogenation of the butadiene and butenes in the crude C4 stream. Partial or selective hydrogenation is preferred when there is a market for iso-butene which finds use in MTBE manufacture. Full hydrogenation is used when cracker feed stock is limited, there is excess hydrogen and no cost effective outlets exist for butenes. Full hydrogenation produces butanes that are excellent crack feed stock. Both selective and full hydrogenation require low to moderate capital expenditure. Both of these options are currently being practiced to remove excess butadiene from the market. The crude C4 to styrene process developed by Dow offers an attractive, high value alternative to an olefins producer. This process selectively upgrades butadiene in C4 streams to styrene monomer and produces raffinate-1 as a by-product. The process is currently being operated at the 18--40 lb/hr scale in a Dow Texas pilot plant.

Dixit, R.S.; Murchison, C.B. [Dow Chemical Co., Midland, MI (United States)

1994-12-31

25

Comparison of sodium naphthenate and air-ionization corona discharge as surface treatments for the ethylene-tetrafluoroethylene polymer (ETFE) to improve adhesion between ETFE and acrylonitrile-butadiene-styrene polymer (ABS) in the presence of a cyanoacrylate adhesive (CAA)  

NASA Astrophysics Data System (ADS)

This study compares two ethylene-tetrafluoroethylene (ETFE) surface activation treatments, namely chemical attack with a solution of sodium naphthenate and plasma erosion via air-ionization corona discharge in order to improve the adhesive properties of the ETFE. An experimental design was prepared for both treatments in order to assess the effect of the treatment characteristics on the tensile load needed to break the bond between the ETFE and the acrylonitrile-butadiene-styrene polymer (ABS) formed with a cyanoacrylate adhesive (CAA) applied between them. The reason for the selection of this problem is that both polymers are frequently used in the biomedical industry for their properties, and they need to be joined firmly in biomedical devices, and the cyanoacrylate adhesive is the adhesive traditionally used for fluoropolymers, in this case the ETFE, and the same CAA has also shown good adhesion with ABS. However, the strength of the bond for the triplet ETFE-CAA-ABS has not been reported and the improvement of the strength of the bond with surface treatments is not found in scholarly journals for modern medical devices such as stents and snares. Both treatments were compared based on the aforementioned design of experiments. The case where ETFE receives no surface treatment serves as the reference. The results indicated that the three factors evaluated (initial drying of the material, temperature of the chemical bath, and immersion time), and their interactions have no significant effect over the tensile load at failure (tensile strength) of the adhesive bond being evaluated. For the air-ionization corona discharge treatment, two factors were evaluated: discharge exposition time and air pressure. The results obtained from this experimental design indicate that there is no significant difference between the levels of the factors evaluated. These results were unexpected as the ranges used were representative of the maximum ranges permissible in manufacturing operations. As for the comparison of the treatments, it was determined that the treatments have statistically significant differences. It was also determined that there is a significant statistical difference between the processes where a surface treatment is performed and the process where no surface treatment is applied to the ETFE. The chemical treatment results in a higher tensile load at failure (tensile strength) of 276.6 N on average, the air ionization treatment has an average of 248.4 N, and the process with no treatment has the lower ultimate tensile strength average of 53 N. This comparison has demonstrated that the best treatment is the chemical treatment with sodium naphthenate under the conditions tested.

Lucía Johanning-Solís, Ana; Stradi-Granados, Benito A.

2014-09-01

26

A study of the kinetics of radiational graft polymerization of acrylic monomers on a butadiene-styrene thermoelastomer  

Microsoft Academic Search

1.The kinetics of radiochemical grafting of acrylonitrile and acrylic acid to a butadiene-styrene thermoelastomer have been studied by irradiating a material impregnated with the monomer; it has been shown that kinetic chain rupture in such systems is a monomolecular process.2.The rate constant for propagation of the graft polyacrylonitrile chain and the activation energy for grafting have been calculated, the values

V. F. Timofeeva; G. G. Ryabchikova; A. K. Pikaev; V. I. Spitsyn

1982-01-01

27

Morphology and properties of miktoarm star styrene-butadiene rubber  

Microsoft Academic Search

In order to obtain the optimized structure rubber, a novel miktoarm star styrene-butadiene rubber (MS-SBR) was initiated by\\u000a a multifunctional macromolecular initiator with polydiene arm and Sn-C bond. The properties of MS-SBR were investigated with\\u000a respect to the morphology, mechanical properties, and dynamic viscoelasticity in comparison with those of the blends, natural\\u000a rubber (NR)\\/star styrene-butadiene random rubber(S-SBR) blend rubber and

Haiyan Zhang; Yong Ke; Kejing Yu; Xingying Zhang

2011-01-01

28

Characterization and development of new hydrogenated acrylonitrile-butadiene rubber blends  

NASA Astrophysics Data System (ADS)

Characteristics were determined for hydrogenated acrylonitrile-butadiene rubber (HNBR), which is a copolymer of butadiene and acrylonitrile made from hydrogenation of the diene segment in acrylonitrile rubber. There was close attention given to the glass transition behavior of HNBR and its tendency to crystallize in the quiescent and in stretching state. The glass transition behavior in HNBR was similar to that of other ethylene copolymers such as for example ethylene vinyl-acetate etc. The crystallinity in HNBR at high acrylonitrile content was due to alternating sequence of acrylonitrile and hydrogenated trans-1,4 butadiene rubber. Furthermore, the structure of HNBR does not have any effect on it rheological properties at the temperature investigated. HNBR exhibits a zero shear viscosity. It is common knowledge that most polymers are immiscible. However, over the years scientists have found numerous miscible polymers. On that basis we investigated miscibility between HNBR with ethylenic copolymers, chlorinated polymers, diene polymers, and hydrogenated acrylonitrile-butadiene rubber. HNBR is miscible with high chlorine content chlorinated polymers like chlorinated polyethylene (42% Cl), chlorosulfonated polyethylene (43% Cl), PVC and CPVC. We have also developed dynamically vulcanized blends of HNBR with polychloroprene, epoxydized natural rubber, chlorobutyl, and carboxylated acrylonitrile-butadiene copolymer. Most of the blends at 75/25 composition have promising properties.

Severe, Geralda

29

Adhesion of Styrene-Butadiene Rubbers with Different Silica Content  

Microsoft Academic Search

The influence of silica content of four styrene-butadiene rubbers on their adhesion to polyurethane adhesives was studied. Untreated rubber shows no adhesion due to a weak boundary layer of zinc stearate. Roughening removed zinc stearate from the rubber surface, increased the surface energy and produced surface roughness, so improved adhesion was obtained. The adhesion increased as the silica content in

A. Torró-Palau; J. C. Fernández-García; A. C. Orgilés-Barceló; J. M. Martín-Martínez

1996-01-01

30

Recycling of Chrome Tanned Leather Dust in Acrylonitrile Butadiene Rubber  

NASA Astrophysics Data System (ADS)

Concerns on environmental waste problem caused by chrome tanned leather wastes in huge amount have caused an increasing interest in developing this wastes in many composite formation. This leather dust was used as filler in acrylonitrile butadiene rubber (NBR) before treatment and after treatment with ammonia solution and sod. formate. Different formulations of NBR/ leather dust (untreated-treated with ammonia solution—treated with sod. formate) composites are prepared. The formed composite exhibit a considerable improvement in some of their properties such as rheometric characteristics especially with composites loaded with treated leather dust. Tensile strength, modulus at 100% elongation, hardness and youngs modulus were improved then by further loading start to be steady or decrease. Cross linking density in toluene were increased by incorporation of leather dust treated or untreated resulting in decreases in equilibrium swelling. Distinct increase in the ageing coefficient of both treated and untreated leather with drop in NBR vulcanizates without leather dust. Addition of leather dust treated or untreated exhibit better thermal stability.

El-Sabbagh, Salwa H.; Mohamed, Ola A.

2010-06-01

31

The Effect of Styrene-Butadiene-Styrene Modification on the Characteristics and Performance of Bitumen  

Microsoft Academic Search

Summary.  In order to cover the effect of styrene-butadiene-styrene (SBS) modification on the characteristics of bitumen, two types of bitumen, one plain bitumen, and one polymer modified bitumen\\u000a produced with the plain bitumen as base material were characterized in terms of chemical composition, microstructure, micromechanical\\u000a properties, and thermoanalytical behavior. In order to determine the complex chemical composition of bitumen, elemental analysis,

Klaus Stangl; Andreas Jäger; Roman Lackner

2007-01-01

32

Blends of styrene–butadiene–styrene tri-block copolymer\\/polyaniline—Characterization by SAXS  

Microsoft Academic Search

The electrically conductive elastomer blends based on styrene–butadiene–styrene (SBS) tri-block copolymer and polyaniline–dodecylbenzene sulfonic acid (PANI.DBSA) were prepared by two methods, namely, melt mixing and in situ polymerization of aniline in the presence of SBS. The influence of composition and synthetic methods on the properties of SBS\\/PANI has been studied. SBS\\/PANI blends are characterized for physico-mechanical properties such as density,

Fernando G. Souza; B. G. Soares; Siddaramaiah; A. Manjunath; R. Somashekar

2008-01-01

33

Submicron Ion-Exchange Fibers of Polystyrene and Styrene-Butadiene-Styrene Copolymer Blends  

Microsoft Academic Search

In the present study, submicron ion-exchange fibers (IEF) of polystyrene (PS) and its blends with styrene-butadiene-styrene block copolymer (SBS) were prepared by electrospinning and post-sulfonating modification. Scanning electron microscopy (SEM) images showed that the diameters of the fibers enlarged significantly after treatment and the surfaces become rougher. Mechanical properties analysis showed that the electrospun fibers (EF) and the IEFs from

Shu-Qin Feng; Xin-Yuan Shen; Ya-Li Ji

2011-01-01

34

Weak Boundary Layers in Styrene-Butadiene Rubber  

Microsoft Academic Search

In this paper two kinds of weak boundary layers (WBL) in synthetic vulcanized styrene-butadiene rubber are described.i) WBL produced by the presence of antiadhesion compounds of the rubber formulation (zinc stearate, microcrystalline paraffin wax). These WBL cannot be effectively removed by solvent wiping, whether followed by washing with an ethanol\\/water mix or not. Although this treatment allowed a significant removal

M. M. Pastor-Blas; M. S. Sánchez-Adsuar; J. M. Martín-Martínez

1995-01-01

35

40 CFR 63.500 - Back-end process provisions-carbon disulfide limitations for styrene butadiene rubber by emulsion...  

Code of Federal Regulations, 2010 CFR

...Back-end process provisions-carbon disulfide limitations for styrene butadiene rubber...Back-end process provisions—carbon disulfide limitations for styrene butadiene rubber...operate the process such that the carbon disulfide concentration in each crumb dryer...

2010-07-01

36

Study on the thermal stability of styrene butadiene rubber nanocomposites  

NASA Astrophysics Data System (ADS)

This study aims to investigate the thermal stability of the styrene butadiene rubber (SBR) nanocomposites containig surface modified calcium carbonate (MCC). All nanocomposites were produced at various nanofiller contents, utilizing a laboratory scale two-roll mill. The thermal stability parameters including initial decomposing temperature, temperature at maximum rate of weight loss, and char content of the MCC/SBR nanocomposites were then compared. It was found that by increasing the filler content, the decomposition temperature of MCC/SBR nanocomposites increases. Furthermore, the char content at high temperatures rises by increasing nanofiller content.

Saeb, M. R.; Chenari, T. N.; Parast, O. Yazdan; Jafari, B.; Asadi, H.; Safari, M. Arfavi; Holisaz, H.

2012-07-01

37

Compatibility Investigation of Microwave Irradiated Acrylonitrile Butadiene\\/Ethylene Propylene Diene Rubber Blends  

Microsoft Academic Search

The physicomechanical properties, infrared spectra, and dielectric relaxations of acrylonitrile butadiene\\/ethylene propylene diene rubber (NBR\\/EPDM) blends with different compositions were studied. Microwave irradiation with different powers and different exposing time was used to improve the compatibility of such blends. The structure of NBR, EPDM, and NBR\\/EPDM blends before and after exposing to microwave irradiation were characterized by Fourier transform infrared–attenuated

S. L. Abd-El-Messieh; D. E. El-Nashar; M. G. Khafagi

2004-01-01

38

Computation of Mechanical Properties of a Poly(Styrene-Butadiene-Styrene) Copolymer using a Mixed Finite Element Approach  

Microsoft Academic Search

Despite of several decades of research, the nature of linear elasticity in microphase-separated copolymers with chemically connected glass-rubber phases is still not fully understood. In this presentation we discuss the results of an investigation of the linear elastic properties of a poly-(styrene-butadiene-styrene) triblock copolymer using a mixed finite element approach. The technique permits to deal with phases of full incompressibility

Stephan A. Baeurle; Glenn H. Fredrickson; Andrei A. Gusev

2004-01-01

39

Prediction of Elastic Properties of a Poly(styrene?butadiene?styrene) Copolymer Using a Mixed Finite Element Approach  

Microsoft Academic Search

Despite several decades of research, the nature of linear elasticity in microphase-separated copolymers with chemically connected glass-rubber phases is still not fully understood. In this paper we investigate the linear elastic properties of a poly(styrene-butadiene-styrene) triblock copolymer using a mixed finite element approach. The technique permits phases of full incompressibility as well as phases of near incompressibility as they occur

Stephan A. Baeurle; Glenn H. Fredrickson; Andrei A. Gusev

2004-01-01

40

Influence of the styrene content of thermoplastic styrene–butadiene rubbers in the effectiveness of the treatment with sulfuric acid  

Microsoft Academic Search

Three thermoplastic block styrene–butadiene–styrene (TR) rubbers were treated with sulfuric acid to improve their adhesion to polyurethane adhesives. T-peel test, scanning electron microscopy (SEM), contact-angle measurements (water, ethane diol), infra red spectroscopy (ATR-IR) and stress–strain experiments were used to analyze the nature of surface modifications produced in the rubber. The length of the treatment and the neutralization procedure (with and

Carmen M Cepeda-Jiménez; M Mercedes Pastor-Blas; T. P Ferrándiz-Gómez; J. M Mart??n-Mart??nez

2001-01-01

41

Analysis of styrene-butadiene-styrene polymer modified bitumen using fluorescent microscopy and conventional test methods.  

PubMed

This paper presents a laboratory study of modified bitumen containing styrene-butadiene-styrene (SBS) copolymer. Polymer modified bitumen (PMB) samples have been produced by mixing a 50/70 penetration grade unmodified (base) bitumen with SBS Kraton D1101 copolymer at five different polymer contents. The fundamental characteristics of the SBS PMB samples have been determined using conventional methods. The morphology of the samples as well as the percent area (%) distribution of SBS polymers throughout the base bitumen have been characterized and determined by means of fluorescence microscopy and Qwin Plus image analysis program, respectively. The mechanical properties of the hot-mix asphalt (HMA) containing SBS PMBs have also been analyzed and compared with HMA incorporating base bitumen. The effect of polymer addition on the short and long term aging characteristics of HMA have been evaluated by indirect tensile strength (ITS) test. The results indicated that polymer modification improved the conventional properties (penetration, softening point, etc.) and the mechanical properties (Marshall, ITS, etc.) of the base bitumen. It was also concluded that at low polymer contents, the samples revealed the existence of dispersed polymer particles in a continuous bitumen phase, whereas at high polymer contents a continuous polymer phase has been observed. Moreover, it was found out that the polymer addition minimizes the short and long term aging of HMA. PMID:17544580

Sengoz, Burak; Isikyakar, Giray

2008-01-31

42

Radiation-induced crosslinking of poly(styrene-butadiene-styrene) block copolymers and their sulfonation  

NASA Astrophysics Data System (ADS)

Several crosslinked poly(styrene-butadiene-styrene) (c-SBS) block copolymer films were prepared using a gamma ray or electron beam with various irradiation doses and the prepared c-SBS film was then subjected to sulfonation using a chlorosulfonic acid (CSA) solution to introduce a sulfonic acid group. To estimate the degree of crosslinking, the gel fractions and FT-IR spectra of the c-SBS films were used and the results indicate that the degree of crosslinking is increased with an increase in the radiation dose. The surface morphology and mechanical property of the c-SBS films were observed using SEM and UTM instruments, respectively. The sulfonated c-SBS films were investigated by measuring the ion exchange capacity (IEC) and by observing the cross-sectional distribution patterns of sulfonic acid group using an SEM-EDX instrument. The IEC and SEM-EDX studies indicate that the sulfonated c-SBS membranes can be successfully prepared through the radiation crosslinking of the SBS film and the subsequent sulfonation with a diluted CSA solution.

Lee, Sun-Young; Song, Ju-Myung; Sohn, Joon-Yong; Shul, Yong-Gun; Shin, Junhwa

2013-12-01

43

Application of Lignin as Antioxidant in Styrene Butadiene Rubber Composite  

NASA Astrophysics Data System (ADS)

Lignin isolated from enzymatic hydrolyzed cornstalks (EHL) is a renewable natural polymer, and rubber is one of the most important polymer materials. The application of EHL in rubber industry is of great significance. The influence of EHL and antioxidant RD on the vulcanizing characteristics, thermal oxidative aging stability under free condition, and water extraction resistance of styrene-butadiene rubber (SBR) were investigated. The effect of EHL/antioxidant D composite antioxidant on the thermal oxidative ageing of SBR was also evaluated. Results showed that the protection of SBR from thermal oxidative aging by EHL/antioxidant D composite antioxidant was superior to that of antioxidant D. This is because EHL molecules have hindered phenol group and have excellent auxiliary antioxidant role with antioxidant D. Moreover, the influence of EHL on the vulcanizing characteristics of SBR compounds was better than that of antioxidant RD, and EHL can reduce the cure rate and increase the optimum cure time. It is because that the EHL molecules have hindered phenol group and methoxy group, which can form a special structure to capture free radical and terminate the chain reaction. The retained tensile strength of SBR compounds with EHL was similar to that of the samples with antioxidant RD, while the retained elongation at break of SBR compounds with EHL was higher than that of the samples with antioxidant RD. In addition, the SBR compounds with EHL have a good water extraction resistance property, which was similar to the samples with antioxidant RD. This is because EHL have large molecular weight, good stability and low solubility in water. In conclusion, due to the low price, abundant resources, non-toxic and pollution-free, etc., EHL will have broad application prospect.

Liu, Shusheng; Cheng, Xiansu

2010-11-01

44

Barrierity of hydrogenated butadiene-acrylonitrile rubber and butyl rubber after exposure to organic solvents.  

PubMed

Resistance of antichemical clothing primarily depends on the type of material it is made from, in particular on the type of polymer used for coating the fabric carrier. This paper reports on systematic investigations on the influence of the cross-linking density of an elastomer and the composition of a cross-linked elastomer on its resistance to permeation of selected organic solvents. Tests of barrier material samples made from nonpolar butyl rubber (IIR) and polar hydrogenated butadiene-acrylonitrile rubber (HNBR) showed that (a) in rubber-solvent systems with medium thermodynamic affinity, cross-linking density influenced resistance to permeation and (b) the polarity of the system had a significant influence on barrierity. PMID:21375953

Krzemi?ska, Sylwia; Rzymski, W?adys?aw M

2011-01-01

45

Preparation and characterization of poly(3,4-ethylenedioxythiophene) (PEDOT) using partially sulfonated poly(styrene-butadiene-styrene) triblock copolymer as a polyelectrolyte  

Microsoft Academic Search

An aqueous dispersion of poly(3,4-ethylenedioxythiophene) (PEDOT) was prepared using a partially sulfonated poly(styrene-b-butadiene-b-styrene) (s-SBS) as a polyanion. For the preparation of s-SBS, poly(styrene-b-butadiene-b-styrene) was sulfonated to four different levels ranging from 44.1 to 64.8mol%. These sulfonated polymers were characterized with IR spectroscopy and 1H NMR analysis to confirm sulfonation reaction. The preparation of the PEDOT complex was carried out through

TaeYoung Kim; JongEun Kim; YunSang Kim; TaeHee Lee; WonJung Kim; Kwang S. Suh

2009-01-01

46

Kinetic study of the sulfonation of hydrogenated styrene butadiene block copolymer (HSBS)  

Microsoft Academic Search

In this work homogeneous sulfonation kinetic and both, microstructural and electrical characterizations of hydrogenated styrene butadiene block copolymer (HSBS) were studied. The incorporation of sulfonic groups was checked by infrared spectroscopy (FTIR-ATR) and the sulfonation level was determined by both, elemental analysis (E.A.) and chemical titration. Thermal behavior was studied by differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA), in

A. Navarro; C. del Río; J. L. Acosta

2007-01-01

47

Birchwood biochar as partial carbon black replacement in styrene-butadiene rubber composites  

Technology Transfer Automated Retrieval System (TEKTRAN)

Birchwood feedstock was used to make slow pyrolysis biochar that contained 89% carbon and < 2% ash. This biochar was blended with carbon black as filler for styrene-butadiene rubber. Composites made from blended fillers of 25/75 biochar/carbon black were equivalent to or superior to their 100% carbo...

48

Polymer composites prepared from heat-treated starch and styrene-butadiene latex  

Technology Transfer Automated Retrieval System (TEKTRAN)

Thermoplastic starch/latex polymer composites were prepared using styrene–butadiene (SB) latex and heat-treated cornstarch. The composites were prepared in a compression mold at 130 °C, with starch content 20%. An amylose-free cornstarch, waxy maize, was used for this research and the heat treatment...

49

Chitosan/polyanion surface modification of styrene-butadiene-styrene block copolymer membrane for wound dressing.  

PubMed

The surface of styrene-butadiene-styrene block copolymer (SBS) membrane is modified with tri-steps in this study. At first, two step modified SBS membrane (MSBS) was prepared with epoxidation and ring opening reaction with maleated ionomer. Then chitosan was used as the polycation electrolyte and sodium alginate, poly(?-glutamic acid) (PGA) and poly(aspartic acid) (PAsp) were selected as polyanion electrolytes to deposit on the surfaces of MSBS membrane by the layer-by-layer self-assembly (LbL) deposition technique to get three [chitosan/polyanion] LbL modified SBS membranes, ([CS/Alg], [CS/PGA] and [CS/PAsp]). From the quantitative XPS analysis and water contact angle measurement, it is found that the order of wettability and the content of functional group percentages of COO(-) and OCN on the three [CS/polyanion] systems are [CS/Alg]>[CS/PGA]>[CS/PAsp]. Performances of water vapor transmission rates, fibronectin adsorption, antibacterial assessment and 3T3 fibroblast cell growth on [CS/Alg], [CS/PGA] and [CS/PAsp] membranes were also evaluated. With the evaluation of water vapor transmission rate, these [CS/Alg], [CS/PGA] and [CS/PAsp] membranes are sterile semipermeable with water evaporation at about 82±8g/day·m(2). It is found that the amount of fibronectin adsorption on the three [CS/polyanion] systems is significantly determined by the sum of the functional group of COO(-) and OCN on the surfaces of [CS/Alg], [CS/PGA] and [CS/PAsp] systems. The results are inverse with the sum of the functional group of COO(-) and OCN on the three [CS/polyanion]. From the cytotoxicity test and cell adhesion and proliferation assay of 3T3 fibroblasts on the three [CS/polyanion] systems, it revealed that the cells not only remained viable but they also proliferated on the surfaces of [CS/Alg], [CS/PGA] and [CS/PAsp]. The bactericidal activity was found on [CS/Alg], [CS/PGA] and [CS/PAsp]. The transport of bacterial through these [CS/polyanion] membranes was also conducted. No bacterial transport was found. PMID:24268243

Yang, Jen Ming; Yang, Jhe-Hao; Huang, Huei Tsz

2014-01-01

50

Reprocessable ionic elastomers based on styrene-butadiene rubber  

Microsoft Academic Search

Zinc sulfonated SBR prepared by the sulfonation of styrene units in SBR, followed by the neutralization of the resultant SBR sulfonic acids, behaves as ionic thermoplastic elastomer, and shows improved physical properties compared to SBR. Studies include X-ray fluorescence analyses (XRF), FTIR spectroscopy, dynamic mechanical analyses (DMA) and measurement of physical properties.

Jacob Samuel; Kochu Baby Manjooran; Thomas Kurian

2003-01-01

51

Weak boundary layers on vulcanized styrene–butadiene rubber treated with sulfuric acid  

Microsoft Academic Search

A synthetic vulcanized styrene-butadiene rubber (R2) was used in this study. The presence of paraffin wax and zinc stearate in the rubber composition prevented the adhesion of R2 rubber to solvent-based polyester-urethane adhesive. To increase the adhesion properties of R2 rubber, a surface treatment with sulfuric acid (cyclization) was applied, and the length of the immersion in sulfuric acid and

Carmen M. Cepeda-Jiménez; M. Mercedes Pastor-Blas; José Miguel Martín-Martínez

2001-01-01

52

Historical Estimation of Exposure to 1,3Butadiene, Styrene, and Dimethyldithiocarbamate Among Synthetic Rubber Workers  

Microsoft Academic Search

Quantitative estimates of exposure to 1,3-butadiene (BD), styrene (STY), and dimethyldithiocarbamate (DMDTC) were developed for a follow-up study of workers at six North American synthetic rubber plants. Procedures entailed identifying tasks and jobs involving exposure, identifying factors influencing historical changes in exposure potential, and using mathematical models to calculate job- and time-period-specific exposures. Exposure metrics included 8-hour time-weighted average (TWA)

Maurizio Macaluso; Rodney Larson; Jeremiah Lynch; Sydney Lipton; Elizabeth Delzell

2004-01-01

53

Flame retardant brominated styrene-based polymers. II. Synthesis, characterization and application of dibromostyrene, styrene and butadiene terpolymers  

SciTech Connect

Brominated styrene-based polymers having surprisingly good physical properties in combination with flame retardancy are prepared from terpolymers of dibromostyrene, styrene and butadiene. Polymerization compositions were determined by bromine contents (% Br) of the polymers by Schoeninger Combustion Method and {sup 1}H NMR integration. Weight losses (% loss) were measured at 20{degrees}C/min by Thermogravimetric Analysis (TGA). Molecular weights were measured by GPC based on a standard molecular weight (MW) of polystyrene (PS)> Flammability of the latex products when used in textile backcoatings was testing by Motor Vehicle Safety Standard 302 (MVSS-302) flammability test. As latexes were used as non-woven binders, flammability was tested by exposure to a 4 in high, 1950{degrees}F propane flame from a Fisher Burner. When latexes were employed for carpet backing, flammability was tested by DOC. FF-1-70 (pill test) flammability tests.

Wang, J.L.; Favstritsky, N.A. [Great Lakes Chemical Corporation, West Lafayette, IN (United States)

1993-12-31

54

Enhanced photorefractive performance in CdSe quantum-dot-dispersed poly(styrene-co-acrylonitrile) polymers  

SciTech Connect

This paper reports on the enhanced photorefractive behavior of a CdSe quantum-dot-dispersed less expensive polymer of poly(styrene-co-acrylonitrile). The capability of CdSe quantum dots used as photosensitizers and the associated photorefractive performance are characterized through a photocurrent experiment and a two-beam coupling experiment, respectively. An enhanced two-beam coupling gain coefficient of 12.2 cm{sup -1} at 46 V/mum was observed owning to the reduced potential barrier. The photorefractive performance per CdSe quantum dot is three orders of magnitude higher than that in the sample sensitized by trinitrofluorenone in poly(styrene-co-acrylonitrile), and almost ten times higher than that in the CdSe quantum-dot-sensitized poly(N-vinylcarbazole) polymers.

Li Xiangping; Embden, Joel van; Chon, James W. M.; Gu Min [Centre for Micro-Photonics, Faculty of Engineering and Industrial Sciences, Swinburne University of Technology, Hawthorn, Victoria 3122 (Australia); Evans, Richard A. [CSIRO Molecular and Health Technologies, Bag 10, Clayton South, Victoria 3169 (Australia)

2010-06-21

55

Sorption and diffusion of ethanol vapor in polybutadiene\\/acrylonitrile, polybutadiene\\/styrene and polybutadiene based polyurethanes  

Microsoft Academic Search

The sorption and diffusion behavior of ethanol vapor in series of polyolefine based polyurethanes (PU) made from hydroxyl-terminated polybutadiene\\/acrylonitrile (HTBN), hydroxyl-terminated polybutadiene\\/styrene (HTBS) and hydroxyl-terminated polybutadiene (HTPB) were investigated by using the quartz-spring, DSC, FTIR and AFM. The equilibrium absorption reduced with increasing content of hard segments for all the three types of PUs. The values of the maximum absorption

Yurun Yang; Yongmin Huang; Dening Wang; Honglai Liu; Chunpu Hu

2004-01-01

56

Morphology, Thermal and Mechanical Properties of Poly (Styrene-Acrylonitrile) (SAN)\\/Clay Nanocomposites from Organic-Modified Montmorillonite  

Microsoft Academic Search

Poly (styrene-acrylonitrile) (SAN)\\/clay nanocomposites have successfully been prepared by melt intercalation method. The hexadecyl triphenyl phosphonium bromide (P16) and cetyl pyridium chloride (CPC) are used to modify the montmorillonite (MMT). The structure and thermal stability property of the organic modified MMT are, respectively characterized by Fourier transfer infrared (FT-IR) spectra, X-ray diffraction (XRD) and thermogravimetric analysis (TGA). The results indicate

Yibing Cai; Yuan Hu; Junfeng Xiao; Lei Song; Weicheng Fan; Huaxia Deng; Xinglong Gong; Zuyao Chen

2007-01-01

57

High-Energy-Density Poly(styrene-co-acrylonitrile) Thin Films  

NASA Astrophysics Data System (ADS)

The dielectric response of poly(styrene-co-acrylonitrile) (PSAN) thin films fabricated by a solution casting process was investigated in this work. Linear dielectric behavior was obtained in PSAN films under an electric field at frequencies from 100 Hz to 1 MHz and temperature of -50°C to 100°C. The polymer films exhibited an intermediate dielectric permittivity of 4 and low dielectric loss (tan ?) of 0.027. Under 400 MV/m, the energy density of the PSAN films was 6.8 J/cm3, which is three times higher than that of biaxially oriented polypropylene (BOPP) (about 1.6 J/cm3). However, their charge-discharge efficiency (about 90%) was rather close to that of BOPP. The calculated effective dielectric permittivity of the PSAN films under high electric field was as high as 9, which may be attributed to the improved displacement of the cyanide groups (-CN) polarized at high electric fields. These high-performance features make PSAN attractive for high-energy-density capacitor applications.

Wen, Fei; Xu, Zhuo; Xia, Weimin; Ye, Hongjun; Wei, Xiaoyong; Zhang, Zhicheng

2013-12-01

58

EFFECT OF PH ON THE COMPOSITE MODULUS OF SOY PROTEIN AGGREGATES AND CARBOXYLATED STYRENE-BUTADIENE LATEX  

Technology Transfer Automated Retrieval System (TEKTRAN)

Soy protein isolate (SPI) has been reported to have a significant reinforcement effect in styrene-butadiene composites prepared under alkaline condition. SPI is a soy product that remains after soybean oil and soy carbohydrates (both soluble and insoluble) are removed from soybean flakes. SPI is a...

59

Evaluation of the polymer–solvent interaction parameter ? for the system cured styrene butadiene rubber and toluene  

Microsoft Academic Search

One of the most popular cured rubbers used in industrial applications is styrene butadiene rubber (SBR) and frequently its network structure is studied by means of swelling techniques in solvent. Normally, toluene is used as solvent in this test. In order to estimate the crosslink density from the equilibrium volume fraction of rubber in the swollen state, the correct evaluation

A. J. Marzocca

2007-01-01

60

Heterogeneous sulfonation of blend systems based on hydrogenated poly(butadiene–styrene) block copolymer. Electrical and structural characterization  

Microsoft Academic Search

Conducting membranes of hydrogenated poly(butadiene–styrene) block copolymer (HPBS) were obtained by heterogeneous sulfonation and then their electrical properties were studied. In addition, the effects of PP content on the morphology of these blends, as well as their conducting properties, were considered. The degree of sulfonation was determined by means of photoelectron spectroscopy (XPS) and the structural characterization was carried out

H Bashir; A Linares; J. L Acosta

2001-01-01

61

On the form of the strain energy function for a family of SBR materials. [Styrene-Butadiene Rubber  

NASA Technical Reports Server (NTRS)

Styrene-butadiene materials with varying crosslink densities are analyzed through use of a strain energy function of the type introduced by Valanis and Landel (1967). A form of the strain energy function derived from strip biaxial tests proves to be accurate when checked against uniaxial and other biaxial test results.

Arenz, R. J.

1977-01-01

62

Laser heating effect on Raman spectra of styrene-butadiene rubber/multiwalled carbon nanotube nanocomposites  

NASA Astrophysics Data System (ADS)

The laser heating effect on MWCNTs in styrene-butadiene rubber/multiwalled carbon nanotube (SBR/MWCNT) composites were studied by Raman spectra. The intensity ratio of the D band to G band (ID/IG) of SBR/MWCNT composites largely decreased with temperature. This indicates the self-rearranging behavior of MWCNTs in the SBR/MWCNTs system during temperature increase. In addition, the temperature-dependent downward shift of the G band of SBR/MWCNT composites was smaller than that of MWCNTs samples. The self-rearrangement of MWCNTs in SBR/MWCNT composites and a mechanical compression were explained as two possible reasons for the different behavior of the G band shift.

Yan, Xinlei; Kitahama, Yasutaka; Sato, Harumi; Suzuki, Toshiaki; Han, Xiaoxia; Itoh, Tamitake; Bokobza, Liliane; Ozaki, Yukihiro

2012-01-01

63

Radiation crosslinking of styrene-butadiene rubber containing waste tire rubber and polyfunctional monomers  

NASA Astrophysics Data System (ADS)

The objective of this study was to investigate the influence of polyfunctional monomers (PFMs) and absorbed dose on the final characteristics of styrene-butadiene rubber (SBR) mixed with waste tire rubber (WTR). A series of SBR/WTR blends were prepared by varying the ratios of WTR in the presence of PFMs, namely trimethylolpropane trimethacrylate (TMPTMA) and trimethylolpropane triacrylate (TMPTA) and crosslinked using gamma rays. The physicochemical characteristics of the prepared blends were investigated. It was observed that tensile strength, hardness and gel content of the blends increased with absorbed dose while the blends containing TMPTA showed higher tensile strength, gel content and thermal stability as compared to the blends containing TMPTMA. Higher thermal stability was observed in the blends which were crosslinked by radiation as compared to the blends crosslinked by sulfur. These blends exhibited higher rate of swelling in organic solvents, whereas negligible swelling was observed in acidic and basic environment.

Yasin, Tariq; Khan, Sara; Shafiq, Muhammad; Gill, Rohama

2015-01-01

64

Effect of strain on the electrical conductivity of a styrene-butadiene rubber  

NASA Astrophysics Data System (ADS)

When the carbon black-filled rubbers are stretched, the electrical resistivity increases at lower extension ranges, and then it decreases with further extension. This complex behavior is attributed to the morphology changes of carbon black particles during extension, i.e., breaking and forming conducting paths. In this study, highly conductive carbon blacks were compounded with high styrene content SBR matrix with contents varying from 5phr, 10phr, 15phr and 20phr. All the compounds measured the electrical resistance at room temp., 40°C, 80°C, respectively. The electrical resistances are decreased as the conductive carbon blacks are higher and temperature is increased. The electrical resistivity and tensile behaviors were investigated as a function of stretching at 80°C. The conductive carbon black-filled a styrene-butadiene rubber vulcanizate showed much higher conductivity and the electrical resistivity is more stable by increase of contents. In tensile behaviors, as the contents of conductive carbon blacks increase, it shows the increase of strength.

Kim, Young Hee; Lim, Jee Young; Jose, Jobin; Kim, Jae Young; Lee, Gi-Bbeum; Gent, Alan N.; Nah, Changwoon

2010-04-01

65

Thermal and mechanical properties of styrene-butadiene rubber\\/lead oxide composites as gamma-radiation shields  

Microsoft Academic Search

Styrene-butadiene rubber\\/lead oxide composites were prepared as ?-radiation shields. The composites were prepared with three different types of lead oxide, namely lead mono-oxide (PbO), lead dioxide (PbO2) and red lead oxide (Pb3O4). Concentrations of about 87–88 wt% for the three lead oxides were used. The assessment of the linear attenuation coefficient of the SBR\\/lead oxide composites for ?-rays from different

M. M. Abdel-Aziz; S. E. Gwaily

1997-01-01

66

Peculiarities in liquid phase of Styrene Butadiene rubber surface induced by Atomic Force Microscopy-assisted electrostatic nanolithography  

Microsoft Academic Search

Nanoscale surface changes are reported for styrene butadiene rubber (SBR) films (10-100 nm) using protocol derived from Atomic Force Microscopy (AFM) electrostatic nanolithography. Under appropriate tip bias conditions, the electric field magnitude induced in SBR films is of the order of 10^8-10^9 V m-1, which is sufficiently large to initiate cross-linking in the rubber. Peaklike surface features, surrounded by a

Mindaugas Rackaitis; Sergei Lyuksyutov; Dmytro Kashyn; Pavel Paramonov; Robert Mallik

2009-01-01

67

Leukemia and exposure to 1,3-butadiene, styrene and dimethyldithiocarbamate among workers in the synthetic rubber industry  

Microsoft Academic Search

This study evaluated relations between exposure to 1,3-butadiene (BD), styrene (STY) and dimethyldithiocarbamate (DMDTC) and mortality from leukemia among synthetic rubber industry workers. Subjects were 13?130 men employed for at least 1 year during 1943–1991 at any of six plants that manufactured synthetic rubber. Death certificates and medical records identified workers with leukemia. Cumulative exposure estimates were based on plant-

Elizabeth Delzell; Maurizio Macaluso; Nalini Sathiakumar; Robert Matthews

2001-01-01

68

Effect of concentration and humidity on the formation of porous polymer films using Styrene Butadiene Co-Polymer  

NASA Astrophysics Data System (ADS)

Honeycomb structured porous materials from complex polymers are formed using water droplet templating method. In the present work microporous films were prepared from styrene butadiene rubber (SBR) using emulsion technique. The pore sizes can be easily tuned by changing the concentration and the humidity condition. The pore size is characterized by optical microscope and Scanning electron microscope (SEM). These films can be used for various applications in optoelectronics, photonics, catalysis, tissue engineering, bioanalytical purposes etc.

Jose, Renu; Sujith, A.; Predeep, P.

2011-10-01

69

About the cure kinetics in natural rubber/styrene Butadiene rubber blends at 433 K  

NASA Astrophysics Data System (ADS)

Vulcanized blends of elastomers are employed in several goods mainly to improve physical properties and reduce costs. One of the most used blends of this kind is that composed by natural rubber (NR) and styrene butadiene rubber (SBR). The cure kinetic of these blends depends mainly on the compound formulation and the cure temperature and time. The preparation method of the blends can influence the mechanical properties of the vulcanized compounds. In this work the cure kinetic at 433 K of NR/SBR blends vulcanized with the system sulfur/TBBS (N-t-butyl-2-benzothiazole sulfenamide) is analyzed in samples prepared by mechanical mixing and solution blending. The two methods produce elastomer domains of NR and SBR, which present different microstructure due to the cure level attained during vulcanization. The cure kinetics is studied by means of rheometer tests and the model proposed by Kamal and Sourour. The analysis of the cure rate is presented and is related to the structure obtained during the vulcanization process.

Mansilla, M. A.; Marzocca, A. J.

2012-08-01

70

Performance of Styrene Butadiene Rubber as a Concrete Repair Material in tropical climate  

NASA Astrophysics Data System (ADS)

Deterioration of Concrete due to variety of reasons like corrosion of steel, inferior quality of materials as well as workmanship and exposure to aggressive environment like thermal cycling affect the performance or damage a number of Reinforced cement concrete structures. In order to repair these structures for enhancing the service life, number of methods and materials are available. But the degree of success of any repair in concrete depends mainly on the correct choice and the method of application of repair materials. This paper discusses the details of an experimental investigation on the performance of Styrene ñ Butadiene Rubber (SBR) as a concrete repair material in tropical climatic conditions. Resistance to water penetration and tensile cracking are two important performance criteria for any repair material. Cement mortar cubes of mix proportion 1:3 with SBR added at the rate of 20% of the weight of cement, and control specimens without SBR were made. Compressive strength and sorptivity values of the cubes were determined. Shear Bond strength (by slant shear test) and splitting tensile strength of the repaired cylinder specimens of standard dimensions, in which SBR used as a bonding agent were determined. These values were compared with the values obtained for the similar specimens, in which the bonding agent applied was conventional cement slurry. The influence of thermal cycling on the properties of repaired concrete specimens were also studied. A comparison has also been made with the values required to meet the standard specifications of a repair material.

Radhakrishnan, R.; Prakash, V. Syam; Thampan, C. K.; Varma, Prasad

2012-11-01

71

Cavitation in Filled Styrene-butadiene Rubber: A Real Time SAXS Observation  

NASA Astrophysics Data System (ADS)

Cavitation of filled and unfilled elastomers under confinement at the macroscopic scale has been experimentally reported and theoretically modeled. However, cavitation occurring at the nanometer length scale has not yet been demonstrated conclusively in rubbers. Real time SAXS with synchrotron radiation was employed to probe the structure changes in carbon black filled styrene-butadiene rubber (SBR) under uniaxial loading. The scattering invariant was calculated and increased sharply at a critical extension depending on both filler content and crosslinking density around q = 0.1 nm-1, which we attributed to the formation of voids. At very large strains, a sharp and wide streak developed perpendicular to the tensile axis in reciprocal space, suggesting the deformation of the voids in elliptical voids along the tensile direction. In step cycle test, we observed that voids only appeared when the current strain exceeded the maximum historical strain (Mullins effect) and attributed the increase of the scattering invariant outside the Mullins region to the creation of new voids rather than to the reopening of old ones.

Zhang, Huan; Scholz, Arthur K.; Vion-Loisel, Fabien; Kramer, Edward J.; Creton, Costantino

2011-03-01

72

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

Code of Federal Regulations, 2013 CFR

...IVB, V, VIB, (except bottles intended to hold carbonated beverages), VIIA, VIIB, VIII and IX, under conditions of...section are not authorized to be used to fabricate beverage containers. [42 FR 14572, Mar. 15,...

2013-04-01

73

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

Code of Federal Regulations, 2010 CFR

...IVB, V, VIB, (except bottles intended to hold carbonated beverages), VIIA, VIIB, VIII and IX, under conditions of...section are not authorized to be used to fabricate beverage containers. [42 FR 14572, Mar. 15,...

2010-04-01

74

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

Code of Federal Regulations, 2011 CFR

...IVB, V, VIB, (except bottles intended to hold carbonated beverages), VIIA, VIIB, VIII and IX, under conditions of...section are not authorized to be used to fabricate beverage containers. [42 FR 14572, Mar. 15,...

2011-04-01

75

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

...IVB, V, VIB, (except bottles intended to hold carbonated beverages), VIIA, VIIB, VIII and IX, under conditions of...section are not authorized to be used to fabricate beverage containers. [42 FR 14572, Mar. 15,...

2014-04-01

76

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

Code of Federal Regulations, 2012 CFR

...IVB, V, VIB, (except bottles intended to hold carbonated beverages), VIIA, VIIB, VIII and IX, under conditions of...section are not authorized to be used to fabricate beverage containers. [42 FR 14572, Mar. 15,...

2012-04-01

77

Strengthening acrylonitrile-butadiene-styrene (ABS) with nano-sized and micron-sized calcium carbonate  

Microsoft Academic Search

ABS was reinforced by both micron-sized (MCC) and nano-sized precipitated calcium carbonate (NPCC) particles through melt compounding. The MCC\\/ABS composites were found to have higher modulus but lower tensile and impact strength than neat ABS. In contrast, NPCC increased modulus of ABS whilst maintained or even increased its impact strength for a certain NPCC loading range. SEM examinations revealed that

L. Jiang; Y. C. Lam; K. C. Tam; T. H. Chua; G. W. Sim; L. S. Ang

2005-01-01

78

21 CFR 177.1040 - Acrylonitrile/styrene copoly-mer.  

Code of Federal Regulations, 2011 CFR

...for 2 h.1 Minimum 10 pct solution viscosity at 25 °C (77 °F) is 10cP. 1 ...average molecular weight, and solution viscosity, titled: “Determination of Residual Acrylonitrile...Analytical Method for 10% Solution Viscosity of Tyril,” which are...

2011-04-01

79

21 CFR 177.1040 - Acrylonitrile/styrene copoly-mer.  

Code of Federal Regulations, 2012 CFR

...for 2 h.1 Minimum 10 pct solution viscosity at 25 °C (77 °F) is 10cP. 1 ...average molecular weight, and solution viscosity, titled: “Determination of Residual Acrylonitrile...Analytical Method for 10% Solution Viscosity of Tyril,” which are...

2012-04-01

80

21 CFR 177.1040 - Acrylonitrile/styrene copoly-mer.  

...for 2 h.1 Minimum 10 pct solution viscosity at 25 °C (77 °F) is 10cP. 1 ...average molecular weight, and solution viscosity, titled: “Determination of Residual Acrylonitrile...Analytical Method for 10% Solution Viscosity of Tyril,” which are...

2014-04-01

81

21 CFR 177.1040 - Acrylonitrile/styrene copoly-mer.  

Code of Federal Regulations, 2013 CFR

...for 2 h.1 Minimum 10 pct solution viscosity at 25 °C (77 °F) is 10cP. 1 ...average molecular weight, and solution viscosity, titled: “Determination of Residual Acrylonitrile...Analytical Method for 10% Solution Viscosity of Tyril,” which are...

2013-04-01

82

21 CFR 177.1050 - Acrylonitrile/styrene copoly-mer modified with butadiene/styrene elastomer.  

Code of Federal Regulations, 2012 CFR

...limitations. The following extractives limitations are determined by an infrared spectro-photo-metric method titled “Infrared Spectro-photo-metric Determination of Polymer Extracted from Borex ® 210 Resin Pellets,” which...

2012-04-01

83

21 CFR 177.1050 - Acrylonitrile/styrene copoly-mer modified with butadiene/styrene elastomer.  

...limitations. The following extractives limitations are determined by an infrared spectro-photo-metric method titled “Infrared Spectro-photo-metric Determination of Polymer Extracted from Borex ® 210 Resin Pellets,” which is...

2014-04-01

84

21 CFR 177.1050 - Acrylonitrile/styrene copoly-mer modified with butadiene/styrene elastomer.  

Code of Federal Regulations, 2013 CFR

...limitations. The following extractives limitations are determined by an infrared spectro-photo-metric method titled “Infrared Spectro-photo-metric Determination of Polymer Extracted from Borex ® 210 Resin Pellets,” which...

2013-04-01

85

21 CFR 177.1050 - Acrylonitrile/styrene copoly-mer modified with butadiene/styrene elastomer.  

Code of Federal Regulations, 2010 CFR

...limitations. The following extractives limitations are determined by an infrared spectro-photo-metric method titled “Infrared Spectro-photo-metric Determination of Polymer Extracted from Borex ® 210 Resin Pellets,” which...

2010-04-01

86

21 CFR 177.1050 - Acrylonitrile/styrene copoly-mer modified with butadiene/styrene elastomer.  

Code of Federal Regulations, 2011 CFR

...limitations. The following extractives limitations are determined by an infrared spectro-photo-metric method titled “Infrared Spectro-photo-metric Determination of Polymer Extracted from Borex ® 210 Resin Pellets,” which...

2011-04-01

87

Temperature dependence on free volume in cured natural rubber and styrene-butadiene rubber blends  

NASA Astrophysics Data System (ADS)

A systematic study on the evolution of free volume as a function of the temperature in vulcanized at 433 K natural rubber (NR) and styrene butadiene rubber (SBR) in 25-75, 50-50, 75-25 NR-SBR (percent content of pure NR and SBR, respectively) blends was studied by positron annihilation lifetime spectroscopy. All samples were prepared with sulfur and TBBS (n-t-butyl-2-benzothiazole sulfenamide) as accelerator. The glass transition temperatures of the samples studied were determined by differential scanning calorimetry (DSC) and from lifetime data. In general, a sigmoidal-like complex behavior of the long-lived lifetime component, linked to the nanohole free volume, as a function of the temperature was found. For SBR, the slope of the ortho-positronium lifetime against temperature curves could be well-fitted using a linear function. For blends and also for NR, two different linear functions were necessary. This last behavior is explained in terms of the supercooled process involving a reconfiguration of the elastomeric chains. In the case of blends, the state of cure of NR and SBR in each NR-SBR sample was also taken into account in the discussion of the results obtained. Besides, thermal expansion coefficients of the free volumes in the transition and glassy region of all compounds were estimated. The differences observed in the values of this parameter are discussed by taking into account the morphology and formulation of each blend, the crosslink densities, and the role of the interphases formed between both NR and SBR elastomers.

Salgueiro, W.; Somoza, A.; Silva, L.; Consolati, G.; Quasso, F.; Mansilla, M. A.; Marzocca, A. J.

2011-05-01

88

Cure kinetics and mechanical properties of the blend system of epoxy\\/diaminodiphenyl sulfone and amine terminated polyetherimide-carboxyl terminated poly(butadiene-co-acrylonitrile) block copolymer  

Microsoft Academic Search

The cure kinetics of blends of epoxy resin (4,4’-tetraglycidyl diaminodiphenyl methane; TGDDM)\\/curing agent (diaminodiphenyl\\u000a sulfone; DDS) with ATPEI (amine terminated poly-etherimide) -CTBN (carboxyl terminated poly (butadiene-co-acrylonitrile))\\u000a block copolymer (AB type) were studied using differential scanning calorimetry under isothermal conditions to determine the\\u000a reaction kinetic parameters such as activation energy and reaction constants. Final cure conversion decreased with increasing\\u000a amount of

Donghyon Kim; Jung-ok Beak; Youngson Choe; Wonho Kim

2005-01-01

89

Flame retardant brominated styrene-based polymers. I. Synthesis, characterization and application of dibromostyrene and butadiene copolymers  

SciTech Connect

Brominated styrene-based polymers having surprisingly good physical properties in combination with flame retardancy are prepared from copolymers of dibromostyrene and butadiene. Polymerization compositions were measured by bromine contents (% Br) of the polymers by Schoeninger Combustion Method. Weight losses (% loss) were measured at 20{degrees}C/min by Thermogravimetric Analysis (TGA). Molecular weights were measured by GPC based on a standard molecular weight (MW) of polystyrene (PS). Flammability of the latex products when used in textile backcoatings was tested by Motor Vehicle Safety Standard 302 (MVSS-302) flammability test.

Wang, J.L.; Favstritsky, N.A. [Great Lakes Chemical Corporation, West Lafayette, IN (United States)

1993-12-31

90

Effect of crosslinking density on biaxial relaxation of SBR by using reduced variables. [Styrene-Butadiene Rubber  

NASA Technical Reports Server (NTRS)

The use of reduced variables to account for the effect of crosslinking density in a styrene-butadiene rubber (SBR) system is demonstrated for general biaxial stress states. Recently published results from stress relaxation tests on five SBR vulcanizates crosslinked to different degrees by tetramethylthiuram disulfide were superposed by using the crosslinking density as a reduction variable. The equilibrium shear modulus calculated from the master relaxation curve at long reduced times was in satisfactory agreement with other results for SBR. The time-axis shifts were related in a linear logarithmic manner to the crosslinking density but had a slope slightly less than values previously reported for elastomer systems.

Arenz, R. J.

1974-01-01

91

The Influence of Stabilizing Agents on the Interaction between Styrene\\/Butadiene Latex and Calcium Carbonate: A Calorimetric and a Dynamic Electrokinetic Study  

Microsoft Academic Search

The role of stabilizing agents in the interaction between styrene\\/butadiene latex and calcium carbonate particles has been studied using isothermal titration calorimetry (ITC) and an electrokinetic sonic amplitude (ESA) technique. It is demonstrated that the polyacrylate sodium salt (dispersing agent, referred to as NaPA) used as stabilizing agent for the calcium carbonate suspensions principally affects the interfacial properties of the

Kaj Backfolk; Serge Lagerge; Jarl B. Rosenholm

2002-01-01

92

Spinodal decomposition as a probe to measure the effects on molecular motion in poly(styrene-co-acrylonitrile) and poly(methyl methacrylate) blends after mixing with a low molar mass liquid crystal or commercial lubricant  

Microsoft Academic Search

The effects on molecular motion observed through early stage phase separation via spinodal decomposition, in melt mixed poly(styrene-co-acrylonitrile) (SAN) containing 25% by weight of acrylonitrile (AN) and poly(methyl methacrylate) (PMMA) (20\\/80wt%) blends after adding two low molar mass liquid crystals (CBC33 and CBC53) and two lubricants (GMS and zinc stearate) were investigated using light scattering techniques. The samples were assessed

S. Wacharawichanant; S. Thongyai; S. Tanodekaew; J. S. Higgins; N. Clarke

2004-01-01

93

Synthesis and characterization of new ion conductors based on butadiene styrene copolymers  

Microsoft Academic Search

In this work, we report the synthesis, kinetic study and microstructure characterization of a new proton conductor based on sulfonated polybutadiene–styrene copolymer (HPBS). Block copolymer ionomers were prepared through sulfonation of part of the styrene units. The free acid (HPBS-SH) sample was characterized using FT-IR spectroscopy and X-ray Photoelectron Spectroscopy (XPS) to confirm and quantify sulfonation. Microstructural characterization of the

A. Mokrini; C. Del R??o; J. L. Acosta

2004-01-01

94

Pore-filling electrolyte membranes based on plasma-activated microporous PE matrices and sulfonated hydrogenated styrene butadiene block copolymer (SHSBS)  

Microsoft Academic Search

In this research the performance of proton exchange membrane fuel cells (PEMFC's) was studied, using pore-filling electrolyte membranes based on plasma-activated microporous polyethylene (PE) matrices coated with sulfonated hydrogenated butadiene–styrene block copolymer (SHSBS). The voltage–current and power density curves were recorded under different experimental temperature and pressure conditions. In addition, an electrochemical study was completed by means of electrochemical impedance

A. Navarro; C. del Río; J. L. Acosta

2009-01-01

95

Preparation, characterization and evaluation of proton-conducting hybrid membranes based on sulfonated hydrogenated styrene–butadiene and polysiloxanes for fuel cell applications  

Microsoft Academic Search

This paper describes the preparation of proton-conducting hybrid membranes (HMs) obtained by a solvent casting procedure using a solution containing sulfonated hydrogenated styrene–butadiene (HSBS-S) and an inorganic–organic mixture (polysiloxanes) previously prepared by a sol–gel route. HSBS-S copolymers with different sulfonation degrees were obtained and characterized by means of elemental analysis (EA), chemical titration and electrochemical impedance spectroscopy (EIS). HSBS-S with

M. Monroy-Barreto; J. L. Acosta; C. del Río; M. C. Ojeda; M. Muñoz; J. C. Aguilar; E. Rodríguez de San Miguel; J. de Gyves

2010-01-01

96

High vinyl high styrene solution SBR  

Microsoft Academic Search

Objective: the objective of this study is to prepare high vinyl copolymers containing various levels of styrene and butadiene, and also to prepare random butadiene in high styrene content styrene–butadiene copolymers (SBR) while controlling the styrene block length. These materials could be used in race tread applications. Summary: This reports presents the synthesis and characterization of random, high vinyl copolymers

Adel F. Halasa; Jim Prentis; Bill Hsu; Chad Jasiunas

2005-01-01

97

Synthesis and electrical conductivity studies of metal chloro and nitroxide group containing styrene butadiene rubber  

NASA Astrophysics Data System (ADS)

The introduction of different functional group in SBR was done by a simple reaction between sodium nitrite and mercuric chloride in the presence of phase transfer catalyst. The attachment of chlorine and NO2 functional group in the double bond of the butadiene was monitored by FTIR and UV spectroscopy. The structure and morphology of chloro nitro SBR was studied by SEM and XRD. Flame retardency studies revealed that the chemical modification imparts better flame resistance to chemically modified SBR. AC conductivity and dielectric properties of chloro- nitro SBR was higher than that of SBR and conductivity increases with the level of chemical modification.

Anilkumar, T.; Ramesan, M. T.

2014-10-01

98

An approach based on liquid chromatography/electrospray ionization–mass spectrometry to detect diol metabolites as biomarkers of exposure to styrene and 1,3-butadiene  

PubMed Central

Styrene and 1,3-butadiene are important intermediates used extensively in the plastics industry. They are metabolized mainly through cytochrome P450-mediated oxidation to the corresponding epoxides, which are subsequently converted to diols by epoxide hydrolase or through spontaneous hydration. The resulting styrene glycol and 3-butene-1,2-diol have been suggested as biomarkers of exposure to styrene and 1,3-butadiene, respectively. Unfortunately, poor ionization of the diols within electrospray mass spectrometers becomes an obstacle to the detection of the two diols by liquid chromatography/electrospray ionization–mass spectrometry (LC/ESI–MS). We developed an LC/ESI–MS approach to analyze styrene glycol and 3-butene-1,2-diol by means of derivatization with 2-bromopyridine-5-boronic acid (BPBA), which not only dramatically increases the sensitivity of diol detection but also facilitates the identification of the diols. The analytical approach developed was simple, quick, and convincing without the need for complicated chemical derivatization. To evaluate the feasibility of BPBA as a derivatizing reagent of diols, we investigated the impact of diol configuration on the affinity of a selection of diols to BPBA using the established LC/ESI–MS approach. We found that both cis and trans diols can be derivatized by BPBA. In conclusion, BPBA may be used as a general derivatizing reagent for the detection of vicinal diols by LC/MS. PMID:19111668

Shen, Shuijie; Zhang, Fan; Zeng, Su; Zheng, Jiang

2012-01-01

99

Mortality of a cohort of workers in the styrene-butadiene polymer manufacturing industry (1943-1982).  

PubMed Central

A cohort of 12,110 male workers employed 1 or more years in eight styrene-butadiene polymer (SBR) manufacturing plants in the United States and Canada has been followed for mortality over a 40-year period, 1943 to 1982. The all-cause mortality of these workers was low [standardized mortality ratio (SMR) = 0.81] compared to that of the general population. However, some specific sites of cancers had SMRs that exceeded 1.00. These sites were then examined by major work divisions. The sites of interest included leukemia and non-Hodgkin's lymphoma in whites. The SMRs for cancers of the digestive tract were higher than expected, especially esophageal cancer in whites and stomach cancer in blacks. The SMR for arteriosclerotic heart disease in black workers was significantly higher than would be expected based on general population rates. Employees were assigned to a work area based on job longest held. The SMRs for specific diseases differed by work area. Production workers showed increased SMRs for hematologic neoplasms and maintenance workers, for digestive cancers. A significant excess SMR for arteriosclerotic heart disease occurred only in black maintenance workers, although excess mortality from this disease occurred in blacks regardless of where they worked the longest. A significant excess SMR for rheumatic heart disease was associated with work in the combined, all-other work areas. For many causes of death, there were significant deficits in the SMRs. PMID:2401250

Matanoski, G M; Santos-Burgoa, C; Schwartz, L

1990-01-01

100

Rheological properties of styrene-butadiene rubber filled with electron beam modified surface treated dual phase fillers  

NASA Astrophysics Data System (ADS)

The rheological properties of styrene-butadiene rubber (SBR) loaded with dual phase filler were measured using Monsanto Processability Tester (MPT) at three different temperatures (100°C, 110°C and 130°C) and four different shear rates (61.3, 306.3, 613, and 1004.5 s -1). The effect of electron beam modification of dual phase filler in absence and presence of trimethylol propane triacrylate (TMPTA) or triethoxysilylpropyltetrasulphide (Si-69) on melt flow properties of SBR was also studied. The viscosity of all the systems decreases with shear rate indicating their pseudoplastic or shear thinning nature. The higher shear viscosity for the SBR loaded with the electron beam modified filler is explained in terms of variation in structure of the filler upon electron beam irradiation. Die swell of the modified filler loaded SBR is slightly higher than that of the unmodified filler loaded rubber, which is explained by calculating normal stress difference for the systems. Activation energy of the modified filler loaded SBR systems is also slightly higher than that of the control filler loaded SBR system.

Shanmugharaj, A. M.; Bhowmick, Anil K.

2004-01-01

101

Quadratic Electro-Optic Effect in the Nonconjugated Conductive Co-polymer Iodine-doped Styrene-Butadiene-Rubber Measured at 633 nm and 1550 nm  

NASA Astrophysics Data System (ADS)

The quadratic electro-optic effect in the nonconjugated conductive co-polymer film of styrene-butadiene-rubber (SBR) has been measured using field-induced birefringence method. Thin films of styrene-butadiene-rubber have been prepared on various substrates from a chloroform solution and characterized using optical absorption spectroscopy, FTIR and DSC before and after doping with iodine. The optical absorption spectrum at low doping shows two peaks: one at 4.27 eV and the other at 3.2 eV corresponding to the radical cation and charge-transfer transition. FTIR data indicate =C-H vibration bands (964 cm-1 and 910 cm-1) of polybutadiene decrease upon doping due to transformation of the double bonds into radical cations. The Kerr coefficients as measured at 633 nm and at 1550 nm are 3.1x10-10 m/V^2 and 1.3x10-10 m/V^2 respectively. These exceptionally large values have been attributed to the subnanometer metallic domains formed upon doping and charge-transfer involving isolated double-bonds.

Telang, Gurudutt; Thakur, Mrinal

2012-02-01

102

Trans-stereospecific polymerization of butadiene and random copolymerization with styrene using borohydrido neodymium / magnesium dialkyl catalysts  

E-print Network

borohydrido neodymium / magnesium dialkyl catalysts A. Venturaa , T. Chenalb,c,d,e, *, M. Briab,f , F. Bonnetb neodymium and magnesium, and significant amounts of 1,2-units are observed. When considered for butadiene

Boyer, Edmond

103

Two-dimensional chromatography applied to the study of the thermo-oxidative degradation of poly(styrene-b-butadiene) star block copolymers.  

PubMed

Two-dimensional chromatography with gradient polymer elution chromatography in the first dimension and gel permeation chromatography in the second dimension was used to characterize a poly(styrene-b-butadiene) star block copolymer. The data evidence several populations that are clues left by the different steps in the sequential reaction employed to make the polymer. The sample was subjected to thermo-oxidative degradation at 180°C and was analyzed at different times during the process. After a relatively long induction period, the two-dimensional chromatograms show how the different populations are progressively degraded via random chain scission of the polybutadiene block to leave essentially polystyrene as the only soluble component. With longer thermal aging times, the polystyrene also degrades via chain scission. PMID:22807356

Moyses, Stephan

2012-07-01

104

A lutetium allyl complex that bears a pyridyl-functionalized cyclopentadienyl ligand: dual catalysis on highly syndiospecific and cis-1,4-selective (co)polymerizations of styrene and butadiene.  

PubMed

A novel linked-half-sandwich lutetium-bis(allyl) complex [(C(5)Me(4)-C(5)H(4)N)Lu(?(3)-C(3)H(5))(2)] (1) attached by a pyridyl-functionalized cyclopentadienyl ligand was synthesized and fully characterized. Complex 1 in combination with [Ph(3)C][B(C(6)F(5))(4)] exhibited unprecedented dual catalysis with outstanding activities in highly syndiotactic (rrrr>99%) styrene polymerization and distinguished cis-1,4-selective (99%) butadiene polymerization, respectively. Strikingly, this catalyst system exhibited remarkable activity (396 kg copolymer?(mol(Lu) h)(-1)) for the copolymerization of butadiene and styrene. Irrespective of whether the monomers were fed in concurrent mode or sequential addition of butadiene followed by styrene, diblock copolymers were obtained exclusively, which was confirmed by a kinetics investigation of monomer conversion of copolymerization with time. In the copolymers, the styrene incorporation rate varied from 4.7 to 85.4 mol%, whereas the polybutadiene (PBD) block was highly cis-1,4-regulated (95%) and the polystyrene segment remained purely syndiotactic (rrrr>99%). Correspondingly, the copolymers exhibited glass transition temperatures (T(g)) around -107 °C and melting points (T(m)) around 268 °C; typical values for diblock microstructures. Such copolymers cannot be accessed by any other methods known to date. X-ray powder diffraction analysis of these diblock copolymers showed that the crystallizable syndiotactic polystyrene (syn-PS) block was in the toluene ? clathrate form. The AFM micrographs of diblock copolymer showed a remarkable phase-separation morphology of the cis-1,4-PBD block and syn-PS block. This represents the first example of a lutetium-based catalyst showing both high activity and selectivity for the (co)polymerization of styrene and butadiene. PMID:20967902

Jian, Zhongbao; Tang, Shijia; Cui, Dongmei

2010-12-17

105

Comparative study of the effect of untreated, silanized and grafted alumina nanoparticles on thermal and dynamic mechanical properties of the styrene-butadiene rubber  

NASA Astrophysics Data System (ADS)

Elastomers filled with hard nanoparticles are of great technical importance for the rubber industry. In general, fillers improve mechanical properties of polymer materials, e.g. elastic moduli, tensile strength etc. The smaller the size of the particles the larger is the interface where interactions between polymer molecules and fillers can generate new properties. Using Temperature Modulated Differential Scanning Calorimetry (TMDSC) and Dynamic Mechanical Analysis (DMA), we investigated the properties of the pure styrene-butadiene rubber (SBR), SBR/ alumina nanoparticles, SBR/silanized alumina and SBR/alumina grafted to polymer chains. Beside a general reinforcement effect seen in the complex elastic moduli, the studies revealed that: i) small concentrations of nanoparticles (of 1.5-2 wt%) lead to a minimum in the glass transition temperature as a function of nanoparticle content; ii) for the grafted nanocomposites increasing the nanoparticle concentration beyond 4 wt% yields an increase of Tg by 4 K; iii) DMA mastercurves showed that in case of untreated and silanized alumina mechanical behaviour of the composite systems is rather near to the one of the SBR matrix, but the grafting of elastomer molecules to the silanized fillers induces a quasi-solid like response of the system in the low frequency regime.

Sushko, Rymma; Baller, Joerg; Filimon, Marlena; Sanctuary, Roland

2014-05-01

106

Utilizing carbon dioxide as a reaction medium to mitigate production of polycyclic aromatic hydrocarbons from the thermal decomposition of styrene butadiene rubber.  

PubMed

The CO(2) cofeed impact on the pyrolysis of styrene butadiene rubber (SBR) was investigated using thermogravimetric analysis (TGA) coupled to online gas chromatography/mass spectroscopy (GC/MS). The direct comparison of the chemical species evolved from the thermal degradation of SBR in N(2) and CO(2) led to a preliminary mechanistic understanding of the formation and relationship of light hydrocarbons (C(1-4)), aromatic derivatives, and polycyclic aromatic hydrocarbons (PAHs), clarifying the role of CO(2) in the thermal degradation of SBR. The identification and quantification of over 50 major and minor chemical species from hydrogen and benzo[ghi]perylene were carried out experimentally in the temperature regime between 300 and 500 °C in N(2) and CO(2). The significant amounts of benzene derivatives from the direct bond dissociation of the backbone of SBR, induced by thermal degradation, provided favorable conditions for PAHs by the gas-phase addition reaction at a relatively low temperature compared to that with conventional fuels such as coal and petroleum-derived fuels. However, the formation of PAHs in a CO(2) atmosphere was decreased considerably (i.e., ?50%) by the enhanced thermal cracking behavior, and the ultimate fates of these species were determined by different pathways in CO(2) and N(2) atmospheres. Consequently, this work has provided a new approach to mitigate PAHs by utilizing CO(2) as a reaction medium in thermochemical processes. PMID:22950720

Kwon, Eilhann E; Yi, Haakrho; Castaldi, Marco J

2012-10-01

107

Mechanism of aggregate formation in simplified industrial silica styrene-butadiene nanocomposites: effect of chain mass and grafting on rheology and structure.  

PubMed

The formation of aggregates in simplified industrial styrene-butadiene nanocomposites with silica filler has been studied using a recent model based on a combination of electron microscopy, computer simulations, and small-angle X-ray scattering. The influence of the chain mass (40 to 280 kg mol(-1), PI < 1.1), which sets the linear rheology of the samples, was investigated for a low (9.5 vol%) and high (19 vol%) silica volume fraction. 50% of the chains bear a single graftable end-group, and it is shown that the (chain-mass dependent) grafting density is the structure-determining parameter. A model unifying all available data on this system is proposed and used to determine a critical aggregate grafting density. The latter is found to be closely related to the mushroom-to-brush transition of the grafted layer. To our best knowledge, this is the first comprehensive evidence for the control of the complex nanoparticle aggregate structure in nanocomposites of industrial relevance by the physical parameters of the grafted layer. PMID:25060535

Baeza, Guilhem P; Genix, Anne-Caroline; Degrandcourt, Christophe; Gummel, Jérémie; Couty, Marc; Oberdisse, Julian

2014-09-21

108

HEALTH ASSESSMENT OF 1,3-BUTADIENE  

EPA Science Inventory

This assessment was conducted to review the new information that has become available since EPA's 1985 health assessment of 1,3-butadiene. 1,3-Butadiene is a gas used commercially in the production of styrene-butadiene rubber, plastics, and thermoplastic resins. The major...

109

The industrial production and use of 1,3-butadiene.  

PubMed Central

This presentation provides a brief overview of the production and use of 1,3-butadiene in the United States. Starting as a coproduct of ethylene, the 1,3-butadiene monomer is extracted and purified, then transferred to consumers. Major uses of 1,3-butadiene include the manufacture of styrene-butadiene rubber, polybutadiene rubber, and adiponitrile. PMID:2205493

Morrow, N L

1990-01-01

110

Morphology and Dynamic Mechanical Properties of Styrene Containing Tri-Block Copolymers for Electromagnetic Wave Interaction Applications  

Microsoft Academic Search

Styrene containing triblock copolymers, namely poly(styrene-ethylene\\/butylene-styrene) (SEBS) and poly(styrene-butadiene-styrene)] (SBS), were selectively modified by attaching polar groups to facilitate the in-growth of an inorganic component. In case of SEBS, the styrene block was sulfonated, and in SBS, the butadiene block was hydroxylated. The extent of modification was determined by analytical and spectroscopic methods. This presentation shows the morphology and dynamical

S. Peddini; K. Mauritz; D. Nikles; J. Weston

2008-01-01

111

CASE-COHORT STUDY OF STYRENE EXPOSURE AND ISCHEMIC HEART DISEASE INVESTIGATORS  

EPA Science Inventory

Investigators examined workers exposed to styrene while working in styrene-butadiene polymer manufacturing plants between 1943 and 1982. Workers who had died from ischemic heart disease were compared to a subgroup of all men employed in two styrene-butadiene polymer manufac...

112

Batch polymerization of styrene initiated by alkyl lithiums  

E-print Network

HISTORICAL REVIEW Study of organic metals in styrene, isoprene, and butadiene date back to 1917 when Schlenk (25), successfully isolated the alkyls of sodium and lithium. Ziegler (33), in 1929 polym rized butadiene with butyl lithium and suggested a rapid..., that interest in this system was revived. Since 1956, extensive work has been done on it. Commerical preparation of co-polymers of styrene, isoprene and butadiene in alkyl lithiums has catalyzed the study of this system. CHAPTER III POLYMERIZATIOH MECIVi...

Desai, Rashmi R

1970-01-01

113

Batch polymerization of styrene and isoprene by n-butyl lithium initiator  

E-print Network

. Rayford G. Anthony Considering an isothermal batch reactor Reich (18-20) proposed reaction mechanisms for homogeneous anionic polymerization of styrene, isoprene and butadiene via alkyl lithium initiator in hydrocarbon solvents. Based... on alkyl lithium initiated polymerization of butadiene, isoprene, styrene and methyl methacrylate has substantially increased. General polymeriza- tion mechanisms have been advanced for polymerization of styrene, butadiene and isoprene in polar and non...

Hasan, Sayeed

1970-01-01

114

Polybenzoxazole-filled nitrile butadiene rubber compositions  

NASA Technical Reports Server (NTRS)

An insulation composition that comprises at least one nitrile butadiene rubber (NBR) having an acrylonitrile content that ranges from approximately 26% by weight to approximately 35% by weight and polybenzoxazole (PBO) fibers. The NBR may be a copolymer of acrylonitrile and butadiene and may be present in the insulation composition in a range of from approximately 45% by weight to approximately 56% by weight of a total weight of the insulation composition. The PBO fibers may be present in a range of from approximately 3% by weight to approximately 10% by weight of a total weight of the insulation composition. A rocket motor including the insulation composition and a method of insulating a rocket motor are also disclosed.

Gajiwala, Himansu M. (Inventor); Guillot, David G. (Inventor)

2008-01-01

115

Cross-linking of sulfonated styrene–ethylene\\/butylene–styrene triblock polymer via sulfonamide linkages  

Microsoft Academic Search

Sulfonated styrene–butadiene–styrene (SSBS) triblock copolymer was cross-linked through condensation of sulfonic acid groups with bis(4-aminophenyl)sulfone to form sulfonamide linkages using a coupling agent (carbonyldiimidazole). Intact and clear light brown membranes were obtained when cast from solution, and cross-linking was established by measuring percent water uptake, determined gravimetrically and by near-IR (NIR) spectroscopy, and percent sulfonation by titration. The cross-linked SSBS

S Kaur; G Florio; D Michalak

2002-01-01

116

Preparation of candidate reference materials for the determination of phosphorus containing flame retardants in styrene-based polymers.  

PubMed

Candidate reference materials (RM) for the analysis of phosphorus-based flame retardants in styrene-based polymers were prepared using a self-made mini-extruder. Due to legal requirements of the current restriction for the use of certain hazardous substances in electrical and electronic equipment, focus now is placed on phosphorus-based flame retardants instead of the brominated kind. Newly developed analytical methods for the first-mentioned substances also require RMs similar to industrial samples for validation and verification purposes. Hence, the prepared candidate RMs contained resorcinol-bis-(diphenyl phosphate), bisphenol A bis(diphenyl phosphate), triphenyl phosphate and triphenyl phosphine oxide as phosphorus-based flame retardants. Blends of polycarbonate and acrylonitrile-co-butadiene-co-styrene as well as blends of high-impact polystyrene and polyphenylene oxide were chosen as carrier polymers. Homogeneity and thermal stability of the candidate RMs were investigated. Results showed that the candidate RMs were comparable to the available industrial materials. Measurements by ICP/OES, FTIR and NMR confirmed the expected concentrations of the flame retardants and proved that analyte loss and degradation, respectively, was below the uncertainty of measurement during the extrusion process. Thus, the candidate RMs were found to be suitable for laboratory use. PMID:25410641

Roth, Thomas; Urpi Bertran, Raquel; Latza, Andreas; Andörfer-Lang, Katrin; Hügelschäffer, Claudia; Pöhlein, Manfred; Puchta, Ralph; Placht, Christian; Maid, Harald; Bauer, Walter; van Eldik, Rudi

2014-11-20

117

NTP Toxicology and Carcinogenesis Studies of 1,3-Butadiene (CAS No. 106-99-0) in B6C3F1 Mice (Inhalation Studies).  

PubMed

1,3-Butadiene is used as an intermediate in the production of elastomers, polymers, and other chemicals. Of the 1,3-butadiene used in 1978, 44% was used to manufacture styrene-butadiene rubber (a substitute for natural rubber, produced by copolymerization of 1,3-butadiene with styrene), and 19% was used to produce polybutane elastomer (a substance that increases resistance of tire products to wear, heat degradation, and blowouts). Chloroprene monomer, derived from 1,3-butadiene, is used exclusively to manufacture neoprene elastomers for non-tire and latex applications. Commercial nitrile rubber, used largely in rubber hoses, seals, and gaskets for automobiles, is a copolymer of 1,3-butadiene and acrylonitrile. Acrylonitrile- butadiene- styrene resins, usually containing 20%-30% 1,3-butadiene by weight, are used to make parts for automobiles and appliances. Other polymer uses include specialty polybutadiene polymers, thermoplastic elastomers, nitrile barrier resins, and K resins(R). 1,3-Butadiene is used as an intermediate in the production of a variety of industrial chemicals, including two fungicides, captan and captofol. It is approved by the U.S. Food and Drug Administration for use in the production of adhesives used in articles for packaging, transporting, or holding food; in components of paper and paperboard that are in contact with dry food; and as a modifier in the production of semigrid and rigid vinyl chloride plastic food-contact articles. No information was located on the levels of monomer or on its elution rate from any of the commercially available polymers. It is not known if unreacted 1,3-butadiene migrated from packaging materials. Male and female B6C3F1 mice were exposed to air containing 1,3-butadiene (greater than 99% pure) at concentrations of 0-8,000 ppm in 15-day and 14-week inhalation studies. In the 15-day studies, survival was unaffected by dose, and no pathologic effects were observed; slight decreases in mean body weight occurred at the high concentrations. In the 14-week studies, mean body weight gain decreased with dose, and survival in the 5,000-ppm and 8,000-ppm groups of males was markedly reduced; no other compound-related effects were reported. Inhalation carcinogenesis studies of 1,3-butadiene were conducted by exposing groups of 50 male and female B6C3F1 mice 6 hours per day for 5 days per week to air containing the test chemical at concentrations of 0 (chamber controls), 625, or 1,250 ppm. These studies were planned for 103-week exposures but were terminated at week 60 for male mice and week 61 for female mice because of the rapidly declining survival, primarily due to neoplasia. Body weights were not affected by 1,3-butadiene. Significantly increased incidences of neoplasms at multiple sites were observed in mice exposed to 1,3-butadiene. Hemangiosarcomas of the heart occurred at increased incidences in exposed males and females (male: control, 0/50; low dose, 16/49; high dose, 7/49; female: 0/50; 11/48; 18/49). Hemangiosarcomas were also observed in the peritoneal cavity (one high dose male), subcutaneous tissue (two low dose females), and liver (one high dose female). Malignant lymphomas, diagnosed as early as week 20, were observed at increased incidences in exposed male and female mice (male: 0/50; 23/50; 29/50; female: 1/50; 10/49; 10/49). Alveolar/bronchiolar adenomas and alveolar/bronchiolar (both separately and combined) occurred at increased incidences in exposed male and female mice (combined incidences -- male: 2/50; 14/49; 15/49; female: 3/49; 12/48; 23/49). Epithelial hyperplasia of the forestomach occurred at increased incidences in dosed mice (male: 0/49; 5/40; 7/44; female: 0/49; 5/42; 9/49). Papillomas of the forestomach occurred in low dose male and in low dose and high dose female mice (male: 0/49; 5/40; 0/44; female: 0/49; 4/42; 10/49). Squamous cell carcinomas of the forestomach were observed in dosed mice (male: 0/49, 2/40, 1/44; female: 0/49, 1/42, 1/49). Acinar cell carcinomas of the mammary gland were observed at an increased incidence in high dose female r

1984-08-01

118

Effect of an anionic emulsifier on the structure of butadiene-nitrile elastomers  

Microsoft Academic Search

X-ray diffraction and TMA studies show that surfactant sodium alkyl sulfonate (C15) forms one of its two LC structures (distinguished by the smallest layer periodicity) in butadiene-nitrile elastomers containing\\u000a different amounts of acrylonitrile units. In this case, the surfactant serves as a structural plasticizer and facilitates\\u000a a more complete selective segregation of microblocks of trans-1,4-butadiene units and, especially, of sequences

L. V. Sokolova; E. V. Matukhina

2010-01-01

119

Separation of Styrene-Butyl Methacrylate Copolymers by High Performance Liquid Chromatography  

Microsoft Academic Search

Styrene\\/n-butyl methacrylate (S\\/nBMA) and styrene\\/t-butyl methacrylate (S\\/tBMA) copolymers were separated by chemical composition using HPLC. In the case of normal phase HPLC using acrylamide gel or acrylonitrile gel as a stationary phase, S\\/nBMA and S\\/tBMA copolymers were separated by chemical composition. S\\/BMA copolymers were eluted from higher styrene content using dichloromethane\\/n-hexane as an eluent, while with the opposite elution order

Kenji Ogino; Tooru Maruo; Hisaya Sato

1994-01-01

120

The acrylonitrile dimer ion  

NASA Astrophysics Data System (ADS)

Large energy barriers prohibit the rearrangement of solitary acrylonitrile ions, CH2CHCN+, into their more stable hydrogen-shift isomers CH2CCNH+ or CHCH-CNH+. This prompted us to examine if these isomerizations occur by self-catalysis in acrylonitrile dimer ions. Such ions, generated by chemical ionization experiments of acrylonitrile with an excess of carbon dioxide, undergo five dissociations in the [mu]s time frame, as witnessed by peaks at m/z 53, 54, 79, 80 and 105 in their metastable ion mass spectrum. Collision experiments on these product ions, deuterium labeling, and a detailed computational analysis using the CBS-QB3 model chemistry lead to the following conclusions: (i) the m/z 54 ions are ions CH2CHCNH+ generated by self-protonation in ion-dipole stabilized hydrogen-bridged dimer ions [CH2CHCN...H-C(CN)CH2]+ and [CH2CHCN...H-C(H)C(H)CN]+; the proton shifts in these ions are associated with a small reverse barrier; (ii) dissociation of the H-bridged ions into CH2CCNH+ or CHCH-CNH+ by self-catalysis is energetically feasible but kinetically improbable: experiment shows that the m/z 53 ions are CH2CHCN+ ions, generated by back dissociation; (iii) the peaks at m/z 79, 80 and 105 correspond with the losses of HCN, C2H2 and H, respectively. The calculations indicate that these ions are generated from dimer ions that have adopted the (much more stable) covalently bound "head-to-tail" structure [CH2CHCN-C(H2)C(H)CN]+; experiments indicate that the m/z 79 (C5H5N) and m/z 105 (C6H6N2) ions have linear structures but the m/z 80 (C4H4N2) ions consist of ionized pyrimidine in admixture with its stable pyrimidine-2-ylidene isomer. Acrylonitrile is a confirmed species in interstellar space and our study provides experimental and computational evidence that its dimer radical cation yields the ionized prebiotic pyrimidine molecule.

Ervasti, Henri K.; Jobst, Karl J.; Burgers, Peter C.; Ruttink, Paul J. Ae; Terlouw, Johan K.

2007-04-01

121

An evaluation of styrene levels emitted during cast polymer production of cultured marble building materials  

E-print Network

in the manufacture of unsaturated polyester (alkyd) resins. These resins are primarily used as feed stocks for the boat building and cultured marble industries. A composite mixture of styrene copolymerized with an unsaturated polyester resin plus a filler material... as an intermediate chemical feed stock for use in the production of polystyrene, styrene butadiene elastomers, latex and unsaturated polyester resins (UPR). A polyester (or alkyd) resin is a solution of a linear polymer in a liquid monomer that is capable...

Bell, Lewis Ray

1994-01-01

122

AMBIENT ACRYLONITRILE LEVELS NEAR MAJOR ACRYLONITRILE PRODUCTION AND USE FACILITIES  

EPA Science Inventory

In this study, ambient acrylonitrile (AN) levels were measured in the vicinity of two major AN user facilities and two major AN production facilities. Approximately 100 duplicate air samples were collected on charcoal sorption tubes at different locations at or beyond the fenceli...

123

Design and Characterization of Styrene-Based Proton Exchange Membranes  

Microsoft Academic Search

This paper deals with preparation of PEM, based on commercial block copolymer of the styrene-butadiene. The copolymer was\\u000a structurally changed by sulfonation followed by cross linking, in order to design a Proton Exchange Membrane for Fuel Cells.\\u000a The membranes were structural tested by FTIR Spectroscopy and Scanning Electron Microscopy. Ionic Exchange Capacity (IEC)\\u000a and thermal behavior by Differential Scanning Calorimetry

D. Ebrasu; I. Petreanu; L. Patularu; I. Stefanescu; M. Valeanu

2008-01-01

124

Design and Characterization of Styrene-Based Proton Exchange Membranes  

NASA Astrophysics Data System (ADS)

This paper deals with preparation of PEM, based on commercial block copolymer of the styrene-butadiene. The copolymer was structurally changed by sulfonation followed by cross linking, in order to design a Proton Exchange Membrane for Fuel Cells. The membranes were structural tested by FTIR Spectroscopy and Scanning Electron Microscopy. Ionic Exchange Capacity (IEC) and thermal behavior by Differential Scanning Calorimetry (DSC) were measured too.

Ebrasu, D.; Petreanu, I.; Patularu, L.; Stefanescu, I.; Valeanu, M.

125

Gold catalyst Styrene Benzaldehyde Styrene oxide Acetophenone  

E-print Network

O O O + + O2 Gold catalyst Styrene Benzaldehyde Styrene oxide Acetophenone studies. However, the study by Turner et al.1 seems to be the first to use Au55 in the synthesis of supported gold catalysts attempts to relate structure to activity in gold catalysis. What, then, makes gold particles of this size

Rouyer, Francois

126

ACRYLONITRILE PLANT AIR POLLUTION CONTROL  

EPA Science Inventory

Based on available literature, the report identifies and ranks (in terms of efficiency, cost, and energy requirements) air pollution control technologies for each of four major air pollutant emission sources in acrylonitrile plants. The sources are: (1) absorber vent gas streams,...

127

Charcoal byproducts as potential styrene-butadiene rubber composte filler  

Technology Transfer Automated Retrieval System (TEKTRAN)

Carbon black, a byproduct of the petroleum industry, is the world's most predominant filler for rubber composites. In this study, various renewable charcoals in the form of pyrolyzed agricultural byproducts were evaluted as potential carbon-based filler for rubber composites made with carboxylated s...

128

Reduction of acrylamide and acrylonitrile emissions  

SciTech Connect

A method comprising contacting a vapor stream resulting from air sparging of aqueous acrylamide containing acrylonitrile with sufficient activated carbon adsorbent to substantially remove acrylamide and acrylonitrile from the vapor stream. This is a particularly advantageous method when aqueous acrylamide is stored in remote locations.

Knee, W. R.; Cutie, S. S.

1985-10-01

129

Ion-Molecule Association in Acrylonitrile  

NASA Technical Reports Server (NTRS)

Acrylonitrile (propernenitrile or vinyl cyanide) polymerizes readily via a radical mechanism in solution at room temparature. The propensity to polymerize is sufficiently strong that it is usual to add a radical scavenger to the solution to prevent polymerization when oxygen (an inhibitor) is removed. Polymerization of acrylonitrile is also know to occur via nucleophilic addition of an anion by a michael-type reaction.

Wilson, Paul F.; Milligan, Daniel B.; McEwan, Murray J.

1997-01-01

130

HEALTH ASSESSMENT DOCUMENT FOR ACRYLONITRILE (REVISED DRAFT)  

EPA Science Inventory

Acrylonitrile is readily absorbed in animals following ingestion or inhalation, while dermal absorption is poor (1%) compared to that of the lungs. Acrylonitrile is metabolized to cyanide, which is transformed to thiocyanic acid and by cyanoethylation of sulfhydryl groups to S-(2...

131

Disclosed dielectric and electromechanical properties of hydrogenated nitrile-butadiene dielectric elastomer  

NASA Astrophysics Data System (ADS)

This paper presents a comprehensive study of the effects of acrylonitrile content, crosslink density and plasticization on the dielectric and electromechanical performances of hydrogenated nitrile-butadiene dielectric elastomer. It was found that by increasing the acrylonitrile content of hydrogenated nitrile-butadiene dielectric elastomer, the dielectric constant will be improved accompanied with a sharp decrease of electrical breakdown strength leading to a small actuated strain. At a fixed electric field, a high crosslink density increased the elastic modulus of dielectric elastomer, but it also enhanced the electrical breakdown strength leading to a high actuated strain. Adding a plasticizer into the dielectric elastomer decreased the dielectric constant and electrical breakdown strength slightly, but reduced the elastic modulus sharply, which was beneficial for obtaining a large strain at low electric field from the dielectric elastomer. The largest actuated strain of 22% at an electric field of 30 kV mm-1 without any prestrain was obtained. Moreover, the hydrogenated nitrile-butadiene dielectric actuator showed good history dependence. This proposed material has great potential to be an excellent dielectric elastomer.

Yang, Dan; Tian, Ming; Dong, Yingchao; Liu, Haoliang; Yu, Yingchun; Zhang, Liqun

2012-03-01

132

Blood styrene and urinary metabolites in styrene polymerisation.  

PubMed Central

The results of the analysis of blood and urine samples for styrene and its metabolites in 491 workers in a styrene polymerisation plant in the United States are reported. The levels of exposure to styrene were estimated to be less than 10 ppm, but nevertheless styrene and metabolites were detectable in more than 50% of workers in polymerisation jobs, within 4 h of exposure. Workers involved in the manufacture and purification of styrene from ethyl benzene also had detectable blood styrene and urinary metabolites in 83% of recently exposed subjects. The relationship between styrene in blood and in subcutaneous fat and urinary metabolites as pharmacokinetic variables is discussed. PMID:737139

Wolff, M S; Lorimer, W V; Lilis, R; Selikoff, I J

1978-01-01

133

Appendix B: Glossary of Polymer Materials  

E-print Network

temperature to be a successful elastomer (see Acrylate elastomers). Acrylonitrile-butadiene-styrene The first polybutadiene rubber particles are dis- persed in a poly(styrene-co-acrylonitrile) SAN matrix. The dispersed polymer which has evolved by a long development path from the homopolyniers polystyrene, polyacrylonitrile

Hall, Christopher

134

Present and Future Uses of Industrial Absorption Heat Pumps  

E-print Network

Acid Acrylonitrile Amines BTX Butadiene e3' Cit, and, Cs splitters Ethanol Ethylene glycols Isopropanol Methanol Methyl Ethyl Ketone Styrene and Ethylbenzene Terepthalic Acid Vinyl Acetate Monomer Vinyl Chloride Monomer Natural Gas...

Erickson, D. C.; Davidson, W. F.

135

Recycling of engineering plastics from waste electrical and electronic equipments: influence of virgin polycarbonate and impact modifier on the final performance of blends.  

PubMed

This study is focused on the recovery and recycling of plastics waste, primarily polycarbonate, poly(acrylonitrile-butadiene-styrene) and high impact polystyrene, from end-of-life waste electrical and electronic equipments. Recycling of used polycarbonate, acrylonitrile-butadiene-styrene, polycarbonate/acrylonitrile-butadiene-styrene and acrylonitrile-butadiene-styrene/high impact polystrene material was carried out using material recycling through a melt blending process. An optimized blend composition was formulated to achieve desired properties from different plastics present in the waste electrical and electronic equipments. The toughness of blended plastics was improved with the addition of 10 wt% of virgin polycarbonate and impact modifier (ethylene-acrylic ester-glycidyl methacrylate). The mechanical, thermal, dynamic-mechanical and morphological properties of recycled blend were investigated. Improved properties of blended plastics indicate better miscibility in the presence of a compatibilizer suitable for high-end application. PMID:24695435

Ramesh, V; Biswal, Manoranjan; Mohanty, Smita; Nayak, Sanjay K

2014-05-01

136

[Identification of migrants from nitrile-butadiene rubber gloves].  

PubMed

Polyvinyl chloride gloves containing di(2-ethylhexyl) phthalate are restricted for food contact use. In their place, disposable gloves made from nitrile-butadiene rubber (NBR) are used in contact with foodstuffs. Some unknown substances were found to migrate into n-heptane from NBR gloves. By GC/MS, HR-MS and NMR, their chemical structures were confirmed to be 2,2,4-trimethyl-1,3-pentanediol diisobutyrate (used as a plasticizer), 4,4'-butylidenedi(6-tert-butyl-m-cresol), a mixture of styrenated phenols consisting of 2-(alpha-methylbenzyl)phenol, 4-(alpha-methylbenzyl)phenol, 2,6-di(alpha-methylbenzyl)phenol, 2,4-di(alpha-methylbenzyl)phenol and 2,4,6-tri(alpha-methylbenzyl)phenol (used as antioxidants), and 2,4-di-tert-butylphenol, which seems to a degradation product of antioxidant. Migration levels of these compounds were 1.68 micrograms/cm2 of 2,4-di-tert-butylphenol, 2.80 micrograms/cm2 of 2,2,4-trimethyl-1,3-pentanediol diisobutyrate, 46.08 micrograms/cm2 of styrenated phenols and 4.22 micrograms/cm2 of 4,4'-butylidenedi(6-tert-butyl-m-cresol) into n-heptane, respectively. The content of total styrenated phenols was 6,900 micrograms/g in NBR gloves. PMID:12846157

Mutsuga, Motoh; Kawamura, Yoko; Wakui, Chiseko; Maitani, Tamio

2003-04-01

137

Styrene Purification and Recovery Using Freeze Crystallization  

E-print Network

Lab tests have demonstrated the ability to separate styrene from ABS and SAN plastics wastes by cooling the waste until the styrene begins to crystallize. The same process that recovers styrene from these wastes can be used to purify styrene...

Heist, J. A.; Wrobel, P. J.

138

Species differences in metabolism of 1,3-butadiene  

SciTech Connect

1,3-Butadiene (BD) is a 4-carbon gaseous compound with two double bonds. Used in high tonnage to make styrene-butadiene polymers in the rubber industry. Because of large amounts in use, BD was tested for toxicity in 2-year inhalation exposures of both Sprague-Dawley rats and B6C3F{sub 1} mice. The results of the two-species studies were dramatically different. In the initial study in mice, BD was shown to be a potent multiple-site carcinogen at exposure levels of 625 and 1250 ppM. There were increased incidences of neoplasia in the heart, lung, mammary gland, and ovary; malignant lymphomas resulted in early deaths of the mice so that the planned 2-year study was stopped after only 61 weeks of exposure. The second study in mice was conducted at much lower exposure concentrations (6.25, 20, 62.5, 200, and 625 ppM) and lasted 104 weeks. Increased incidences of hemangiosarcomas of the heart and lung neoplasia were observed in males exposed to 62.5 ppM BD, while females had increased lung neoplasia even at the 6.25 ppM exposure level. Early deaths from lymphomas were again observed at the high exposure concentration (625 ppm). A noncancer toxicity observed in mice was a macrocytic, megaloblastic anemia.

Henderson, R.F.

1995-02-01

139

Thermal stability, flammability and fire hazard of butadiene-acrylonitrile rubber nanocomposites  

Microsoft Academic Search

This article presents the effect of the method of NBR cross linking on the thermal properties, flammability and fire hazard\\u000a of its nanocomposites containing modified montmorillonite (NanoBent or Nanofil), using test results obtained by means of a\\u000a derivatograph, oxygen index and cone calorimetry. It has been found that the thermal stability and flammability of the nanocomposites\\u000a investigated depend on both

Gra?yna Janowska; Agnieszka Kucharska-Jastrz?bek; Przemys?aw Rybi?ski

2011-01-01

140

Improved Dipole Moments for Acrylonitrile and Propionitrile  

NASA Astrophysics Data System (ADS)

Previous determinations of the electric dipole moment of acrylonitrile, while in agreement on the total dipole moment, showed an appreciable difference in the value of the smaller ?_b component. The value of this component is important for intensity considerations in the THz spectrum of this molecule, which is dominated by b-type transitions. We decided to update the dipole moment determination of acrylonitrile, and also of propionitrile (ethyl cyanide) by making Stark measurements in supersonic expansion. We used the Stark electrode arrangement developed in our laboratory and the program QSTARK for fitting Stark measurements on resolved nuclear quadrupole hyperfine structure. The results for acrylonitrile show a further, significant difference in the value of ?_b, while those for propionitrile, while more precise, are essentially consistent with previous values. The evidence from ab initio calculations and from relative intensity measurements supporting the current dipole moment determinations is presented. W.S.Wilcox, J.H.Goldstein, J.W.Simmons, J.Chem.Phys., 22, 516 (1954) M.Stolze, D.H.Sutter, Z.Naturforsch., 40a, 998 (1985) Z.Kisiel, L.Pszczó?kowski, B.J.Drouin, C.S.Brauer, S.Yu, J.C.Pearson, J. Mol. Spectrosc. 258, 26 (2009). Z.Kisiel, J.Kosarzewski, B.A.Pietrewicz, L.Pszczó?kowski, Chem.Phys.Lett. 325, 523 (2000). H.M.Heise, H.Lutz, H.Dreizler, Z.Naturforsch., 29a, 1345 (1974)

Kisiel, Zbigniew; Kra?nicki, Adam

2011-06-01

141

ABSORPTION OF CO2 IN HIGH ACRYLONITRILE CONTENT COPOLYMERS: DEPENDENCE ON ACRYLONITRILE CONTENT. (R829555)  

EPA Science Inventory

In continuation of our goal to determine the ability of CO2 to plasticize acrylonitrile (AN) copolymers and facilitate melt processing at temperatures below the onset of thermal degradation, a systematic study has been performed to determine the influence of AN cont...

142

Vapor-liquid equilibria of copolymer + solvent and homopolymer + solvent binaries: New experimental data and their correlation  

Microsoft Academic Search

Sixty-four isothermal data sets for vapor-liquid equilibria (VLE) for polymer + solvent binaries have been obtained using a gravimetric sorption technique, in the range of 23.5--80 C. Solvents studied were acetone, acetonitrile, 1-butanol, 1,2-dichloroethane, chloroform, cyclohexane, hexane, methanol, octane, pentane, and toluene. Copolymers studied were poly(acrylonitrile-co-butadiene), poly(styrene-co-acrylonitrile), poly(styrene-co-butadiene), poly(styrene-co-butyl methacrylate), poly(vinyl acetate-co-ethylene), and poly(vinyl acetate-co-vinyl chloride). All copolymers were random

Ram B. Gupta; John M. Prausnitz

1995-01-01

143

Vapor-liquid equilibria for copolymer+solvent systems: Effect of intramolecular repulsion  

Microsoft Academic Search

Role of intramolecular interactions in blend miscibility is well documented for polymer+copolymer mixtures. Some copolymer+polymer mixtures are miscible although their corresponding homopolymers are not miscible; for example, over a range of acrylonitrile content, styrene\\/acrylonitrile copolymers are miscible with poly(methyl methacrylate) but neither polystyrene nor polyacrylonitrile is miscible with poly(methyl methacrylate). Similarly, over a composition range, butadiene\\/acrylonitrile copolymers are miscible with

R. B. Gupta; J. M. Prausnitz

1995-01-01

144

Effect of phosphorous flame retardants on the thermal decomposition of vinyl polymers and copolymers  

Microsoft Academic Search

The effect of ammonium polyphosphate (APP) and tris(2,4-di-ter-butylphenyl)phosphite (TBP) flame retardants and polyphosphoric acid (PPA) was examined on the thermal decomposition reactions of polystyrene (PS), styrene-acrylonitrile copolymer (SAN), acrylonitrile-butadiene-styrene copolymer (ABS) and polyacrylonitrile (PAN) by pyrolysis-gas chromatography\\/mass spectrometry (Py-GC\\/MS) and thermogravimetry (TG) techniques.The effect of APP and PPA proved to be significant on the thermal decomposition of polymers investigated. The

Zsuzsanna Czégény; Marianne Blazsó

2008-01-01

145

Butenes and butadiene in urban air.  

PubMed

Samples of urban air hydrocarbons were taken on specifically made adsorbent cartridges and analysed by gas chromatography after thermal desorption. The four isomeric butenes and 1,3-butadiene were favourably resolved and separated from the abundant alkanes on an aluminium oxide PLOT column. The concentrations of butadiene, reflecting outdoor urban exposure, were in the range of 0.5-5 micrograms/m3. An approximate 1:4 ratio was observed between butadiene and propene which both originate predominantly from vehicle exhaust. The four butenes made up approximately 50% of the propene concentration in exhaust-polluted air, with methylpropene greater than 1-butene greater than trans-2-butene greater than cis-2-butene. Petrol vapour contributed less than exhaust but about five times more to the 2-butenes than to methylpropene and 1-butene. The highest exposure levels of butadiene and butenes were consistently observed in the vicinity of exhaust pipes and petrol-fuelled vehicles. PMID:1384124

Löfgren, L; Petersson, G

1992-05-01

146

Styrene exposure and risk of cancer  

PubMed Central

Styrene is widely used in the manufacture of synthetic rubber, resins, polyesters and plastics. Styrene and the primary metabolite styrene-7,8-oxide are genotoxic and carcinogenic. Long-term chemical carcinogenesis bioassays showed that styrene caused lung cancers in several strains of mice and mammary cancers in rats and styrene-7,8-oxide caused tumours of the forestomach in rats and mice and of the liver in mice. Subsequent epidemiologic studies found styrene workers had increased mortality or incidences of lymphohematopoietic cancers (leukaemia or lymphoma or all), with suggestive evidence for pancreatic and esophageal tumours. No adequate human studies are available for styrene-7,8-oxide although this is the primary and active epoxide metabolite of styrene. Both are genotoxic and form DNA adducts in humans. PMID:21724974

Huff, James; Infante, Peter F.

2011-01-01

147

Isolation and identification of styrene-degrading Corynebacterium strains, and their styrene metabolism.  

PubMed

By supplying styrene in the gas phase as the sole carbon and energy source, styrene-degrading aerobic microorganisms were readily isolated from soil samples. They were identified as Corynebacterium pseudodiphtheriticum and similar species, or Pseudomonas sp. Growth experiments on some aromatic compounds, resting-cell reactions with them, and the measurement of degrading enzyme activities suggest that Corynebacterium sp. AC-5 and St-5 strains metabolize styrene through styrene oxidation into styrene oxide, then convert it into phenylacetaldehyde by a reaction using styrene oxide isomerase, and phenylacetaldehyde is reduced to 2-phenylethanol. The Corynebacterium sp. ST-10 strain did not have styrene oxide isomerase, and metabolized styrene oxide by an unknown enzymatic reaction. Possible metabolism of styrene was proposed for the Corynebacterium strains. PMID:8987859

Itoh, N; Yoshida, K; Okada, K

1996-11-01

148

21 CFR 177.1480 - Nitrile rubber modified acrylonitrile-methyl acrylate copolymers.  

Code of Federal Regulations, 2011 CFR

...2011-04-01 false Nitrile rubber modified acrylonitrile-methyl acrylate copolymers...ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) FOOD FOR...Surfaces § 177.1480 Nitrile rubber modified acrylonitrile-methyl acrylate...

2011-04-01

149

21 CFR 177.1480 - Nitrile rubber modified acrylonitrile-methyl acrylate copolymers.  

...2014-04-01 false Nitrile rubber modified acrylonitrile-methyl acrylate...ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) INDIRECT...177.1480 Nitrile rubber modified acrylonitrile-methyl acrylate copolymers. Nitrile rubber modified...

2014-04-01

150

21 CFR 177.1480 - Nitrile rubber modified acrylonitrile-methyl acrylate copolymers.  

Code of Federal Regulations, 2013 CFR

...2013-04-01 false Nitrile rubber modified acrylonitrile-methyl acrylate copolymers...ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) FOOD FOR...Surfaces § 177.1480 Nitrile rubber modified acrylonitrile-methyl acrylate...

2013-04-01

151

[Toxicology of acrylonitrile (AN) (author's transl)].  

PubMed

Acrylonitrile (AN, CH2 = CH CN), a highly reactive compound having an active vinyl and cyanide group, has been widely used in various synthetic chemical industries. AN is known to produce toxic actions to human beings as well as experimental animals by inhalation and cutaneous contact. Its oral LD50 in animals are between 50 mg (for mouse) and 100 mg/kg (for rat, guinea pig, rabbit), and IC50 in 4 hours are between 110-140 ppm for mouse and dog, and 400-500 ppm for guinea pig. Although the mechanism of action of AN has not been completely understood, the action of both cyanide which is liberated in the organism and AN molecules themselves is considered to play some roles. Recent studies have shown that AN also produces chronic toxicity to human beings and experimental animals, and mutagenicity to microorganisms. In the U.S.A. experimental studies have shown an increased incidence of tumor in various organs after long-term administration of AN in rats. A preliminary report on an epidemiologic study conducted in the U.S.A. indicated excess cancer incidence and cancer mortality among workers exposed to AN. Further investigations will be needed to elucidate the carcinogenicity of the compound. PMID:7024596

Hashimoto, K

1980-09-01

152

Diacetoxylation of 1,3-butadiene  

SciTech Connect

The homogeneous catalytic diacetoxylation of 1,3-butadiene was found to proceed in a medium of acetic acid, palladium complexes and acetate ions more efficiently than upon using the nitrate-iodate reoxidative system. The major reaction products are cis- and trans-1,4-diacetoxy-2-butenes formed in 15-17 mass % yield and 48-50% selectivity and 3,4-diacetoxy-1-butene formed in 10 mass % yield and selectivity of about 40%. Two alternative mechanisms were proposed and the reasons for the low reactivity of butadiene under homogeneous catalysis conditions were discussed.

Devekki, A.V.; Yakushkin, M.I.

1988-03-01

153

High-speed testing and material modeling of unfilled styrene butadiene vulcanizates at impact rates  

Microsoft Academic Search

High-speed tensile tests were performed on unfilled SBR strip and sheet specimens at room temperature. Uniaxial dynamic stress-extension ratio curves indicated three distinct regions of rate-dependent behavior when strain rates were below 180 s-1, between 180–280 s-1and above 280 s-1. With increasing strain rate, the toughness increased in the first region, remained roughly constant in the second region, and decreased

M. S. Hoo Fatt; I. Bekar

2004-01-01

154

EFFECT OF SOY PROTEIN AND CARBOHYDRATE RATIO ON THE VISCOELASTIC PROPERTIES OF STYRENE-BUTADIENE COMPOSITES  

Technology Transfer Automated Retrieval System (TEKTRAN)

When soy products including soy protein isolate, defatted soy flour, soy protein concentrate, and soy spent flakes were incorporated into rubber latex to form composites, they showed substantial reinforcement effects as measured by rheological and mechanical methods. It was observed that different ...

155

Extrudate characteristics and morphology of styrene butadiene rubber/high density polyethylene blends  

NASA Astrophysics Data System (ADS)

When HDPE is added to SBR, the melt elasticity of the system gets reduced. The morphology of the extrudates of the blends has been found to be dependent on the shear rate. Dynamic crosslinking with DCP has been improved the processability of SBR/HDPE blends by reducing the melt elasticity of the system considerably.

Jayasree, T. K.; Manuvel, Jayan

2013-06-01

156

DEVELOPMENT AND VALIDATION OF A TEST METHOD FOR ACRYLONITRILE EMISSIONS  

EPA Science Inventory

Acrylonitrile (AN) has been identified as a suspected carcinogen and may be regulated in the future as a hazardous air pollutant under Section 112 of the Clean Air Act. A method was validated that utilizes a midget impinger containing methanol for trapping AN vapors followed by a...

157

Case-cohort study of styrene exposure and ischemic heart disease.  

PubMed

Recent epidemiologic studies have consistently reported increased daily mortalities and hospital admissions associated with exposure to particulate air pollution. Ischemic heart disease (IHD*, International Classification of Diseases, Eighth Revision [ICD-8], codes 410-414) is among those diseases that contribute in large measure to this excess mortality. Some occupational studies have suggested elevated risk of IHD among workers exposed for short periods to styrene, which can be emitted from fossil fuel combustion, aircraft exhausts, and motor vehicle exhausts. Styrene is found in ambient air at average concentrations of a few micrograms per cubic meter or less but may reach very high concentrations at particular locations and times. Unmeasured aerosols of styrene may also increase population exposures. This case-cohort study explored a possible association and dose-response relation between styrene exposure and risk of acute IHD in an occupational setting. The population under study was 6587 male workers employed between 1943 and 1982 in two US plants manufacturing styrene-butadiene polymers used in synthetic rubber. The study assessed all 498 subjects who died from IHD along with a subcohort of twice that size, 997 subjects, selected as a 15% random sample of the full target cohort. IHD deaths during the study led to some overlap between cases and the subcohort, leaving 1424 unique subjects. Job histories were collected for all subjects. Industrial hygienists and engineers from the industry estimated relative exposures for all jobs. Exposure data were collected for many of the jobs from different sources. For any job with no available exposure measurements, z scores were used to estimate job exposure in each plant from the relative exposure level for that job in similar plants and the measurement distribution parameters of the study plant. Standardized mortality ratio (SMR) analyses were used to examine the overall risk of dying from IHD among study subjects compared with the US general population. A significantly elevated SMR of 1.47 with a 95% confidence interval (95% CI) of 1.17 to 1.77 for chronic IHD was found among black workers who had left the plants. A modification of the Cox proportional hazard regression model was used to control for confounders and examine dose-response relations between styrene exposure and the risk of IHD. Employment time-weighted average (TWA) styrene concentration intensity for the most recent 2 years was found significantly associated with death from acute IHD among active workers with a relative hazard of 3.26 to 6.60, depending on duration of employment. In this analysis, the highest relative hazard of 6.60 (95% CI, 1.78-24.54) was among active workers who had been employed for at least 5 years. The results suggest that the exposure intensity was more important than duration of exposure. On the basis of the dose-response relation established in this study, we estimate that for each 10 microg/m3 increase in ambient styrene, acute IHD mortality might increase 0.4%. At normal ambient styrene levels, the relative risk would be increased, at most, 0.1% compared with no exposure. At certain locations and times, however, ambient styrene could reach levels that would result in a relative hazard for acute IHD mortality as high as 3.386-fold the risk at no exposure. PMID:12214600

Matanoski, Genevieve M; Tao, Xuguang

2002-05-01

158

The centimeter and millimeter microwave spectra of butadiene sulfone and ?,?'-D 4 butadiene sulfone  

NASA Astrophysics Data System (ADS)

Microwave measurements on the ground and first eight excited states of the ring-puckering vibration of butadiene sulfone have been extended to millimeter wavelengths. The microwave spectra of the same vibrational states of ?,?'-D 4 butadiene sulfone have been observed. For both isotopomers the Coriolis interaction between the v = 0 and v = 1 states has been analyzed to give the energy separation between these two states. These data and the variation of the rotational constants have been used to derive reduced potential functions for the ring-puckering vibration. The barrier to ring inversion is 49(2) cm -1 for butadiene sulfone and 44(2) cm -1 for the ?,?'-D 4 isotopomer. The ring-puckering vibrational dependence of the quartic centrifugal distortion constants, including a small dependence of ? J and ?J, has been accounted for.

Lesarri, Alberto G.; Charro, M. Elena; Villamañán, Rosa M.; Lister, David G.; López, Juan C.; Alonso, JoséL.

1991-10-01

159

Styrene  

MedlinePLUS

... Where do I go for more information? National Toxicology Program http://ntp.niehs.nih.gov/go/roc12candidates ... Carcinogens, Twelfth Edition, is prepared by the National Toxicology Program, an interagency group coordinated by the U.S. ...

160

A photocrosslinkable melt processible acrylonitrile terpolymer as carbon fiber precursor  

Microsoft Academic Search

A novel photocrosslinkable and melt processible terpolymer precursor for carbon fiber has been successfully synthesized and characterized. The terpolymer was synthesized by an efficient emulsion polymerization route and has a typical composition of acrylonitrile\\/methyl acrylate\\/acryloyl benzophenone in the mole ratio, 85\\/14\\/1. It has been characterized by FTIR, NMR, intrinsic viscosity and GPC molecular weights. The composition of the monomer repeat

T. Mukundan; V. A. Bhanu; K. B. Wiles; H. Johnson; M. Bortner; D. G. Baird; A. K. Naskar; A. A. Ogale; D. D. Edie; J. E. McGrath

2006-01-01

161

Composite electrodes based on carbonized poly(acrylonitrile) foams  

SciTech Connect

The authors report here the preparation and electroanalytical utility of a new composite material based on microcellular carbon foam. The carbon-foam composites are prepared in a two-step process, the first being a controlled pyrolysis of a poly(acrylonitrile) (PAN) foam, followed by filling the resulting carbon foam with an insulating polymer. The morphology and dimensions of the three-dimensional carbon foam thus define the geometry of the active carbon elements in the two-dimensional surface.

Wang, J.; Brennsteiner, A. (New Mexico State Univ., Las Cruces (USA)); Sylwester, A.P. (Sandia National Laboratories, Albuquerque, NM (USA))

1990-05-15

162

MUTAGENICITY AND CARCINOGENICITY ASSESSMENT OF 1,3-BUTADIENE  

EPA Science Inventory

1,3-Butadiene has been shown to be an indirect mutage in bacteria. Two of its potential metabolites, 3,4- epoxybutene and diepoxybutane, are genotoxic in prokaryote as well as eukaryote test systems. Exposure of rodents to 1,3-butadiene results in ovarian tumors in mice and testi...

163

ENGINEERING THE BIOSYNTHESIS OF STYRENE IN YEAST  

EPA Science Inventory

The strategy pursued was to insert genes for phenylalanine ammonia lysase (pal) and phenolic acid decarboxylase (pad) into the yeast that would convert phenylalanine to styrene through a cinnamic acid intermediate. ...

164

The centimeter and millimeter microwave spectra of butadiene sulfone and alpha,alpha'-D4 butadiene sulfone  

Microsoft Academic Search

Microwave measurements on the ground and first eight excited states of the ring-puckering vibration of butadiene sulfone have been extended to millimeter wavelengths. The microwave spectra of the same vibrational states of alpha,alpha'-D4 butadiene sulfone have been observed. For both isotopomers the Coriolis interaction between the v = 0 and v = 1 states has been analyzed to give the

Alberto G. Lesarri; M. Elena Charro; Rosa M. Villamañán; David G. Lister; Juan C. López; Josél. Alonso

1991-01-01

165

Relationship between Hansen Solubility Parameters of ABS and its Homopolymer Components of PAN, PB, and PS  

Microsoft Academic Search

ABS, an important terpolymer produced from acrylonitrile, butadiene, and styrene, is widely used in the form of ABS alloys. Because the microstructure of ABS and its alloys shows a multiphase, researching the miscibility is of significant concern for ABS applications. In order to completely understand the special solubility properties of ABS resin, the relationship between Hansen solubility parameters (HSP) of

Ping Peng; Baoli Shi; Lina Jia; Bin Li

2010-01-01

166

Laser transmission welding of ABS: Effect of CNTs concentration and process parameters on material integrity and weld formation  

NASA Astrophysics Data System (ADS)

This paper reports a study of the laser transmission welding of polymeric joints composed by two ABS (acrylonitrile/butadiene/styrene) sheets, one transparent (natural ABS) and the other absorbent (filled by different percentages of carbon nanotubes (CNTs)). The objective of this work is to analyze the effect of process parameters and CNTs concentrations on weld formation and mechanical resistance of the weld joints.

Rodríguez-Vidal, E.; Quintana, I.; Gadea, C.

2014-04-01

167

Selectivity of MH Ion-Exchange Absorption on Sulfonic Resins in Ternary Solutions  

Microsoft Academic Search

The selectivity of M-H ion-exchange absorption (M = Na or K) on sulfonated acrylonitrile-butadiene-styrene copolymer previously crosslinked with resol has been investigated in ternary MCl-HCOOH-H2O solutions at 298 K. Hypotheses are put forward concerning the factors determining the selectivity of the cation-exchange resins in solutions of weak organic acids.

M. S. Metwally; T. M. Samy

1993-01-01

168

RADIATION INDUCED BLOCK AND GRAFT COPOLYMERIZATION OF DISPERSION OF POLYMETHACRYLATES WITH ACRYLONITRILE  

Microsoft Academic Search

Graft and block copolymers were prepared by grafting acrylonitrile onto ; preirradiated aqueous dispersions of polymethylmethacrylate. The influence of ; different experimental conditions as irradiation time, dose rate, and the time ; between irradiation and addition to the monomer on the course of the reaction was ; studied in detail. Fractional precipitation of the copolymer showed no ; homopolymer acrylonitrile,

C. Schneider; J. Herz; D. Hummel

1962-01-01

169

Photochemical and discharge-driven pathways to aromatic products from 1,3-butadiene.  

PubMed

A detailed study of the photochemical and discharge-driven pathways taken by gas-phase 1,3-butadiene has been carried out. Photolysis or discharge excitation was initiated inside a short reaction tube attached to the outlet of a pulsed valve. Bath gas temperatures near 100 K were achieved in the reaction tube by the constrained expansion of the gas mixture into the tube, simulating temperatures of relevance in Titan's atmosphere. Photolysis of 1,3-butadiene was initiated at 218 nm with a laser pulse that counter-propagated the reaction tube. Discharge excitation was carried out using discharge electrodes imbedded in the reaction tube walls, enabling the study of the photochemical and discharge products under similar conditions. Products were detected using either single-photon VUV photoionization (118 nm = 10.5 eV) or resonant two-photon ionization (R(2)PI) spectroscopy in a time-of-flight mass spectrometer. Emphasis was placed on characterization of the aromatic products formed, since these may be of particular relevance to Titan's atmosphere, where benzene has been positively identified and 1,3-butadiene is projected as the principle pathway to its formation. Consistent with previous studies of the photodissociation of 1,3-butadiene, C(3)H(3) + CH(3) is the dominant primary product formed. Under the temperature-pressure conditions present in the reaction tube (T approximately 75-100 K, P = 50 mbar), C(6)H(6) is the dominant secondary photochemical product formed. A 1:1 C(4)H(6):C(4)D(6) mixture was used to prove that the C(6)H(6) product was formed by recombination of two C(3)H(3) radicals; however, a careful search for benzene revealed none, indicating that less than 1% of the C(6)H(6) formed in the reaction tube is benzene. This is consistent with expectations for these temperatures and pressures based on previous modeling of propargyl recombination. Two aromatic products were observed from the photochemistry: ethylbenzene and 3-phenylpropyne. Plausible pathways leading to these products are proposed. In the discharge, C(3)H(3) + CH(3) are also identified as significant primary neutral products and C(6)H(6) as a dominant higher-mass product. In this case, the C(6)H(6) was identified as benzene via its R2PI spectrum, appearing with intensity about 10 times larger than any other aromatic formed in the discharge. R2PI spectra of a total of about 15 aromatic products were recorded from the 1,3-butadiene discharge, among them toluene; styrene; phenylacetylene; o-, m-, and p-xylene; ethylbenzene; indane; indene; beta-methylstyrene; and naphthalene. Previously unidentified spectra in the m/z 142 and 144 mass channels were positively identified as the 1,3- and 1,4-isomers of phenylcyclopentadiene and the analogous 1-phenylcyclopentene. PMID:17929788

Newby, Josh J; Stearns, Jaime A; Liu, Ching-Ping; Zwier, Timothy S

2007-11-01

170

Kinetic and equilibrium studies of acrylonitrile binding to cytochrome c peroxidase and oxidation of acrylonitrile by cytochrome c peroxidase compound I  

SciTech Connect

Highlights: •Cytochrome c peroxidase (CcP) binds acrylonitrile in a pH-independent fashion. •The spectrum of the CcP/acrylonitrile complex is that of a 6c–ls ferric heme. •The acrylonitrile/CcP complex has a K{sub D} value of 1.1 ± 0.2 M. •CcP compound I oxidizes acrylonitrile with a maximum turnover rate of 0.61 min{sup ?1}. -- Abstract: Ferric heme proteins bind weakly basic ligands and the binding affinity is often pH dependent due to protonation of the ligand as well as the protein. In an effort to find a small, neutral ligand without significant acid/base properties to probe ligand binding reactions in ferric heme proteins we were led to consider the organonitriles. Although organonitriles are known to bind to transition metals, we have been unable to find any prior studies of nitrile binding to heme proteins. In this communication we report on the equilibrium and kinetic properties of acrylonitrile binding to cytochrome c peroxidase (CcP) as well as the oxidation of acrylonitrile by CcP compound I. Acrylonitrile binding to CcP is independent of pH between pH 4 and 8. The association and dissociation rate constants are 0.32 ± 0.16 M{sup ?1} s{sup ?1} and 0.34 ± 0.15 s{sup ?1}, respectively, and the independently measured equilibrium dissociation constant for the complex is 1.1 ± 0.2 M. We have demonstrated for the first time that acrylonitrile can bind to a ferric heme protein. The binding mechanism appears to be a simple, one-step association of the ligand with the heme iron. We have also demonstrated that CcP can catalyze the oxidation of acrylonitrile, most likely to 2-cyanoethylene oxide in a “peroxygenase”-type reaction, with rates that are similar to rat liver microsomal cytochrome P450-catalyzed oxidation of acrylonitrile in the monooxygenase reaction. CcP compound I oxidizes acrylonitrile with a maximum turnover number of 0.61 min{sup ?1} at pH 6.0.

Chinchilla, Diana, E-mail: Diana_Chinchilla@yahoo.com; Kilheeney, Heather, E-mail: raindropszoo@yahoo.com; Vitello, Lidia B., E-mail: lvitello@niu.edu; Erman, James E., E-mail: jerman@niu.edu

2014-01-03

171

New dual-phase polymer electrolytes prepared from NBR\\/SBR lattices. [polyacryloNitrile-Butadiene Rubber\\/poly(Styrene-Butadiene) copolymer Rubber  

Microsoft Academic Search

A new type of Li[sup +] ion conducting polymer electrolytes consisting of two phases, one of which is a highly polar region (impregnated with lithium salt solution), forming ion-conductive channels, while the other is a nonpolar region, forming supporting polymer matrices have been prepared from NBR\\/SBR lattices. TEM measurement and EDX analysis show evidence that dual-phase structure is constructed in

Morihiko Matsumoto; Toshihiro Ichino; J. S. Rutt; Shiro Nishi

1993-01-01

172

New dual-phase polymer electrolytes prepared from NBR/SBR lattices. [polyacryloNitrile-Butadiene Rubber/poly(Styrene-Butadiene) copolymer Rubber  

SciTech Connect

A new type of Li[sup +] ion conducting polymer electrolytes consisting of two phases, one of which is a highly polar region (impregnated with lithium salt solution), forming ion-conductive channels, while the other is a nonpolar region, forming supporting polymer matrices have been prepared from NBR/SBR lattices. TEM measurement and EDX analysis show evidence that dual-phase structure is constructed in the electrolyte. Ionic conductivity of the electrolyte increases with increase of lithium salt solution content. Maximum ionic conductivity of 2.2 [times] 10[sup [minus]3] S/cm is obtained at the lithium salt solution content of 60.5% (w/w). The electrolyte retains rubber-like film with good mechanical strength despite the presence of the solution.

Matsumoto, Morihiko; Ichino, Toshihiro; Rutt, J.S.; Nishi, Shiro (Nippon Telegraph and Telephone Corp., Tokyo (Japan). NTT Interdisciplinary Research Lab.)

1993-10-01

173

Photodegradation mechanisms of tetraphenyl butadiene coatings for liquid argon detectors  

E-print Network

We report on studies of degradation mechanisms of tetraphenyl butadiene (TPB) coatings of the type used in neutrino and dark matter liquid argon experiments. Using gas chromatography coupled to mass spectrometry we have ...

Jones, Benjamin James Poyner

174

Development of Enantioselective Polyclonal Antibodies to Detect Styrene Oxide Protein  

E-print Network

, California 95616 Styrene has been reported to be pneumotoxic and hepa- totoxic in humans and animals. Styrene that can stereoselectively recognize proteins modified by styrene oxide enantiomers at cysteine residues in factories fabricating reinforced plastics products. Humans are potentially exposed to this widespread

Hammock, Bruce D.

175

Kinetic and equilibrium studies of acrylonitrile binding to cytochrome c peroxidase and oxidation of acrylonitrile by cytochrome c peroxidase compound I  

PubMed Central

Ferric heme proteins bind weakly basic ligands and the binding affinity is often pH dependent due to protonation of the ligand as well as the protein. In an effort to find a small, neutral ligand without significant acid/base properties to probe ligand binding reactions in ferric heme proteins we were led to consider the organonitriles. Although organonitriles are known to bind to transition metals, we have been unable to find any prior studies of nitrile binding to heme proteins. In this communication we report on the equilibrium and kinetic properties of acrylonitrile binding to cytochrome c peroxidase (CcP) as well as the oxidation of acrylonitrile by CcP compound I. Acrylonitrile binding to CcP is independent of pH between pH 4 and 8. The association and dissociation rate constants are 0.32 ± 0.16 M?1s?1 and 0.34 ± 0.15 s?1, respectively, and the independently measured equilibrium dissociation constant for the complex is 1.1 ± 0.2 M. We have demonstrated for the first time that acrylonitrile can bind to a ferric heme protein. The binding mechanism appears to be a simple, one-step association of the ligand with the heme iron. We have also demonstrated that CcP can catalyze the oxidation of acrylonitrile, most likely to 2-cyanoethylene oxide in a “peroxygenase”-type reaction, with rates that are similar to rat liver microsomal cytochrome P450-catalyzed oxidation of acrylonitrile in the monooxygenase reaction. CcP compound I oxidizes acrylonitrile with a maximum turnover number of 0.61 min?1 at pH 6.0. PMID:24291498

Chinchilla, Diana; Kilheeney, Heather; Vitello, Lidia B.; Erman, James E.

2013-01-01

176

Reaction of disubstituted aromatic compounds with styrene  

SciTech Connect

Hydrocarbons of the 1,1-diphenylethane type were obtained by the reaction of styrene with various disubstituted derivatives of benzene in the presence of titanium tetrachloride. It was found that the yield of the desired compound depends on the strength of the electron-donating substituents and on steric factors in the aromatic ring.

Grushin, A.I.; Grigor'ev, V.V.; Prokof'ev, K.V.; Kozlova, N.M.

1988-03-20

177

Texture and Properties of Acrylonitrile–Ammonium Itaconate Copolymer Precursor Fibers and Carbon Fibers  

Microsoft Academic Search

Acrylonitrile–ammonium itaconate copolymer {P[AN-co-(NH4)2IA]} was fabricated by free-radical solution copolymerization of acrylonitrile (AN) and ammonium itaconate [(NH4)2IA]. The copolymer was confected into a spinning solution (dope) and spun into precursor fibers. Then the precursor fibers\\u000a were converted to carbon fibers by stabilization and carbonization processes. Another copolymer of acrylonitrile–itaconic\\u000a acid [P(AN-co-IA)] and its resultant fibers were studied in contrast. Due

He-yi Ge; Jian-jun Liu; Juan Chen; Cheng-guo Wang

2007-01-01

178

Vapor-liquid equilibria of copolymer + solvent and homopolymer + solvent binaries: New experimental data and their correlation  

SciTech Connect

Sixty-four isothermal data sets for vapor-liquid equilibria (VLE) for polymer + solvent binaries have been obtained using a gravimetric sorption technique, in the range of 23.5--80 C. Solvents studied were acetone, acetonitrile, 1-butanol, 1,2-dichloroethane, chloroform, cyclohexane, hexane, methanol, octane, pentane, and toluene. Copolymers studied were poly(acrylonitrile-co-butadiene), poly(styrene-co-acrylonitrile), poly(styrene-co-butadiene), poly(styrene-co-butyl methacrylate), poly(vinyl acetate-co-ethylene), and poly(vinyl acetate-co-vinyl chloride). All copolymers were random copolymers. Some homopolymers were also studied: polyacrylonitrile, polybutadiene, poly(butyl methacrylate), poly(ethylene oxide), polystyrene, and poly(vinyl acetate). The composition of the copolymer may have a surprising effect on VLE. Normally, deviation from ideal behavior lies between those of the constituent homopolymers, according to the copolymer composition, as observed for cyclohexane + poly(ethylene-co-vinyl acetate) and chloroform + poly(styrene-co-butyl methacrylate). However, the strong nonideal behavior observed for systems containing hydrocarbons and poly(butadiene-co-acrylonitrile) shows that the effect of acrylonitrile is in excess of that expected form the copolymer composition. The perturbed hard-sphere chain (PHSC) equation of state was used to represent VLE of the copolymer solutions studied here.

Gupta, R.B.; Prausnitz, J.M. [Lawrence Berkeley Lab., CA (United States)

1995-07-01

179

Occupational exposure of workers to 1,3-butadiene.  

PubMed Central

Researchers from the National Institute for Occupational Safety and Health (NIOSH) conducted an extent-of-exposure study of the 1,3-butadiene monomer, polymer, and end-user industries to determine the size of the exposed workforce, evaluate control technologies and personal protective equipment programs, and assess occupational exposure to 1,3-butadiene. A new analytical method was developed for 1,3-butadiene that increased the sensitivity and selectivity of the previous NIOSH method. The new method is sensitive to 0.2 microgram per 1,3-butadiene sample. Walk-through surveys were conducted in 11 monomer, 17 polymer, and 2 end-user plants. In-depth industrial hygiene surveys were conducted at 4 monomer, 5 polymer, and 2 end-user plants. Airborne exposure concentrations of 1,3-butadiene were determined using personal sampling for each job category. A total of 692 full shift and short-term personnel and 259 area air samples were examined for the presence of 1,3-butadiene. Sample results indicated that all worker exposures were well below the current OSHA PEL of 1000 ppm. Exposures ranged from less than 0.006 ppm to 374 ppm. The average exposure for all samples was less than 2 ppm. The present American Conference of Governmental Industrial Hygienists (ACGIH) threshold limit value for 1,3-butadiene is 10 ppm. To reduce the potential for occupational exposure, it is recommended that quality control sampling be conducted using a closed loop system. Also all process pumps should be retrofitted with dual mechanical seals, magnetic gauges should be used in loading and unloading rail cars, and engineering controls should be designed for safely voiding quality control cylinders. PMID:2401251

Fajen, J M; Roberts, D R; Ungers, L J; Krishnan, E R

1990-01-01

180

Degradation of chlorinated butenes and butadienes in granular iron columns.  

PubMed

Manufacturing facilities for production of chlorobutyl rubber have the potential to release a mixture of at least 5 chlorinated butenes and butadienes including trans-1,4-dichlorobutene-2 (1,4-DCB-2), 3,4-dichlorobutene-1 (3,4-DCB-1), 2,3,4-trichlorobutene-1 (TCB), 2-chlorobutadiene-1,3 (chloroprene) and 2,3-dichlorobutadiene-1,3 (DCBD) into groundwater environment. To evaluate the potential of using granular iron in the remediation of the above contaminants, a series of column experiments were conducted. Degradation of all 5 compounds followed pseudo-first-order kinetics. The three chlorinated butenes degraded much faster (surface area normalized half-lives, t(1/2)', ranged from 1.6 to 5.2 min m2/mL) than the 2 chlorinated butadienes (t(1/2)' ranged from 102 to 197 min m2/mL). All contaminants fully dechlorinated by granular iron to 1,3-butadiene as a common reaction intermediate that then degraded to a mixture of relatively non-harmful end products consisting of 1-butene, cis-2-butene, trans-2-butene and n-butane. Based on the kinetic data, product distributions, and chlorine mass balances, reaction pathways for these compounds are proposed. For the chlorinated butenes, 3,4-DCB-1 and TCB, undergo reductive beta-elimination reactions resulting in 1,3-butadiene and chloroprene intermediates. Dechlorination of 1,4-DCB-2 to 1,3-butadiene occurs through a reductive elimination similar to reductive beta-elimination. For dechlorination of the two chlorinated butadienes, chloroprene and DCBD, dechlorination occurs through a hydrogenolysis pathway. The common non-chlorinated intermediate, 1,3-butadiene, undergoes catalytic hydrogenation resulting in a mixture of butane isomers and n-butane. The results suggest that granular iron is an effective material for treatment of groundwater contaminated with these compounds. PMID:19847707

Hughes, Rodney; Gui, Lai; Gillham, Robert W

2009-10-01

181

ABSORPTION OF CO2 AND SUBSEQUENT VISCOSITY REDUCTION OF AN ACRYLONITRILE COPOLYMER. (R829555)  

EPA Science Inventory

Acrylonitrile (AN) copolymers (AN content greater than about 85 mol%) are traditionally solution processed to avoid a cyclization and crosslinking reaction that takes place at temperatures where melt processing would be feasible. It is well known that carbon dioxide (CO...

182

21 CFR 177.1480 - Nitrile rubber modified acrylonitrile-methyl acrylate copolymers.  

Code of Federal Regulations, 2012 CFR

...locations.html. (iii) Residual acrylonitrile monomer content is not more than 11 parts per million as determined by gas chromatography. (iv) Acetonitrile-soluble fraction after refluxing the base polymer in acetonitrile for 1 hour is not greater...

2012-04-01

183

Pervaporative removal of acrylonitrile from aqueous streams through polydimethylsiloxane membrane.  

PubMed

This study describes the successful separation of acrylonitrile (ACN) from dilute aqueous streams using pervaporation process. The influences of ACN feed concentration, permeate pressure, operating temperature, feed flow rate and membrane thickness on the membrane separation performance were investigated. The results showed that with an increase in ACN concentration in the feed solution, the permeation flux of ACN increased while the enrichment factor decreased. It was also indicated that increasing the permeate pressure reduced the driving force for mass transfer and consequently the permeation flux dropped while the enrichment factor enhanced. Polydimethylsiloxane membranes used in this study showed very good properties in the separation process, leading to enrichment factors in the range of 70-140. Furthermore, the activation energy for pervaporation of both ACN and water calculated from Arrhenius plot indicated that the permeation of water through the membrane was more temperature dependant than ACN. PMID:22049705

Aliabadi, Majid; Aroujalian, Abdolreza; Raisi, Ahmadreza

2011-01-01

184

Multisubstituted indole-acrylonitrile hybrids as potential cytotoxic agents.  

PubMed

A series of multisubstituted indole-acrylonitrile hybrids were designed, synthesized and evaluated for their potential cytotoxic activities. The bio-evaluation results indicated that some of the target compounds (such as 3a, 3f, 3k, 3n) exhibited good to moderate cytotoxic effect on HepG2, BCG-823, BEL-7402, and HL-7702 cell lines. Especially, the compounds 3a and 3k also exhibited high cytotoxic activities (3a, 19.38±3.38 ?M; 3k, 15.43±3.54 ?M) against the BEL-7402 cell line resistant to Taxol (>25?M) and 5-FU (>500 ?M), which might be developed as novel lead scaffold for potential anticancer agents. PMID:24684840

Ke, Shaoyong; Yang, Ziwen; Zhang, Zhigang; Liang, Ying; Wang, Kaimei; Liu, Manli; Shi, Liqiao

2014-04-15

185

40 CFR Table 6 to Subpart Jjj of... - Known Organic HAP Emitted From the Production of Thermoplastic Products  

...a continuous mass process ? ? ? ASA/AMSAN ? ? EPS ? MABS ? ? ? MBS ? ? ? Nitrile resin ...Acrylonitrile styrene resin/alpha methyl styrene acrylonitrile resin. EPS = expandable polystyrene resin. MABS = methyl...

2014-07-01

186

HEALTH ASSESSMENT DOCUMENT FOR 1,3-BUTADIENE (EXTERNAL REVIEW DRAFT)  

EPA Science Inventory

This risk assessment of 1,3-butadiene, a gas used commercially in the production of various resins and plastics, concludes that 1,3-butadiene is a known human carcinogen, based on three types of evidence: 1) excess leukemias in workers occupationally exposed to 1,3-butadiene (by ...

187

Effect of electron beam irradiation on the properties of natural rubber (NR)/styrene-butadiene rubber (SBR) blend  

NASA Astrophysics Data System (ADS)

In this study, physico-mechanical properties of NR/SBR blends cured by electron beam irradiation and sulfur were compared. The NR/SBR blends were prepared using a two-roll mill. Electron beam irradiations of 100-400 kGy were applied to cure the blends and changes in physico-mechanical properties were studied as a function of irradiation. Also, oil resistance and the effect of thermal ageing on mechanical properties of the blends were investigated. The results show that the irradiated blends have better mechanical properties than those cured by sulfur system. The irradiation cured samples also exhibited better heat stability than the sulfur cured samples. The blend cured by the highest dose shows the lowest swelling and high oil resistance compared with the other samples cured by irradiation.

Manshaie, R.; Nouri Khorasani, S.; Jahanbani Veshare, S.; Rezaei Abadchi, M.

2011-01-01

188

Aggregate structure and effect of phthalic anhydride modified soy protein on the mechanical properties of styrene-butadiene copolymer  

Technology Transfer Automated Retrieval System (TEKTRAN)

The aggregate structure of phthalic anhydride (PA) modified soy protein isolate (SPI) was investigated by estimating its fractal dimension from the equilibrated dynamic strain sweep experiments. The estimated fractal dimensions of the filler aggregates were less than 2, indicating that these partic...

189

Simple Replica Micromolding of Biocompatible Styrenic Elastomers†  

PubMed Central

In this work, we introduce a simple solvent-assisted micromolding technique for the fabrication of high-fidelity styrene-ethylene/butylene-styrene (SEBS) microfluidic devices with high polystyrene (PS) content (42 wt% PS). SEBS triblock copolymers are styrenic thermoplastic elastomers that exhibit both glassy thermoplastic and elastomeric properties resulting from their respective hard PS and rubbery ethylene/butylene fractions. The PS fraction gives SEBS microdevices many of the appealing properties of pure PS devices, while the elastomeric fraction simplifies fabrication of the devices, similar to PDMS. SEBS42 devices have wettable, stable surfaces (both contact angle and zeta potential) that support cell attachment and proliferation consistent with tissue culture dish substrates, do not adsorb hydrophobic molecules, and have high bond strength to wide range of substrates (glass, PS, SEBS). Furthermore, SEBS42 devices are mechanically robust, thermally stable, as well as exhibit low auto-fluorescence and high transmissivity. We characterize SEBS42 surface properties by contact angle measurements, cell culture studies, zeta potential measurements, and the adsorption of hydrophobic molecules. The PS surface composition of SEBS microdevices cast on different substrates is determined by time-of-flight secondary ion mass spectrometry (ToF-SIMS). The attractive SEBS42 material properties, coupled with the simple fabrication method, make SEBS42 a quality substrate for microfluidic applications where the properties of PS are desired but the ease of PDMS micromolding is favoured. PMID:23670166

Bielawski, Kevin S.; Sniadecki, Nathan J.; Jenkel, Colin F.; Vogt, Bryan D.; Posner, Jonathan D.

2013-01-01

190

Simple replica micromolding of biocompatible styrenic elastomers.  

PubMed

In this work, we introduce a simple solvent-assisted micromolding technique for the fabrication of high-fidelity styrene-ethylene/butylene-styrene (SEBS) microfluidic devices with high polystyrene (PS) content (42 wt% PS, SEBS42). SEBS triblock copolymers are styrenic thermoplastic elastomers that exhibit both glassy thermoplastic and elastomeric properties resulting from their respective hard PS and rubbery ethylene/butylene segments. The PS fraction gives SEBS microdevices many of the appealing properties of pure PS devices, while the elastomeric properties simplify fabrication of the devices, similar to PDMS. SEBS42 devices have wettable, stable surfaces (both contact angle and zeta potential) that support cell attachment and proliferation consistent with tissue culture dish substrates, do not adsorb hydrophobic molecules, and have high bond strength to wide range of substrates (glass, PS, SEBS). Furthermore, SEBS42 devices are mechanically robust, thermally stable, as well as exhibit low auto-fluorescence and high transmissivity. We characterize SEBS42 surface properties by contact angle measurements, cell culture studies, zeta potential measurements, and the adsorption of hydrophobic molecules. The PS surface composition of SEBS microdevices cast on different substrates is determined by time-of-flight secondary ion mass spectrometry (ToF-SIMS). The attractive SEBS42 material properties, coupled with the simple fabrication method, make SEBS42 a quality substrate for microfluidic applications where the properties of PS are desired but the ease of PDMS micromolding is favoured. PMID:23670166

Borysiak, Mark D; Bielawski, Kevin S; Sniadecki, Nathan J; Jenkel, Colin F; Vogt, Bryan D; Posner, Jonathan D

2013-07-21

191

Neurobehavioral effects of occupational exposure to low-level styrene.  

PubMed

Eighty-six workers in six fiberglass-reinforced plastics manufacturing plants in Taiwan were given a detailed evaluation including medical and occupational questionnaires, symptom questionnaires, blood sampling, and neurobehavioral tests, including cognitive performance, vibratory perception threshold, and thermal perception threshold. A Chinese version of cognitive tests modified from the Neurobehavioral Evaluation System 2 was applied. Forty-one workers directly exposed to styrene at the mean concentration of 22 ppm are compared with 45 workers not subject to styrene exposure. Multiple linear regression analysis controlling for age, sex, education, and alcohol intake revealed significant associations between styrene exposure and responses in some neuropsychologic measurements. No acute or chronic symptom had significant correlation with styrene exposure. Among the neurobehavioral tests, only the continuous performance test and vibration threshold were significantly and adversely affected in workers exposed to styrene. Significant changes in the central and peripheral nervous system were thus detected at a mean styrene exposure of 22 ppm. PMID:8866539

Tsai, S Y; Chen, J D

1996-01-01

192

Selective hydrogenation of crude high-butadiene C4 cuts  

SciTech Connect

A process is described for the selective hydrogenation of 1,3-butadiene to butenes in the liquid phase or trickle phase in contact with a fixed-bed supported noble metal catalyst, wherein a C[sub 4] stream having a 1,3-butadiene content of from 20 to 80% w/w, based on the weight of the C[sub 4] stream, is hydrogenated in a cascade of two reaction zones wherein each of the two reaction zones is operated at reaction temperatures ranging from 40 C to 120 C, pressures ranging from 5 to 50 bar wherein the pressure in the second reaction zone is lower than the pressure in the first reaction zone, and liquid hourly space velocities of the C[sub 4] stream ranging from 0.1 to 30 h[sup [minus]1], such that the hydrogenation product from the first reaction zone has a 1,3-butadiene content of from 0.1 to 20% w/w and the hydrogenation product from the second reaction zone has a 1,3-butadiene content of from 0.005 to 1% w/w, based in both cases on the weight of the C[sub 4] stream, wherein the 1,3-butadiene content of the hydrogenation product from the second reaction zone is at least 5 times smaller than that of the hydrogenation product from the first reaction zone, and wherein the selectivity achieved for the conversion of 1,3-butadiene in the direction of butenes is at least 96%.

Polanek, P.; Posselt, D.; Schreyer, P.

1993-07-13

193

Enrichment of fungi and degradation of styrene in biofilters  

Microsoft Academic Search

Summary Experiments were set up in order to enrich styrene-degrading fungi in biofilters under conditions representative for industrial off-gas treatment. From the support materials tested, polyurethane and perlite proved to be most suitable for enrichment of styrene-degrading fungi. The biofilter with perlite completely degraded styrene when amounts ranging between 290 and 675 mg\\/m in the influent gas were present. An

Huub H. J. Cox; José H. M. Houtman; Hans J. Doddema; Wim Harder

1993-01-01

194

Thermodynamic Behavior of Poly(styrene-b-styrene sulfonate) Block Copolymers With Varying Counterions  

NASA Astrophysics Data System (ADS)

A series of poly(styrene-b-styrene sulfonate) (PS-b-PSS) block copolymers have been prepared by RAFT polymerization. The counterions in the PSS block have been varied by neutralizing the sulfonate groups with alkyl amines or quaternary ammonium ions. The choice of counterion has a strong effect on the lipophilicity of the PSS block. This presentation will focus on the resulting morphology and bulk thermodynamic behavior of these polymers as a function of the PSS counterion. The use of these materials for preparing ion-exchange membranes will be discussed.

Cavicchi, Kevin; Pollack, Kevin

2009-03-01

195

40 CFR 721.3700 - Fatty acid, ester with styrenated phenol, ethylene oxide adduct.  

Code of Federal Regulations, 2010 CFR

...ester with styrenated phenol, ethylene oxide adduct. 721.3700 Section 721.3700...ester with styrenated phenol, ethylene oxide adduct. (a) Chemical substances and...ester with styrenated phenol, ethylene oxide adduct (P-90-364) is subject...

2010-07-01

196

40 CFR 721.3800 - Formaldehyde, condensated polyoxyethylene fatty acid, ester with styrenated phenol, ethylene...  

...ester with styrenated phenol, ethylene oxide adduct. 721.3800 Section 721.3800...ester with styrenated phenol, ethylene oxide adduct. (a) Chemical substances and...ester with styrenated phenol, ethylene oxide adduct (PMN P-90-360) is...

2014-07-01

197

40 CFR 721.3800 - Formaldehyde, condensated polyoxyethylene fatty acid, ester with styrenated phenol, ethylene...  

Code of Federal Regulations, 2012 CFR

...ester with styrenated phenol, ethylene oxide adduct. 721.3800 Section 721.3800...ester with styrenated phenol, ethylene oxide adduct. (a) Chemical substances and...ester with styrenated phenol, ethylene oxide adduct (PMN P-90-360) is...

2012-07-01

198

40 CFR 721.3800 - Formaldehyde, condensated polyoxyethylene fatty acid, ester with styrenated phenol, ethylene...  

Code of Federal Regulations, 2011 CFR

...ester with styrenated phenol, ethylene oxide adduct. 721.3800 Section 721.3800...ester with styrenated phenol, ethylene oxide adduct. (a) Chemical substances and...ester with styrenated phenol, ethylene oxide adduct (PMN P-90-360) is...

2011-07-01

199

40 CFR 721.3700 - Fatty acid, ester with styrenated phenol, ethylene oxide adduct.  

...ester with styrenated phenol, ethylene oxide adduct. 721.3700 Section 721.3700...ester with styrenated phenol, ethylene oxide adduct. (a) Chemical substances and...ester with styrenated phenol, ethylene oxide adduct (P-90-364) is subject...

2014-07-01

200

40 CFR 721.3700 - Fatty acid, ester with styrenated phenol, ethylene oxide adduct.  

Code of Federal Regulations, 2011 CFR

...ester with styrenated phenol, ethylene oxide adduct. 721.3700 Section 721.3700...ester with styrenated phenol, ethylene oxide adduct. (a) Chemical substances and...ester with styrenated phenol, ethylene oxide adduct (P-90-364) is subject...

2011-07-01

201

40 CFR 721.3700 - Fatty acid, ester with styrenated phenol, ethylene oxide adduct.  

Code of Federal Regulations, 2012 CFR

...ester with styrenated phenol, ethylene oxide adduct. 721.3700 Section 721.3700...ester with styrenated phenol, ethylene oxide adduct. (a) Chemical substances and...ester with styrenated phenol, ethylene oxide adduct (P-90-364) is subject...

2012-07-01

202

40 CFR 721.3700 - Fatty acid, ester with styrenated phenol, ethylene oxide adduct.  

Code of Federal Regulations, 2013 CFR

...ester with styrenated phenol, ethylene oxide adduct. 721.3700 Section 721.3700...ester with styrenated phenol, ethylene oxide adduct. (a) Chemical substances and...ester with styrenated phenol, ethylene oxide adduct (P-90-364) is subject...

2013-07-01

203

40 CFR 721.10389 - Styrene, copolymer with acrylic acid, salt with alkoxylated alkenylamine (generic).  

Code of Federal Regulations, 2012 CFR

...Styrene, copolymer with acrylic acid, salt with alkoxylated alkenylamine (generic...Styrene, copolymer with acrylic acid, salt with alkoxylated alkenylamine (generic...styrene, copolymer with acrylic acid, salt with alkoxylated alkenylamine (PMN...

2012-07-01

204

21 CFR 177.2710 - Styrene-divinylbenzene resins, cross-linked.  

Code of Federal Regulations, 2010 CFR

...2009-04-01 true Styrene-divinylbenzene resins, cross-linked. 177.2710 Section...177.2710 Styrene-divinylbenzene resins, cross-linked. Styrene-divinylbenzene cross-linked copolymer resins may be safely used as articles...

2010-04-01

205

21 CFR 173.70 - Chloromethylated aminated styrene-divinylbenzene resin.  

Code of Federal Regulations, 2010 CFR

...Chloromethylated aminated styrene-divinylbenzene resin. 173.70 Section 173.70 Food...Chloromethylated aminated styrene-divinylbenzene resin. Chloromethylated aminated styrene-divinylbenzene...the weight of the solids in the original resin dispersion. (c) The additive is...

2010-04-01

206

1,3-Butadiene working group report.  

PubMed

During the Workshop in North Carolina, the in vivo metabolism, adduct formation and genotoxicity data available from rodent and human exposure to 1,3-butadiente (BD) were reviewed and they are summarized in the present report. BD is metabolized by cytochrome P-450-dependent monoxygenases to the primary metabolite 1,2-epoxybutene-3 (epoxybutene, EB). EB is subjected to further metabolism: oxidation to 1,2:3,4-diepoxybutane (DEB), hydrolysis to 3-butene-1,2-diol and conjugation to glutathione. The first pathway seems to prevail in mice while the latter is characteristic for rats and possibly for humans. Species differences exist in adduct formation of the monoepoxide to hemoglobin, for which the following pattern has been found: mice > rats > humans. Genotoxity of BD was found in mice with all applied tests; however, negative results were obtained in rats. In exposed humans, the cytogenetic studies in peripheral blood lymphocytes did not show genotoxic effects, although one report described elevated hprt variant levels in peripheral blood lymphocytes of exposed workers. It was concluded that the presently available data are insufficient for the application of the parallelogram model to estimate genetic risk for humans. As an alternative approach, a tentative estimate of the doubling dose for induction of hprt mutations in somatic cells of mice and men was performed and the calculated values were surprisingly similar, i.e. 9000 ppmh. However, this estimate is burdened with a number of caveats which were discussed in detail. The working group identified a series of urgent research needs to provide the appropriate data for the application of the parallelogram model, such as identification of metabolic pathways in different rodent species and humans, metabolic studies in mice, rats and humans considering metabolic polymorphisms, studies of adducts to DNA and hemoglobin especially of DEB and other butadiene metabolites in rodents and humans, studies of mutational spectra (mutational fingerprinting) in somatic and germinal cells, confirmation of the human hprt mutation data, conformation of the rodent malformation data, dose-response studies in rodent germ cell tests and studies on repair kinetics of mono-adducts induced by EB as opposed to repair of cross-links produced by DEB. Finally, it was suggested that the original parallelogram consisting of data from somatic cell studies in rodents and humans plus studies of heritable effects in rodents to extrapolate to germ cell risk for humans should be supplemented with studies in sperm of experimental animals and exposed men. PMID:7623862

Adler, I D; Cochrane, J; Osterman-Golkar, S; Skopek, T R; Sorsa, M; Vogel, E

1995-08-01

207

Catalytic transformation of ethanol into 1,3-butadiene.  

PubMed

1,3-Butadiene is an important constituent of many products that we rely upon. It is currently prepared from non-sustainably derived sources. However, in the early part of the 20(th) Century the use of ethanol as a source of 1,3-butadiene has been reported. With the arrival of a cheap and bountiful supply of crude-oil derived sources the need for the sustainable route was deemed unnecessary. In recent years the conversion of ethanol to 1,3-butadiene has undergone somewhat of a mini resurgence as the chemical industry looks to try to find a sustainable and secure route to this important building block. This review will emphasise some of the most recent work in the field and look ahead to what needs to be achieved to make this research a reality. Graphical AbstractThis review focusses on the recent progress in the area of the conversion of ethanol to 1, 3-butadiene. PMID:25254071

Jones, Matthew D

2014-01-01

208

Cancer risk assessment of 1,3-butadiene.  

PubMed Central

This paper discusses the Environmental Protection Agency's (EPA) risk assessment of 1,3-butadiene. The assessment focuses on estimation of increased cancer risk to populations living near industrial sources of 1,3-butadiene emissions rather than occupationally exposed populations. Incremental cancer risk estimates based on extrapolation from laboratory animal data are presented. Pharmacokinetic data published since the EPA's 1985 assessment are incorporated, which somewhat alters the earlier assessment of cancer risk. Characterization of emission sources, estimates of ambient air concentrations, and population exposure are also discussed. The estimate presented in this paper of excess cancer cases resulting from point source exposure to 1,3-butadiene is decreased to approximately 40% of the estimate published in 1985 from 6.4 in 10 to 2.5 chances in 10 for a lifetime exposure to 1 ppm. The current estimate is no more than eight additional cancer incidences in the general population. Increased risk to the most exposed individuals is not anticipated to be greater than 1 in 10. This reduction in the risk estimate is due to a change in the estimate of 1,3-butadiene potency (i.e., incremental unit risk estimate) based on incorporation of new pharmacokinetic data. PMID:2205485

Cote, I L; Bayard, S P

1990-01-01

209

Characterization of Electroinitiated and Radiation Polymerized Poly(Butadiene Sulfone)  

Microsoft Academic Search

Polymerization of butadiene sulfone was accomplished by using two different methods. The first method involves electrochemical polymerization of the monomer using the constant potential electrolysis technique. Oxidation of the monomer under nitrogen atmosphere in an acetonitrile-tetrabutylammonium tetrafluoroborate system yields brown, tarry polymers. On the other hand, the second initiation method, which was radiation polymerization, yields white, powdery polymers. Structural analyses

B. Hacioglu; S. Suzer; U. Akbulut; L. Toppare; P. Aybar; J. H. P. Utley

1991-01-01

210

STYRENE IMPAIRS SERIAL SPATIAL REVERSAL LEARNING IN RATS  

EPA Science Inventory

Occupational exposure to styrene monomer has been implicated in the etiology of solvent-induced cognitive dysfunction. o evaluate the effects of styrene exposure on learning, rats were trained on a series of reversals of a spatial discrimination, permitting repeated evaluation of...

211

Immunological changes among workers occupationally exposed to styrene  

Microsoft Academic Search

The functional status of the immune system was investigated in a group of 71 workers exposed to styrene and in 65 control subjects, recruited according to the same selection criteria and comparable as to sex, age, and confounding variables. Air and biological monitoring were used to characterize styrene exposure (median of the main urinary metabolites in the “next-morning” spot samples:

Enrico Bergamaschi; Audrey Smargiassi; Antonio Mutti; Innocente Franchini; Roberto Lucchini; L. Alessio

1995-01-01

212

Reaction Between CH2 and HCCN: A Theoretical Approach to Acrylonitrile Formation in the Interstellar Medium  

NASA Astrophysics Data System (ADS)

Acrylonitrile (CH2CHCN) was first detected in dense molecular cloud SgrB2. The synthesis of this interstellar molecule is reported to be quite difficult. Therefore, in the present work an attempt has been made to explore the possibility of formation of acrylonitrile from some simple molecules and radicals detected in interstellar space by radical-radical interaction scheme, both in the gas phase and in the icy grains. All calculations are performed using quantum chemical methods with density functional theory (DFT) at the B3LYP/6-311G (d,p) level and Møller-Plesset perturbation theory at the MP2/6-311G (d,p) level. In the discussed chemical pathway, the reaction is found to be totally exothermic and barrier less giving rise to a high probability of acrylonitrile formation in Interstellar space.

Shivani; Misra, Alka; Tandon, Poonam

2014-04-01

213

Preparation, characterization and antibacterial activity of chitosan-g-poly acrylonitrile/silver nanocomposite.  

PubMed

Chitosan-grafted-poly acrylonitrile silver nanocomposites (Cs-g-PAN/Ag) were prepared via in-situ chemical reduction of Ag ions in graft copolymerization of acrylonitrile onto chitosan. Graft copolymerization process was provided by FTIR and gravimetric methods. UV spectra and TEM images show silver nanoparticles with average 15-20nm dispersed homogeneously in CS-g-PAN/Ag nanocomposite-ray and TGA evident the change in crystallography and thermal stability in consequence of presence Ag nanoparticles. Cs-g-PAN/Ag nanocomposite showed excellent antimicrobial performance towards bacteria such as Escherichia coli and Staphylococcus aureus. PMID:24768973

Hebeish, A A; Ramadan, M A; Montaser, A S; Farag, Ahmed M

2014-07-01

214

Toxicokinetics of inhaled 1,3-butadiene in monkeys: Comparison to toxicokinetics in rats and mice  

SciTech Connect

1,3-Butadiene is a potent carcinogen in mice and a weaker carcinogen in rats. People are exposed to butadiene through its industrial use--largely in rubber production (over 3 billion pounds of butadiene were produced in 1989)--and because it is common in the environment, occurring in cigarette smoke, gasoline vapor and in the effluents from fossil fuel incineration. Epidemiological studies have provided some evidence for butadiene carcinogenicity in people. Differences in the uptake and metabolism of inhaled butadiene between rodents and primates, including people, might be reflected in differences in its toxicity. In order to compare uptake and metabolism in primates to that in rodents--for which data were already available--the authors exposed cynomolgus monkeys (Macaca fascicularis) to 14C-labeled butadiene at concentrations of 10.1, 310 or 7760 ppm for 2 hr. Exhaled air and excreta were collected during exposure and for 96 hr after exposure. The uptake of butadiene as a result of metabolism was much lower in monkeys than in rodents. For equivalent inhalation exposures, the concentrations of total butadiene metabolites in the blood were 5-50 times lower in monkey than in the mouse, the more sensitive rodent species, and 4-14 times lower than in the rat. If the toxicokinetics of butadiene in people is more like that of the monkey than that of rodents, then our data suggest that people will receive lower doses of butadiene and its metabolites than rodents following equivalent inhalation exposures to butadiene. This has important implications for assessing the risk to humans of butadiene exposure based on animal studies.

Dahl, A.R.; Sun, J.D.; Birnbaum, L.S.; Bond, J.A.; Griffith, W.C. Jr.; Mauderly, J.L.; Muggenburg, B.A.; Sabourin, P.J.; Henderson, R.F. (Inhalation Toxicology Research Inst., Lovelace Biomedical and Environmental Research Inst., Albuquerque, NM (USA))

1991-08-01

215

Influence of carboxyl-terminated butadiene acrylonitrile (CTBN) in carbon/epoxy composites on the property changes in medium high temperatures  

SciTech Connect

The weight loss and flexural property changes of the autoclave cured carbon/epoxy (0{degree}){sub 8} laminates toughened by CTBN at the temperatures of 200, 250 and 300{degree}C for the endurance times of 1, 2, 4, 8 and 16 hours were measured. The matrix resins is composed of 100 phr of tetrafunctional epoxy resin (MY-720), 28 phr of Diamine-diphenyl sulfone (DDS) and 1 phr of Borontrifluoride monoethylene amine (BF{sub 3}{center_dot}MEA). The added contents of CTBN were 5, 10 and 15% by weight to the matrix resins. The addition of CTBN improves the thermal stability of the carbon/epoxy specimens in terms of weight loss and flexural modulus. But the flexural strength was decreased by addition of CTBN.

Lee, J.R.; Kim, J.H. [Korea Research Institute of Chemical Technology, Daedeog Danji (Korea, Republic of). Engineering Materials Lab.

1993-12-31

216

Synthesis and characterization of acrylonitrile methyl acrylate statistical copolymers as melt processable carbon fiber precursors  

Microsoft Academic Search

Statistical (random) copolymers of acrylonitrile (AN) and methyl acrylate (MA) have been synthesized by free radical homogeneous (solution) and heterogeneous (suspension) methods. Selected compositions can be fabricated by environment friendly, solvent-free melt spinning and are of interest as precursors for carbon fibers. The dynamic and steady state melt viscosities of these copolymers were studied as a function of molecular weight

V. A Bhanu; P Rangarajan; K Wiles; M Bortner; M Sankarpandian; D Godshall; T. E Glass; A. K Banthia; J Yang; G Wilkes; D Baird; J. E McGrath

2002-01-01

217

Carcinogenicity and Other Health Effects of Acrylonitrile with Reference to Occupational Exposure Limit  

Microsoft Academic Search

The occupational exposure limit for acrylonitrile (AN) has been set by many organizations on the basis of its carcinogenicity. However, recent epidemiological studies do not afford evidence supporting the hypothesis that AN is carcinogenic to humans. Review of the 18 published cohort studies revealed that, although there is not adequate evidence in humans for carcinogenicity of AN, the possibility of

Haruhiko SAKURAI

2000-01-01

218

Modeling of 1,3-butadiene in urban and industrial areas  

NASA Astrophysics Data System (ADS)

1,3-butadiene is an important pollutant in terms of public health and important driver for photochemical processes influencing ozone formation in the area of Houston. Ambient levels of 1,3-butadiene were simulated with the Community Multiscale Air Quality model (CMAQ) including the SAPRC99-extended mechanism and the results were compared to spatially and temporally resolved observations of 1,3-butadiene for an episodic period during Summer 2006. Relative contributions of different type of emissions and chemical reactions to 1,3-butadiene concentrations were examined, the highest contribution was found to be from industrial emission sources. 1,3-butadiene mixing ratios in the urban area were found to be lower than in the industrial area. Although emissions of 1,3-butadiene peak during daytime its mixing ratios are lower during daytimes as compared to nighttime. 1,3-butadiene is removed from the surface through vertical upward transport (?90%) and chemical reactions (?10%). During daytime 1,3-butadiene reacts mainly with the OH radical (90%), during nighttime this reaction pathway is still significant in the industrial area (57% of all reaction pathways). Reaction with NO3 during nighttime contributes 33% in industrial and 56% in urban areas, where high NOx emissions occur. Reaction with ozone contributes 10% and 13% in industrial and urban areas, respectively. Analysis of measured data revealed that episodically very high emissions spikes of 1,3-butadiene occur. CMAQ often underpredicts 1,3-butadiene mixing ratios when sites are exposed to sporadic releases from industrial facilities. These releases are not accounted for in the emission inventory. It also appears that emissions of 1,3-butadiene from point sources have much more variability than those listed in the emission inventory.

Czader, Beata H.; Rappenglück, Bernhard

2015-02-01

219

Viscoelastic properties of POSS–styrene nanocomposite blended with polystyrene  

Microsoft Academic Search

Polyhedral oligomeric silsesquioxane (POSS) are hybrid nanostructures of about 1.5 nm in size. These silicon (Si)-based polyhedral\\u000a nanostructures are attached to a polystyrene (PS) backbone to produce a polymer nanocomposite (POSS–styrene). We have solution\\u000a blended POSS–styrene of with commercial polystyrene (PS), , and studied the rheological behavior and thermal properties of the neat polymeric components and their blends. The concentration\\u000a of

Maria Eugenia Romero-Guzmán; Angel Romo-Uribe; B. Manuel Zárate-Hernández; Rodolfo Cruz-Silva

2009-01-01

220

Toluene and styrene removal from air in biofilters  

Microsoft Academic Search

Two identical sized laboratory-scale biofilters, filled with the same type of packing material, consisting of a mixture of peat and glass beads in a 4:1 volume ratio, are investigated for the purification of toluene and styrene-containing off-gas streams. One of the biofilters was inoculated with a toluene-degrading strain of Acinetobacter sp. NCIMB 9689, and the other with a styrene-degrading strain

Mario Zilli; Emilio Palazzi; Luciane Sene; Attilio Converti; Marco Del Borghi

2001-01-01

221

Evaluation of respiratory effects of thermal decomposition products following single and repeated exposures of guinea pigs  

Microsoft Academic Search

Groups of guinea pigs were exposed to the thermal decomposition products (TDP) released from acrylonitrile butadiene styrene\\u000a (ABS), polypropylene-polyethylene copolymer (CP), polypropylene homopolymer (HP), or plasticized polyvinyl chloride (PVC).\\u000a In single 50-min exposures to the TDP, guinea pigs exhibited sensory irritation, coughing, and airways constriction. Significant\\u000a decreases in respiratory frequency (f) occurred during TDP exposure which were magnified during CO2

Katherine Detwiler-Okabayashi; Michelle Schaper

1995-01-01

222

Thermal stability, flame retardancy and rheological behavior of ABS filled with magnesium hydroxide sulfate hydrate whisker  

Microsoft Academic Search

Summary  Halogen-free and flame-retardant acrylonitrile–butadiene–styrene copolymer (ABS) composites were prepared using magnesium\\u000a hydroxide sulfate hydrate (MHSH) whisker as a flame retardant, and the effect of zinc stearate (ZnSt2) as a dispersion additive on the morphology and properties of the ABS\\/MHSH composites was studied. The morphology observation\\u000a by using scanning electronic microscope (SEM) indicates that the addition of zinc stearate could improve

Bo Liu; Yong Zhang; Chaoying Wan; Yinxi Zhang; Rongxun Li; Guangye Liu

2007-01-01

223

Modification of ABS Membrane by PEG for Capturing Carbon Dioxide from CO2\\/N2 Streams  

Microsoft Academic Search

Carbon dioxide capture and storage (CCS) has been propounded as an important issue in greenhouse gas emissions control. In this connection, in the present article, the advantages of using polymeric membrane for separation of carbon dioxide from CO2\\/N2 streams have been discussed. A novel composition for fabrication of a blend membrane prepared from acrylonitrile-butadiene-styrene (ABS) terpolymer and polyethylene glycol (PEG)

Abtin Ebadi Amooghin; Hamidreza Sanaeepur; Abdolreza Moghadassi; Ali Kargari; Davood Ghanbari; Zahra Sheikhi Mehrabadi

2010-01-01

224

Viscoplastic modeling of ABS material under high-strain-rate uniaxial elongational deformation  

Microsoft Academic Search

Uniaxial tensile tests were performed on the newest type of Meissner rheometer with an ABS (acrylonitrile-butadiene-styrene) material. Tests were conducted for constant strain rates varying from 0.01 to 1 (1\\/s), at the temperatures ranging from 150 to 200 °C. Based on the experimental data, a new model was proposed, in which, strain hardening, strain rate sensitivity, temperature changes and the

S. Wang; A. Makinouchi; M. Okamoto; T. Kotaka; T. Nakagawa

1999-01-01

225

Preparation and characterization of flame retardant ABS\\/montmorillonite nanocomposite  

Microsoft Academic Search

Flame retardant acrylonitrile–butadiene–styrene (ABS)\\/montmorillonite (MMT) nanocomposites were prepared by direct melt intercalation of ABS, organophilic clay and conventional fire retardants (decabromodiphenyl oxide (DB) and antimony oxide (AO)). Morphology and flammability properties were characterized by X-ray power diffractionmeter (XRD), high resolution electron microscopy (HREM), transmission electron microscopy (TEM), scanning electron microscopy (SEM), limiting oxygen index (LOI) test, UL-94 test and cone

Shaofeng Wang; Yuan Hu; Ruowen Zong; Yong Tang; Zuyao Chen; Weicheng Fan

2004-01-01

226

Pyrolysis of mixed plastics used in the electronics industry  

Microsoft Academic Search

The pyrolysis of three plastics used by the electronics industry has been studied using pyrolysis\\/gas chromatography\\/mass spectrometry (Py\\/GC\\/MS). The materials selected for this study were acrylonitrile–butadiene–styrene (ABS), polycarbonate (PC) and polyoxymethylene (POM). The selection was based upon the analysis of several pieces of electronic equipment, which had been the subject of laboratory studies. Each polymer was pyrolyzed at two pyrolysis

M. Day; J. D. Cooney; C. Touchette-Barrette; S. E. Sheehan

1999-01-01

227

Properties and preparation of compatibilized nylon 6 nanocomposites\\/ABS blends: Part II – Physical and thermal properties  

Microsoft Academic Search

The physical and thermal properties of nanoclay filled nylon 6 (nano-nylon 6) blended with poly(acrylonitrile–butadiene–styrene)terpolymers (ABS) were investigated using metallocene polyethylene grafted maleic anhydride (POE-g-MA) or polybutadiene grafted maleic anhydride (PB-g-MA) as a compatibilizer. Cooling conditions significantly affected the crystalline structure of nano-nylon 6. No clear effect of both compatibilizers on the dispersion of clay has been observed via transmission

S.-M. Lai; H.-C. Li; Y.-C. Liao

2007-01-01

228

Enhanced electromechanical performance of carbon nano-fiber reinforced sulfonated poly(styrene-b-[ethylene\\/butylene]-b-styrene) actuator  

Microsoft Academic Search

In this paper, the carbon nano-fibers (CNFs) were used to improve the performance of sulfonated poly(styrene-b-[ethylene\\/butylene]-b-styrene) (SSEBS) composite actuator. The SSEBS actuator, which was developed in our previous study, does not have good electromechanical performance because the SSEBS ionic polymer is too flexible and soft. CNFs as a reinforcement for the polymer membranes greatly increased the bending performance of the

Xuan-Lun Wang; Il-Kwon Oh; Jin-Bong Kim

2009-01-01

229

Epoxidation of Styrene-Isoprene-Styrene Block Copolymer and Its Use for Hot-Melt Pressure Sensitive Adhesives  

Microsoft Academic Search

The epoxidation of styrene-isoprene-styrene block copolymer (SIS) with performic acid generated in situ from hydrogen peroxide and formic acid was studied, and the hot-melt pressure sensitive adhesives (HMPSA) were prepared with epoxidized SIS (ESIS), SIS and the tackifier ESCOREZ-2203LC. The H nucleal magnetic resonance and Fourier transform infrared spectra revealed that the epoxidation reaction mainly occurred in 1,4-isoprene units of

Hongqiang Li; Xingrong Zeng; Weiqing Wu

2008-01-01

230

SOME INSIGHTS INTO THE MODE OF ACTION OF BUTADIENE BY EXAMINING THE GENOTOXICITY OF ITS METABOLITES  

EPA Science Inventory

1,3-Butadiene (BTD) is an important commodity chemical and air pollutant that has been shown to be a potent carcinogen in mice, and to a lesser extent, a carcinogen in rats. To better assess butadiene's carcinogenic risk to humans, it is important to understand its mode of action...

231

A Practical, Two-Step Synthesis of 2-Substituted 1,3-Butadienes  

PubMed Central

A two-step procedure for preparing 2-alkyl-1,3-butadienes is described. Cuprate addition to commercially available 1,4-dibromo-2-butene yields 3-alkyl-4-bromo-1-butene, a product of SN2? substitution. Dehydrohalogenation gives 2-alkyl-1,3-butadienes. PMID:19260696

Sen, Sushmita; Singh, Swapnil; Sieburth, Scott McN.

2009-01-01

232

40 CFR 80.55 - Measurement methods for benzene and 1,3-butadiene.  

...determination. This procedure is detailed in 40 CFR 86.109. (b) Benzene and 1,3-butadiene must be analyzed by gas chromatography. Expected values for benzene and 1,3-butadiene in bag samples for the baseline fuel are 4.0 ppm and 0.30...

2014-07-01

233

(/sup 14/C)Acrylonitrile: preparation via a stable tosylate intermediate and quantitative reaction with amine residues in collagen  

SciTech Connect

A simple, convenient synthetic procedure for (/sup 14/C)acrylonitrile is described. Na/sup 14/CN is used as the radioactive starting material. Small (milligram) amounts are converted to 3-(/sup 14/C)Hydroxypropionitrile by a substitution reaction with 2-chloroethanol. 3-(/sup 14/C)Hydroxypropionitrile is then tosylated, and the specific activity of this intermediate product is easily determined using its uv extinction coefficient and scintillation counting. (/sup 14/C)Acrylonitrile is obtained rapidly on distillation by heating the tosylate in the presence of a high boiling tertiary amine base catalyst. The tosylate intermediate can be stored, in contrast to radioactive acrylonitrile, which is unstable. The reaction of acrylonitrile with lysine, hydroxylysine, and histidine residues in human Achilles tendon collagen, as well as chromatographic separation and identification of the carboxyethyl derivatives of these amino acids, is also described.

Graham, L.; Mechanic, G.L.

1986-03-01

234

Metabolism of styrene to styrene oxide and vinylphenols in cytochrome P450 2F2- and P450 2E1-knockout mouse liver and lung microsomes  

PubMed Central

Pulmonary toxicity of styrene is initiated by cytochromes P450-dependent metabolic activation. P450 2E1 and P450 2F2 are considered to be two main cytochrome P450 (CYP) enzymes responsible for styrene metabolism in mice. The objective of the current study was to determine the correlation between the formation of styrene metabolites (i.e. styrene oxide and 4-vinylphenol) and pulmonary toxicity of styrene, using Cyp2e1- and Cyp2f2-null mouse models. Dramatic decrease in the formation of styrene glycol and 4-vinylphenol was found in Cyp2f2-null mouse lung microsomes, relative to that in the wild-type mouse lung microsomes. However, no significant difference in the production of the styrene metabolites was observed between lung microsomes obtained from Cyp2e1-null and the wild-type mice. The knock–out and wild-type mice were treated with styrene (6.0 mmol/kg, ip), and cell counts and LDH activity in bronchoalveolar lavage fluids were monitored to evaluate the pulmonary toxicity induced by styrene. Cyp2e1-null mice displayed similar susceptibility to lung toxicity of styrene as the wild-type animals. However, Cyp2f2-null mice were resistant to styrene-induced pulmonary toxicity. In conclusion, both P450 2E1 and P450 2F2 are responsible for the metabolic activation of styrene. The latter enzyme plays an important role in styrene-induced pulmonary toxicity. Both styrene oxide and 4-vinylphenol are suggested to participate in the development of lung injury induced by styrene. PMID:24320693

Shen, Shuijie; Li, Lei; Ding, Xinxin; Zheng, Jiang

2014-01-01

235

Boost refining profits by converting surplus butadiene to valuable feedstocks for MTBE and/or alkylation  

SciTech Connect

Ethylene plants produce a C4 butadiene-rich cut as a by-product. Although it has been a highly valued chemical intermediate for a long time, butadiene is now in over supply due to the installation of new steam cracking plants and the growing use of naphtha, the main butadiene generator, as feedstock. In the meantime, the demand for alkylate and ethers has increased steadily to produce environmentally friendly gasoline. This paper presents processes developed by IFP to convert surplus butadiene into ethers or alkylate for gasoline production. The first process transforms the butadiene-rich stream into a butenes-rich stream, an ideal alkylation feedstock. The second process generates isobutene from the butenes stream by skeletal isomerization for MTBE production.

Nocca, J.L. (IFP Enterprises Texas, Inc., Houston, TX (United States)); Hennico, A.; Cosyns, J.; Torck, B. (Inst. Francais du Petrole, Rueil-Malmaison (France))

1994-01-01

236

21 CFR 177.1820 - Styrene-maleic anhydride copolymers.  

Code of Federal Regulations, 2010 CFR

...II, III, IV-A, IV-B, V, VI-B (except carbonated beverages), VII-A, VII-B, VIII, and IX identified...butadiene rubber units by weight; for use (except carbonated beverage bottles) as articles or as components of...

2010-04-01

237

21 CFR 177.1820 - Styrene-maleic anhydride copolymers.  

Code of Federal Regulations, 2012 CFR

...II, III, IV-A, IV-B, V, VI-B (except carbonated beverages), VII-A, VII-B, VIII, and IX identified...butadiene rubber units by weight; for use (except carbonated beverage bottles) as articles or as components of...

2012-04-01

238

21 CFR 177.1820 - Styrene-maleic anhydride copolymers.  

Code of Federal Regulations, 2011 CFR

...II, III, IV-A, IV-B, V, VI-B (except carbonated beverages), VII-A, VII-B, VIII, and IX identified...butadiene rubber units by weight; for use (except carbonated beverage bottles) as articles or as components of...

2011-04-01

239

21 CFR 177.1820 - Styrene-maleic anhydride copolymers.  

Code of Federal Regulations, 2013 CFR

...II, III, IV-A, IV-B, V, VI-B (except carbonated beverages), VII-A, VII-B, VIII, and IX identified...butadiene rubber units by weight; for use (except carbonated beverage bottles) as articles or as components of...

2013-04-01

240

Medical applications of poly(styrene-block-isobutylene-block-styrene) ("SIBS").  

PubMed

Poly(Styrene-block-IsoButylene-block-Styrene) ("SIBS") is a biostable thermoplastic elastomer with physical properties that overlap silicone rubber and polyurethane. Initial data collected with SIBS stent-grafts and coatings on metallic stents demonstrate hemocompatibility, biocompatibility and long-term stability in contact with metal. SIBS has been used successfully as the carrier for a drug-eluting coronary stent; specifically Boston Scientific's TAXUS stent, and its uses are being investigated for ophthalmic implants to treat glaucoma, synthetic heart valves to possibly replace tissue valves and other applications. At present, researchers developing medical devices utilizing SIBS have found the following: (1) SIBS does not substantially activate platelets in the vascular system; (2) polymorphonuclear leukocytes in large numbers are not commonly observed around SIBS implants in the vascular system or in subcutaneous implants or in the eye; (3) myofibroblasts, scarring and encapsulation are not clinically significant with SIBS implanted in the eye; (4) embrittlement has not been observed in any implant location; (5) calcification within the polymer has not been observed; and (6) degradation has not been observed in any living system to date. Some deficiencies of SIBS that need to be addressed include creep deformation in certain load-bearing applications and certain sterilization requirements. The reason for the excellent biocompatibility of SIBS may be due to the inertness of SIBS and lack of cleavable moieties that could be chemotactic towards phagocytes. PMID:17980425

Pinchuk, Leonard; Wilson, Gregory J; Barry, James J; Schoephoerster, Richard T; Parel, Jean-Marie; Kennedy, Joseph P

2008-02-01

241

Interfacial Dynamics and Structure of thin films of sulfonated poly (styrene Sulfonate ethylene\\/butylene-styrene Sulfonate) Triblock Copolymers  

Microsoft Academic Search

AFM, optical microscopy and SAXS have been used to study the interfacial structure and dynamics in thin films of a triblock copolymer which consists of two sulfonated polystyrene blocks (Mw=8500, of which 60% is sulfonated), connected by a hydrogenated butadiene block (Mw=16872). The incompatibility between the blocks allows controlling the surface structure and properties, leading to various applications from coatings

Neetal B. Timble; Dvora Perahia; Gary E. Wnek

2001-01-01

242

[Degradation of styrene by coupling ultraviolet and biofiltration].  

PubMed

Purification of styrene by ultraviolet (UV)-biofiltration was studied in this paper. The light source and the biofilm carrier were ozone producing lamp at 185 nm and the peat, palm fiber, porous acticarbon, respectively. Styrene inlet concentration was controlled between 320-583 mg x m(-3), and the removal efficiency remained above 95% after stabilization. The UV converted styrene into more soluble and biodegradable intermediates, such as alcohol, aldehyde and acid, thus the performance of biofilter can be improved. In the stable operation stage, the variation of inlet concentration did not affect the removal efficiency when the total residence time (TRT) was long, however, the inlet concentration obviously affected the removal efficiency when the TRT decreased. The removal load of coupling system increased linearly with increasing inlet load, and the removal efficiency was higher than 95% under a TRT of 102 s. When TRT was 68 s and the inlet load was low, the variation of removal load complied with the law described above, but it gradually deviated from the straight line and tended to stabilized at a certain value when the inlet load became higher than 30 g x (m3 x h)(-). If considering the fluctuation of styrene concentration only, the contribution rate of ultraviolet photolysis to styrene removal was greater than that of the biofilter, and the removal effect could be restored on the fourth day, after closing the system for ten days and restarting. PMID:24640911

Sha, Hao-Lei; Yang, Guo-Jing; Xia, Jing-Fen

2013-12-01

243

Poly (acrylonitrile – co -1-vinylimidazole): A new melt processable carbon fiber precursor  

Microsoft Academic Search

Acrylonitrile\\/1-vinylimidazole (AN\\/VIM) copolymers containing various mol% of VIM were synthesized by free radical solution polymerization. The copolymers were characterized by Attenuated Total Reflectance-Fourier Transform Infrared (ATR-FTIR) spectroscopy, 1H NMR spectroscopy, gel permeation chromatography (GPC) and differential scanning calorimetry (DSC). Char yields of the copolymers were 40–48% as determined by thermogravimetric analysis (TGA) while gel fractions were found to be 90–99%

Wenjin Deng; Alexander Lobovsky; Scott T. Iacono; Tianyu Wu; Neetu Tomar; Stephen M. Budy; Timothy Long; Wesley P. Hoffman; Dennis W. Smith

2011-01-01

244

Vibrational Energies for Acrylonitrile from Mm-Wave to Thz Rotational Spectra  

NASA Astrophysics Data System (ADS)

The THz rotational spectrum of acrylonitrile has recently been studied in detail. The coverage of the ground state rotational transitions has been extended up to J=128, K_a=29 and it was found that at very high-J there are multiple manifestations of a perturbation between the ground state and the lowest vibrationally excited state, V11=1. The perturbation has been successfully fitted and the excited state energy determined at 228.29991(2) Cm-1, which turns out to be the largest energy difference between any two neighboring vibrational states of acrylonitrile. Extensive broadband rotational spectra of acrylonitrile have been recorded at JPL and at OSU and provide coverage from the mm-wave region up to well into the THz. The analysis of these spectra performed with the AABS package allowed identification of a ladder of pairwise perturbations extending from the ground state and connecting all successive low lying vibrational states. A global fit of all of the observed effects is expected to deliver accurate energies for the lowest vibrational states from only the rotational spectrum. The progress made towards achieving this goal is described. Z.Kisiel, L.Pszczó?kowski, B.J.Drouin, C.S.Brauer, S.Yu, J.C.Pearson, J. Mol. Spectrosc., 258, 26 (2009). Z.Kisiel, L.Pszczó?kowski, I.R.Medvedev, M.Winewisser, F.C.De Lucia, E.Herbst, J. Mol. Spectrosc., 233, 231 (2005).

Kisiel, Zbigniew; Pszczó?kowski, Lech; Drouin, Brian J.; Brauer, Carolyn S.; Yu, Shanshan; Pearson, John C.; Medvedev, Ivan R.; Fortman, Sarah; Neese, Christopher

2011-06-01

245

Reliable passive-sampling method for determining outdoor 1,3-butadiene concentrations in air  

NASA Astrophysics Data System (ADS)

We have developed a simple and reliable passive-sampling method for determining outdoor 1,3-butadiene concentrations in air. In this method, 1,3-butadiene is adsorbed on Carboxen 1000 uniformly packed in a porous polytetrafluoroethylene tube and then analyzed by thermal desorption-gas chromatography/mass spectrometry. The amounts of 1,3-butadiene adsorbed on Carboxen 1000 were 2.8 times as high as those adsorbed on activated carbon. Much greater amounts of 1,3-butadiene were collected with the passive sampler than with an active sampler even though ozone, which reacts rapidly with 1,3-butadiene, could penetrate the passive-sampling tube. These results demonstrate that our method sensitively and reliably determines outdoor 1,3-butadiene concentrations in air, that ambient ozone slowly react with 1,3-butadiene adsorbed by the passive sampler, and that the KI ozone scrubber in an active-sampling system does not completely remove ozone from the system.

Sakurai, Kenji; Miyake, Yuichi; Amagai, Takashi

2013-12-01

246

Microbial degradation of styrene: biochemistry, molecular genetics, and perspectives for biotechnological applications  

Microsoft Academic Search

Large quantities of the potentially toxic compound styrene are produced and used annually by the petrochemical and polymer-processing industries. It is as a direct consequence of this that significant volumes of styrene are released into the environment in both the liquid and the gaseous forms. Styrene and its metabolites are known to have serious negative effects on human health and

Aisling Mooney; Patrick G. Ward; Kevin E. O’Connor

2006-01-01

247

New styrene-b-isobutylene-b-styrene (SIBS) glaucoma drainage implant  

NASA Astrophysics Data System (ADS)

Purpose: To design and test the Miami-InnFocus Drainage Implant (MiDi) as a glaucoma shunt that is biocompatible, flexible, and significantly smaller than existing commercial implants in order to prevent postoperative hypotony, inflammation, scarring, erosion, and extrusion. Methods: A new biomaterial composed of styrene-b-isobutylene-b-styrene (SIBS) was used in a novel design for a glaucoma drainage implant. The implant consists of a tube 11mm long with an inner diameter of 70, 100, and 150 ?m and outer diameter of 250 ?m with a 1mm2 tab located 4.5mm from the proximal tip to prevent migration. The device was implanted in 15 New Zealand White rabbits for biocompatibility and efficacy testing. A similarly designed implant made of polydimethylsiloxane was implanted in 6 other animals as a pseudo-control. Typical GDI implantation technique was modified for this device. The proximal end of the new SIBS implant was inserted 2mm into the anterior chamber and the distal end placed in a subconjunctival space created by the surgeon. Biocompatibility of the device was studied by slit-lamp follow-up and intraocular pressure (IOP) measurements recorded periodically. Results: Biocompatibility of the MiDi was excellent. A low and diffuse bleb was observed with these devices. All SIBS tubes were patent 9 months after insertion. Immunostaining demonstrated non-continuous deposition of collagen with virtually no encapsulation. No macrophages or myofibroblast were visible around the SIBS polymer which was found more bioinert than the control PDMS. Conclusion: This newly designed glaucoma implant is clinically biocompatible in the rabbit model and maintained 100% patency at 9 months.

Orozco, Marcia A.; Acosta, Ana C.; Espana, Edgar M.; Pinchuk, Leonard; Weber, Bruce; Davis, Stewart; Arrieta, Esdras; Dubovy, Sander; Fantes, Francisco; Aly, Mohamed; Zhou, Yonghua; Parel, Jean-Marie

2006-02-01

248

Comparative studies on the removal of heavy metals ions onto cross linked chitosan-g-acrylonitrile copolymer.  

PubMed

The graft copolymerization of acrylonitrile onto cross linked chitosan was carried out using ceric ammonium nitrate as an initiator. The prepared cross linked chitosan-g-acrylonitrile copolymer was characterized using FT-IR and XRD studies. The adsorption behavior of chromium(VI), copper(II) and nickel(II) ions from aqueous solution onto cross linked chitosan graft acrylonitrile copolymer was investigated through batch method. The efficiency of the adsorbent was identified from the varying the contact time, adsorbent dose and pH. The results evident that the adsorption of metal ions increases with the increase of shaking time and metal ion concentration. An optimum pH was found to be 5.0 for both Cr(VI) and Cu(II), whereas the optimum pH is 5.5 for the adsorption of Ni(II) onto cross linked chitosan-g-acrylonitrile copolymer. The Langmuir and Freundlich adsorption models were applied to describe the isotherms and isotherm constants. Adsorption isothermal data could be well interpreted by the Freundlich model. The kinetic experimental data properly correlated with the second-order kinetic model. From the above results it was concluded that the cross linked chitosan graft acrylonitrile copolymer was found to be the efficient adsorbent for removing the heavy metals under optimum conditions. PMID:24680901

Shankar, P; Gomathi, Thandapani; Vijayalakshmi, K; Sudha, P N

2014-06-01

249

Photodegradation Mechanisms of Tetraphenyl Butadiene Coatings for Liquid Argon Detectors  

E-print Network

We report on studies of degradation mechanisms of tetraphenyl butadiene (TPB) coatings of the type used in neutrino and dark matter liquid argon experiments. Using gas chromatography coupled to mass spectrometry we have detected the ultraviolet-blocking impurity benzophenone (BP). We monitored the drop in performance and increase of benzophenone concentration in TPB plates with exposure to ultraviolet (UV) light, and demonstrate the correlation between these two variables. Based on the presence and initially exponential increase in the concentration of benzophenone observed, we propose that TPB degradation is a free radical-mediated photooxidation reaction, which is subsequently confirmed by displaying delayed degradation using a free radical inhibitor. Finally we show that the performance of wavelength-shifting coatings of the type envisioned for the LBNE experiment can be improved by 10-20%, with significantly delayed UV degradation, by using a 20% admixture of 4-tert-Butylcatechol.

B. J. P. Jones; J. K. VanGemert; J. M. Conrad; A. Pla-Dalmau

2012-11-30

250

Characteristics of styrene degradation by Rhodococcus pyridinovorans isolated from a biofilter.  

PubMed

A novel strain (PYJ-1) of Rhodococcus pyridinovorans that was isolated from a biofilter was able to degrade styrene at a maximum rate of 0.16 mg (mg protein)(-1) h(-1) in batch culture at 97 mg l(-1) of initial styrene gas concentration. The optimum pH and temperature for styrene degradation were 7 and 32 degrees C, respectively. The degradation kinetic constants were obtained using substrate inhibition kinetics. In a perlite-packed biofilter the maximum styrene removal rate by the strain was 279 gm(-3)h(-1). Styrene removal in the biofilter was more sensitive to the temperature than in the batch culture. PMID:16202798

Jung, In-Gyung; Park, Chang-Ho

2005-10-01

251

CYTOGENETIC STUDIES OF MICE EXPOSED TO STYRENE BY INHALATION  

EPA Science Inventory

The published data for the in vivo genotoxicity of styrene (STY) are equivocal. o evaluate the clastogenicity and sister chromatid exchange (SCE)-inducing potential of STY in vivo under carefully controlled conditions, 36C3F1 female mice were exposed by inhalation for 6 hours/day...

252

Comparing in situ removal strategies for improving styrene bioproduction.  

PubMed

As an important conventional monomer compound, the biological production of styrene carries significant promise with respect to creating novel sustainable materials. Since end-product toxicity presently limits styrene production by previously engineered Escherichia coli, in situ product removal by both solvent extraction and gas stripping were explored as process-based strategies for circumventing its inhibitory effects. In solvent extraction, the addition of bis(2-ethylhexyl)phthalate offered the greatest productivity enhancement, allowing net volumetric production of 836 ± 64 mg/L to be reached, representing a 320 % improvement over single-phase cultures. Gas stripping rates, meanwhile, were controlled by rates of bioreactor agitation and, to a greater extent, aeration. A periodic gas stripping protocol ultimately enabled up to 561 ± 15 mg/L styrene to be attained. Lastly, by relieving the effects of styrene toxicity, new insight was gained regarding subsequent factors limiting its biosynthesis in E. coli and strategies for future strain improvement are discussed. PMID:25034182

McKenna, Rebekah; Moya, Luis; McDaniel, Matthew; Nielsen, David R

2015-01-01

253

Silver-catalyzed decarboxylative acylfluorination of styrenes in aqueous media.  

PubMed

A mild catalytic decarboxylative acylfluorination of styrenes with ?-oxocarboxylic acids and Selectfluor is reported. This operationally simple and efficient method provides a fundamentally novel approach toward the synthesis of ?-fluorinated 3-aryl ketones with a wide range of substrate scope. PMID:24870605

Wang, Hua; Guo, Li-Na; Duan, Xin-Hua

2014-07-14

254

Ethylbenzene dehydrogenation into styrene: kinetic modeling and reactor simulation  

E-print Network

. Experimental data were obtained for different operating conditions, i.e., temperature, feed molar ratio of steam to ethylbenzene, styrene to ethylbenzene, and hydrogen to ethylbenzene and space time. The effluent of the reactor was analyzed on-line using two...

Lee, Won Jae

2007-04-25

255

Chain- and Regioselective Ethylene and Styrene Dimerization Reactions Catalyzed by a Well-Defined Cationic Ruthenium-Hydride Complex: New Insights on the Styrene Dimerization Mechanism  

PubMed Central

The cationic ruthenium-hydride complex [(?6-C6H6)(PCy3)(CO)RuH]+BF4? was found to be a highly regioselective catalyst for the ethylene dimerization reaction to give 2-butene products (TOF = 1910 h?1, >95% selectivity for 2-butenes). The dimerization of styrene exclusively produced the head-to-tail dimer (E)-PhCH(CH3)CH=CHPh at an initial turnover rate of 2300 h?1. A rapid and extensive H/D exchange between the vinyl hydrogens of styrene-d8 and 4-methoxystyrene was observed within 10 min without forming the dimer products at room temperature. The inverse deuterium isotope effect of kH/kD = 0.77±0.10 was measured from the first order plots on the dimerization reaction of styrene and styrene-d8 in chlorobenzene at 70 °C. The pronounced carbon isotope effect on both vinyl carbons of styrene as measured by using Singleton's method (13C(recovered)/13C(virgin) at C1 = 1.096 and C2 = 1.042) indicates that the C–C bond formation is the rate-limiting step for the dimerization reaction. The Eyring plot of the dimerization of styrene in the temperature range of 50–90 °C led to ?H‡ = 3.3(6) kcal/mol and ?S‡ = ?35.5(7) e.u. An electrophilic addition mechanism has been proposed for the dimerization of styrene. PMID:20694188

Lee, Do W.; Yi, Chae S.

2010-01-01

256

Metabolism of styrene by Rhodococcus rhodochrous NCIMB 13259.  

PubMed Central

Rhodococcus rhodochrous NCIMB 13259 grows on styrene, toluene, ethylbenzene, and benzene as sole carbon sources. Simultaneous induction tests with cells grown on styrene or toluene showed high rates of oxygen consumption with toluene cis-glycol and 3-methylcatechol, suggesting the involvement of a cis-glycol pathway. 3-Vinylcatechol accumulated when intact cells were incubated with styrene in the presence of 3-fluorocatechol to inhibit catechol dioxygenase activity. Experiments with 18O2 showed that 3-vinylcatechol was produced following a dioxygenase ring attack. Extracts contained a NAD-dependent cis-glycol dehydrogenase, which converted styrene cis-glycol to 3-vinylcatechol. Both catechol 1,2- and 2,3-dioxygenase activities were present, and these were separated from each other and from the activities of cis-glycol dehydrogenase and 2-hydroxymuconic acid semialdehyde hydrolase by ion-exchange chromatography of extracts. 2-Vinylmuconate accumulated in the growth medium when cells were grown on styrene, apparently as a dead-end product, and extracts contained no detectable muconate cycloisomerase activity. 3-Vinylcatechol was cleaved by catechol 2,3-dioxygenase to give a yellow compound, tentatively identified as 2-hydroxy-6-oxoocta-2,4,7-trienoic acid, and the action of 2-hydroxymuconic acid semialdehyde hydrolase on this produced acrylic acid. A compound with the spectral characteristics of 2-hydroxypenta-2,4-dienoate was produced by the action of 2-hydroxymuconic acid semialdehyde hydrolase on the 2,3-cleavage product of 3-methylcatechol. Extracts were able to transform 2-hydroxypenta-2,4-dienoate and 4-hydroxy-2-oxopentanoate into acetaldehyde and pyruvate.(ABSTRACT TRUNCATED AT 250 WORDS) PMID:8017910

Warhurst, A M; Clarke, K F; Hill, R A; Holt, R A; Fewson, C A

1994-01-01

257

Stable-Isotope-Based Labeling of Styrene-Degrading Microorganisms in Biofilters†  

PubMed Central

Deuterated styrene ([2H8]styrene) was used as a tracer in combination with phospholipid fatty acid (PLFA) analysis for characterization of styrene-degrading microbial populations of biofilters used for treatment of waste gases. Deuterated fatty acids were detected and quantified by gas chromatography-mass spectrometry. The method was evaluated with pure cultures of styrene-degrading bacteria and defined mixed cultures of styrene degraders and non-styrene-degrading organisms. Incubation of styrene degraders for 3 days with [2H8]styrene led to fatty acids consisting of up to 90% deuterated molecules. Mixed-culture experiments showed that specific labeling of styrene-degrading strains and only weak labeling of fatty acids of non-styrene-degrading organisms occurred after incubation with [2H8]styrene for up to 7 days. Analysis of actively degrading filter material from an experimental biofilter and a full-scale biofilter by this method showed that there were differences in the patterns of labeled fatty acids. For the experimental biofilter the fatty acids with largest amounts of labeled molecules were palmitic acid (16:0), 9,10-methylenehexadecanoic acid (17:0 cyclo9-10), and vaccenic acid (18:1 cis11). These lipid markers indicated that styrene was degraded by organisms with a Pseudomonas-like fatty acid profile. In contrast, the most intensively labeled fatty acids of the full-scale biofilter sample were palmitic acid and cis-11-hexadecenoic acid (16:1 cis11), indicating that an unknown styrene-degrading taxon was present. Iso-, anteiso-, and 10-methyl-branched fatty acids showed no or weak labeling. Therefore, we found no indication that styrene was degraded by organisms with methyl-branched fatty fatty acids, such as Xanthomonas, Bacillus, Streptomyces, or Gordonia spp. PMID:11571187

Alexandrino, Maria; Knief, Claudia; Lipski, André

2001-01-01

258

Bimetallic effects in homopolymerization of styrene and copolymerization of ethylene and styrenic comonomers: scope, kinetics, and mechanism.  

PubMed

This contribution describes the homopolymerization of styrene and the copolymerization of ethylene and styrenic comonomers mediated by the single-site bimetallic "constrained geometry catalysts" (CGCs), (mu-CH2CH2-3,3'){(eta(5)-indenyl)[1-Me2Si(tBuN)](TiMe2)}2 [EBICGC(TiMe2)2; Ti2], (mu-CH2CH2-3,3'){(eta(5)-indenyl)[1-Me2Si(tBuN)](ZrMe2)}2 [EBICGC(ZrMe2)2; Zr2], (mu-CH2-3,3'){(eta(5)-indenyl)[1-Me2Si(tBuN)](TiMe2)}2 [MBICGC(TiMe2)2; C1-Ti2], and (mu-CH2-3,3'){(eta(5)-indenyl)[1-Me2Si(tBuN)](ZrMe2)}2 [MBICGC(ZrMe2)2; C1-Zr2], in combination with the borate activator/cocatalyst Ph3C+ B(C6F5)4- (B1). Under identical styrene homopolymerization conditions, C1-Ti2 + B1 and Ti2 + B1 exhibit approximately 65 and approximately 35 times greater polymerization activities, respectively, than does monometallic [1-Me2Si(3-ethylindenyl)(tBuN)]TiMe2 (Ti1) + B1. C1-Zr2 + B1 and Zr2 + B1 exhibit approximately 8 and approximately 4 times greater polymerization activities, respectively, than does the monometallic control [1-Me2Si(3-ethylindenyl)(tBuN)]ZrMe2 (Zr1) + B1. NMR analyses show that the bimetallic catalysts suppress the regiochemical insertion selectivity exhibited by the monometallic analogues. In ethylene copolymerization, Ti2 + B1 enchains 15.4% more styrene (B), 28.9% more 4-methylstyrene (C), 45.4% more 4-fluorostyrene (D), 41.2% more 4-chlorostyrene (E), and 31.0% more 4-bromostyrene (F) than does Ti1 + B1. This observed bimetallic chemoselectivity effect follows the same general trend as the pi-electron density on the styrenic ipso carbon (D > E > F > C > B). Kinetic studies reveal that both Ti2 + B1 and Ti1 + B1-mediated ethylene-styrene copolymerizations follow second-order Markovian statistics and tend to be alternating. Moreover, calculated reactivity ratios indicate that Ti2 + B1 favors styrene insertion more than does Ti1 + B1. All the organozirconium complexes (C1-Zr2, Zr2, and Zr1) are found to be incompetent for ethylene-styrene copolymerization, yielding only mixtures of polyethylene and polystyrene. Model compound (mu-CH2CH2-3,3'){(eta(5)-indenyl)[1-Me2Si(tBuN)][Ti(CH2Ph)2]}2 {EBICGC[Ti(CH2Ph)2]2; Ti2(CH2Ph)4} was designed, synthesized, and structurally characterized. In situ activation studies with cocatalyst B(C6F5)3 suggest an eta(1)-coordination mode for the benzyl groups, thus supporting the proposed polymerization mechanism. For ethylene-styrene copolymerization, polar solvents are found to increase copolymerization activities and coproduce atactic polystyrene impurities in addition to ethylene-co-styrene, without diminishing the comonomer incorporation selectivity. Both homopolymerization and copolymerization results argue that substantial cooperative effects between catalytic sites are operative. PMID:18220391

Guo, Neng; Stern, Charlotte L; Marks, Tobin J

2008-02-20

259

Structure-toxicity relationship study of para-halogenated styrene analogues in CYP2E1 transgenic cells.  

PubMed

Styrene is one of the most important industrial intermediates consumed in the world and is mainly used as a monomer for reinforced plastics and rubber. Styrene has been found to be hepatotoxic and pneumotoxic in humans and experimental animals. The toxicity of styrene is suggested to be metabolism-dependent. Styrene-7,8-oxide has been considered as the major metabolite responsible for styrene-induced cytotoxicity. The objective of the study was to investigate the correlation between cytotoxicity of styrene and chemical and biochemical properties of the vinyl group of styrene by development of structure activity relationships (SAR). 4-Fluorostyrene, 4-chlorostyrene and 4-bromostyrene were selected for the SAR study. Cytotoxicity of styrene and the halogenated styrene derivatives with an order of 4-bromostyrene>4-chlorostyrene>4-fluorostyrene?styrene was observed in CYP2E1 transgenic cells. Similar orders in the efficiency of the metabolism of styrene and the halogenated styrene analogues to their oxides and in the electrophilicity of the corresponding oxides were observed. Additionally, the order of the potency of cellular glutathione depletion and the degree of protein adduction induced by styrene and the halogenated styrenes were consistent with that of their cytotoxicities. The wild-type cells were less susceptible to the toxicity of the corresponding model compounds than CYP2E1 cells. The present study provided insight into the roles of the biochemical and chemical properties of styrene in its cytotoxicity. PMID:22366341

Chung, Jou-Ku; Shen, Shuijie; Jiang, Zhiteng; Yuan, Wei; Zheng, Jiang

2012-05-01

260

Development of polyclonal antibodies for the detection of styrene oxide modified proteins.  

PubMed

Styrene is widely used as one of the most important industrial materials for the production of synthetic rubbers, plastic, insulation, fiberglass, and automobile parts. Inhaled styrene has been reported to produce respiratory toxicity in humans and animals. Styrene oxide, a reactive metabolite of styrene formed via cytochrome P450 enzymes, has been reported to form covalent bonds with proteins, such as albumin and hemoglobin. Among all of the amino acids, cysteine is the most reactive amino acid to be modified by electrophilic species. The purpose of this study is to develop polyclonal antibodies for the detection of styrene oxide cysteinyl protein adducts. Two immunogens were designed, synthesized, and used to induce polyclonal antibodies in rabbits. Immune responses were observed from the raised antibodies by antiserum dilution tests. Competitive ELISA demonstrated that the resulting antibodies specifically recognized the styrene oxide-derived N-acetylcysteine adduct. Western blot results showed that the antibodies recognize styrene oxide-modified albumin. The binding was found to depend on the amount of protein adducts blotted and hapten loading in protein adducts. No cross reaction was observed from the native protein. Competitive Western blots further indicated that these antibodies specifically recognized styrene oxide cysteinyl-protein adducts. Immunoblots revealed the presence of several bands at a molecular weight ranging from 50 to 80 kDa in rat nasal mucosa treated with styrene. In conclusion, we successfully raised polyclonal antibodies to detect styrene oxide-derived protein/cysteine adducts. PMID:17266334

Yuan, Wei; Chung, Jouku; Gee, Shirley; Hammock, Bruce D; Zheng, Jiang

2007-02-01

261

Discovery and Optimization of Sulfonyl Acrylonitriles as Selective, Covalent Inhibitors of Protein Phosphatase Methylesterase-1  

PubMed Central

The serine hydrolase protein phosphatase methylesterase-1 (PME-1) regulates the methylesterification state of protein phosphatase 2A (PP2A) and has been implicated in cancer and Alzheimer's disease. We recently reported a fluorescence polarization-activity-based protein profiling (fluopol-ABPP) high-throughput screen for PME-1 that uncovered a remarkably potent and selective class of aza-?-lactam (ABL) PME-1 inhibitors. Here, we describe a distinct set of sulfonyl acrylonitrile inhibitors that also emerged from this screen. The optimized compound, 28 (AMZ30), selectively inactivates PME-1 and reduces the demethylated form of PP2A in living cells. Considering that 28 is structurally unrelated to ABL inhibitors of PME-1, these agents, together, provide a valuable set of pharmacological probes to study the role of methylation in regulating PP2A function. We furthermore observed that several serine hydrolases were sensitive to analogs of 28, suggesting that more extensive structural exploration of the sulfonyl acrylonitrile chemotype may result in useful inhibitors for other members of this large enzyme class. PMID:21639134

Bachovchin, Daniel A.; Zuhl, Andrea M.; Speers, Anna E.; Wolfe, Monique R.; Weerapana, Eranthie; Brown, Steven J.; Rosen, Hugh; Cravatt, Benjamin F.

2011-01-01

262

Manganese triacetate as an efficient catalyst for bisperoxidation of styrenes.  

PubMed

A method was developed for the bisperoxidation of styrenes with tert-butyl hydroperoxide in the presence of a catalytic amount of manganese(iii) acetate. It was shown that compounds of manganese in oxidation states 2, 4, and 7 also catalyze this reaction. The target [1,2-bis(tert-butylperoxy)ethyl]arenes were synthesized in yields from 46 to 75%. PMID:25469680

Terent'ev, Alexander O; Sharipov, Mikhail Yu; Krylov, Igor B; Gaidarenko, Darya V; Nikishin, Gennady I

2015-01-21

263

High performance light-colored nitrile-butadiene rubber nanocomposites.  

PubMed

High mechanical performance nitrile-butadiene rubber (NBR) with light color was fabricated by the method of in situ formation of zinc disorbate (ZDS) or magnesium disorbate (MDS). The in situ formed ZDS and its polymerization via internal mixing was confirmed by X-ray diffaraction. The mechanical properties, ageing resistance, morphology and the dynamic mechanical analysis were fully studied. It was found that with increasing loading of metallic disorbate both the curing rate and the ionic crosslink density was largely increased. The modulus, tensile strength and tear strength were largely increased. With a comparison between internal mixing and opening mixing, the mechanical performance for the former one was obviously better than the latter one. The high performance was ascribed to the finely dispersion nano domains with irregular shape and obscure interfacial structures. Except for the NBR vulcanizate with a high loading of MDS, the others' ageing resistance with incorporation of these two metallic disorbate was found to be good. Dynamic mechanical analysis (DMA) showed that, with increasing loading of metallic disorbate, the highly increased storage modulus above -20 degrees C, the up-shifted glass transition temperature (Tg) and the reduced mechanical loss were ascribed to strengthened interfacial interactions. PMID:22408977

Lei, Yanda; Guo, Baochun; Chen, Feng; Zhu, Lixin; Zhou, Wenyou; Jia, Demin

2011-12-01

264

Ultrasonic velocity and absorption study of binary mixtures of cyclohexane with acrylonitrile by interferometric method at different frequencies  

NASA Astrophysics Data System (ADS)

The ultrasonic velocity (u), absorption (?), density (?), and viscosity (?) has been measured at different frequencies (1MHz to 10MHz) in the binary mixtures of cyclohexane with acrylonitriile over the entire range of composition at temperature 303K. Vander Waal's constant (b), adiabatic compressibility (?a), acoustic impedance (Z), molar volume (V), free length (Lf), free volume, internal pressure, intermolecular radius and relative association have been also calculated. A special application for acrylonitrile is in the manufacture of carbon fibers. These are produced by paralysis of oriented poly acrylonitrile fibers and are used to reinforce composites for high-performance applications in the aircraft, defense and aerospace industries. Other applications of acrylonitrile are in the production of fatty amines, ion exchange resins and fatty amine amides used in cosmetics, adhesives, corrosion inhibitors and water-treatment resins. Cyclohexane derivatives can be used for the synthesis of pharmaceuticals, dyes, herbicides, plant growth regulator, plasticizers, rubber chemicals, nylon, cyclamens and other organic compounds. In the view of these extensive applications of acrylonitrile and cyclohexane in the engineering process, textile and pharmaceutical industries present study provides qualitative information regarding the nature and strength of interaction in the liquid mixtures through derive parameters from ultrasonic velocity and absorption measurement.

Pawar, N. R.; Chimankar, O. P.; Bhandakkar, V. D.; Padole, N. N.

2012-12-01

265

Effects of hyperoxia and acrylonitrile on the phospholipase C isozyme protein levels in rat heart and brain  

Microsoft Academic Search

We previously showed that hyperoxia exerts oxidative stress on the rat cerebral cortex, and the protein levels of phospholipase C (PLC) -?1 and -?1, but not PLC-?1, were changed. Acrylonitrile (ACN) appears to induce astrocytomas through induction of oxidative stress on the rat brain selectively. This study compared hyperoxia or ACN treatments of rats with respect to lipid peroxidation and

Kazuki Nagasawa; Hiroko Tanino; Shun Shimohama; Sadaki Fujimoto

2003-01-01

266

Nickel-catalyzed regioselective hydroalkynylation of styrenes: improved catalyst system, reaction scope, and mechanism.  

PubMed

Addition of the sp-C-H bond of triisopropylsilylacetylene to the carbon-carbon double bonds of styrenes bearing functional groups proceeded efficiently at room temperature in the presence of 3 mol % of Ni(cod)(2) with a PMePh(2) ligand. Use of 2-deuteriotriisopropylsilylacetylene in the hydroalkynylation of styrenes resulted in regioselective incorporation of deuterium into the beta-positions of recovered styrenes, along with its regioselective introduction into the product's methyl group. PMID:19143513

Shirakura, Masamichi; Suginome, Michinori

2009-02-01

267

Influence of the water content and water activity on styrene degradation by Exophiala jeanselmei in biofilters  

Microsoft Academic Search

The performance at low water availability of styrene-degrading biofilters with the fungus Exophiala jeanselmei growing on perlite, the inert support, was investigated. E. jeanselmei degrades styrene at a water activity of 0.91–1. In biofilters, the styrene elimination capacity at a water activity of 0.91\\u000a is 5% of the maximal elimination capacity of 79?g?m-3?h-1 (water activity 1). Application of dry air

H. H. J. Cox; F. J. Magielsen; H. J. Doddema; W. Harder

1996-01-01

268

Nitroxide mediated living radical polymerization of styrene in miniemulsion—modelling persulfate-initiated systems  

Microsoft Academic Search

Recently we have constructed a mechanistic model describing the nitroxide mediated miniemulsion polymerization (NMMP) of styrene at 135°C, using alkoxyamine initiators to control polymer growth (Nitroxide-Mediated Polymerization of Styrene in Miniemulsion. Modeling Studies of Alkoxyamine-Initiated Systems, 2001b). The model has since been expanded to describe styrene NMMP at 135°C using TEMPO and the free radical initiator, potassium persulfate (KPS). The

John W. Ma; Michael F. Cunningham; Kim B. McAuley; Barkev Keoshkerian; Michael Georges

2003-01-01

269

REPRODUCTIVE EFFECTS ASSESSMENT GROUP'S REPORT ON THE MUTAGENICITY OF 1.3-BUTADIENE AND ITS REACTIVE METABOLITES  

EPA Science Inventory

A major data gap for assessing heritable risk from exposure to 1,3-butadiene is the lack of mammalian mutagenicity data. The data base on the mutagenic potential of 1,3-butadiene is limited to three bacterial studies from the same laboratory. Two of these studies were positive on...

270

Design of a metal-promoted oxide catalyst for the selective synthesis of butadiene from ethanol.  

PubMed

The synthesis of buta-1,3-diene from ethanol has been studied over metal-containing (M=Ag, Cu, Ni) oxide catalysts (MO(x)=MgO, ZrO2, Nb2O5, TiO2, Al2O3) supported on silica. Kinetic study of a wide range of ethanol conversions (2-90%) allowed the main reaction pathways leading to butadiene and byproducts to be determined. The key reaction steps of butadiene synthesis were found to involve ethanol dehydrogenation, acetaldehyde condensation, and the reduction of crotonaldehyde with ethanol into crotyl alcohol. Catalyst design included the selection of active components for each key reaction step and merging of these components into multifunctional catalysts and adjusting the catalyst functions to achieve the highest selectivity. The best catalytic performance was achieved over the Ag/ZrO2/SiO2 catalyst, which showed the highest selectivity towards butadiene (74?mol%). PMID:25123990

Sushkevich, Vitaly L; Ivanova, Irina I; Ordomsky, Vitaly V; Taarning, Esben

2014-09-01

271

Chain- and Regioselective Ethylene and Styrene Dimerization Reactions Catalyzed by a Well-Defined Cationic Ruthenium-Hydride Complex: New Insights on the Styrene Dimerization Mechanism.  

PubMed

The cationic ruthenium-hydride complex [(eta(6)-C(6)H(6))(PCy(3))(CO)RuH](+)BF(4) (-) was found to be a highly regioselective catalyst for the ethylene dimerization reaction to give 2-butene products (TOF = 1910 h(-1), >95% selectivity for 2-butenes). The dimerization of styrene exclusively produced the head-to-tail dimer (E)-PhCH(CH(3))CH=CHPh at an initial turnover rate of 2300 h(-1). A rapid and extensive H/D exchange between the vinyl hydrogens of styrene-d(8) and 4-methoxystyrene was observed within 10 min without forming the dimer products at room temperature. The inverse deuterium isotope effect of k(H)/k(D) = 0.77+/-0.10 was measured from the first order plots on the dimerization reaction of styrene and styrene-d(8) in chlorobenzene at 70 degrees C. The pronounced carbon isotope effect on both vinyl carbons of styrene as measured by using Singleton's method ((13)C(recovered)/(13)C(virgin) at C(1) = 1.096 and C(2) = 1.042) indicates that the C-C bond formation is the rate-limiting step for the dimerization reaction. The Eyring plot of the dimerization of styrene in the temperature range of 50-90 degrees C led to DeltaH(double dagger) = 3.3(6) kcal/mol and DeltaS(double dagger) = -35.5(7) e.u. An electrophilic addition mechanism has been proposed for the dimerization of styrene. PMID:20694188

Lee, Do W; Yi, Chae S

2010-01-01

272

Rich premixed laminar methane flames doped by light unsaturated hydrocarbons. II. 1,3-Butadiene  

SciTech Connect

In line with the study presented in Part I of this paper, the structure of a rich premixed laminar methane flame doped with 1,3-butadiene has been investigated. The flame contains 20.7% (molar) of methane, 31.4% of oxygen, and 3.3% of 1,3-butadiene, corresponding to an equivalence ratio of 1.8, and a C{sub 4}H{sub 6}/CH{sub 4} ratio of 16%. The flame has been stabilized on a burner at a pressure of 6.7 kPa using argon as dilutant, with a gas velocity at the burner of 36 cm/s at 333 K. The temperature ranged from 600 K close to the burner up to 2150 K. Quantified species included the usual methane C{sub 0}-C{sub 2} combustion products and 1,3-butadiene, but also propyne, allene, propene, propane, 1,2-butadiene, butynes, vinylacetylene, diacetylene, 1,3-pentadiene, 2-methyl-1,3-butadiene (isoprene), 1-pentene, 3-methyl-1-butene, benzene, and toluene. To model these new results, some improvements have been made to a mechanism previously developed in our laboratory for the reactions of C{sub 3}-C{sub 4} unsaturated hydrocarbons. The main reaction pathways of consumption of 1,3-butadiene and of formation of C{sub 6} aromatic species have been derived from flow rate analyses. In this case, the C{sub 4} route to benzene formation plays an important role in comparison to the C{sub 3} pathway. (author)

Gueniche, H.A.; Glaude, P.A.; Fournet, R.; Battin-Leclerc, F. [Departement de Chimie-Physique des Reactions, UMR 7630 CNRS, INPL-ENSIC, 1 rue Grandville, BP 20451, 54001 Nancy Cedex (France)

2007-10-15

273

Enantioselective C-H crotylation of primary alcohols via hydrohydroxyalkylation of butadiene.  

PubMed

The direct, by-product-free conversion of basic feedstocks to products of medicinal and agricultural relevance is a broad goal of chemical research. Butadiene is a product of petroleum cracking and is produced on an enormous scale (about 12 × 10(6) metric tons annually). Here, with the use of a ruthenium catalyst modified by a chiral phosphate counterion, we report the direct redox-triggered carbon-carbon coupling of alcohols and butadiene to form products of carbonyl crotylation with high levels of anti-diastereoselectivity and enantioselectivity in the absence of stoichiometric by-products. PMID:22442385

Zbieg, Jason R; Yamaguchi, Eiji; McInturff, Emma L; Krische, Michael J

2012-04-20

274

Study of gamma-ray radiation induced polymerization of butadiene in ethanol  

NASA Astrophysics Data System (ADS)

The 60Co ?-ray radiation induced polymerization of butadiene in bulk and in ethanol at temperature ranging from 15 to 45°C has been studied. Hydrogen peroxide was used as initiator in some occasions. The mechanisms of polymerization in ethanol seems to fit the no-energy transfer kinetics described by Chapiro (1962) and the ratio of relative rate of free radical production of solvent/monomer ? rel is 19. When hydrogen peroxide was added to the butadiene-ethanol system the polymerization rate increased and hydroxyl terminated polybutadiene was obtained. The microstructure of polybutadiene was studied by IR and NMR spectra.

Jian, Zhang; Zhi-Ping, Zhang; Shang-Kang, Ying

275

Synthesis and flocculation properties of gum ghatti and poly(acrylamide-co-acrylonitrile) based biodegradable hydrogels.  

PubMed

This article reports the development of biodegradable flocculants based on graft co-polymers of gum ghatti (Gg) and a mixture of acrylamide and acrylonitrile co-monomers (AAm-co-AN). The hydrogel polymer exhibited an excellent swelling capacity of 921% in neutral medium at 60°C. The polymer was used to remove saline water from various petroleum fraction-saline water emulsions. The flocculation characteristics of the hydrogel polymer were studied in turbid kaolin solution as a function of the amount of polymer and the solution temperature and pH. Biodegradation studies of hydrogel polymer were conducted using the soil composting method, and the degradation process was constantly monitored using scanning electron microscopy and Fourier transform infrared spectroscopy techniques. The results demonstrated an 89.47% degradation of the polymer after 60 days. Finally, the hydrogel polymer adsorbed 98% of cationic dyes from the aqueous solutions. PMID:25263897

Mittal, Hemant; Jindal, Rajeev; Kaith, Balbir Singh; Maity, Arjun; Ray, Suprakas Sinha

2014-12-19

276

Intumescent flame retardants for polymers. I. The poly(acrylonitrile)-ammonium polyphosphate-hexabromocyclododecane system  

SciTech Connect

The influence of ammonium polyphosphate (APP) and hexabromocyclododecane (HBCD) as flame retardant (FR) on poly(acrylonitrile) (PAN) has been examined. The APP-HBCD system behaves as an intumescent flame retardant (IFR) formulation, APP being the char-forming agent and HBCD the blowing agent. A negligible gas-phase mode of action was ascertained for HBCD with this substrate. A synergism between the two FR agents was observed, corresponding to about 50% increased efficacy with respect to the separate effects of the two components. Thermogravimetry (TG), oxygen index (OI), nitrous oxide index (NOI) experiments and phosphorous residue measurements were performed to substantiate the conclusion that a condensed phase mechanism of action accounts for all the facts observed.

Ballistreri, A.; Montaudo, G.; Puglisi, C.; Scamporrino, E.; Vitalini, D.

1983-05-01

277

Lithium-7 NMR and ionic conductivity studies of gel electrolytes based on poly(acrylonitrile)  

SciTech Connect

Composite gel electrolytes prepared from mixtures of poly(acrylonitrile) (PAN), ethylene carbonate (EC), propylene carbonate (PC), and LiClO[sub 4] or LiAsF[sub 6] have been investigated by complex impedance, differential scanning calorimetry (DSC), and [sup 7]Li nuclear magnetic resonance (NMR) spectroscopy. The ionic conductivity of a gel containing LiAsF[sub 6] reaches 10[sup [minus]2] S/cm at 60[degrees]C. Although the conductivity of the gels approach that found in EC/PC liquid electrolytes, NMR line width, and spin-lattice relaxation time (T[sub 1]) measurements indicate that even short-range ionic mobility is impeded by the presence of the PAN. As in the case of amorphous polyether-salt polymer electrolytes, the onset of [sup 7]Li motional line narrowing in the gels is strongly correlated with the DSC-determined glass transition temperature. 6 figs., 1 tab.

Croce, F. (Univ. of Rome (Italy)); Brown, S.D.; Greenbaum, S.G. (Hunter College of CUNY, New York, NY (United States)); Slane, S.M.; Salomon, M. (Army Research Lab., Fort Monmouth, NJ (United States))

1993-09-01

278

40 CFR 721.7020 - Distillates (petroleum), C(3-6), polymers with styrene and mixed terpenes (generic name).  

Code of Federal Regulations, 2012 CFR

...2012-07-01 false Distillates (petroleum), C(3-6), polymers with styrene...Substances § 721.7020 Distillates (petroleum), C(3-6), polymers with styrene...The chemical substance distillates (petroleum), C(3-6), polymers with...

2012-07-01

279

40 CFR 721.7020 - Distillates (petroleum), C(3-6), polymers with styrene and mixed terpenes (generic name).  

Code of Federal Regulations, 2013 CFR

...2013-07-01 false Distillates (petroleum), C(3-6), polymers with styrene...Substances § 721.7020 Distillates (petroleum), C(3-6), polymers with styrene...The chemical substance distillates (petroleum), C(3-6), polymers with...

2013-07-01

280

40 CFR 721.7020 - Distillates (petroleum), C(3-6), polymers with styrene and mixed terpenes (generic name).  

...2014-07-01 false Distillates (petroleum), C(3-6), polymers with styrene...Substances § 721.7020 Distillates (petroleum), C(3-6), polymers with styrene...The chemical substance distillates (petroleum), C(3-6), polymers with...

2014-07-01

281

Acid-catalyzed ortho-alkylation of anilines with styrenes: an improved route to chiral anilines with bulky substituents.  

PubMed

[reaction: see text] Reaction of para-substituted anilines with styrene derivatives at elevated temperatures, when catalyzed by CF3SO3H, results in highly chemoselective ortho-alkylation of the aniline. When R = H, dialkylation can be achieved by varying the ratio of styrene to aniline. Several different substituted anilines and styrenes were examined, and good yields (42-87%) were obtained, except in the case where electron-withdrawing substituents are present on the styrene. PMID:16268521

Cherian, Anna E; Domski, Gregory J; Rose, Jeffrey M; Lobkovsky, Emil B; Coates, Geoffrey W

2005-11-10

282

Spectrum of styrene-induced DNA adducts: the relationship to other biomarkers and prospects in human biomonitoring  

Microsoft Academic Search

Styrene is an important industrial chemical that has shown genotoxicity in many toxicology assays. This is believed to be related to the DNA-binding properties of styrene-7,8-oxide (SO), a major metabolite of styrene. In this review, we have summarized knowledge on various aspects of styrene genotoxicity, especially in order to understand the formation and removal of primary DNA lesions, and the

Pavel Vodicka; Mikko Koskinen; Michael Arand; Franz Oesch; Kari Hemminki

2002-01-01

283

Development of Polyclonal Antibodies for the Detection of Styrene Oxide Modified Proteins  

E-print Network

Development of Polyclonal Antibodies for the Detection of Styrene Oxide Modified Proteins Wei Yuan, and automobile parts. Inhaled styrene has been reported to produce respiratory toxicity in humans and animals, cysteine is the most reactive amino acid to be modified by electrophilic species. The purpose of this study

Hammock, Bruce D.

284

Light induced refractive index changes in PMMA films doped with styrene  

Microsoft Academic Search

Solutions of poly(methyl methacrylate) in styrene are used to produce thin polymer films (1µm–20µm) saturated with styrene monomer. In the illuminated areas refractive index changes up to 10-2 are achieved by photoinduced polymerisation. The index patterns may be fixed by annealing treatments removing the residual monomer.

H. Franke; H. G. Festl; E. Krätzig

1984-01-01

285

Initiation precursors and initiators in laser-induced copolymerization of styrene and maleic anhydride in acetone  

NASA Technical Reports Server (NTRS)

The initiation step of photopolymerized styrene/maleic anhydride copolymer was investigated at 365 nm. UV absorption measurements provide decisive evidence that the styrene/maleic anhydride charge transfer complex is the sole absorbing species; however, key laser experiments suggest intermediate reactions lead to a monoradical initiating species. A mechanism for the photoinitiation step of the copolymer is proposed.

Miner, Gilda A.; Meador, Willard E.; Chang, C. Ken

1990-01-01

286

Synthesis of macroporous poly(styrene-divinyl benzene) microspheres by surfactant reverse micelles swelling method  

E-print Network

Synthesis of macroporous poly(styrene-divinyl benzene) microspheres by surfactant reverse micelles poly(styrene-divinyl benzene) microspheres with pore size of about 500 nm were prepared by a new method, surfactant reverse micelles swelling method. The macroporous microspheres were prepared by convenient

Gu, Tingyue

287

Hepatotoxicity and pneumotoxicity of styrene and its metabolites in glutathione S-transferase-deficient mice.  

PubMed

Styrene is known to be hepatotoxic and pneumotoxic in rodents, and these adverse effects are related to its metabolism. Mice deficient in the enzymes responsible for both the activation and detoxification of styrene are useful in examining this relationship more closely. In the current study, mice deficient in glutathione S-transferase P1P2(-/-) (GST(-/-)) were compared with wild-type mice. Similar changes in serum sorbitol dehydrogenase, as an indicator of hepatotoxicity, and bronchioalveolar levels of protein, cells, and lactate dehydrogenase, as indicators of pneumotoxicity, were observed after styrene administration. Glutathione depletion followed a similar pattern. The administration of the toxic metabolite, styrene oxide, which is a direct substrate for glutathione metabolism, and 4-vinylphenol, which is a minor metabolite but is more potent than either styrene oxide, yielded results similar to those of styrene. The results indicate that either other isoforms of glutathione S-transferase are more important than the P1P2 form in styrene detoxification or that this pathway contributes in only a minor way to styrene detoxification, compared to other pathways. PMID:21749217

Carlson, Gary P

2011-10-01

288

Grafting of diethyl maleate and maleic anhydride onto styrene- b-(ethylene- co-1-butene)- b-styrene triblock copolymer (SEBS)  

Microsoft Academic Search

In this paper a study of the bulk functionalization of styrene-b-(ethylene-co-1-butene)-b-styrene triblock copolymer (SEBS) with diethyl maleate (DEM) or maleic anhydride (MAH) and dicumyl peroxide (DCP) as initiator in a Brabender mixer is described. The determination of the functionalization degree (FD) by NMR analysis indicates that the FD values depend on the feed composition and in particular on the DEM\\/DCP

E. Passaglia; S. Ghetti; F. Picchioni; G. Ruggeri

2000-01-01

289

Mechanical and structural investigation of isotropic and anisotropic thermoplastic magnetorheological elastomer composites based on poly(styrene-b-ethylene-co-butylene-b-styrene) (SEBS)  

Microsoft Academic Search

Novel smart thermoplastic magnetorheological elastomer composites containing micron-sized magnetic carbonyl iron (CI) particles\\u000a were prepared with a poly(styrene-ethylene-butylene-styrene) (SEBS) triblock copolymer utilized as the thermoplastic matrix\\u000a rubber, and the structures and properties of the CI-SEBS composites were examined. The CI particles were uniformly dispersed\\u000a in the composites prepared in the absence of the magnetic field at high temperatures T (>T,

Xiushou Lu; Xiuying Qiao; Hiroshi Watanabe; Xinglong Gong; Tao Yang; Wei Li; Kang Sun; Meng Li; Kang Yang; Hongen Xie; Qi Yin; Dong Wang; Xiaodong Chen

290

Depletion by Styrene of Glutathione in Plasma and Bronchioalveolar Lavage Fluid of Non-Swiss Albino (NSA) Mice  

Microsoft Academic Search

Styrene is a widely used chemical, but it is known to produce lung and liver damage in mice. This may be related to oxidative stress associated with the decrease in the levels of reduced glutathione (GSH) in the target tissues. The purpose of this study was to investigate the effect of styrene and its primary metabolites R-styrene oxide (R-SO) and

Gary P. Carlson

2010-01-01

291

Thermal annealing effects on the physical properties of styrenic pentablock ionomers and their electromechanical responses.  

PubMed

Thermal annealing effect on the physical properties of two ionic (poly((t-butyl-styrene)-b-(ethylene-r-propylene)-b-(styrene-r-styrene sulfonate)-b-(ethylene-r-propylene)-b-(t-butyl-styrene (SSPB) pentablock copolymers with different ion exchange capacities (IEC; 1.5 and 2.0 meq/g) and their electromechanical responses in ionic polymer-metal composite (IPMC) devices have been investigated. The ionic SSPB formed the microphase-separated morphology on the several tens nanometer scale and the selectively sulfonated styrene middle blocks formed the ionic channels through which ions can pass in the membrane. The thermal annealing at a high temperature led to the well developed interconnectivity between adjacent ionic channels, and thus enhanced the ion conductivity and mechanical strength of membranes, resulting in an actuation enhancement of the SSPB-based ionic actuator. PMID:23858912

Lee, Jang-Woo; Lee, Jin Hong; Kim, Minho; Hong, Soon Man; Koo, Chong Min

2013-05-01

292

Alkyltransferase-mediated Toxicity of 1,3-Butadiene Diepoxide  

PubMed Central

Human O6-alkylguanine-DNA alkyltransferase (hAGT) expression increases mutations and cytotoxicity following exposure to 1,3-butadiene diepoxide (BDO) and hAGT-DNA cross-links are formed in the presence of BDO. We have used hAGT mutants to investigate the mechanism of cross-link formation and genotoxicity. Formation of a hAGT-DNA conjugate in vitro was observed with C145S and C145A mutant proteins but was considerably diminished with the C145A/C150S double mutant confirming that cross-linking primarily involves either of these two cysteine residues, which are located in the active site pocket of the protein. Cross-link formation by BDO occurred both via (a) an initial reaction of BDO with hAGT followed by attack of the reactive hAGT complex on DNA, and (b) the initial reaction of BDO with DNA followed by a reaction between hAGT and the DNA adduct. These results differ from those with 1,2-dibromoethane (DBE) where Cys145 is the only site of attachment and pathway (b) does not occur. The complex formed between hAGT at Cys145 and BDO was very unstable in aqueous solution. However, the BDO-hAGT complex at Cys150 exhibited stability for more than 1 h. The effect of hAGT and mutants on BDO-induced genotoxicity was studied in E. coli using the forward assay to rifampicin resistance. Both mutations and cell killing were greatly increased by wild type hAGT and there was a smaller but significant effect with the C145A mutant. The R128A mutant and R128A/C145A and C145A/C150S double mutants were ineffective supporting the hypothesis that the formation of hAGT-DNA cross-links is responsible for the enhanced genotoxicity detected in this biological system. In the absence of hAGT, there were equal proportions of G:C to A:T transitions, G:C to T:A transversions and A:T to T:A transversions. Wild type hAGT expression yielded significantly greater G:C to A:T and A:T to G:C transitions, whereas C145A mutant expression resulted in more transitions and transversions at A:T base-pairs. PMID:18712882

Kalapila, Aley G.; Loktionova, Natalia A.; Pegg, Anthony E.

2008-01-01

293

Alkyltransferase-mediated toxicity of 1,3-butadiene diepoxide.  

PubMed

Human O(6)-alkylguanine-DNA alkyltransferase (hAGT) expression increases mutations and cytotoxicity following exposure to 1,3-butadiene diepoxide (BDO), and hAGT-DNA cross-links are formed in the presence of BDO. We have used hAGT mutants to investigate the mechanism of cross-link formation and genotoxicity. Formation of a hAGT-DNA conjugate in vitro was observed with C145S and C145A mutant proteins but was considerably diminished with the C145A/C150S double mutant confirming that cross-linking primarily involves either of these two cysteine residues, which are located in the active site pocket of the protein. Cross-link formation by BDO occurred both via (a) an initial reaction of BDO with hAGT followed by attack of the reactive hAGT complex on DNA, and (b) the initial reaction of BDO with DNA followed by a reaction between hAGT and the DNA adduct. These results differ from those with 1,2-dibromoethane (DBE) where Cys(145) is the only site of attachment and pathway (b) does not occur. The complex formed between hAGT at Cys(145) and BDO was very unstable in aqueous solution. However, the BDO-hAGT complex at Cys(150) exhibited stability for more than 1 h. The effect of hAGT and mutants on BDO-induced genotoxicity was studied in E. coli using the forward assay to rifampicin resistance. Both mutations and cell killing were greatly increased by wild type hAGT, and there was a smaller but significant effect with the C145A mutant. The R128A mutant and R128A/C145A and C145A/C150S double mutants were ineffective, supporting the hypothesis that the formation of hAGT-DNA cross-links is responsible for the enhanced genotoxicity detected in this biological system. In the absence of hAGT, there were equal proportions of G:C to A:T transitions, G:C to T:A transversions, and A:T to T:A transversions. Wild type hAGT expression yielded significantly greater G:C to A:T and A:T to G:C transitions, whereas C145A mutant expression resulted in more transitions and transversions at A:T base-pairs. PMID:18712882

Kalapila, Aley G; Loktionova, Natalia A; Pegg, Anthony E

2008-09-01

294

HEALTH AND ENVIRONMENTAL EFFECTS PROFILE FOR 2-CHLORO-1,3-BUTADIENE  

EPA Science Inventory

The Health and Environmental Effects Profile for 2-Chloro-1,3-Butadiene was prepared by the Office of Health and Environmental Assessment, Environmental criteria assessment Office, Cincinnati, OH for the Office of Solid Waste to support listings of hazardous constituents of a wid...

295

HYDROXYL RADICAL AND OZONE INITIATED PHOTOCHEMICAL REACTIONS OF 1,3-BUTADIENE. (R826247)  

EPA Science Inventory

1,3-Butadiene, classified as hazardous in the 1990 Clean Air Act Amendments, is an important ambient air pollutant. Understanding its atmospheric transformation is useful for its own sake, and is also helpful for eliciting isoprene's fate in the atmosphere (isoprene dominates ...

296

Hydrogenation of 1,3-Butadiene on Platinum Surfaces of DifferentStructures  

SciTech Connect

1,3-butadiene hydrogenation is studied on platinum foil and Pt(111), Pt(100), Pt(755) single-crystal surfaces at 300-375 K. The results are compared with the data of alkene hydrogenation reactions. Similar to the hydrogenation kinetics of butenes, 1,3-butadiene hydrogenation exhibits near zeroth-order dependence on hydrocarbon and near first-order dependence on hydrogen pressure. With the same hydrocarbon (3.5-70 Torr) and hydrogen (14-140 Torr) pressure, the rate of 1,3-butadiene hydrogenation is one order of magnitude lower than for the rates for n-butenes. The hydrogenation products include 1-butene, trans- and cis-2-butene, and n-butane. The reaction selectivity is independent of reactant mixture and platinum surface structure, but changes slightly as a function of reaction temperature. The butene product distribution is determined by surface reaction kinetics. While 1-butene is thermodynamically less stable than trans- and cis-2-butene, it is the major butene product in 1,3-butadiene hydrogenation.

Yoon, Cheonho; Yang, M.X.; Somorjai, G.A.

1997-05-01

297

Synthesis and Characterization of Proton Exchange Membrane Using Polystyrene-butadiene Rubber  

Microsoft Academic Search

The challenges in proton exchange membrane fuel cell research and development are to reduce the production cost of the fuel cell by reducing the membrane cost. This is possible by the development of an alternative membrane from a cheap source having a good prospect in fuel cell application. Sulphonation of locally available polystyrene butadiene rubber was carried out. The sulphonated

A. S. Abdulkareem; C. A. Idibie; H. C. Vz Piennar; L. Van Dyk; S. E. Iyuke

2010-01-01

298

THE OZONE REACTION WITH BUTADIENE: FORMATION OF TOXIC PRODUCTS. (R826236)  

EPA Science Inventory

Abstract The formation yields of acrolein, 1,2-epoxy-3-butene and OH radicals have been measured from reaction of ozone with 1,3-butadiene at room temperature and atmosphere pressure. 1,3,5-Trimethyl benzene was added to scavenge OH radicals in measurements of product ...

299

Ternary Ag/MgO-SiO2 Catalysts for the Conversion of Ethanol into Butadiene.  

PubMed

Ternary Ag/Magnesia-silica catalysts were tested in the direct synthesis of 1,3-butadiene from ethanol. The influence of the silver content and the type of silica source on catalytic performance has been studied. Prepared catalysts were characterized by (29) Si NMR, N2 sorption, small-angle X-ray scattering measurements, XRD, environmental scanning electron microscopy with energy dispersive X-ray analysis (ESEM/EDX), FTIR spectroscopy of adsorbed pyridine and CO2 , temperature-programmed desorption of CO2 and UV/Vis diffuse reflectance spectroscopy. Based on these characterization results, the catalytic performance of the catalysts in the 1,3-butadiene formation process was interpreted and a tentative model explaining the role of the different catalytically active sites was elaborated. The balance of the active sites is crucial to obtain an active and selective catalyst to form 1,3-butadiene from ethanol. The optimal silver loading is 1-2?wt?% on a MgO-silica support with a molar Mg/Si ratio of 2. The silver species and basic sites (Mg?O pairs and basic OH groups) are of prime importance in the 1,3-butadiene production, catalyzing mainly the ethanol dehydrogenation and the aldol condensation, respectively. PMID:25410420

Janssens, Wout; Makshina, Ekaterina V; Vanelderen, Pieter; De Clippel, Filip; Houthoofd, Kristof; Kerkhofs, Stef; Martens, Johan A; Jacobs, Pierre A; Sels, Bert F

2014-11-19

300

EFFECTS OF 1,3-BUTADIENE, ISOPRENE, AND THEIR PHOTOCHEMICAL DEGRADATION PRODUCTS ON HUMAN LUNG CELLS  

EPA Science Inventory

Because of potential exposure both in the workplace and from ambient air, the known carcinogen 1,3-butadiene (BD) is considered a priority hazardous air pollutant. BD and its 2-methyl analog, isoprene (ISO), are chemically similar but have very different toxicities, with ISO show...

301

Occupational Styrene Exposure Induces Stress-Responsive Genes Involved in Cytoprotective and Cytotoxic Activities  

PubMed Central

Objective The aim of this study was to evaluate the expression of a panel of genes involved in toxicology in response to styrene exposure at levels below the occupational standard setting. Methods Workers in a fiber glass boat industry were evaluated for a panel of stress- and toxicity-related genes and associated with biochemical parameters related to hepatic injury. Urinary styrene metabolites (MA+PGA) of subjects and environmental sampling data collected for air at workplace were used to estimate styrene exposure. Results Expression array analysis revealed massive upregulation of genes encoding stress-responsive proteins (HSPA1L, EGR1, IL-6, IL-1?, TNSF10 and TNF?) in the styrene-exposed group; the levels of cytokines released were further confirmed in serum. The exposed workers were then stratified by styrene exposure levels. EGR1 gene upregulation paralleled the expression and transcriptional protein levels of IL-6, TNSF10 and TNF? in styrene exposed workers, even at low level. The activation of the EGR1 pathway observed at low-styrene exposure was associated with a slight increase of hepatic markers found in highly exposed subjects, even though they were within normal range. The ALT and AST levels were not affected by alcohol consumption, and positively correlated with urinary styrene metabolites as evaluated by multiple regression analysis. Conclusion The pro-inflammatory cytokines IL-6 and TNF? are the primary mediators of processes involved in the hepatic injury response and regeneration. Here, we show that styrene induced stress responsive genes involved in cytoprotection and cytotoxicity at low-exposure, that proceed to a mild subclinical hepatic toxicity at high-styrene exposure. PMID:24086524

Strafella, Elisabetta; Bracci, Massimo; Staffolani, Sara; Manzella, Nicola; Giantomasi, Daniele; Valentino, Matteo; Amati, Monica; Tomasetti, Marco; Santarelli, Lory

2013-01-01

302

Sequence analysis of styrenic copolymers by tandem mass spectrometry.  

PubMed

Styrene and smaller molar amounts of either m-dimethylsilylstyrene (m-DMSS) or p-dimethylsilylstyrene (p-DMSS) were copolymerized under living anionic polymerization conditions, and the compositions, architectures, and sequences of the resulting copolymers were characterized by matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF-MS) and tandem mass spectrometry (MS(2)). MS analysis revealed that linear copolymer chains containing phenyl-Si(CH3)2H pendants were the major product for both DMSS comonomers. In addition, two-armed architectures with phenyl-Si(CH3)2-benzyl branches were detected as minor products. The comonomer sequence in the linear chains was established by MS(2) experiments on lithiated oligomers, based on the DMSS content of fragments generated by backbone C-C bond scissions and with the help of reference MS(2) spectra obtained from a polystyrene homopolymer and polystyrene end-capped with a p-DMSS block. The MS(2) data provided conclusive evidence that copolymerization of styrene/DMSS mixtures leads to chains with a rather random distribution of the silylated comonomer when m-DMSS is used, but to chains with tapered block structures, with the silylated units near the initiator, when p-DMSS is used. Hence, MS(2) fragmentation patterns permit not only differentiation of the sequences generated in the synthesis, but also the determination of specific comonomer locations along the polymer chain. PMID:25181590

Yol, Aleer M; Janoski, Jonathan; Quirk, Roderic P; Wesdemiotis, Chrys

2014-10-01

303

Effect of Cu(II)\\/H 2 Salen complex on the non-conventional initiated emulsion polymerization of acrylonitrile  

Microsoft Academic Search

Radical polymerization of acrylonitrile was carried out in an emulsifier-free condition initiated by KHSO5 catalyzed with Cu(II)\\/bis-salicylidene ethylene diamine (H2 Salen) complex. The Cu(II) salt alone, Cu(II)\\/salicylaldehyde and Cu(II)\\/ethylene diamine have a retarding effect on the polymerization reaction, while the chelate of Cu(II) with the tetradentate Schiff base ligand, H2 Salen has a catalytic effect. Prior to this, the catalytic

Prafulla K. Sahoo; Gobind C. Sahu; Sarat K. Swain

2002-01-01

304

Ab Initio Determination of the Roto-Torsional Energy Levels of trans-1,3-Butadiene.  

PubMed

In this paper, the flexible model based on relaxed ab initio calculations, which has been several times employed for vibrational calculations, is extended to the analysis of the rotational structures starting by the roto-torsional bands of trans-1,3-butadiene. For this purpose, the potential energy surface and the kinetic energy parameters of the nu13 vibrational mode of butadiene are obtained with the Möller-Plesset perturbation theory up to the second order and the 6-31G(d, p), 6-31G(df, p), 6-311G(d, p), 6-311G(df, p), and 6-311G(df, pd) basis sets. The torsional levels of the -h6, -d4, and -d6 isotopic species are calculated variationally and are compared with experimental data. It may be concluded that the one-dimensional model appears sufficiently accurate for butadiene-h6 and -d4, whereas a large kinetic interaction with the lowest wagging mode is observed for butadiene-d6. The rotational levels corresponding to the first vibrational states of the -h6 and -d4 species are determined variationally up to J = 17 and J = 11 from the ab initio spectroscopic parameters which have been expanded as functions of the torsional coordinate using symmetry adapted series. The torsional wavefunction is contracted to reduce the size of the Hamiltonian matrix. A good agreement with the observed transitions is obtained for the first states v = 0 and v = 1. As is expected, the K doubling obtained is relatively small. For this reason, the quartic and sextic centrifugal distortion constants are obtained from the least-square fit of the variational levels to the perturbation theory equations for the symmetric top. Copyright 1998 Academic Press. PMID:9753561

Senent

1998-10-01

305

Studies of the mutagenic effects of styrene to man: conclusions for the surveillance of styrene-exposed workers  

NASA Astrophysics Data System (ADS)

One hundred fifty-six styrene-exposed workers had a fourfold higher rate of chromosome aberrations in peripheral lymphocytes than the control persons. The parameters of clinical chemistry (liver, kidney, and blood) remained in the normal range. Further analyses of the data of this study revealed no connections of the degree of effects in clinical chemistry and the exposure level. But a connection exists to the duration of exposure (3 - 26 years): in the comparison of the mean values (all mean values within the normal range) significant differences were found between long-term exposed workers (more than ten years) and control persons. In the higher age groups (above 45 years) also the GAP-rate differences are more pronounced. Seventy percent of the TWA-values were found to be below 85 mg/m3; the arithmetic mean of the TWA-values 72,3 mg/m3. A health surveillance program to styrene-exposed workers is to be reviewed (clinical chemistry and genetic effects). Proposals concerning both problems are presented.

Rothe, Roland; Schmidt, P.; Grummt, T.; Grummt, H. J.; Kersten, N.; Weigmann, Hans-Juergen

1993-03-01

306

Living polymerization of butadiene at both chain ends via a bimetallic nickel initiator. Preparation of hydroxytelechelic poly(butadiene) and symmetric poly(isocyanide-b-butadiene-b-isocyanide) elastomeric triblock copolymers  

Microsoft Academic Search

A bifunctional nickel initiator, bis([mu]-trifluoroacetato) ([eta][sup 3]:[eta][sup 3]-2,2[prime]-biallyl)dinickel(II), IV, was synthesized to promote the living polymerization of butadiene to high cis-1,4-content polymer with both chain ends active. Other potential initiators, [1,4-phenylenebis(([eta][sup 3]-1-allyl)nickel trifluoroacetate)][sub n], II, and [1,4-cyclohexanediylbis(([eta][sup 3]-1-allyl)-nickel trifluoroacetate)][sub n], III, were found to be completely ineffective due to intermolecular carboxylate bridges which gave the complexes polymeric structures. The intramolecular

Timothy J. Deming; Bruce M. Novak; Joseph W. Ziller

1994-01-01

307

Leaching of styrene and other aromatic compounds in drinking water from PS bottles.  

PubMed

Bottled water may not be safer, or healthier, than tap water. The present studies have proved that styrene and some other aromatic compounds leach continuously from polystyrene (PS) bottles used locally for packaging. Water sapmles in contact with PS were extracted by a preconcentration technique called as "purge and trap" and analysed by gas chromatograph-mass spectrometer (GC/MS). Eleven aromatic compounds were identified in these studies. Maximum concentration of styrene in PS bottles was 29.5 microg/L. Apart from styrene, ethyl benzene, toluene and benzene were also quantified but their concentrations were much less than WHO guide line values. All other compounds were in traces. Quality of plastic and storage time were the major factor in leaching of styrene. Concentration of styrene was increased to 69.53 microg/L after one-year storage. In Styrofoam and PS cups studies, hot water was found to be contaminated with styrene and other aromatic compounds. It was observed that temperature played a major role in the leaching of styrene monomer from Styrofoam cups. Paper cups were found to be safe for hot drinks. PMID:17915704

Ahmad, Maqbool; Bajahlan, Ahmad S

2007-01-01

308

Technoeconomic evaluation of bio-based styrene production by engineered Escherichia coli.  

PubMed

Styrene is an important commodity chemical used in polymers and resins, and is typically produced from the petrochemical feedstocks benzene and ethylene. Styrene has recently been produced biosynthetically for the first time using engineered Escherichia coli, and this bio-based route may represent a lower energy and renewable alternative to petroleum-derived styrene. However, the economics of such an approach has not yet been investigated. Using an early-stage technoeconomic evaluation tool, a preliminary economic analysis of bio-based styrene from C(6)-sugar feedstock has been conducted. Owing to styrene's limited water solubility, it was assumed that the resulting fermentation broth would spontaneously form two immiscible liquid phases that could subsequently be decanted. Assuming current C(6) sugar prices and industrially achievable biokinetic parameter values (e.g., product yield, specific growth rate), commercial-scale bio-based styrene has a minimum estimated selling price (MESP) of 1.90 USD kg(-1) which is in the range of current styrene prices. A Monte Carlo analysis revealed a potentially large (0.45 USD kg(-1)) standard deviation in the MESP, while a sensitivity analysis showed feedstock price and overall yield as primary drivers of MESP. PMID:24939174

Claypool, Joshua T; Raman, D Raj; Jarboe, Laura R; Nielsen, David R

2014-08-01

309

Trends in Occupational Exposure to Styrene in the European Glass Fibre-Reinforced Plastics Industry  

PubMed Central

Aim: This study presents temporal trends of styrene exposure for workers in the European glass fibre-reinforced plastics (GRP) industry during the period 1966–2002. Methods: Data of personal styrene exposure measurements were retrieved from reports, databases and peer-reviewed papers. Only sources with descriptive statistics of personal measurements were accepted. The styrene exposure data cover personal air samples and biological monitoring data, that is, urinary styrene metabolites (mandelic acid and/or phenylglyoxylic acid) and styrene in blood. Means of series of measurements were categorized by year, country, production process, job and sampling strategy. Linear mixed models were used to identify temporal trends and factors affecting exposure levels. Results: Personal exposure measurements were available from 60 reports providing data on 24145 1–8-h time-weighted average shift personal air samples. Available data of biological exposure indicators included measurements of mandelic acid in post-shift urine (6361 urine samples being analysed). Trend analyses of the available styrene exposure data showed that the average styrene concentration in the breathing zone of open-mould workers in the European GRP industry has decreased on average by 5.3% per year during the period 1966–1990 and by only 0.4% annually in the period after 1990. The highest exposures were measured in Southern Europe and the lowest exposures in Northern Europe with Central Europe in between. Biological indicators of styrene (mandelic acid in post-shift urine) showed a somewhat steeper decline (8.9%), most likely because urine samples were collected in companies that showed a stronger decrease of styrene exposure in air than GRP companies where no biological measurements were carried out. PMID:18550625

Van Rooij, J. G. M.; Kasper, A.; Triebig, G.; Werner, P.; Kromhout, H.

2008-01-01

310

Ab InitioDetermination of the Roto-Torsional Energy Levels of trans-1,3Butadiene  

Microsoft Academic Search

In this paper, the flexible model based on relaxedab initiocalculations, which has been several times employed for vibrational calculations, is extended to the analysis of the rotational structures starting by the roto-torsional bands oftrans-1,3-butadiene. For this purpose, the potential energy surface and the kinetic energy parameters of the ?13vibrational mode of butadiene are obtained with the Möller–Plesset perturbation theory up

M. L Senent

1998-01-01

311

The Effect of Uncertainty in Exposure Estimation on the Exposure-Response Relation between 1,3-Butadiene and Leukemia  

PubMed Central

In a follow-up study of mortality among North American synthetic rubber industry workers, cumulative exposure to 1,3-butadiene was positively associated with leukemia. Problems with historical exposure estimation, however, may have distorted the association. To evaluate the impact of potential inaccuracies in exposure estimation, we conducted uncertainty analyses of the relation between cumulative exposure to butadiene and leukemia. We created the 1,000 sets of butadiene estimates using job-exposure matrices consisting of exposure values that corresponded to randomly selected percentiles of the approximate probability distribution of plant-, work area/job group-, and year specific butadiene ppm. We then analyzed the relation between cumulative exposure to butadiene and leukemia for each of the 1,000 sets of butadiene estimates. In the uncertainty analysis, the point estimate of the RR for the first non zero exposure category (>0–<37.5 ppm-years) was most likely to be about 1.5. The rate ratio for the second exposure category (37.5–<184.7 ppm-years) was most likely to range from 1.5 to 1.8. The RR for category 3 of exposure (184.7–<425.0 ppm-years) was most likely between 2.1 and 3.0. The RR for the highest exposure category (425.0+ ppm-years) was likely to be between 2.9 and 3.7. This range off RR point estimates can best be interpreted as a probability distribution that describes our uncertainty in RR point estimates due to uncertainty in exposure estimation. After considering the complete probability distributions of butadiene exposure estimates, the exposure-response association of butadiene and leukemia was maintained. This exercise was a unique example of how uncertainty analyses can be used to investigate and support an observed measure of effect when occupational exposure estimates are employed in the absence of direct exposure measurements. PMID:19826555

Graff, John J.; Sathiakumar, Nalini; Macaluso, Maurizio; Maldonado, George; Matthews, Robert; Delzell, Elizabeth

2009-01-01

312

Mutagenicity study of workers employed in the styrene and polystyrene processing and manufacturing industry.  

PubMed

Mutagenicity studies were undertaken on lymphocytes from the following groups of persons exposed to styrene or polystyrene: one group from a styrene manufacturing plant, one from a polystyrene plant, and three from plants processing unsaturated polyester resins with different manufacturing methods. For all the groups the concentration of styrene in the atmosphere of the workplace was measured at various points and the amount of urinary mandelic acid was determined. In each case 100 metaphases were analyzed for chromosomal aberrations. The results were compared with reference groups. PMID:734412

Fleig, I; Thiess, A M

1978-01-01

313

Modification of fiber properties through grafting of acrylonitrile to rayon by chemical and radiation methods  

PubMed Central

Fibrous properties of rayon has been modified through synthesis of graft copolymers of rayon with acrylonitrile (AN) by chemical method using ceric ammonium nitrate (CAN/HNO3) as a redox initiator and gamma radiation mutual method. Percentage of grafting (Pg) was determined as a function of initiator concentration, monomer concentration, irradiation dose, temperature, time of reaction and the amount of water. Maximum percentage of grafting (160.01%) using CAN/HNO3 was obtained at [CAN] = 22.80 × 10?3 mol/L, [HNO3] = 112.68 × 10?2 mol/L and [AN] = 114.49 × 10?2 mol/L in 20 mL of water at 45 °C within 120 min while in case of gamma radiation method, maximum Pg (90.24%) was obtained at an optimum concentration of AN of 76.32 × 10?2 mol/L using 10 mL of water at room temperature with total dose exposure of 3.456 kGy/h. The grafted fiber was characterized by FTIR, SEM, TGA and XRD studies. Swelling behavior of grafted rayon in different solvents such as water, methanol, ethanol, DMF and acetone was studied and compared with the unmodified rayon. Dyeing behavior of the grafted fiber was also investigated.

Kaur, Inderjeet; Sharma, Neelam; Kumari, Vandna

2013-01-01

314

Pre-irradiation grafting of acrylonitrile onto chitin for adsorption of arsenic in water  

NASA Astrophysics Data System (ADS)

Radiation-induced grafting is an effective technique for preparation of novel materials. In this study, partially deacetylated chitin with deacetylation degree (DDA) of about 40% was graft-copolymerized with acrylonitrile (AN) by a ?-ray pre-irradiation method. The maximal grafting degree of AN onto pre-irradiated chitin at 25±1.2 kGy was 114% for AN concentration in dimethylformamide of 40% (v/v) at 70 °C for 8 h. The mixture ratio of 0.1 N NH2OH·HCl to 0.1 N NaOH was selected to be 7:3 (v/v) for amidoxime conversion of cyano-groups on grafted chitin (Chi-g-AN). The characteristics of modified chitin were depicted by the FT-IR spectra, BET area and SEM images. Adsorption equilibrium of As(III) onto Chi-g-AN converted amidoxime (Chi-g-AN-C) fits with the Langmuir model and the maximal adsorption capacity was 19.724 mg/g. The break-through times of As(III) on Chi-g-AN-C in column adsorption experiments increased with the increase in bed depths.

Hanh, Truong Thi; Huy, Ha Thuc; Hien, Nguyen Quoc

2015-01-01

315

Omsk plans back integration  

SciTech Connect

Omskhimprom (Omsk), one of Russia's largest producers of polystyrene (PS), is back integrating to styrene and other petrochemicals. As the structure of the chemical industry in the Commonwealth of Independent States (CIS) changes. Omskhimprom will no longer be able to rely on present raw material suppliers Shevchnko in Kazakhstan and Nizhnekamskneftekhim in Taterstan, which have their own development plans. Omskhimprom, recently transformed into a joint stock company and sold to its workers, hopes to complete the back integration in the next five years, says Valeria Voischeva, senior engineer. The company's plants have annual capacities for 100,000 m.t. of high-impact PS, 3,000 m.t. of acrylonitrile butadiene styrene, 30,000 m.t. of acrylonitrile butadiene styrene 30,000 m.t. of 2-ethyl hexanol, and 24,000 m.t. of phthalic anhydride. In the second stage of the development plan, Omskhimprom is studying the feasibility of building a petrochemical complex that would include a 300,000-m.t./year ethylene plant. The company says that it has natural resources locally, and, because Omsknefteorgsintez, one of the world's largest refineries, is located nearby, it will have no problems in obtaining feedstocks.

Alperowicz, N.

1992-12-02

316

A Morphological Study of Isotactic Polypropylene (iPP) Blended with Styrene-ethylene-butylene-styrene (SEBS) Thermoplastic Elastomers  

NASA Astrophysics Data System (ADS)

This work examined isotactic polypropylene (iPP) modified with hydrogenated styrene-ethylene-butylene-styrene (SEBS) copolymers at a blend ratio (by weight) of 80 polymer: 20 elastomer. The modifiers used were Tuftec® H1221, which containing 72% butene-1 mol % or Tuftec® H1062, which contains 50% butene-1 mol%. All materials are manufactured by Asahi Chemicals Ltd… H1062 is marketed as a toughening modifier for PP, exhibiting excellent elongation, brittle temperature properties and a high flexural modulus. H1221 is said to give blends which exhibit excellent softening, anti-scratch properties and anti-stress whitening. Both blends were dry mixed, passed through a twin screw extruder and pelletized. The pellets were used to prepare samples of film material by either compression moulding or sheet extrusion. The transparencies of both blend systems were approximately 92%; however the H1062 blend exhibits a haze value of 15.2% while the H1221 blend shows a value of 4.8%. This work sought an understanding of these optical properties in terms of microstructure of the polymer blends. Measurement of Tg (glass transition temperature) by dynamic mechanical analysis showed that processing methodology influenced the compatibility in the blends. Information on microstructures was sought using transmission electron microscopy, optical and polarized light microscopy as well as thermal analysis. It was found that melting & crystallisation temperatures, % crystallinity and spherulite sizes were dependant on the cooling rate employed. Elastomer domain size was dependent on the vinyl content and its distribution was dependent on the moulding technique. In conclusion, it is suggested that the size of the elastomer domains formed in the polypropylene matrix, rather than spherulite size, determined optical clarity in the films.

Buggy, M.; Ryan, E. A.

2011-01-01

317

OCCUPATIONAL STYRENE EXPOSURE FOR TWELVE PRODUCT CATEGORIES IN THE REINFORCED-PLASTICS INDUSTRY  

EPA Science Inventory

Approximately 1500 occupational styrene exposure values from 28 reinforced-plastic manufacturers were collected retrospectively from companies and state and federal agencies. The report describes the major types of manufacturing processes within the reinforced-plastics industry a...

318

A biofilter integrated with gas membrane separation unit for the treatment of fluctuating styrene loads.  

PubMed

Biofiltration for volatile organic compound control in waste gas streams is best operated at steady contaminant loadings. To provide long-term stable operation of a biofilter under adverse contaminant feeding conditions, an integrated bioreactor system with a gas separation membrane module installed after a biofilter was proposed for styrene treatment. Styrene was treated effectively, with average styrene effluent concentrations maintained at less than 50 mg m(-3) and a total removal efficiency of over 96% achieved when the biofiltration column faced fluctuating loads. The maximum elimination capacity of the integrated bioreactor system was 93.8 g m(-3)h(-1), which was higher than that obtained with the biofiltration column alone. The combination of these two processes (microbial and chemical) led to more efficient elimination of styrene and buffering of the fluctuating loads. The factors on gas membrane separation, microbial characteristics in the integrated bioreactor and membrane fouling were also investigated in this study. PMID:22382297

Li, Lin; Lian, Jing; Han, Yunping; Liu, Junxin

2012-05-01

319

PALLADIUM-CATALYZED OXIDATION OF STYRENE AND ALKENES IN PRESENCE OF IONIC LIQUIDS (WACKER REACTION)  

EPA Science Inventory

The use of ionic liquids in various synthetic transformations is gaining significance due to the enhanced reaction rates, potential for recycling and compatibility with various organic compounds and organometallic catalysts. Palladium-catalyzed oxidation of styrene and other alk...

320

21 CFR 573.870 - Poly(2-vinylpyridine-co-styrene).  

Code of Federal Regulations, 2011 CFR

... Residual styrene 200 parts per billion maximum. Residual 2-vinylstyrene 200 parts per billion maximum. Heavy metals such as lead 10 parts per million maximum. Arsenic 3 parts per million maximum. 1 Inherent viscosity...

2011-04-01

321

21 CFR 573.870 - Poly(2-vinylpyridine-co-styrene).  

... Residual styrene 200 parts per billion maximum. Residual 2-vinylstyrene 200 parts per billion maximum. Heavy metals such as lead 10 parts per million maximum. Arsenic 3 parts per million maximum. 1 Inherent viscosity...

2014-04-01

322

21 CFR 573.870 - Poly(2-vinylpyridine-co-styrene).  

Code of Federal Regulations, 2012 CFR

... Residual styrene 200 parts per billion maximum. Residual 2-vinylstyrene 200 parts per billion maximum. Heavy metals such as lead 10 parts per million maximum. Arsenic 3 parts per million maximum. 1 Inherent viscosity...

2012-04-01

323

21 CFR 573.870 - Poly(2-vinylpyridine-co-styrene).  

Code of Federal Regulations, 2013 CFR

... Residual styrene 200 parts per billion maximum. Residual 2-vinylstyrene 200 parts per billion maximum. Heavy metals such as lead 10 parts per million maximum. Arsenic 3 parts per million maximum. 1 Inherent viscosity...

2013-04-01

324

21 CFR 573.870 - Poly(2-vinylpyridine-co-styrene).  

Code of Federal Regulations, 2010 CFR

... Residual styrene 200 parts per billion maximum. Residual 2-vinylstyrene 200 parts per billion maximum. Heavy metals such as lead 10 parts per million maximum. Arsenic 3 parts per million maximum. 1 Inherent viscosity...

2010-04-01

325

Genotoxicity of 1,3-butadiene and its epoxy intermediates.  

PubMed

Current risk assessments of 1,3-butadiene (BD*) are complicated by limited evidence of its carcinogenicity in humans. Hence, there is a critical need to identify early events and factors that account for the heightened sensitivity of mice to BD-induced carcinogenesis and to deter-mine which animal model, mouse or rat, is the more useful surrogate of potency for predicting health effects in BD-exposed humans. HEI sponsored an earlier investigation of mutagenic responses in mice and rats exposed to BD, or to the racemic mixture of 1,2-epoxy-3-butene (BDO) or of 1,2,3,4-diepoxybutane (BDO2; Walker and Meng 2000). In that study, our research team demonstrated (1) that the frequency of mutations in the hypoxanthine-guanine phosphoribosyl transferase (Hprt) gene of splenic T cells from BD-exposed mice and rats could be correlated with the species-related differences in cancer susceptibility; (2) that mutagenic-potency and mutagenic-specificity data from mice and rats exposed to BD or its individual epoxy intermediates could provide useful information about the BD metabolites responsible for mutations in each species; and (3) that our novel approach to measuring the mutagenic potency of a given chemical exposure as the change in Hprt mutant frequencies (Mfs) over time was valuable for estimating species-specific differences in mutagenic responses to BD exposure and for predicting the effect of BD metabolites in each species. To gain additional mode-of-action information that can be used to inform studies of human responses to BD exposure, experiments in the current investigation tested a new set of five hypotheses about species-specific patterns in the mutagenic effects in rodents of exposure to BD and BD metabolites: 1. Repeated BD exposures at low levels that approach the occupational exposure limit for BD workers (set by the U.S. Occupational Safety and Health Administration) are mutagenic in female mice. 2. The differences in mutagenic responses of the Hprt gene to BD in similarly exposed rodents of a given species (reported in various earlier studies) are primarily associated with age-related thymus activity and trafficking of T cells and with sex-related differences in BD metabolism. 3. The mutagenic potency of the stereochemical forms of BD's epoxy intermediates plays a significant role in the species-related mutagenicity of BD. 4. The hydrolysis-detoxification pathway of BD through 1,2-dihydroxy-3-butene (BD-diol) is a major contributor to mutagenicity at high-level BD exposures in mice and rats. 5. Significant and informative species-specific differences in mutation spectra can be identified by examining both large- and small-scale genetic alterations in the Hprt gene of BD-exposed mice and rats. The first four hypotheses were tested by exposing mice and rats to BD, meso-BDO2, or BD-diol and measuring Hprt Mfs as the primary biomarker. For this, we used the T-cell-cloning assay of lymphocytes isolated from the spleens of exposed and control (sham-exposed) mice and rats. The first hypothesis was tested by exposing female B6C3F1 mice (4 to 5 weeks of age) by inhalation for 2 weeks (6 hours/day, 5 days/week) to 0 or 3 ppm BD. Hprt Mfs were measured at the time of peak mutagenic response after exposure for this age of mice. We then compared the resulting data to those from mutagenicity studies with mice of the same age that had been exposed in a similar protocol to higher levels of BD (Walker and Meng 2000). In mice exposed to 3 ppm BD (n = 27), there was a significant 1.6-fold increase over the mean background Hprt Mf in control animals (n = 24, P = 0.004). Calculating the efficiency of Hprt mutant induction, by dividing induced Hprt Mfs by the respective BD exposure levels, demonstrated that the mutagenic potency of 3 ppm BD was twice that of 20 ppm BD and almost 20 times that of 625 or 1250 ppm BD in exposed female mice. Sample-size calculations based on the Hprt Mf data from this experiment demonstrated the feasibility of conducting a future experiment to find out whether induced Mfs at even lower exposure levels (betw

Walker, Vernon E; Walker, Dale M; Meng, Quanxin; McDonald, Jacob D; Scott, Bobby R; Seilkop, Steven K; Claffey, David J; Upton, Patricia B; Powley, Mark W; Swenberg, James A; Henderson, Rogene F

2009-08-01

326

Palladium-catalyzed 1,4-difunctionalization of butadiene to form skipped polyenes.  

PubMed

A palladium-catalyzed 1,4-addition across the commodity chemical 1,3-butadiene to afford skipped polyene products is reported. Through a palladium ? ? ? ? ? allyl isomerization, two new carbon-carbon bonds are formed with high regioselectivity and trans stereoselectivity of the newly formed alkene. The utility of this method is highlighted by the successful synthesis of the ripostatin A skipped triene core. PMID:23473452

McCammant, Matthew S; Liao, Longyan; Sigman, Matthew S

2013-03-20

327

Efficient regimes of butadiene rubber synthesis on separate supply of feedstock to cascade reactors  

NASA Astrophysics Data System (ADS)

Mathematical simulation of the synthesis of butadiene rubber on the basis of a neodymium-containing catalytic system in a cascade of continuously operating reactors is carried out. Expressions for the characteristics of the branching of the synthesized polymer macromolecules have been derived. Efficient regimes of rubber synthesis on separate supply of feedstock to the cascade reactors allowing one to obtain rubber with specified parameters without losing the cascade capacity have been determined.

Manuiko, G. V.; Bashkirov, D. V.; Aminova, G. A.; Bronskaya, V. V.; Ignashina, T. V.; Ismagilova, A. I.; Diyakonov, G. S.; Sakhabutdinov, A. G.

2011-09-01

328

Production of super-smooth articles  

SciTech Connect

Super-smooth rounded or formed articles made of thermoplastic materials including various poly(methyl methacrylate) or acrylonitrile-butadiene-styrene copolymers are produced by immersing the articles into a bath, the composition of which is slowly changed with time. The starting composition of the bath is made up of at least one solvent for the polymer and a diluent made up of at least one nonsolvent for the polymer and optional materials which are soluble in the bath. The resulting extremely smooth articles are useful as mandrels for laser fusion and should be useful for a wide variety of other purposes, for example lenses.

Duchane, D.V.

1981-05-29

329

Studies on the influence of double-layer electroless metal deposition on the electromagnetic interference shielding effectiveness of carbon fiber\\/ABS composites  

Microsoft Academic Search

Electromagnetic interference (EMI) shielding effectiveness (SE) of single-layer or double-layers electroless metals, such as nickel\\/phosphorus–pure nickel (NiP–Ni), Ni–NiP, NiP–Cu, Ni–Cu, coated carbon fiber reinforced acrylonitrile-butadiene-styrene (ABS) composites was investigated. The resistivity and anti-oxidization of conductive fillers were important factors for EMI shielding composites. Although the resistivity of electroless copper-coated carbon fiber (ECCF) is much lower than that of electroless nickel-coated

Chi-Yuan Huang; Wen-Wei Mo; Ming-Lih Roan

2004-01-01

330

Production of super-smooth articles  

DOEpatents

Super-smooth rounded or formed articles made of thermoplastic materials including various poly(methyl methacrylate) or acrylonitrile-butadiene-styrene copolymers are produced by immersing the articles into a bath, the composition of which is slowly changed with time. The starting composition of the bath is made up of at least one solvent for the polymer and a diluent made up of at least one nonsolvent for the polymer and optional materials which are soluble in the bath. The resulting extremely smooth articles are useful as mandrels for laser fusion and should be useful for a wide variety of other purposes, for example lenses.

Duchane, David V. (Los Alamos, NM)

1983-01-01

331

Intercalation of perfluorobutane sulfonate into layered double hydroxides  

Microsoft Academic Search

ZnMgAl–layered double hydroxides (ZnMgAl–NO3–LDH) intercalated with perfluorobutane sulfonate (PFBS) were investigated as a new flame retardant for acrylonitrile-butadiene-styrene (ABS) resins. Powder X-ray diffraction and FT-IR spectra confirmed the intercalation of PFBS by exchange of nitrate ions. The enhanced performance of the ZnMgAl–PFBS–LDH\\/ABS composites was possibly due to the high char residue of ZnMgAl–PFBS–LDH. Preliminary combustion tests showed that the ZnMgAl–PFBS–LDH\\/ABS

Lixia Zhang; Yanjun Lin; Sailong Xu; Rushi Li; Xiuting Zheng; Fazhi Zhang

2010-01-01

332

Enhancing the electrical and thermal stability of metallic fiber-filled polymer composites by adding tin–lead alloy  

Microsoft Academic Search

This article presents a novel way of greatly enhancing the electrical and thermal stability of copper fiber (CuF)-filled acrylonitrile–butadiene–styrene\\u000a (ABS) composites via the incorporation of small amount of tin–lead (Sn–Pb) alloy. It was observed that many fibers are soldered\\u000a together by Sn–Pb, and a continuous CuF\\/Sn–Pb network is formed throughout the ABS matrix. As a result, the percolation concentration\\u000a of

Guozhang Wu; Bingpeng Li; Jiakun Song

333

A new method to estimate pore volume of porous styrene–divinylbenzene copolymers  

Microsoft Academic Search

A new method to estimate the pore volume of porous styrene–divinylbenzene copolymer beads is proposed. The estimated pore volume (PVe) is based on the solubility parameters (?i) and the corresponding weight fractions (fi) of styrene, divinylbenzenes and diluents in the polymerization mixture. The equation used is: PVe=1.136??ifi2?21.193??ifi+98.825. Regression analysis results show that an ideally close match of the predicted pore

Muhammad Arif Malik; Munir Ahmed; Muhammad Ikram

2004-01-01

334

Styrene-terminated polysulfone oligomers as matrix material for graphite reinforced composites: An initial study  

NASA Technical Reports Server (NTRS)

Styrene terminated polysulfone oligomers are part of an oligomeric class of compounds with end groups capable of thermal polymerization. These materials can be used as matrices for graphite reinforced composites. The initial evaluation of styrene terminated polysulfone oligomer based composites are summarized in terms of fabrication methods, and mechanical and environmental properties. In addition, a description and evaluation is provided of the NASA/Industry Fellowship Program for Technology Transfer.

Garcia, Dana; Bowles, Kenneth J.; Vannucci, Raymond D.

1987-01-01

335

Evaluation of trickle-bed air biofilter performance for styrene removal  

Microsoft Academic Search

A pilot-scale trickle-bed air biofilter (TBAB) was evaluated for the removal of styrene from a waste gas stream. Six-millimeter (6-mm) Celite pellets (R-635) were used as the biological attachment medium. The operating parameters considered in the study included the styrene volumetric loading, the empty-bed residence time (EBRT), the frequency and duration of backwashing, and nutrient–phosphorous (nutrient–P) management as a biomass

George A. Sorial; Francis L. Smith; Makram T. Suidan; Amit Pandit; Pratim Biswas; Richard C. Brenner

1998-01-01

336

Biofiltration of air contaminated by styrene: Effect of nitrogen supply, gas flow rate, and inlet concentration  

SciTech Connect

The biofiltration process is a promising technology for the treatment of dilute styrene emissions in air. The efficiency of this process is however strongly dependent upon various operational parameters such as the filter bed characteristics, nutrient supplies, input contaminant concentrations, and gas flow rates. The biofiltration of air containing styrene vapors was therefore investigated, employing a novel biomass filter material, in two identical but separate laboratory scale biofiltration units (units 1 and 2), both biofilters being initially inoculated with a microbial consortium. Each biofilter was irrigated with a nutrient solution supplying nitrogen in one of two forms; i.e., mainly as ammonia for unit 1 and exclusively as nitrate for unit 2. The experimental results have revealed that greater styrene elimination rates are achieved in the biofilter supplied with ammonia as the major nitrogen source in comparison to the lesser elimination performance obtained with the nitrate provided biofilter. However, in achieving the high styrene removal rates in the ammonia supplied biofilter, the excess of biomass accumulates on the filtering pellets and causes progressive clogging of the filter media. Furthermore, the effectiveness of nitrate supply as the sole nitrogen nutrient form, on reducing or controlling the biomass accumulation in the filter media in comparison to ammonia, could not be satisfactorily demonstrated because the two biofilters operated with very different styrene elimination capacities. The monitoring of the carbon dioxide concentration profile through both biofilters revealed that the ratio of carbon dioxide produced to the styrene removed was approximately 3/1, which confirms the complete biodegradation of removed styrene, given that some of the organic carbon consumed is also used for the microbial growth. The effects of the most important design parameters, namely styrene input concentrations and gas flow rates, were investigated for each nutrient solution.

Jorio, H.; Bibeau, L.; Heitz, M.

2000-05-01

337

Influence of cobalt(III) dimethyldithiocarbamate complexes on styrene polymerization initiated by tert -butyl perbenzoate  

Microsoft Academic Search

Kinetic features of radical polymerization of styrene initiated by tert-butyl perbenzoate in the presence of tris(N,N-dimethyldithiocarbamato)cobalt(III) (CoL3) and its adduct with iodine (CoL3 · 2I2) were studied. The optimal concentration ratios of the activators and tert-butyl perbenzoate, providing fast styrene polymerization at 338–368 K, were determined.

N. V. Khitrich; I. I. Seifullina; Yu. K. Epimakhov; P. A. Ivanchenko

2006-01-01

338

Competitive hydrogenation of butadiene and butene on palladium and platinum catalysts  

SciTech Connect

In a recent study of the selective hydrogenation of butadiene to butenes, the reactivity of palladium (in the form of single crystals and of supported catalysts) was compared with that of platinum. The reactivity of single-crystal faces with (111) orientation is comparable to that of SiO{sub 2}-supported catalysts. The argument put forward to explain the comparatively lower activity of platinum was its lower hydrogen coverage under a given pressure, in the presence of the hydrocarbons, arising from a heat of adsorption smaller than that on palladium (respectively 67 and 85 kJ/mol). Concerning its poorer selectivity toward butenes, the reason invoked was a similar heat of adsorption for butadiene and butenes: the olefinic intermediate compound remains partly on the surface and the reaction proceeds to butane. A powerful kinetic method which is able to provide direct evidence for this different adsorption of dienes and butenes would be the competitive hydrogenation of these two molecules. However, to distinguish between the ethylenic hydrocarbon formed during the reaction and the molecules already present in the reactants, the experiments were performed according to the sequence: competitive hydrogenation of a butadiene-propene mixture followed by the hydrogenation of a 1-butene-propene mixture. This paper describes a study which confirms that the reason for the selectivity of palladium (after stabilization of the catalyst) can be attributed unambiguously to its capacity of adsorbing a diene more strongly than an alkene molecule.

Ouchaib, T.; Massardier, J. Renouprez, A. (Institut de Recherche sur la Catalyse, Villeurbanne (France))

1989-10-01

339

Infrared spectra of 1,3-butadiene matrices containing some atomic metals  

NASA Astrophysics Data System (ADS)

Low-temperature matrices of 1,3-butadiene containing Ni, Pd, Fe or Mg atoms were prepared by codeposition at - 190°C, and their i.r. spectra were examined as the matrices were warmed to various temperatures. With Ni atoms, a charge-transfer complex, NiC 4H 6, whose i.r. spectrum was indistinguishable from that of solid C 4H 6, was formed initially. It rearranged at about -130°C into a yellow ?-complex Ni(C 4H 6) 2 which in turn transformed rapidly into a more stable red polymeric ?-complex (NiC 4H 6) n. The spectra of these ?-complexes showed that the butadiene ligands were in the cis configuration. The polymer decomposed at about -80°C into butadiene, metallic nickel and traces of organonickel residues. It also reacted with water to give butane and butenes. Matrices with Pd or Fe atoms behaved similarly but only a charge-transfer complex was observed with Mg atoms.

Hisatsune, I. C.

340

Evidence of delayed light emission of TetraPhenyl Butadiene excited by liquid Argon scintillation light  

E-print Network

TetraPhenyl Butadiene is the wavelength shifter most widely used in combination with liquid Argon. The latter emits scintillation photons with a wavelength of 127 nm that need to be downshifted to be detected by photomultipliers with glass or quartz windows. TetraPhenyl Butadiene has been demonstrated to have an extremely high conversion efficiency, possibly higher than 100% for 127 nm photons, while there is no precise information about the time dependence of its emission. It is usually assumed to be exponentially decaying with a characteristic time of the order of one ns, as an extrapolation from measurements with exciting radiation in the near UV. This work shows that TetraPhenyl Butadiene, when excited by 127 nm photons, reemits photons not only with a very short decay time, but also with slower ones due to triplet states de-excitations. This fact can strongly contribute to clarify the anomalies of liquid Argon scintillation light reported in literature since seventies, namely the inconsistency in the measured values of the long decay time constant and the appearence of an intermediate component.

Ettore Segreto

2014-11-17

341

Magnetic and dielectric properties of sulfonated (S) poly[(styrene)-(ethylene-co-butylene)]-styrene (SEBS) block copolymer\\/magnetic metal oxide nanocomposites synthesized via an in-situ precipitation method  

Microsoft Academic Search

Block copolymer\\/magnetic metal oxide nanocomposites were synthesized by growing metal oxide nanoparticles (cobalt ferrite, CoFe2O 4 and iron oxide, alpha-Fe2O3) in sulfonated (s) poly (styrene) (PS) block domains of sulfonated poly [(styrene)-(ethylene-co-butylene)-(styrene)] (SEBS) BCP preformed films via an in-situ precipitation method by dissolving the salts of respective metal chloride (s) in a suitable solvent that selectively swells the sPS regions.

Sateesh Kumar Peddini

2009-01-01

342

A correlation study applied to biomarkers of internal and effective dose for acrylonitrile and 4-aminobiphenyl in smokers  

PubMed Central

The urinary metabolites 2-cyanoethylmercapturic acid and 4-aminobiphenyl have been correlated with tobacco smoke exposure. Similarly, 2-cyanoethylvaline and 4-aminobiphenyl haemoglobin adducts have been used as biomarkers of effective dose for the exposure to acrylonitrile and 4-aminobiphenyl, respectively. Each pair of biomarkers is derived from the same parent chemical; however, the correlation between the urinary and the haemoglobin biomarkers has not been investigated. Using clinical study samples, we report a weak correlation between urinary and haemoglobin biomarkers due to different accumulation and elimination rates. Time course analysis showed that a reduction in exposure was paralleled by a delayed reduction in haemoglobin adducts. PMID:24754403

Scherer, Gerhard; Newland, Kirk; Papadopoulou, Ermioni

2014-01-01

343

Destruction of Gaseous Styrene with a Low-Temperature Plasma Induced by a Tubular Multilayer Dielectric Barrier Discharge  

NASA Astrophysics Data System (ADS)

The destruction of gaseous styrene was studied using a low-temperature plasma induced by tubular multilayer dielectric barrier discharge (DBD). The results indicate that the applied voltage, gas flow rate, inlet styrene concentration and reactor configuration play important roles in styrene removal efficiency (?styrene) and energy yield (EY). Values of ?styrene and EY reached 96% and 15567 mg/kWh when the applied voltage, gas flow rate, inlet styrene concentration and layers of quartz tubes were set at 10.8 kV, 5.0 m/s, 229 mg/m3 and 5 layers, respectively. A qualitative analysis of the byproducts and a detailed discussion of the reaction mechanism are also presented. The results could facilitate industrial applications of the new DBD reactor for waste gas treatment.

Zhang, Jiahui; Liu, Juanjuan; Zhang, Renxi; Hou, Huiqi; Chen, Shanping; Zhang, Yi

2015-01-01

344

Modeling contaminant transport and remediation at an acrylonitrile spill site in Turkey.  

PubMed

The August 1999 earthquake in Turkey damaged three acrylonitrile (AN) storage tanks at a plant producing synthetic fiber by polymerization. A numerical modeling study was carried out to analyze the groundwater flow and contaminant (AN) transport at the spill site. This study presents the application of a numerical groundwater model to determine the hydrogeological parameters of the site, where such data were not available during the field surveys prior to the simulation studies. The two- and three-dimensional transient flow and transport models were first calibrated using the first 266days of observed head and concentration data and then verified using the remaining 540-day observed data set. Off-site migration of the contaminant plume was kept under control within the site boundaries owing to the favorable geology of the site, the characteristics of the local groundwater flow regime and the pumping operations. As expected, the applied pump-and-treat system was effective at high-permeability zones, but not fully effective at low-permeability zones. The results of long-term simulations for unconfined aquifer showed that the size of the plume in the high permeability zone shrank significantly due to the dilution by natural recharge. However, in the low permeability zone, it was not significantly affected. The study showed that accurate and sufficient data regarding the source characteristics, concentration and groundwater level measurements, groundwater pumping rates and their durations at each of the extraction points involved in the pump-and-treat system along with the hydrogeological site characterization are the key parameters for successful flow and transport model calibrations. PMID:23680827

Sengör, S Sevinç; Unlü, Kahraman

2013-07-01

345

Uncertainty and variability in the exposure reconstruction of chemical incidents--the case of acrylonitrile.  

PubMed

The application of human physiologically based pharmacokinetic (PBPK) modeling combined with measured biomonitoring data, has a great potential to backtrack external exposure to chemicals during chemical incidents. So far, an important shortcoming of 'reversed dosimetry' is that uncertainty and variability in the model predictions are often neglected. The aim of this paper is to characterize the variation in predicted environmental air concentrations by means of reversed dosimetry as a result of uncertainty in chemical-specific input data and variability in physiological parameters. Human biomonitoring data (N-2-cyanoethylvaline in blood) from a chemical incident with acrylonitrile (ACN) combined with the BioNormtox PBPK model are used as a case to reconstruct the air concentration and uncertainty thereof at the time of the incident. The influence of uncertainty in chemical-specific properties and exposure duration, and interindividual variability in physiological parameters on the reconstructed air exposure concentrations were quantified via nested Monte Carlo simulation. The range in the reconstructed air concentrations of ACN during the incident was within a factor of 3. Uncertainty in the exact exposure duration directly after the chemical accident was found to have a dominant influence on the model outcomes. It was also shown that uncertainty can be further reduced by collecting human biomonitoring data as soon as possible after the incident. Finally, the collection of specific information about individual physiological parameters from the victims, such as body weight, may further reduce the variation by 5 to 20% in our case study. Future research should include the comparison of reversed dosimetry model outcomes with measured air and biological concentrations to further increase the confidence in the model approach and its implementation in practice. PMID:25050995

Huizer, Daan; Ragas, Ad M J; Oldenkamp, Rik; van Rooij, Joost G M; Huijbregts, Mark A J

2014-12-15

346

Controlled Release of Imidacloprid from Poly Styrene-Diacetone - Nanoformulation  

NASA Astrophysics Data System (ADS)

Imidacloprid is a neonicotinoids insecticide, which is important for the cash crops such as tomato, rape and so on. The conventional formulation does not only increase the loss of pesticide but also leads to environmental pollution. Controlled-release formulations of pesticide are highly desirable not only for attaining the most effective utilization of the pesticide, but also for reducing environmental pollution. Pesticide imidacloprid was incorporated in poly (styrene-diacetone crylamide)-based formulation to obtain controlled release properties, and the imidacloprid nanocontrolled release formulation was characterized by infrared (IR) and field emission scanning electron microscope (FESEM). Factors related to loading efficiency, swelling and release behaviors of the formulation were investigated. It showed that the loading efficiency could reach about 40% (w/w). The values for the diffusion exponent "n" were in the range of 0.31-0.58, which indicated that the release of imidacloprid was diffusion-controlled. The time taken for 50% of the active ingredient to be released into water, T50, was also calculated for the comparison of formulations in different conditions. The results showed that the formulation with higher temperature and more diacetone crylamide had lower value of T50, which means a quicker release of the active ingredient. This study highlighted some pieces of evidence that improved pesticide incorporation and slower release were linked to potential interactions between the pesticide and the polymer.

Qian, Kun; Guo, Yanzhen; He, Lin

2012-01-01

347

40 CFR Table 5 to Subpart U of... - Known Organic HAP Emitted From the Production of Elastomer Products  

Code of Federal Regulations, 2011 CFR

...Emission Standards for Hazardous Air Pollutant Emissions: Group I Polymers and Resins Pt. 63, Subpt. U, Table 5 Table 5 to Subpart... PBR/SBRS = Polybutadiene and Styrene Butadiene Rubber by Solution. PSR = Polysulfide Rubber. SBL = Styrene Butadiene...

2011-07-01

348

40 CFR Table 5 to Subpart U of... - Known Organic HAP Emitted From the Production of Elastomer Products  

Code of Federal Regulations, 2012 CFR

...Emission Standards for Hazardous Air Pollutant Emissions: Group I Polymers and Resins Pt. 63, Subpt. U, Table 5 Table 5 to Subpart... PBR/SBRS = Polybutadiene and Styrene Butadiene Rubber by Solution. PSR = Polysulfide Rubber. SBL = Styrene Butadiene...

2012-07-01

349

40 CFR Table 5 to Subpart U of... - Known Organic HAP Emitted From the Production of Elastomer Products  

Code of Federal Regulations, 2013 CFR

...Emission Standards for Hazardous Air Pollutant Emissions: Group I Polymers and Resins Pt. 63, Subpt. U, Table 5 Table 5 to Subpart... PBR/SBRS = Polybutadiene and Styrene Butadiene Rubber by Solution. PSR = Polysulfide Rubber. SBL = Styrene Butadiene...

2013-07-01

350

40 CFR Table 5 to Subpart U of... - Known Organic HAP Emitted From the Production of Elastomer Products  

...Emission Standards for Hazardous Air Pollutant Emissions: Group I Polymers and Resins Pt. 63, Subpt. U, Table 5 Table 5 to Subpart... PBR/SBRS = Polybutadiene and Styrene Butadiene Rubber by Solution. PSR = Polysulfide Rubber. SBL = Styrene Butadiene...

2014-07-01

351

46 CFR 30.25-1 - Cargoes carried in vessels certificated under the rules of this subchapter.  

Code of Federal Regulations, 2010 CFR

...liquid synthetic IIIincluding: Styrene-butadiene rubberIII Carboxylated styrene-butadiene copolymerIII LecithinIII Long chain alkaryl polyether (C11-C20)C Long chain alkaryl sulfonic acid (C16-C60)D Long chain...

2010-10-01

352

Comparison of the technology of oxidative dehydrogenation in a fluidized-bed reactor with those of other reactors for butadiene  

SciTech Connect

This paper describes a comparison among the reactor technologies used in the process of oxidation. For dehydrogenation of butene into butadiene, three reactor types are compared: (1) a fluidized-bed reactor using multi revolving link stoppers with a group VIII variable-valence catalyst, (2) an adiabatic fixed-bed reactor, and (3) a polytube, constant-temperature fixed-bed reactor. The results of the comparison indicate that the polytube fixed-bed reactor at constant temperature is better than the fluidized-bed reactor, which in turn is better than the adiabatic reactor. Using a polytube, constant-temperature fixed-bed reactor with butene`s space velocity of 400 h{sup {minus}1}, butadiene yield reached 78.7%, butene conversion reached 86.1%, and butadiene selectivity reached 91.4%. If these results can be achieved in industry, they will be the world records.

Wu Xingan; Liu Huiqin [Hunan Univ., Changsha (China). Dept. of Chemistry and Chemical Engineering

1996-08-01

353

Exposure assessment of monoterpenes and styrene: a comparison of air sampling and biomonitoring  

PubMed Central

Background: Within- and between-worker variance components have seldom been reported for both environmental and biological data collected from the same persons. Aims: To estimate these variance components and their ratio for air contaminants and urinary metabolites in two different work environments and to predict the attenuation of exposure-response relationships based on these measures. Methods: Parallel measurements of air and urine were performed among workers exposed to monoterpenes in sawmills (urinary metabolite: verbenol) and styrene in reinforced plastics factories (urinary metabolite: mandelic acid). Results: Among the sawmill workers, variance components of the air and urinary verbenol results were similar; for the reinforced plastics workers the estimated between-worker variance component was greater for styrene in air than mandelic acid in urine. This suggests that attenuation bias would be about equal if air or biological monitoring were employed for monoterpene exposures, but would be greater if urinary mandelic acid were used instead of airborne styrene in an investigation of styrene exposure. Conclusions: Personal air samplers provide data with similar or superior quality to urinary metabolites as measures of exposure to these monoterpenes in sawmills and styrene in reinforced plastics factories. PMID:12883022

Liljelind, I; Rappaport, S; Eriksson, K; Andersson, J; Bergdahl, I; Sunesson, A; Jarvholm, B

2003-01-01

354

Case study: Biofiltration of styrene and butylacetate at a dashboard manufacturer  

SciTech Connect

Holzindustie Bruchsal (HIB) was required to treat moderate levels of styrene emissions from their plastic dashboard manufacturing process. After evaluating many types of control technologies, HIB decided to install a Bioton biofiltration system from Monsanto Enviro-Chem Systems Inc. (MEC). After the installation of the Bioton biofilter, HIB and MEC learned that large amounts of butylacetate were also present in the off-gas stream. The presence of butylacetate was found to have inhibitory effects on the removal of styrene. Therefore, MEC performed a series of pilot and laboratory studies to determine if a bacteria strain could be identified that would be capable of removing styrene in the presence of butylacetate. It was found that a specific bacteria strain was capable of achieving high levels of styrene removal without inhibition from butylacetate in laboratory and pilot testing. This strain was inoculated into the full scale system. After acclimation, the full scale inoculation produced a consortium of bacteria that biologically removed the styrene from the dashboard manufacturing process in the presence of butylacetate.

McGrath, M.S.; Nieuwland, J.C.; Lith, C. van

1999-09-30

355

The effect of spraying and rolling process factors on styrene emission during the application of unsaturated polyester resins.  

PubMed

In recent years the awareness of the problems caused by styrene emission during the processing of unsaturated polyester resins has enlarged. The spray-up application of gel coats is especially problematic, and it produces high styrene emission rates. The emission of styrene has been reduced through material changes, work practice controls, and add-on controls. However, the influence of the spray-up process factors on styrene emission has not been studied before. The aim of this study was to examine possibilities to reduce styrene emission by optimization of spray-up process factors. The following factors were studied under controlled laboratory conditions: orifice size and angle of the spray gun tip, spraying pressure, distance between spray gun and mold, and shape of the mold. The influence of the rolling pattern during lamination was also studied. Several significant factors were found. High pressure and long spraying distance increased both the unit styrene emission and the emission rate. The orifice size had two effects; a large orifice decreased the amount of styrene emitted per sprayed amount of resin but increased the emission rate of styrene. The shape of the mold did not affect the styrene emission. Styrene emission is greater if the entire mold area is rolled. To achieve lower emission is it necessary to roll an area as small as possible; this is especially important if a large mold is laminated. The results showed that emission of styrene can be reduced significantly by an optimal selection of the spray gun settings and the way of working. Optimal settings also increased the transfer efficiency resulting in decreased material loss. PMID:12486781

Säämänen, Arto; Skrifvars, Mikael

2002-01-01

356

Asymmetric Dihydroxylation of Cinnamonitrile to trans-3-[(5S,6R)-5,6-Dihydroxycyclohexa-1,3-dienyl]-acrylonitrile  

E-print Network

]-acrylonitrile using Chlorobenzene Dioxygenase in Escherichia coli (pTEZ30) Selcuk Yildirim,a Josef Zezula,b Tomas purposes. We characterized the cis-dihy- droxylation of cinnamonitrile by chlorobenzene dioxy- genase (CDO: asymmetric synthesis; biocatalysis; bio- transformations; chlorobenzene dioxygenase; dihy- droxylation; scale

Hudlicky, Tomas

357

All-solid-state electrochromic window of SnO2/Mo and electrodeposited WO3 film with poly(acrylonitrile) gel electrolyte  

NASA Astrophysics Data System (ADS)

An all solid-state electrochromic smart window employing SnO2/Mo and electrodeposited WO3 film with poly(acrylonitrile)(PAN) gel electrolyte with high conductivity (5 mS/cm) at room temperature has been fabricated. The smart window has been found excellent electrochromism and memory characteristics.

Su, Lianyong

2000-11-01

358

Acrylonitrile potentiates hearing loss and cochlear damage induced by moderate noise exposure in rats  

SciTech Connect

The diversity of chemical and drugs that can potentiate noise-induced hearing loss (NIHL) has impeded efforts to predict such interactions. We have hypothesized that chemical contaminants that disrupt intrinsic antioxidant defenses hold significant risk for potentiating NIHL. If this is true, then acrylonitrile (ACN) would be expected to potentiate NIHL. ACN, one of the 50 most commonly used chemicals in the United States, is metabolized via two pathways that are likely to disrupt intrinsic reactive oxygen species (ROS) buffering systems: (1) it conjugates glutathione, depleting this important antioxidant rapidly; (2) a second pathway involves the formation of cyanide, which can inhibit superoxide dismutase. We hypothesized that moderate noise exposure, that does not produce permanent hearing loss by itself, could initiate oxidative stress and that ACN could render the inner ear more sensitive to noise by disrupting intrinsic antioxidant defenses. Temporary and persistent effects of ACN alone (50 mg/kg, sc 5 days), noise alone (95 or 97 dB octave band noise, 4 h/day for 5 days), or ACN in combination with noise were determined using distortion product otoacoustic emissions (DPOAEs) and compound action potential (CAP) amplitudes. Histopathological damage to hair cells resulting from these treatments was also investigated using surface preparations of the organ of Corti. Individually, neither ACN nor noise exposures caused any permanent hearing or hair cell loss; only a reversible temporary threshold shift was measured in noise-exposed animals. However, when given in combination, ACN and noise induced permanent threshold shifts (13-16 dB between 7 and 40 kHz) and a decrease in DPOAE amplitudes (up to 25 dB at 19 kHz), as well as significant outer hair cell (OHC) loss (up to 20% in the first row between 13 and 47 kHz). This investigation demonstrates that ACN can potentiate NIHL at noise levels that are realistic in terms of human exposure, and that the OHCs are the main target of toxicity. While the exact mechanism is unknown, the results are consistent with the hypothesis of ROS involvement in NIHL at moderate levels.

Pouyatos, BenoIt [Jerry Pettis Memorial Veterans Medical Center, Research Service (151), Loma Linda, CA 92357 (United States)]. E-mail: benoit.pouyatos@med.va.gov; Gearhart, Caroline A. [Jerry Pettis Memorial Veterans Medical Center, Research Service (151), Loma Linda, CA 92357 (United States); Fechter, Laurence D. [Jerry Pettis Memorial Veterans Medical Center, Research Service (151), Loma Linda, CA 92357 (United States)

2005-04-01

359

Mortality study of workers in 1,3-butadiene production units identified from a chemical workers cohort.  

PubMed Central

The International Agency for Research on Cancer has given the designations of "sufficient evidence" of carcinogenicity of 1,3-butadiene in experimental animals and "limited evidence" of carcinogenicity in humans. To investigate the carcinogenic effect in humans, we conducted a cohort mortality study among 364 men who were assigned to any of three 1,3-butadiene production units located within several chemical plants in the Kanawha Valley of West Virginia, including 277 men employed in a U.S. Rubber Reserve Plant which operated during World War II. The butadiene production units included in this study were selected from an index developed by the Union Carbide Corporation, which listed for each chemical production unit within their South Charleston, West Virginia and Institute, West Virginia, plants all products, by-products, and reactants. Departments included in the study were those where butadiene was a primary product and neither benzene nor ethylene oxide was present. A total of 185 deaths were observed; the standardized mortality ratio (SMR) for all causes of death was 91, reflecting lower mortality among the study population than the U.S. population. The study found a significantly elevated standardized mortality ratio (SMR) for lymphosarcoma and reticulosarcoma based on four observed cases (SMR = 577; 95% CI = 157-1480), which persisted in an analysis using county referent rates. An excess of lymphosarcoma and reticulosarcoma among all workers and among workers with routine exposure to 1,3-butadiene was also observed in the only other cohort of 1,3-butadiene production workers previously studied.(ABSTRACT TRUNCATED AT 250 WORDS) PMID:7556014

Ward, E M; Fajen, J M; Ruder, A M; Rinsky, R A; Halperin, W E; Fessler-Flesch, C A

1995-01-01

360

Grafting titanium nitride surfaces with sodium styrene sulfonate thin films.  

PubMed

The importance of titanium nitride lies in its high hardness and its remarkable resistance to wear and corrosion, which has led to its use as a coating for the heads of hip prostheses, dental implants and dental surgery tools. However, the usefulness of titanium nitride coatings for biomedical applications could be significantly enhanced by modifying their surface with a bioactive polymer film. The main focus of the present work was to graft a bioactive poly(sodium styrene sulfonate) (pNaSS) thin film from titanium nitride surfaces via a two-step procedure: first modifying the surface with 3-methacryloxypropyltrimethoxysilane (MPS) and then grafting the pNaSS film from the MPS modified titanium through free radical polymerization. X-ray photoelectron spectroscopy (XPS) and time-of-flight secondary ion mass spectrometry (ToF-SIMS) were used after each step to characterize success and completeness of each reaction. The surface region of the titanium nitride prior to MPS functionalization and NaSS grafting contained a mixture of titanium nitride, oxy-nitride, oxide species as well as adventitious surface contaminants. After MPS functionalization, Si was detected by XPS, and characteristic MPS fragments were detected by ToF-SIMS. After NaSS grafting, Na and S were detected by XPS and characteristic NaSS fragments were detected by ToF-SIMS. The XPS determined thicknesses of the MPS and NaSS overlayers were ?1.5 and ?1.7 nm, respectively. The pNaSS film density was estimated by the toluidine blue colorimetric assay to be 260?±?70 ng/cm(2). PMID:25280842

Zorn, Gilad; Migonney, Véronique; Castner, David G

2014-09-01

361

Synthesis of 5-Substituted Isoxazolidines by [3 plus 2] Cycloaddition of Nitrones Generated in an Unusual Way from Nitrosobenzene and Styrene  

E-print Network

A new synthetic method toward 5-substituted isoxazolidines by [3 plus 2] cycloaddition of nitrones generated from nitrosobenzene and styrene was discovered. The formation of nitrones from nitrosobenzene and mono-substituted aromatic styrenes...

Kang, Jun Yong

2010-01-20

362

Study of gamma-ray radiation-induced polymerization of butadiene in ethanol  

NASA Astrophysics Data System (ADS)

The Co 60 ?-ray radiation induced polymerization of butadiene in bulk and in ethanol at temperatures ranging from 15 to 45°C was studied. Hydrogen peroxide was used as initiator on some occasions. The mechanism of the polymerization in ethanol seems to be fitted to the no energy transfer kinetics as described by Chapiro (1962). The ratio of relative rate of free radical production of solvent/monomer ? rel is 19. When hydrogen peroxide was added, the polymerization rate increased and hydroxyl terminated polybutadiene was obtained. The microstructure of polybutadiene was studied by i.r. and NMR spectra.

Jian, Zhang; Zhiping, Zhang; Shengkang, Ying

363

Synthesis of linear polyenoic acids by reaction of sulfones with butadiene, catalyzed by palladium complexes  

Microsoft Academic Search

1.A convenient and simple method was developed for obtaining the methyl esters of polyunsaturated carboxylic acids by the cleavage of arylß-carbomethoxy-ß'-mono- and bis-2,7-octadienylmethyl sulfones using either Na\\/Hg or EtONa.2.It was shown for the first time that the bis-octadienyl derivatives of arylß-carbomethoxymethyl sulfones can be obtained from butadiene and arylß-carbomethoxymethyl sulfones on the catalyst system: Pd (acac)2-(C6H5)3P-(C2H5)Al.

R. V. Kunakova; G. A. Tolstikov; U. M. Dzhemilev; F. V. Sharipova; D. L. Sazikova

1978-01-01

364

Electrical properties and electromechanical responses of acrylic elastomers and styrene copolymers: effect of temperature  

NASA Astrophysics Data System (ADS)

The electrical properties and electromechanical responses of acrylic elastomers and styrene copolymers were investigated towards electroactive applications such as artificial muscle and/or MEMS (micro-electro-mechanical systems) devices. The effect of temperature, between 300 and 370 K, on electrical conductivity, dielectric constant, storage and loss moduli (G’ and G”), storage modulus response (?G’2 kV/mm), and the storage modulus sensitivity (?G’2 kV/mm/G’0) of acrylic elastomers and styrene copolymers were investigated under applied electric field strengths varying from 0 to 2 kV/mm. The acrylic elastomers (AR70, AR71, and AR72) possess linearly positive storage modulus responses or sensitivities with increasing temperature and dielectric constant. On the other hand, the styrene copolymers (SAR, SBS, and SIS) attain the maximum storage modulus responses or sensitivities at the glass-transition temperature of the hard segments.

Kunanuruksapong, R.; Sirivat, A.

2008-08-01

365

Final Technical Report - Autothermal Styrene Manufacturing Process with Net Export of Energy  

SciTech Connect

The overall objectives of the project were to: (a) develop an economically competitive processing technology for styrene monomer (SM) that would reduce process energy requirements by a minimum 25% relative to those of conventional technology while achieving a minimum 10% ROI; and (b) advance the technology towards commercial readiness. This technology is referred to as OMT (Oxymethylation of Toluene). The unique energy savings feature of the OMT technology would be replacement of the conventional benzene and ethylene feedstocks with toluene, methane in natural gas and air or oxygen, the latter of which have much lower specific energy of production values. As an oxidative technology, OMT is a net energy exporter rather than a net energy consumer like the conventional ethylbenzene/styrene (EB/SM) process. OMT plants would ultimately reduce the cost of styrene monomer which in turn will decrease the costs of polystyrene making it perhaps more cost competitive with competing polymers such as polypropylene.

Trubac, Robert , E.; Lin, Feng; Ghosh, Ruma: Greene, Marvin

2011-11-29

366

Catalytic epoxidation of styrene with molecular oxygen in a flow cell with a manganese porphyrin-modified graphite felt cathode  

Microsoft Academic Search

Epoxidation of styrene with molecular oxygen was achieved using electrochemically reduced manganese porphyrins on chemically modified electrodes in a flow cell. It was possible to recycle the solution through the flow cell and the yield in styrene oxide increased after each electrolysis. © 2000 Académie des sciences\\/Éditions scientifiques et medicales Elsevier SAS

Patricia Jego-Evanno; Claude Moinet; Gérard Simonneaux

2000-01-01

367

Aqueous heterophase polymerization of styrene—a study by means of multi-angle laser light scattering  

Microsoft Academic Search

An online multi-angle laser light scattering study of ab initio surfactant-free styrene emulsion polymerization reveals unexpected results regarding the development of the dispersity during the whole reaction starting from mixing styrene and water at reaction temperature. The experimentally observed change in the dispersity, which is an indirect measure of the average characteristic size of the colloidal objects, allows the identification

Steffen Kozempel; Klaus Tauer; Gudrun Rother

2005-01-01

368

IMPACT OF AN OZONE GENERATOR AIR CLEANER ON STYRENE CONCENTRATIONS IN AN INDOOR AIR QUALITY RESEARCH CHAMBER  

EPA Science Inventory

The paper gives results of an investigation of the impact of an ozone generator air cleaner on vapor-phase styrene concentrations in a full-scale indoor air quality test chamber. The time history of the concentrations of styrene and ozone is well predicted by a simulation model u...

369

7-Alkylguanine adduct levels in urine, lungs and liver of mice exposed to styrene by inhalation  

SciTech Connect

This study describes urinary excretion of two nucleobase adducts derived from styrene 7,8-oxide (SO), i.e., 7-(2-hydroxy-1-phenylethyl)guanine (N7{alpha}G) and 7-(2-hydroxy-2-phenylethyl)guanine (N7{beta}G), as well as a formation of N7-SO-guanine adducts in lungs and liver of two month old male NMRI mice exposed to styrene by inhalation in a 3-week subacute study. Strikingly higher excretion of both isomeric nucleobase adducts in the first day of exposure was recorded, while the daily excretion of nucleobase adducts in following time intervals reached the steady-state level at 4.32 + 1.14 and 6.91 + 1.17 pmol/animal for lower and higher styrene exposure, respectively. {beta}-SO-guanine DNA adducts in lungs increased with exposure in a linear way (F = 13.7 for linearity and 0.17 for non-linearity, respectively), reaching at the 21st day the level of 23.0 adducts/10{sup 8} normal nucleotides, i.e., 0.74 fmol/{mu}g DNA of 7-alkylguanine DNA adducts for the concentration of 1500 mg/m{sup 3}, while no 7-SO-guanine DNA adducts were detected in the liver after 21 days of inhalation exposure to both of styrene concentrations. A comparison of 7-alkylguanines excreted in urine with 7-SO-guanines in lungs (after correction for depurination and for missing {alpha}-isomers) revealed that persisting 7-SO-guanine DNA adducts in lungs account for about 0.5% of the total alkylation at N7 of guanine. The total styrene-specific 7-guanine alkylation accounts for about 1.0 x 10{sup -5}% of the total styrene uptake, while N1-adenine alkylation contributes to this percentage only negligibly.

Vodicka, Pavel Erik [Institute of Experimental Medicine, Academy of Sciences of Czech Republic, Videnska 1083, 14 220 Prague 4 (Czech Republic)]. E-mail: pvodicka@biomed.cas.cz; Linhart, Igor [Department of Organic Chemistry, Institute of Chemical Technology Prague, Technicka 5, 166 28 Prague (Czech Republic); Novak, Jan [Department of Organic Chemistry, Institute of Chemical Technology Prague, Technicka 5, 166 28 Prague (Czech Republic); Koskinen, Mikko [Department of Pharmacokinetics, Orion Pharma, Espoo (Finland); Vodickova, Ludmila [Institute of Experimental Medicine, Academy of Sciences of Czech Republic, Videnska 1083, 14 220 Prague 4 (Czech Republic); National Institute of Public Health, Srobarova 48, 100 42 Prague 10 (Czech Republic); Hemminki, Kari [German Cancer Research Center (DKFZ), Am Neuenheimer Feld 580, Heidelberg (Germany); Department of Biosciences, Karolinska Institute, S-14157 Huddinge (Sweden)

2006-01-15

370

Microstructure analysis of a CO2 copolymer from styrene oxide at the diad level.  

PubMed

A large amount of interesting information on the alternating copolymerization of CO2 with terminal epoxides has already been reported, such as the regiochemistry of epoxide ring-opening and the stereochemistry of the carbonate unit sequence in the polymer chain. Moreover, the microstructures of CO2 copolymers from propylene oxide and cyclohexene oxide have also been well-studied. However, the microstructure of the CO2 copolymer from styrene oxide (SO), an epoxide that contains an electron-withdrawing group, has not yet been investigated. Herein, we focus on the spectroscopic assignment of the CO2 copolymer from styrene oxide at the diad level by using three kinds of model dimer compounds, that is, T-T, H-T, and H-H. By comparing the signals in the carbonyl region, we concluded that the signals at ?=154.3, 153.8, and 153.3 ppm in the (13)C NMR spectrum of poly(styrene carbonate) were due to tail-to-tail, head-to-tail, and head-to-head carbonate linkages, respectively. Moreover, various isotactic and syndiotactic model compounds based on T-T, H-T, and H-H (dimers (R,R)-T-T, (S,S)-T-T, and (R,S)-T-T; (R,R)-H-T, (S,S)-H-T, and (R,S)-H-T; (R,R)-H-H, (S,S)-H-H, and (R,S)-H-H) were synthesized for the further spectroscopic assignment of stereospecific poly(styrene carbonate)s. We found that the carbonate carbon signals were sensitive towards the stereocenters on adjacent styrene oxide ring-opening units. These discoveries were found to be well-matched to the microstructures of the stereoregular poly(styrene carbonate)s that were prepared by using a multichiral Co(III)-based catalyst system. PMID:23712930

Wu, Guang-Peng; Zu, Yu-Ping; Xu, Peng-Xiang; Ren, Wei-Min; Lu, Xiao-Bing

2013-08-01

371

Evaluation of genotoxic potential of styrene in furniture workers using unsaturated polyester resins.  

PubMed

Styrene is a widely used chemical, mostly in making synthetic rubber, resins, polyesters, plastics and insulators. Increasing attention has been focused on this compound since experiments using cytogenetic end-points have implicated styrene as a potential carcinogen and mutagen. In order to perform biological monitoring of genotoxic exposure to styrene monomer, we evaluated the urinary thioether (UT) excretion, and sister chromatid exchanges (SCEs) and micronuclei (MN) in peripheral lymphocytes from 53 furniture workers employed in small workplaces where polyester resin lamination processings were done and from 41 matched control subjects. The mean air concentration of styrene in the breathing zone of workers was 30.3 ppm. As a metabolic marker for styrene exposure, mandelic acid + phenylglyoxylic acid was measured in the urine and the mean value was 207 mg/g creatinine. The mean +/- SD value of UT excretions of workers was 4.43 +/- 3.42 mmol SH-/mol creatinine and also mean UT for controls was found to be a 2.75 +/- 1.78 mmol SH-/mol creatinine. The mean +/- SD/cell values of SCE frequency in peripheral lymphocytes from the workers and controls were 6.20 +/- 1.56 and 5.23 +/- 1.23, respectively. The mean +/- SD frequencies (%o) of MN in the exposed and control groups were 1.98 +/- 0.50 and 2.09 +/- 0.35, respectively. Significant effects of work-related exposure were detected in the UT excretion and SCEs analyzed in peripheral blood lymphocytes (p < 0.05 and p < 0.01, respectively). The MN frequency in lymphocytes from the styrene-exposed group did not differ from that in the controls (p > 0.05). Effect of smoking, age and duration of exposure on the genotoxicity parameters analyzed were also evaluated. In conclusion, although our data do not demonstrate a dose-response relationship, they do suggest that styrene exposure was evident and that this styrene exposure may contribute to the observed genotoxic damage in furniture workers. PMID:9294026

Karakaya, A E; Karahalil, B; Yilmazer, M; Aygün, N; Sarda?, S; Burgaz, S

1997-08-14

372

Storage effects on desorption efficiencies of methyl ethyl ketone and styrene collected on activated charcoal  

E-print Network

STORAGE EFf ECTS ON DESORP'TIC'N EFFICIENCIES OF METHYL ETHYL KF10NE AND STYRENE COLLECTED ON ACTIVATED CHARCOAL A Thesis by RICHARD ALVIN DONiNiER Approved as to style and content by: ( ha1ris a of Coll'Jn1 t tee Nay l978 QQZSGH ABSTRACT... Storage Effects on Desorption Efficiercies of i&lethyl Ethyl Ketone and Styrene Colleci-. ed on Activated Charcoal (liay 1978) Richard A. Dommer, B. S. , Central !'iichigan D&nivers ity Directed by: Dr, Ralph J. Vernon The effects on the desorption...

Dommer, Richard Alvin

1978-01-01

373

Surface modification of poly(styrene-b-(ethylene-co-butylene)-b-styrene) (SEBS) elastomer via covalent immobilization of nonionic sugar-based Gemini surfactants.  

PubMed

Gemini surfactants (GS) with sugar-containing head-groups and different alkyl chains were successfully prepared. Poly(styrene-b-(ethylene-co-butylene)-b-styrene) (SEBS) elastomer was grafted with glycidyl methacrylate (GMA) by means of UV-induced graft polymerization, and then the pGMA-grafted film was chemically immobilized with the GS. The surface graft polymerization was confirmed by ATR-FTIR and XPS. The wettability and hemocompatibility of the modified surface were characterized by means of water contact angle, protein adsorption, and platelet adhesion assays. The results showed that amphiphilic surfactant-containing polymer surfaces presented protein-resistant behavior and anti-platelet adhesion after functionalization with GS, GS1 and GS2. Besides, the hemocompatibility of the modified surface deteriorated as the length of hydrophobic chain of GS increased. PMID:24854325

Xin, Zhirong; Du, Binbin; Yan, Shunjie; Du, Shanshan; Ding, Jiaotong; Yang, Zongfeng; Ren, Wanzhong

2014-07-01

374

Microstructure and magnetorheological properties of the thermoplastic magnetorheological elastomer composites containing modified carbonyl iron particles and poly(styrene-b-ethylene-ethylenepropylene-b-styrene) matrix  

NASA Astrophysics Data System (ADS)

Novel isotropic and anisotropic thermoplastic magnetorheological elastomers (MRE) were prepared by melt blending titanated coupling agent modified carbonyl iron (CI) particles with poly(styrene-b-ethylene-ethylene-propylene-b-styrene) (SEEPS) matrix in the absence and presence of a magnetic field, and the microstructure and magnetorheological properties of these SEEPS-based MRE were investigated in detail. The particle surface modification improves the dispersion of the particles in the matrix and remarkably softens the CI/SEEPS composites, thus significantly enhancing the MR effect and improving the processability of these SEEPS-based MRE. A microstructural model was proposed to describe the interfacial compatibility mechanism that occurred in the CI/SEEPS composites after titanate coupling agent modification, and validity of this model was also demonstrated through adsorption tests of unmodified and surface-modified CI particles.

Qiao, Xiuying; Lu, Xiushou; Li, Weihua; Chen, Jun; Gong, Xinglong; Yang, Tao; Li, Wei; Sun, Kang; Chen, Xiaodong

2012-11-01

375

Controlling Thermal Properties of Asphalt Concrete and its Multifunctional Applications  

E-print Network

.g., Styrene- butadiene-styrene (SBS)) Reclaimed rubber (e.g., crumb rubber from old tires) Plastic Polyethylene/polypropylene Ethylene acrylate copolymer Ethyl-vinyl-acetate (EVA) Polyvinyl chloride (PVC) Ethylene propylene or EPDM Polyolefins.... Since the asphalt has viscoelastic properties, it will have a high stiffness at low temperature or fast loading rate and low stiffness at high temperature or slow loading rate. Styrene-butadiene-styrene (SBS), styrene-butadiene rubber (SBR), ethylene...

Shi, Xijun

2014-08-10

376

Carbon-14 kinetic isotope effects and mechanisms of addition of 2,4-dinitrobenzenesulfenyl chloride to substituted styrenes-1-/sup 14/C and styrenes-2-/sup 14/C  

SciTech Connect

As the first reported examples of carbon isotope effects in simple electrophilic addition reactions we have measured the carbon-14 kinetic isotope effects in the addition of 2,4-dinitrobenzenesulfenyl chloride to a series of para-substituted ..cap alpha.. and ..beta..-labeled styrenes in acetic acid at 30.1 /sup 0/C: for para substituents Cl, H, and CH/sub 3/ the k//sup 14/K values for ..cap alpha.. labeling are 1.027, 1.022, and 1.004, and the k//sup 14/k values for ..beta.. labeling are 1.035, 1.032, and 1.037, all +/-approx.0.004. The kinetics of the reaction were measured for the p-CH/sub 3/O,p-CH/sub 3/, unsubstituted, p-Cl, and m-NO/sub 2/ styrenes; electron-donating groups strongly accelerate the reaction, and electron-withdrawing groups retard it. The Hammett plot is curved with p/sup +/ values ranging from about -4.6 at the electron-donating group (EDG) end to about -1.8 at the electron-withdrawing group (EWG) end. Both the isotope effect and kinetic data, and related data from the literature, are interpreted in terms of a changing mechanism, with the activated complexes of the rate-determining steps having much open carbenium ion (ion pair) character for EDG-substituted styrenes and much cyclic thiiranium io (ion par) character for EWG-substituted styrenes. 1 figure, 2 tables.

Kanska, M.; Fry, A.

1983-12-28

377

Modification on liquid retention property of cassava starch by radiation grafting with acrylonitrile. I. Effect of ?-irradiation on grafting parameters  

NASA Astrophysics Data System (ADS)

Radiation modification on liquid retention properties of native cassava starch, gelatinized at 85°C, by graft copolymerization with acrylonitrile was carried out by mutual irradiation to gamma-rays. A thin aluminum foil was used to cover the inner wall of the reaction vessel, so that the homopolymer concentration was reduced to be less than 1.0% with a distilled water retention value of 665 g/g of the dry weight of the saponified grafted product. Confirmation of graft copolymerization and saponification reactions was made by the infrared spectrophotometric technique. The combined effect of radiation parameters in terms of an irradiation time and a dose rate to the total dose on the extent of the grafting reaction expressed in terms of grafting parameters which directly influenced liquid retention values was evaluated in conjunction with statistical analysis.

Kiatkamjornwong, S.; Chvajarernpun, J.; Nakason, C.

1993-07-01

378

A NEW METHOD FOR THE PREPARATION OF 2,3DIARYL1,1-DIFLUORO-1,3-BUTADIENES  

Microsoft Academic Search

Reactions of 1-trifluoromethyl-1,2-diarylvinyl sulfones 3 with aryllithium afforded aryl substituted adduct 4. Bromination of 4 with NBS, followed by debromofluorination with Mg, provided 2,3-diaryl-1,1-difluoro-1,3-butadienes (6) in good yields.

In Howa Jeong; Young Sam Park; Min Wook Chung; Bum Tae Kim

2001-01-01

379

Telomerization of butadiene and isoprene with sulfones containing active methine and methylene groups, catalyzed by palladium complexes  

Microsoft Academic Search

A study was carried out on the telomerization of butadiene and isoprene withß-sulfonoesters,ß-ketoesters, andß-nitrosulfones catalyzed by palladium catalysts. Independently of the reagent ratios, nitrosulfones and ketosulfones predominantly form dialkylation products. The reaction in the case of sulfonoesters may be stopped at the stage of monooctadienylation.

G. A. Tolstikov; O. A. Rozentsvet; R. V. Kunakova; N. N. Novitskaya

1983-01-01

380

THE GAS PHASE REACTION OF OZONE WITH 1,3-BUTADIENE: FORMATION YIELDS OF SOME TOXIC PRODUCTS. (R826236)  

EPA Science Inventory

The formation yields of acrolein, 1,2-epoxy-3-butene and OH radicals have been measured from reaction of ozone with 1,3-butadiene at room temperature and atmosphere pressure. 1,3,5-Trimethyl benzene was added to scavenge OH radicals in measurements of product yields. In separa...

381

Ambient air 1,3-butadiene concentrations in Canada (1995-2003): seasonal, day of week variations, trends, and source influences  

NASA Astrophysics Data System (ADS)

Since 1987, the Environmental Protection Service of Environment Canada has operated a field program for measuring 1,3-butadiene and other volatile organic compounds (VOCs) in ambient air. With the co-operation of provincial and municipal environmental agencies, samples have been collected at urban and rural monitoring sites across the country. Samples were collected in evacuated canisters and analyzed by gas chromatography with a mass-selective detector. Using data from all sites, the composite average 1,3-butadiene concentration at urban sites in Canada for the years 1995-2003 was found to be 0.22 ?g m -3 and the composite median was 0.17 ?g m -3. In general, 1,3-butadiene concentrations were higher at commercial and industrial sites than at residential sites, particularly at sites close to street level in the urban core. The highest 24-h 1,3-butadiene concentration of 2.58 ?g m -3 was measured at the Sarnia, Ontario, site in 2001; this site was significantly influenced by industrial point sources. Mean 24-h 1,3-butadiene concentrations at rural sites were typically an order of magnitude lower than at urban sites. 1,3-Butadiene concentrations varied by season, particularly in western Canada, and by day of week. Concentrations of 1,3-butadiene decreased from 1995 to 2003 in response to reduced rates of emissions from mobile and point sources. At most urban monitoring sites, the concentrations of 1,3-butadiene and acetylene were highly correlated; this supports the hypothesis that 1,3-butadiene is emitted primarily by mobile sources.

Curren, Kristina C.; Dann, Tom F.; Wang, Daniel K.

382

PAH formation under single collision conditions: reaction of phenyl radical and 1,3-butadiene to form 1,4-dihydronaphthalene.  

PubMed

The crossed beam reactions of the phenyl radical (C(6)H(5), X(2)A(1)) with 1,3-butadiene (C(4)H(6), X(1)A(g)) and D6-1,3-butadiene (C(4)D(6), X(1)A(g)) as well as of the D5-phenyl radical (C(6)D(5), X(2)A(1)) with 2,3-D2-1,3-butadiene and 1,1,4,4-D4-1,3-butadiene were carried out under single collision conditions at collision energies of about 55 kJ mol(-1). Experimentally, the bicyclic 1,4-dihydronaphthalene molecule was identified as a major product of this reaction (58 ± 15%) with the 1-phenyl-1,3-butadiene contributing 34 ± 10%. The reaction is initiated by a barrierless addition of the phenyl radical to the terminal carbon atom of the 1,3-butadiene (C1/C4) to form a bound intermediate; the latter underwent hydrogen elimination from the terminal CH(2) group of the 1,3-butadiene molecule leading to 1-phenyl-trans-1,3-butadiene through a submerged barrier. The dominant product, 1,4-dihydronaphthalene, is formed via an isomerization of the adduct by ring closure and emission of the hydrogen atom from the phenyl moiety at the bridging carbon atom through a tight exit transition state located about 31 kJ mol(-1) above the separated products. The hydrogen atom was found to leave the decomposing complex almost parallel to the total angular momentum vector and perpendicularly to the rotation plane of the decomposing intermediate. The defacto barrierless formation of the 1,4-dihydronaphthalene molecule involving a single collision between a phenyl radical and 1,3-butadiene represents an important step in the formation of polycyclic aromatic hydrocarbons (PAHs) and their partially hydrogenated counterparts in combustion and interstellar chemistry. PMID:22497458

Kaiser, R I; Parker, D S N; Zhang, F; Landera, A; Kislov, V V; Mebel, A M

2012-05-01

383

Antimony leaching in plastics from waste electrical and electronic equipment (WEEE) with various acids and gamma irradiation  

SciTech Connect

Highlights: • We have proposed a method to recover antimony from electronic plastics. • The most efficient acid solution was sodium hydrogen tartrate in dimethyl sulfoxide. • Gamma irradiation did not influence the antimony leaching ability. - Abstract: There has been a recent interest in antimony since the availability in readily mined areas is decreasing compared to the amounts used. It is important in many applications such as flame retardants and in the production of polyester, which can trigger an investigation of the leachability of antimony from plastics using different acids. In this paper, different types of acids are tested for their ability to leach antimony from a discarded computer housing, made of poly(acrylonitrile butadiene styrene), which is a common plastic type used in electrical and electronic equipment. The acid solutions included sodium hydrogen tartrate (0.5 M) dissolved in either dimethyl sulfoxide or water (at ca. 23 °C and heated to ca. 105 °C). The metal content after leaching was determined by inductively coupled plasma optical emission spectroscopy. The most efficient leaching medium was the heated solution of sodium hydrogen tartrate in dimethyl sulfoxide, which leached almost half of the antimony from the poly(acrylonitrile butadiene styrene). Gamma irradiation, which is proposed to improve the mechanical properties in plastics, was used here to investigate the influence of antimony leaching ability. No significant change in the amount of leached antimony could be observed.

Tostar, Sandra, E-mail: sandra.tostar@chalmers.se [Department of Industrial Materials Recycling, Chalmers University of Technology, 412 96 Gothenburg (Sweden); Stenvall, Erik; Boldizar, Antal [Department of Material and Manufacturing Technology, Chalmers University of Technology, 412 96 Gothenburg (Sweden); Foreman, Mark R. St. J. [Department of Industrial Materials Recycling, Chalmers University of Technology, 412 96 Gothenburg (Sweden)

2013-06-15

384

Antimony leaching in plastics from waste electrical and electronic equipment (WEEE) with various acids and gamma irradiation.  

PubMed

There has been a recent interest in antimony since the availability in readily mined areas is decreasing compared to the amounts used. It is important in many applications such as flame retardants and in the production of polyester, which can trigger an investigation of the leachability of antimony from plastics using different acids. In this paper, different types of acids are tested for their ability to leach antimony from a discarded computer housing, made of poly(acrylonitrile butadiene styrene), which is a common plastic type used in electrical and electronic equipment. The acid solutions included sodium hydrogen tartrate (0.5M) dissolved in either dimethyl sulfoxide or water (at ca. 23°C and heated to ca. 105°C). The metal content after leaching was determined by inductively coupled plasma optical emission spectroscopy. The most efficient leaching medium was the heated solution of sodium hydrogen tartrate in dimethyl sulfoxide, which leached almost half of the antimony from the poly(acrylonitrile butadiene styrene). Gamma irradiation, which is proposed to improve the mechanical properties in plastics, was used here to investigate the influence of antimony leaching ability. No significant change in the amount of leached antimony could be observed. PMID:23561798

Tostar, Sandra; Stenvall, Erik; Boldizar, Antal; Foreman, Mark R St J

2013-06-01

385

Visible light-induced difunctionalization of electron-enriched styrenes: synthesis of tetrahydrofurans and tetrahydropyrans.  

PubMed

The difunctionalization of electron-enriched styrenes for the synthesis of substituted tetrahydrofurans and tetrahydropyrans in the presence of photoredox catalysts is described. The procedure is highlighted by its operational simplicity, low catalyst loadings (1 mol%), excellent stereoselectivity and mild reaction conditions. PMID:25407086

Lin, Run; Sun, Hongnan; Yang, Chao; Shen, Wenbo; Xia, Wujiong

2015-01-01

386

Toxicity of styrene vapor in hepatocyte monolayers at low oxygen tensions.  

PubMed Central

Hepatocyte monolayer cultures were exposed to 6000 ppm styrene vapor at 20%, 2%, or 1% O2 and assayed for signs of cell damage immediately following the 2-hr exposure and then 24 hr later. Oxygen concentrations were used that were previously shown to maximize lipid peroxidation and to predispose hepatocyte monolayers to chemical injury. The use of two time points allowed assessment of acute injury as well as injury that requires several hours to manifest itself. The uptake of styrene into the buffer in the culture dishes was measured by gas chromatography and was found to be 0.49, 0.68, and 0.74 mM at 15, 60, and 120 min, respectively. However, as measured by release of aspartate aminotransferase and inclusion of trypan blue, no toxicity was evident at either time point, irrespective of the oxygen concentration. This study shows that despite the weakening of hepatocyte defense mechanisms by hypoxia, styrene is not acutely toxic to these cells. Furthermore, if any damage to DNA, RNA, or the capability for protein synthesis occurs during exposure to styrene, it is insufficient to cause lysis within 24 hr. PMID:2351122

Costa, A K; Trudell, J R

1990-01-01

387

Carbon Tetrachloride as Thermoporometry Liquid-probe to Study the Cross linking of Styrene Copolymer  

E-print Network

styrene copolymer networks have been measured by thermoporometry using CCl4 as a probe liquid. All-to-solid and the solid-to-solid thermal transitions of CCl4 and successfully validated on test samples. It was found hand. Keywords Photo-cross linking, benzil, thermoporometry, CCl4, polystyrene, nanoporous silica hal

Paris-Sud XI, Université de

388

Studies in hydrocarboxylation of styrene and derivatives using palladium complex catalysts  

E-print Network

above 99% regio-selectivity to 2-phenylpropionic acid as well as high activity. Therefore, this work mainly investigated the kinetics of hydrocarboxylation of styrene using Pd(pyca)(PPh3)(OTs)/PPh3/TsOH/LiCl catalyst system. Particularly, parametric...

Li, Yuanchun

2010-07-15

389

Studies on the graft polymerizations of styrene and methyl methacrylate to hydroxyl terminated polybutadiene  

Microsoft Academic Search

Hydroxyl terminated Polybutadiene (HTPB) was grafted with styrene (St) or methyl methacrylate (MMA) by free radical solution polymerization. The graft copolymerizations were conducted in benzene at 70 °C. The initiators used were benzoyl peroxide (BPO) and azobis-isobutyronitrile (AIBN). The microstructures of theobtained graft copolymers were characterized by13C NMR measurement and the DEPT technique, as well as by IR spectrometer. The

Chang-Tay Lin; Mon-Chun Liu

1995-01-01

390

Mechanical and Curing Properties of a Styrene-based Shape Memory Polymer  

Microsoft Academic Search

Presented is an experimental investigation into the characteristics of a particular styrene-based shape memory polymer, Veriflex®. Tensile, 3 point bend, and creep tests are conducted yielding the Young’s modulus, yield strength, flexural modulus, flexure strength, and creep modulus of the polymer both above and below the glass transition temperature. The results of the characterization may be used to populate a

Richard Beblo; Korey Gross; Lisa Mauck Weiland

2010-01-01

391

Durability Assessment of Styrene and Epoxy-based Shape-memory Polymer Resins  

Microsoft Academic Search

The present study is a baseline assessment of the durability of styrene- and epoxy-based shape memory polymer resin materials being considered for morphing applications when exposed to service environment. The approach for the experimental evaluation is a measurement of the shape memory properties and elastomeric response before and after separate environmental exposure to (i) water at 49°C for 4 days,

G. P. Tandon; K. Goecke; K. Cable; J. Baur

2009-01-01

392

Hole transport in poly(styrene) doped with p-diarylaminostilbene molecules  

Microsoft Academic Search

Hole mobilities have been measured in poly(styrene) (PS) doped with a series of p-diarylaminostilbene molecules (DAS) with different dipole moments. At room temperature, the mobilities vary by a factor of approximately 20, decreasing with increasing dipole moment. The results are described by a model based on disorder, due to Bässler and coworkers. The model is based on the argument that

P. M. Borsenberger; J. R. Cowdery-Corvan; E. H. Magin; J. A. Sinicropi

1997-01-01

393

ASSESSMENT OF STYRENE EMISSION CONTROLS FOR FRP/C AND BOAT BUILDING INDUSTRIES  

EPA Science Inventory

The report gives results of an evaluation of several conventional and novel emission control technologies that have been used or could be used to treat styrene emissions from open molding processes in fiberglass-reinforced plastics/composites (FRP/C) and fiberglass boat building ...

394

The relative signs of the NMR coupling constants in styrene oxide by double resonance  

Microsoft Academic Search

The relative signs of the nuclear magnetic resonance spin-spin coupling constants between the three protons of the oxirane ring of styrene oxide have been determined to be the same by the audio side band phase detection proton-proton decoupling technique.

Daniel D. Elleman; Stanley L. Manatt

1962-01-01

395

The optimization of processing parameters used to form aluminum oxide-styrene acrylate composite capacitors  

Microsoft Academic Search

The dielectric characteristics, thickness and the glass transition temperature of composite dielectric coatings containing electrophoretically deposited styrene acrylate plus anodically formed aluminum oxide can be altered by varying the processing conditions. The processing conditions varied here include: (1) the nature of the anodic aluminum oxide (barrier vs porous AlâOâ), (2) the thickness of the aluminum oxide, and (3) the curing

J. K. G. Panitz; W. G. Yelton

1989-01-01

396

EVALUATION OF THE POLYAD FB AIR PURIFICATION AND SOLVENT RECOVERY PROCESS FOR STYRENE REMOVAL  

EPA Science Inventory

The report gives results of a study evaluating the Polyad fluidized-bed (FB) process for controlling styrene emissions at a representative fiberglass shower stall and bath tub manufacturing plan*t. he process was evaluated using a transport able unit supplied by Weatherly, Inc., ...

397

QSRR correlation of free-radical polymerization chain-transfer constants for styrene.  

PubMed

Quantitative structure-reactivity relationships (QSRR) are deduced for kinetic chain-transfer constants for 90 agents on styrene polymerization at 60 degrees C. Three- and five-parameter correlations were obtained with R2 of 0.725 and 0.818, respectively. The descriptors involved in the correlations are consistent with the proposed mechanism of the chain-transfer reactions. PMID:11277714

Ignatz-Hoover, F; Petrukhin, R; Karelson, M; Katritzky, A R

2001-01-01

398

Synthesis and characterization of Cr-MSU-1 and its catalytic application for oxidation of styrene  

SciTech Connect

Chromium-containing mesoporous silica material Cr-MSU-1 was synthesized using lauryl alcohol-polyoxyethylene (23) ether as templating agent under the neutral pH condition by two-step method. The sample was characterized by XRD, TEM, FT-IR, UV-Vis, ESR, ICP-AES and N{sub 2} adsorption. Its catalytic performance for oxidation of styrene was studied. Effects of the solvent used, the styrene/H{sub 2}O{sub 2} mole ratio and the reaction temperature and time on the oxidation of styrene over the Cr-MSU-1 catalyst were examined. The results indicate that Cr ions have been successfully incorporated into the framework of MSU-1 and the Cr-MSU-1 material has a uniform worm-like holes mesoporous structure. After Cr-MSU-1 is calcined, most of Cr{sup 3+} is oxidized to Cr{sup 5+} and Cr{sup 6+} in tetrahedral coordination and no extra-framework Cr{sub 2}O{sub 3} is formed. The Cr-MSU-1 catalyst is highly active for the selective oxidation of styrene and the main reaction products over Cr-MSU-1 are benzaldehyde and phenylacetaldehyde. Its catalytic performance remains stable within five repeated runs and no leaching is noticed for this chromium-based catalyst. - Graphical abstract: Mesoporous Cr-MSU-1 with worm-like holes was synthesized by a novel two-step method. The Cr-MSU-1 material is highly active and stable for the selective oxidation of styrene.

Liu Hong, E-mail: liuhong@shu.edu.c [Department of Chemical Engineering, Shanghai University, Shanghai 201800 (China); Wang Zhigang [Department of Chemical Engineering, Shanghai University, Shanghai 201800 (China); Hu Hongjiu [College of Science, Shanghai University, Yanchang Road, Shanghai 200072 (China); Liang Yuguang; Wang Mengyang [Department of Chemical Engineering, Shanghai University, Shanghai 201800 (China)

2009-07-15

399

Initiated chemical vapor deposition of alternating copolymers of styrene and maleic anhydride.  

PubMed

Initiated chemical vapor deposition (iCVD) of alternating copolymer thin films has been achieved for the first time. Copolymerization is desirable for maleic anhydride (Ma) since this monomer does not homopolymerize to an appreciable extent. At conditions where the observed deposition rates for styrene (S) and Ma homopolymers were only 0 and 5.5 nm/min, respectively, combining the two monomers resulted in a much higher deposition rate of 75.4 nm/min. iCVD processes utilize low energy (<30 W) to generate peroxy radicals from initiator molecules while avoiding degradation of functional groups in the monomers. Indeed, full retention of the anhydride functionality from the Ma monomer and avoidance of undesirable side reactions was observed in iCVD of poly(styrene-alt-maleic anhydride) (PSMa) copolymer films. Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy, and 13C nuclear magnetic resonance (NMR) conclusively demonstrate that all of the copolymer films contain 50% styrene and 50% Ma (within experimental error), irrespective of gas feed ratios employed during the deposition. The 13C NMR signal in the 136-140 ppm region from the quaternary carbon in styrene and additional distortionless enhancement polarization transfer experiments confirmed that the copolymers are strictly alternating. Varying the gas feed ratio of Ma to styrene provided control over deposition rates and number-average molecular weights. Number-average molecular weights varied from 1380 to 4680 g/mol, and deposition rates varied from 6.3 to 75.4 nm/min. PMID:17451257

Tenhaeff, Wyatt E; Gleason, Karen K

2007-06-01

400

Increase in neuropsychiatric symptoms after occupational exposure to low levels of styrene.  

PubMed Central

The results of this study suggest that exposure to styrene below the current Swedish permissible exposure limit of 20 ppm induces neurotoxic effects expressed as an increased number of neuropsychiatric symptoms. Twenty men exposed to styrene at a plastics factory participated. The reference group included 20 non-exposed men matched for age, working schedule, and physical work load. Exposure to styrene during one workday was assessed by personal air monitoring and biological monitoring. To evaluate the physical work load the pulse(heart) rate was measured. One week before the study each man completed a neuropsychiatric symptom questionnaire containing 16 items. Also 17 questions regarding acute symptoms of local irritation and symptoms of the central nervous system were presented after the psychometric tests were performed. The tests were simple reaction time, colour word vigilance, and symbol digit. A follow up with regard to the symptoms among the exposed men was done after their summer vacation, about two to five weeks after their last exposure. The mean eight hour time weighted average (TWA) concentration of styrene in air, measured by passive dosimetry was 8.6 ppm (range 0.04-50.4 ppm). The exposed men had significantly more symptoms than the referents although there were no significant differences for the psychometric tests. At the follow up the exposed men reported fewer symptoms. This study indicates that symptoms are earlier indicators of adverse effects than complex tests and underlines the importance of regular follow up of people exposed to styrene (and probably organic solvents in general). PMID:8398879

Edling, C; Anundi, H; Johanson, G; Nilsson, K

1993-01-01

401

Postmortem and insitu TEM methods to study the mechanism of failure in controlled-morphology high-impact polystrene resin  

SciTech Connect

Advanced Styrenic resins are being developed throughout the industry to bridge the properties gap between traditional HIPS (High Impact Polystyrene) and ABS (Acrylonitrile-Butadiene-Styrene copolymers) resins. These new resins have an unprecedented balance of high gloss and high impact energies. Dow Chemical`s contribution to this area is based on a unique combination of rubber morphologies including labyrinth, onion skin, and core-shelf rubber particles. This new resin, referred as a controlled morphology resin (CMR), was investigated to determine the toughening mechanism of this unique rubber morphology. This poster will summarize the initial studies of these resins using the double-notch four-point bend test of Su and Yee, tensile stage electron microscopy, and Poisson Ratio analysis of the fracture mechanism.

Cieslinski, R.C.; Dineen, M.T.; Hahnfeld, J.L. [Dow Chemical Company, Midland, MI (United States)

1996-12-31

402

Synthesis of catalytically active polymer-bound Mn(III) salen complexes for enantioselective epoxidation of styrene derivatives  

Microsoft Academic Search

Catalytically active metal-complexing polymer-containing chiral Mn(III) salen moieties derived from (1R, 2R)-(?)-diphenylethylenediamine, (1S, 2S)-(+)-cyclohexanediamine, and (S)-(+)-diaminopropane with ?-naphthyl salicylaldehyde anchored to the polymeric matrix obtained from styrene-4-vinyl pyridine-divinyl benzene (PVPD) have been synthesised. These catalysts were used for enantioselective epoxidation of styrene and substituted styrenes, viz. 4-chloro-, 4-methyl and4-nitrostyrene using iodosyl benzene as terminal oxidant by GLC. The enantiomeric excess

R. I. Kureshy; N. H. Khan; S. H. R. Abdi; P. Iyer

1997-01-01

403

Migration study of 1,3-butadiene in eye-drop solutions.  

PubMed

The potential deleterious effects of extractables/leachables in pharmaceutical products led the USP, EP, and JP to require extractable and toxicity testing of container/closure systems. To that, a headspace gas chromatography flame ionization detection method was developed and validated for the determination of 1,3-butadiene (1,3-BD) as a potential extractable residue from a pharmaceutical container/closure system into eye-drop solutions. A migration study was further applied in eight eye-drop solutions (currently marketed products) after short- and long-term exposure of these products at various temperatures. This method allows the establishment of safety-qualification thresholds for 1,3-BD being capable of monitoring eye-drop solution products for this residue. PMID:22187982

Pistos, Constantinos; Karampela, Sevasti; Vardakou, Ioanna; Papoutsis, Ioannis; Spiliopoulou, Chara; Athanaselis, Sotiris

2012-07-01

404

Laser-Induced Selectivity for Dimerization Versus Polymerization of Butadiene Under Pressure  

NASA Astrophysics Data System (ADS)

The pressure-induced chemical reaction of liquid butadiene was studied by Fourier transform infrared spectroscopy in a diamond anvil cell. Dimerization was found to occur above 0.7 gigapascal, giving vinylcyclohexene according to a cyclo-addiction reaction and only a trace amount of polybutadiene forms. By irradiating the high-pressure sample with a few milliwatts of the 488-nanometer argon+ laser line, the dimerization was completely inhibited, and the rapid formation of pure trans-polybutadiene was observed. The use of different excitation wavelength allows us to emphasize the selectivity of the process and to identify the active role of the 21Ag state in this pressure- and laser-induced chemical reaction.

Citroni, Margherita; Ceppatelli, Matteo; Bini, Roberto; Schettino, Vincenzo

2002-03-01

405

Designing zeolite catalysts for size- and shape-selective reactions: Selective hydrogenation of acetylene in the presence of butadiene and ethylene  

SciTech Connect

In the production of ethylene from the steam cracking of natural gas, small amounts of acetylene and butadiene are produced. Downstream, acetylene can present a hazard in a cryogenic separation process while nonselective hydrogenation removes acetylene as well as valuable ethylene and butadiene. With the aid of adsorption measurements, a selective hydrogenation catalyst has been designed. Small-pore zeolites, which serve as catalytic supports and provide reactant selective control, were ion-exchanged with Ni{sup 2+} and subsequently reduced. Compared to a commercial catalyst in which 60% of butadiene and all of the acetylene are hydrogenated, these new catalysts totally hydrogenate acetylene with only 10-20% hydrogenation of the butadiene and almost no hydrogenation of ethylene. To achieve selective hydrogenation, poisoning of the metal sites on the external zeolite surface is essential in order to obtain a product spectrum dominated by catalytic sites within the zeolite framework.

Corbin, D.R.; Abrams, L.; Bonifaz, C. (E.I. du Pont de Nemours Company, Wilmington, DE (USA))

1989-02-01

406

Effect of acrylonitrile on the rat pituitary: enlargement of Golgi region in prolactin cells, crinophagy in prolactin cells and growth hormone cells.  

PubMed Central

Since it has been shown that acrylonitrile prevents the appearance of spontaneous pituitary adenomas, we have investigated its effect in acute experiments on rat pituitaries by histology, immunocytochemistry, electron microscopy and morphometry; in addition, serum prolactin and growth hormone levels were measured by radioimmunoassay. Electron microscopy of prolactin cells revealed hypertrophy of the Golgi region without significant change in volume densities and diameters of forming and storage granules. In the 24 h group, crinophagy was observed in prolactin cells and growth hormone cells. Corticotrophs, thyrotrophs and gonadotrophs were unaltered. Dilation, congestion and rupture of capillaries, as well as pericapillary and intercellular oedema were evident in the 24 h group. One hour after intravenous acrylonitrile injection, serum prolactin levels were within the normal range, whereas at 24 h, hyperprolactinemia was noted. Serum growth hormone concentrations were unchanged. It can be concluded that acrylonitrile has a complex effect on prolactin cells. Hypertrophy of Golgi complex and hyperprolactinemia may reflect increased prolactin synthesis and release. Since volume densities and diameters of secretory granules in prolactin cells remained unchanged, it appears that newly synthesized prolactin was preferentially released and not the prolactin stored in secretory granules. Crinophagy may be the morphological manifestation of a discrepancy between hormone synthesis and release suggesting increased degradation of unused hormone by lysosomes. Images Fig. 1 Fig. 2 Fig. 3 Fig. 4 Fig. 5 Fig. 6 Fig. 7 Fig. 8 PMID:3718845

Kamijo, K.; Kovacs, K.; Szabo, S.; Bollinger-Gruber, J. N.; Reichlin, S.

1986-01-01

407

Synthesis of 1,1,4,4-tetrabromo-2-butenes and related compounds via desilylation-bromination of silylated 1,3-butadiene derivatives.  

PubMed

The combination of zirconocene-mediated coupling of silylated alkynes with a protonation-desilylation or bromination-desilylation process afforded otherwise unavailable butadiene derivatives. When (E,E)-2,3-dialkyl-1,4-bis(trimethylsilyl)-1,3-butadienes were treated with 3 equiv of Br(2) in CH(2)Cl(2), (E)-2,3-dialkyl-1,1,4,4-tetrabromo-2-butenes were obtained in excellent yields with perfect stereoselectivity. PMID:15549842

Xi, Zhenfeng; Liu, Xiaozhong; Lu, Jianming; Bao, Fengyu; Fan, Hongtao; Li, Zhiping; Takahashi, Tamotsu

2004-11-26

408

Effect of equivalent weight on electrochemical mass transport properties of oxygen in proton exchange membranes based on sulfonated ?,?,?-trifluorostyrene (BAM®) and sulfonated styrene-(ethylene-butylene)-styrene triblock (DAIS-analytical) copolymers  

Microsoft Academic Search

Mass transport parameters and limiting current densities are determined for a series of sulfonated ?,?,?-trifluorostyrene-co-substituted-?,?,?-trifluorostyrene (BAM®) (EW 407-735 g mol?1) and sulfonated styrene-(ethylene-butylene)-styrene copolymers (DAIS-Analytical) (EW 585–1062 g mol?1) proton exchange membranes using microelectrode techniques. These materials were investigated in an environment that mimics proton exchange membrane fuel cells. The oxygen diffusion coefficient increases with temperature, while its solubility decreases.

V. I. Basura; C. Chuy; P. D. Beattie; S. Holdcroft

2001-01-01

409

Equilibrium and kinetic aspects of the pH-dependent swelling of poly(2-vinylpyridine-co-styrene) microgels  

Microsoft Academic Search

Monodisperse, cationic microgels were synthesized by surfactant-free emulsion copolymerization of 2-vinylpyridine and styrene,\\u000a using the cationic initiator 2,2?-azobis(2-amidinopropane) dihydrochloride. Low levels of divinylbenzene were employed as\\u000a a cross-linking agent. The particle morphologies and diameters were characterized by a combination of TEM and photon correlation\\u000a spectroscopy. At styrene contents less than 40% by weight, the particles were spherical with diameters of

A. Loxley; B. Vincent

1997-01-01

410

Determination of migration monomer styrene from GPPS (general purpose polystyrene) and HIPS (high impact polystyrene) cups to hot drinks  

PubMed Central

In this study, 162 samples were analysed for monomer styrene content with using high performance liquid chromatography (HPLC) method in hot tea, milk, cocoa milk. The monomer styrene content, expressed in ?g/l of drink and the level of migration of styrene monomer were varied from 0.61 to 8.15 for hot tea, from 0.65 to 8.30 for hot milk, from 0.71 to 8.65 for hot cocoa milk in GPPS (general purpose polystyrene), from 0.48 to 6.85 for hot tea, from 0.61 to 7.65 for hot milk, from 0.72 to 7.78 for hot cocoa milk in HIPS (high performance polystyrene) cups in different temperatures and times. The estimated limit of detection of (HPLC) method for all samples was 0.001 mg/kg. There is linear regression for styrene monomer from 1 to 10 ng/ml. Several samples spiked with a known amount of styrene monomer. The results of the recovery in study for styrene monomer were determinate to be mean, 96.1 ± 1.92 to 99.7 ± 1.15%. The results of this study indicate that styrene monomer from polystyrene disposable into hot and fat drinks was migrated and this migration was highly dependent on fat content and temperature of drinks. The derived concentration of styrene monomer in this study was above the EPA (Environmental protection agency) recommended level, especially in MCLG (Maximum contaminant level goal) standard. More study is needed to further elucidate this finding. PMID:19750020

Khaksar, Mohammad-Reza; Ghazi-Khansari, Mahmoud

2009-01-01

411

Enhanced styrene recovery from waste polystyrene pyrolysis using response surface methodology coupled with Box-Behnken design.  

PubMed

A work applied response surface methodology coupled with Box-Behnken design (RSM-BBD) has been developed to enhance styrene recovery from waste polystyrene (WPS) through pyrolysis. The relationship between styrene yield and three selected operating parameters (i.e., temperature, heating rate, and carrier gas flow rate) was investigated. A second order polynomial equation was successfully built to describe the process and predict styrene yield under the study conditions. The factors identified as statistically significant to styrene production were: temperature, with a quadratic effect; heating rate, with a linear effect; carrier gas flow rate, with a quadratic effect; interaction between temperature and carrier gas flow rate; and interaction between heating rate and carrier gas flow rate. The optimum conditions for the current system were determined to be at a temperature range of 470-505°C, a heating rate of 40°C/min, and a carrier gas flow rate range of 115-140mL/min. Under such conditions, 64.52% WPS was recovered as styrene, which was 12% more than the highest reported yield for reactors of similar size. It is concluded that RSM-BBD is an effective approach for yield optimization of styrene recovery from WPS pyrolysis. PMID:24491383

Mo, Yu; Zhao, Lei; Wang, Zhonghui; Chen, Chia-Lung; Tan, Giin-Yu Amy; Wang, Jing-Yuan

2014-04-01

412

Experimental study of the structure of rich premixed 1,3-butadiene/CH4/O2/Ar flame  

E-print Network

The structure of a laminar rich premixed 1,3-C4H6/CH4/O2/Ar flame have been investigated. 1,3-Butadiene, methane, oxygen and argon mole fractions are 0.033; 0.2073; 0.3315, and 0.4280, respectively, for an equivalent ratio of 1.80. The flame has been stabilized on a burner at a pressure of 6.7 kPa (50 Torr). The concentration profiles of stable species were measured by gas chromatography after sampling with a quartz probe. Quantified species included carbon monoxide and dioxide, methane, oxygen, hydrogen, ethane, ethylene, acetylene, propyne, allene, propene, cyclopropane, 1,3-butadiene, butenes, 1-butyne, vinylacetylene, diacetylene, C5 compounds, benzene, and toluene. The temperature was measured thanks to a thermocouple in PtRh (6%)-PtRh (30%) settled inside the enclosure and ranged from 900 K close to the burner up to 2100 K.

Gueniche, Hadj-Ali; Fournet, René; Battin-Leclerc, Frédérique

2006-01-01

413

Dominant lethal study in CD-1 mice following inhalation exposure to 1,3-butadiene: Final technical report  

SciTech Connect

The effects of whole-body inhalation exposures to 1,3-butadiene on the reproductive system was evaluated. The results of dominant lethality in CD-1 male mice that were exposed to 1,3-butadiene are described. Subsequent to exposure, males were mated with two unexposed females. Mating was continued for 8 weeks with replacement of two females each week. Gravid uteri were removed, and the total number, position and status of implantations were determined. The mice were weighed prior to exposure and at 0, 1, 2, 3, 4, 5, 6, 7, and 8 weeks after exposure and at sacrifice. The animals were observed for mortality, morbidity and signs of toxicity throughout the study. 19 refs., 5 figs., 9 tabs.

Hackett, P.L.; Mast, T.J.; Brown, M.G.; Clark, M.L.; Evanoff, J.J.; Rowe, S.E.; McClanahan, B.J.; Buschbom, R.L.; Decker, J.R.; Rommereim, R.L.; Westerberg, R.B.

1988-04-01

414

Synthesis and properties study of the uniform nonspherical styrene/methacrylic Acid copolymer latex particles.  

PubMed

A facile method to prepare the nonspherical amphiphilic random copolymer of poly(styrene-co-methacrylic acid) (poly(St-co-PMAA)) latex particles with well-defined shapes and high yields by one-step batch emulsifier-free polymerization was demonstrated. In our strategy, only varying the molar ratio of styrene (St) to methacrylic acid (MAA), no seed-particles, no cross-linker, and no multistep control procedures were needed. Due to the presence of carboxyl groups on the surface of (poly(St-co-PMAA) latex particles, these latex particles can be used as templates for fabricating core-shell nonspherical functional materials, such as poly(St-co-PMAA)@SiO2 and poly(St-co-PMAA)@polypyrrole). The corresponding nonspherical hollow structures (SiO2 and polypyrrole) could be obtained after removal of the templates. In addition, poly(St-co-PMAA) latex particles exhibit interesting morphologies in ethanol. PMID:25513835

Wang, Wenqin; Ren, Guohong; Yang, Yanqiong; Cai, Wujin; Chen, Tao

2015-01-13

415

Preparation and characterization of graphite-dispersed styrene-acrylic emulsion composite coating on magnesium alloy  

NASA Astrophysics Data System (ADS)

In this work, an electrically conductive, corrosion resistant graphite-dispersed styrene-acrylic emulsion composite coating on AZ91D magnesium alloy was successfully produced by the method of anodic deposition. The microstructure, composition and conductivity of the composite coating were characterized using optical microscope (OM), scanning electron microscope (SEM), X-ray diffraction (XRD), Fourier transform infrared spectrometer (FTIR) and four electrode volume resistivity instrument, respectively. The corrosion resistance of the coating was evaluated using potentiodynamic polarization measurements and salt spray tests. It is found that the graphite-dispersed styrene-acrylic emulsion composite coating was layered structure and displayed good electrical conductivity. The potentiodynamic polarization tests and salt spray tests reveal that the composite coating was successful in providing superior corrosion resistance to AZ91D magnesium alloy.

Zhang, Renhui; Liang, Jun; Wang, Qing

2012-03-01

416

Damage Resistance of Composites Based on Glass Fibre Reinforced Low Styrene Emission Resins for Marine Applications  

NASA Astrophysics Data System (ADS)

Composites based on glass fiber reinforced low styrene emission polyester resins have been widely used over the last 10 years, in order to meet increasingly strict safety regulations, particularly in the pleasure boat industry. Previous studies of their mechanical properties suggested that although these resins are generally more brittle than traditional orthophthalic polyester resins this did not adversely affect the properties commonly used for quality control (short beam shear and tensile failure strength of mat reinforced composites). In the present paper results from a more detailed study of damage behaviour are presented. Tests include fracture toughness (K Ic ) tests on resins, fibre/matrix interface energy, detection of composite damage initiation in tension by acoustic emission, composite delamnation (G Ic and G IIc ), and low energy impact. Overall the results indicate that the low failure strain of low styrene emission resins results in significantly lower composite damage resistance.

Perrot, Y.; Baley, C.; Grohens, Y.; Davies, P.

2007-01-01

417

Diffusion and polymerization of styrene in an aqueous solution of potassium persulfate under static conditions  

SciTech Connect

The potassium persulfate-initiated polymerization of styrene in a mechanically agitated mixture of water and monomer leads to the formation of a stable, monodisperse latex. In order to explain the mechanism of the stabilization of the latex particles in this system, the authors present a detailed investigation of the polymerization of styrene in a specially constructed electrochemical cell under static conditions. A schematic of the cell is shown. Results show that the capacity of the electrical double layer on the platinum electrode remains constant with time in a system containing only a solution of electrolyte, either K/sub 2/SO/sub 4/ or K/sub 2/S/sub 2/O/sub 8/.

Oganesyan, A.A.; Boyadzhyan, V.G.; Gritskova, I.A.; Gukasyan, A.V.; Matsoyan, S.G.; Pravednikov, A.N.

1985-10-01

418

Biphasic telomerization of 1,3-butadiene with HNEt 2 catalyzed by palladium\\/sulphonated–phosphine complexes  

Microsoft Academic Search

The catalytic telomerization of 1,3-butadiene with diethylamine has been performed using palladium\\/sulfonated–phosphine complexes immobilized in 1-n-butyl-3-methylimidazolium tetrafluoroborate [BMI][BF4] ionic liquid. This process affords selectively 1-octadienyl amines with high E\\/Z ratios. The rate of product formation as well as the regioselectivity of the reaction was found to depend largely on the ligand and catalyst concentrations. Selectivities of up to 99% in

Gledison Santos Fonseca; Roberto Fernando de Souza; Jairton Dupont

2002-01-01

419

Stereospecific synthesis of 1Z,3E-butadiene-1-sulfonic acids from ?,?-unsaturated ?-sultones and ?-sultams  

Microsoft Academic Search

Conclusions 1.The reaction of strong bases with ?,?-unsaturated ?-sultones and ?-sultams opens up a simple route for the stereospecific synthesis of hitherto unknown functional derivatives of 1Z, 3 (E)-butadiene-1-sulfonic acids.2.From the stereochemistry of the products of ring-opening of these heterocycles, their isomerization at the deprotonation stage is preferably to be regarded as an intramolecular synchronous anionotropic process.

A. M. Moiseenkov; E. V. Polunin; I. M. Zaks

1984-01-01

420

Atmospheric oxidation of isoprene and 1,3-butadiene: influence of aerosol acidity and relative humidity on secondary organic aerosol  

NASA Astrophysics Data System (ADS)

The effects of acidic seed aerosols on the formation of secondary organic aerosol (SOA) have been examined in a number of previous studies, several of which have observed strong linear correlations between the aerosol acidity (measured as nmol H+ per m3 air sample volume) and the percent change of secondary organic carbon (SOC). The measurements have used several precursor compounds representative of different classes of biogenic hydrocarbons including isoprene, monoterpenes, and sesquiterpenes. To date, isoprene has displayed the most pronounced increase in SOC, although few measurements have been conducted with anthropogenic hydrocarbons. In the present study, we examine several aspects of the effect of aerosol acidity on the secondary organic carbon formation from the photooxidation of 1,3-butadiene, as well as extending the previous analysis of isoprene. The photooxidation products measured in the absence and presence of acidic sulfate aerosols were generated either through photochemical oxidation of SO2 or by nebulizing mixtures of ammonium sulfate and sulfuric acid into a 14.5 m3 smog chamber system. The results showed that, like isoprene and ?-caryophyllene, 1,3-butadiene SOC yields linearly correlate with increasing acidic sulfate aerosol. The observed acid sensitivity of 0.11% SOC increase per nmol m-3 increase in H+ was approximately a factor of three less than that measured for isoprene. The results also showed that the aerosol yield decreased with increasing humidity for both isoprene and 1,3-butadiene, although to different degrees. Increasing the absolute humidity from 2 to 12 g m-3 reduced the 1,3-butadiene yield by 45% and the isoprene yield by 85%.

Lewandowski, M.; Jaoui, M.; Offenberg, J. H.; Krug, J. D.; Kleindienst, T. E.

2014-11-01

421

Hole transport in bis(ditolylaminostyryl)benzene doped poly(styrene)  

Microsoft Academic Search

Hole mobilities have been measured in poly(styrene) (PS) doped with bis(ditolylaminostyryl)benzene (TASB). TASB is a weakly polar molecule that contains two aniline donor functionalities. The dipole moment is 0.54 D. The results are described by a formalism based on disorder, due to Bässler and coworkers. According to the formalism, charge transport occurs by hopping within a manifold of localized states

P. M. Borsenberger; W. T. Gruenbaum; E. H. Magin

1996-01-01

422

Effect of porosity on sulfonation of macroporous styrene-divinylbenzene beads  

Microsoft Academic Search

Macroporous styrene-divinylbenzene beads having pore volume in the range of 0.1–2.2 ml\\/g were synthesized by o\\/w suspension polymerization using petroleum ether and cyclohexanone as porogen. As the pore volume was increased the pore size distribution shifted towards large pore diameter and the mechanical strength of the beads in the dry state decreased. The copolymers were converted into cation-exchange resins by

Munir Ahmed; Muhammad Arif Malik; Shahid Pervez; Muhammad Raffiq

2004-01-01

423

Reaction of aldehyde oils with a resinous polyol, styrene-allyl alcohol copolymer  

Microsoft Academic Search

A series of film formers based on aldehyde oils, derived by reductive ozonolysis of soybean and linseed oils was prepared\\u000a by a two-step reaction with a resinous polyol, styrene-allyl alcohol copolymer. The methyl acetals of the di- and monoaldehyde\\u000a oils were interchanged with the hydroxyl functionality of the resinous polyol with potassium acid sulfate as the catalyst\\u000a as follows: (a)

A. E. Rheineck; P. R. Lakshmanan

1969-01-01

424

Change in semen quality and sperm chromatin structure following occupational styrene exposure  

Microsoft Academic Search

Objectives: Organic solvents have been suspected to exert detrimental effects on human spermiogenesis. Styrene, which is both mutagenic\\u000a and neurotoxic, was selected as a suitable organic solvent for further assessment of a possible effect on semen quality and\\u000a sperm DNA damage. Subjects and methods: Semen samples were collected from 23 reinforced plastics workers at the time of employment and after

Henrik A. Kolstad; Jens Peter Bonde; Marcello Spano; Aleksander Giwercman; Wolfgang Zschiesche; Ditte Kaae; Solveig Brixen Larsen; Nel Roeleveld

1999-01-01

425

Investigating bacterial populations in styrene-degrading biofilters by 16S rDNA tag pyrosequencing.  

PubMed

Microbial biofilms are essential components in the elimination of pollutants within biofilters, yet still little is known regarding the complex relationships between microbial community structure and biodegradation function within these engineered ecosystems. To further explore this relationship, 16S rDNA tag pyrosequencing was applied to samples taken at four time points from a styrene-degrading biofilter undergoing variable operating conditions. Changes in microbial structure were observed between different stages of biofilter operation, and the level of styrene concentration was revealed to be a critical factor affecting these changes. Bacterial genera Azoarcus and Pseudomonas were among the dominant classified genera in the biofilter. Canonical correspondence analysis (CCA) and correlation analysis revealed that the genera Brevundimonas, Hydrogenophaga, and Achromobacter may play important roles in styrene degradation under increasing styrene concentrations. No significant correlations (P?>?0.05) could be detected between biofilter operational/functional parameters and biodiversity measurements, although biological heterogeneity within biofilms and/or technical variability within pyrosequencing may have considerably affected these results. Percentages of selected bacterial taxonomic groups detected by fluorescence in situ hybridization (FISH) were compared to results from pyrosequencing in order to assess the effectiveness and limitations of each method for identifying each microbial taxon. Comparison of results revealed discrepancies between the two methods in the detected percentages of numerous taxonomic groups. Biases and technical limitations of both FISH and pyrosequencing, such as the binding of FISH probes to non-target microbial groups and lack of classification of sequences for defined taxonomic groups from pyrosequencing, may partially explain some differences between the two methods. PMID:24950754

Portune, Kevin J; Pérez, M Carmen; Álvarez-Hornos, F Javier; Gabaldón, Carmen

2015-01-01

426

Function of styrene-acrylic ester copolymer latex in cement mortar  

Microsoft Academic Search

This paper focuses on the effect of the styrene-acrylic ester copolymer (SAE) latex on the performance of cement mortar, through\\u000a studying on the water-reduction and water-retention effects of the SAE latex in the mortar, and the influence of the SAE latex\\u000a on the air-content and the bulk density of the fresh mortar and the bulk density, compressive and flexural strengths,

Ru Wang; Peiming Wang

2010-01-01

427

Styrene epoxidation catalysed by manganese(III) salen complex supported on activated carbons  

Microsoft Academic Search

The hydroxyl functionalised manganese(III) salen complex, bearing a large ? delocalisation, [Mn(4-HOsaldPh)Cl], was immobilised onto a commercial activated carbon and its air and acid oxidised forms using three different metal loadings. For all the materials the manganese contents were determined by ICP-AES and they were screened as heterogeneous catalysts in the epoxidation of styrene, using iodosylbenzene as oxygen source and

Mário Cardoso; Ana Rosa Silva; Baltazar de Castro; Cristina Freire

2005-01-01

428

Scattering of electrons by a 1,2-butadiene (C4H6) molecule: measurements and calculations  

NASA Astrophysics Data System (ADS)

We present the results of experimental and theoretical study on electron collisions with a 1,2-butadiene (H2C=C=CHCH3) molecule. Absolute grand-total cross sections (TCSs) were measured using a linear electron-transmission method for collision energies in the 0.5–300 eV range. Two distinct features in the TCS energy curve were detected: a narrow peak located at 2.3 eV and a broad enhancement centered around 9 eV. We attributed these features to the formation of negative-ion resonant states, based on comparisons with the existing data for other targets of similar structure. Experimental findings indicate a bonding effect on the TCS when confronting TCS curves for allenes with those for respective acetylenes. Clear differences in experimental TCS energy dependences for C4H6 isomers (1,2-butadiene, 1,3-butadiene, 1-butyne and 2-butyne) show on the isomeric effect. The independent atom approximation was employed to calculate the elastic (ECS) cross section from 25 to 3000 eV, while the binary-encounter-Bethe approach was used for computation of the ionization (ICS) cross section, from the threshold up to 3 keV. The sum of computed cross sections (ECS+ICS) quite reasonably reproduces the experimental TCS values above 35 eV. The reported TCS experimental values are not corrected for the forward-angle scattering effect.

Szmytkowski, Czes?aw; Mo?ejko, Pawe?; Zawadzki, Mateusz; Ptasi?ska-Denga, El?bieta

2015-01-01

429

Design and evaluation of a monolithic drug-in-adhesive patch for testosterone based on styrene-isoprene-styrene block copolymer.  

PubMed

The purpose of the present study was to design and evaluate a monolithic drug-in-adhesive patch with a novel pressure-sensitive adhesive (PSA) matrix based on styrene-isoprene-styrene (SIS) block copolymer. Testosterone was selected as the model drug. The orthogonal array design for ternary mixtures was employed to optimize the amounts of SIS, C-5 hydrocarbon resin, and liquid paraffin. The drug release percentage, water vapor permeability, adhesive properties were chosen as response variables. The patch formulation was optimized by investigating the effects of the drug loading capacity, the type, and amount of permeation enhancer on the adhesive properties and skin permeation. The compositions of the optimal matrix were: 120 g of SIS copolymer, 120 g of C-5 hydrocarbon resin, 60 g of liquid paraffin. An optimized formulation with maximum skin permeation and acceptable adhesive properties was developed incorporating 2% testosterone and 6% isopropyl myristate. No significant differences for in vitro release, skin permeation, and in vivo absorption were observed between the optimal formulation and Testopatch®. The stability evaluation showed that the patches were stable at 25°C/60% relative humidity for 6 months. The result indicated that SIS copolymer was a suitable and compatible polymer for the development of PSA. PMID:23650152

Ma, Jianfang; Wang, Chengxiao; Luo, Huafei; Zhu, Zhuangzhi; Wu, Yubo; Wang, Hao

2013-07-01

430

Evaluation of drug release profile from patches based on styrene-isoprene-styrene block copolymer: the effect of block structure and plasticizer.  

PubMed

We prepared pressure-sensitive adhesive (PSA) patches based on styrene-isoprene-styrene (SIS) thermoplastic elastomer using hot-melt coating method. The liquid paraffine is added in the PSA matrices as a plasticizer to moderate the PSA properties. Three drugs, methyl salicylate, capsaicin, and diphenhydramine hydrochloride are selected as model drugs. The Fourier transform infrared spectroscopy, differential scanning calorimetry test, and wide-angle X-ray diffraction test indicate a good compatibility between drugs and matrices. Peppas equation is used to describe drug release profile. Different drug-matrix absorption, as indicative of drug-matrix interaction, accounts for the variation in release profiles of different drugs. Furthermore, atomic force microscopy and rheological studies of the PSA samples are performed to investigate the effect of SIS structure and plasticizer of PSA on drug release behaviors. For methyl salicylate and capsaicin, drug diffusion in the PSA matrices is the main factor controlled by the release kinetic constant k. The high [SI] diblock content and high plasticizer amount in matrix provide the PSA with a homogeneous and soften microstructure, resulting in a high diffusion rate. But for water-soluble drugs such as diphenhydramine hydrochloride, the release rate is governed by water penetration with the competition from diffusion mechanisms. PMID:22476973

Wang, ChengXiao; Han, Wei; Tang, XiuZhen; Zhang, Hao

2012-06-01

431

Substituent effects on the kinetics of bifunctional styrene SAM formation on H-terminated Si.  

PubMed

Self-assembled monolayers (SAMs) on metal and semiconductor surfaces are of interest in electronic devices, molecular and biosensors, and nanostructured surface preparation. Bifunctionalized molecules, where one functional group attaches to the surface while the other remains free for further modification, allow for the rational design of multilayer chemisorbed thin films. In this study, substituted styrenes acted as a model system for SAM formation through an alkene moiety. Substituents ranging from activating to strongly deactivating for aromatic reactions were used to probe the effect of the electronic properties of functionalizing molecules on the rate of SAM formation. Substituted styrene SAMs were formed on hydrogen-terminated p-type Si(100) and n-type Si(111) via sonochemical functionalization. Monolayers were characterized via ellipsometry, IR spectroscopy, contact angle goniometry, and X-ray photoelectron spectroscopy (XPS). Initial rates of reaction for molecules that selectively attached through the alkene were further studied. A linear relationship was observed between the initial rates of surface functionalization and the substituent electron donating/withdrawing ability for the substituted styrenes, as described by their respective Hammett constants. This study provides precedent for applying well quantified homogeneous chemical reaction relationships to reactions at the solid-liquid interface. PMID:24911116

Frederick, Esther; Dickerson, Pearl N; Zhong, Yu Lin; Bernasek, Steven L

2014-07-01

432

Studies of electron-beam irradiation on ethylene-styrene interpolymers  

NASA Astrophysics Data System (ADS)

Electron-beam irradiation-induced structural and properties changes on ethylene-styrene interpolymers (ESI) have been studied at electron doses ranging from 0 to 200 kGy. The amounts of species generated by irradiation such as hydroxyls, hydroperoxides, carbonyls and unsaturated double bonds have been analyzed using ATR-FTIR. While the structural changes are minimal for ESI69 comprising 69 wt.% styrene regardless of the dose level, the changes for ESI40 comprising 40 wt.% styrene are dose dependent and reaches a maximum at a dose of 100 kGy. Gel permeation chromatography analysis indicates that macromolecular chain scission occurs at low irradiation dose and crosslinking dominates at high irradiation doses. The average molecular weights between crosslinks, MC's, have been calculated using the Flory-Rehner equation based on data collected from solvent extraction experiments. The MC's of ESI40 samples are much smaller than those of ESI69 samples. Irradiated ESI samples have higher glass transition temperatures as well as thermal decomposition temperatures. The electron-beam irradiation also causes an increase in the Young's modulus of ESI69 samples and a decrease in the elongation at break of ESI40 samples.

Liu, I.-C.; Tsiang, R. C.-C.

2002-12-01

433

Gold(I)-Catalyzed Cycloisomerizations and Alkoxycyclizations of ortho-(Alkynyl)styrenes.  

PubMed

Indenes and related polycyclic structures have been efficiently synthesized by gold(I)-catalyzed cycloisomerizations of appropriate ortho-(alkynyl)styrenes. Disubstitution at the terminal position of the olefin was demonstrated to be essential to obtain products originating from a formal 5-endo-dig cyclization. Interestingly, a complete switch in the selectivity of the cyclization of o-(alkynyl)-?-methylstyrenes from 6-endo to 5-endo was observed by adding an alcohol to the reaction media. This allowed the synthesis of interesting indenes bearing an all-carbon quaternary center at C1. Moreover, dihydrobenzo[a]fluorenes can be obtained from substrates bearing a secondary alkyl group at the ?-position of the styrene moiety by a tandem cycloisomerization/1,2-hydride migration process. In addition, diverse polycyclic compounds were obtained by an intramolecular gold-catalyzed alkoxycyclization of o-(alkynyl)styrenes bearing a nucleophile in their structure. Finally, the use of a chiral gold complex allowed access to elusive chiral 1H-indenes in good enantioselectivities. PMID:25557166

Sanjuán, Ana M; Rashid, Muhammad A; García-García, Patricia; Martínez-Cuezva, Alberto; Fernández-Rodríguez, Manuel A; Rodríguez, Félix; Sanz, Roberto

2015-02-01

434

Pyrolysis of polystyrene - polyphenylene oxide to recover styrene and useful products  

DOEpatents

A process of using fast pyrolysis in a carrier gas to convert a polystyrene and polyphenylene oxide plastic waste to a given polystyrene and polyphenylene oxide prior to pyrolysis of other plastic components therein comprising: selecting a first temperature range to cause pyrolysis of given polystyrene and polyphenylene oxide and its high value monomeric constituent prior to a temperature range that causes pyrolysis of other plastic components; selecting a catalyst and a support and treating the feed stream with the catalyst to affect acid or base catalyzed reaction pathways to maximize yield or enhance separation of high value monomeric constituent of styrene from polystyrene and polyphenylene oxide in the first temperature range; differentially heating the feed stream at a heat rate within the first temperature range to provide differential pyrolysis for selective recovery of the high value monomeric constituent of styrene from polystyrene and polyphenylene oxide prior to pyrolysis of other plastic components; separating the high value monomer constituent of styrene; selecting a second higher temperature range to cause pyrolysis to a different derived high value product of polyphenylene oxide from the plastic waste and differentially heating the feed stream at the higher temperature range to cause pyrolysis of the plastic into a polyphenylene oxide derived product; and separating the different derived high value polyphenylene oxide product.

Evans, Robert J. (Lakewood, CO); Chum, Helena L. (Arvada, CO)

1995-01-01

435

Polymerization of styrene in microemulsions and water-in-oil-in-water emulsions  

SciTech Connect

Two types of emulsion polymerization media were studied in the formation of polystyrene: two O/W microemulsions and a WOW emulsion. The microemulsions and isolated polystyrene were studied using photon correlation spectroscopy and time-averaged light scattering. GPC verified the polymer's size distribution and FTIR determined the polymer's end groups. Photomicroscopy was used to size the WOW emulsion droplets. The effect of an oil-soluble, azoisobisbutyronitrile (AIBN), versus water-soluble, potassium persulfate (KPS), free-radical generator in the polymerization of styrene in microemulsions was investigated. The microemulsions contained styrene, brine, sodium dodecyl sulfate (SDS), and pentanol. Under the dilute conditions the microemulsions and lattices were stable and the droplets independent of each other. Both AIBN and KPS produced polystyrene containing two different size fractions; the molecular weight of the two fractions were of the order of magnitude of 10{sup 5} and 10{sup 6}. End group analysis indicated that initiator fragments and alcohol fragments were present in the polystyrene. The WOW emulsions contained styrene, water, Tween 80, and Span 80. The multiple phase emulsion had a polydisperse droplet size distribution with globule diameters ranging from 1 {mu}m to 190 {mu}m. Both single and multiple phase globules were present in the emulsion due to < 100% yield. WOW emulsion polymerization was slower than microemulsion polymerization and the reaction never reached completion. The isolated polymer showed a wide size distribution with an average molecular weight of {approximately} 4.6 {times} 10{sup 5}.

Johnson, P.L.

1984-01-01

436

Adsorption of branched alkylbenzene sulfonate onto styrene and acrylic ester resins.  

PubMed

In this study, a series of acrylic ester resins were prepared and characterized. The adsorption behaviors of sodium 6-dodecyl benzenesulfonate (6-NaDBS) on styrene resin XAD-4 and acrylic ester resins have been studied. As compared to commercial acrylic ester resins Amberlite XAD-7 and Diaion HP2MG, YWB-38, one of the as-prepared resins, exhibits better adsorption properties toward 6-NaDBS. The experimental equilibrium data were fitted to the Langmuir and double-Langmuir models. The two models provide very good fit for all acrylic ester resins over the temperature range studied, whereas fitted results for styrene resin XAD-4 are less accurate. The investigation indicates that the adsorbate molecules are directly adsorbed on acrylic ester resins as a bi-layer, while the molecules are adsorbed on XAD-4 as monolayer formation followed by the establishment of bi-layer. Adsorption kinetics and elution processes were also investigated for further exploring the adsorption behavior and mechanism on styrene resin XAD-4 and YWB-38. PMID:16504247

Yang, Wei Ben; Li, Aimin; Fan, Jun; Yang, Licheng; Zhang, Quanxing

2006-08-01

437

Oxidative Stress Due to (R)Styrene Oxide Exposure and The Role of Antioxidants in Non-Swiss Albino (NSA) Mice  

Microsoft Academic Search

Styrene produces lung and liver damage that may be related to oxidative stress. The purpose of this study was to investigate the toxicity of (R)-styrene oxide (R-SO), the more active enantiomeric metabolite of styrene, and the protective properties of the antioxidants glutathione (GSH), N-acetylcysteine (NAC), and 4-methoxy-L-tyrosinyl-?-L-glutamyl-L-cysteinyl-glycine (UPF1) against R-SO-induced toxicity in non-Swiss Albino (NSA) mice. UPF1 is a synthetic

Anna Meszka-Jordan; Riina Mahlapuu; Ursel Soomets; Gary P. Carlson

2009-01-01

438

Borane and borohydride complexes of the rare-earth elements: synthesis, structures, and butadiene polymerization catalysis.  

PubMed

The reaction of potassium 2,5-bis[N-(2,6-diisopropylphenyl)iminomethyl]pyrrolyl [(dip(2)-pyr)K] with the borohydrides of the larger rare-earth metals, [Ln(BH(4))(3)(thf)(3)] (Ln=La, Nd), afforded the expected products [Ln(BH(4))(2)(dip(2)-pyr)(thf)(2)]. As usual, the trisborohydrides reacted like pseudohalide compounds forming KBH(4) as a by-product. To compare the reactivity with the analogous halides, the dimeric neodymium complex [NdCl(2)(dip(2)-pyr)(thf)](2) was prepared by reaction of [(dip(2)-pyr)K] with anhydrous NdCl(3). Reaction of [(dip(2)-pyr)K] with the borohydrides of the smaller rare-earth metals, [Sc(BH(4))(3)(thf)(2)] and [Lu(BH(4))(3)(thf)(3)], resulted in a redox reaction of the BH(4) (-) group with one of the Schiff base functions of the ligand. In the resulting products, [Ln(BH(4)){(dip)(dip-BH(3))-pyr}(thf)(2)] (Ln=Sc, Lu), a dinegatively charged ligand with a new amido function, a Schiff base, and the pyrrolyl function is bound to the metal atom. The by-product of the reaction of the BH(4) (-) anion with the Schiff base function (a BH(3) molecule) is trapped in a unique reaction mode in the coordination sphere of the metal complex. The BH(3) molecule coordinates in an eta(2) fashion to the metal atom. The rare-earth-metal atoms are surrounded by the eta(2)-coordinated BH(3) molecule, the eta(3)-coordinated BH(4) (-) anion, two THF molecules, and the nitrogen atoms from the Schiff base and the pyrrolyl function. All new compounds were characterized by single-crystal X-ray diffraction. Low-temperature X-ray diffraction data at 6 K were collected to locate the hydrogen atoms of [Lu(BH(4)){(dip)(dip-BH(3))-pyr}(thf)(2)]. The (DIP(2)-pyr)(-) borohydride and chloride complexes of neodymium, [Nd(BH(4))(2)(dip(2)-pyr)(thf)(2)] and [NdCl(2)(dip(2)-pyr)(thf)](2), were also used as Ziegler-Natta catalysts for the polymerization of 1,3-butadiene to yield poly(cis-1,4-butadiene). Very high activities and good cis selectivities were observed by using each of these complexes as a catalyst in the presence of various cocatalyst mixtures. PMID:20397155

Jenter, Jelena; Meyer, Nils; Roesky, Peter W; Thiele, Sven K-H; Eickerling, Georg; Scherer, Wolfgang

2010-05-10

439

Quantitative analysis of styrene monomer in polystyrene and foods including some preliminary studies of the uptake and pharmacodynamics of the monomer in rats.  

PubMed Central

A variety of food containers, drinking cups and cutlery, fabricated from polystyrene (PS) or polystyrene-related plastic, were analyzed for their styrene monomer content. Samples of yogurt, packaged in PS cups, were similarly analyzed and the leaching of styrene monomer from PS containers by some food simulants was also determined. Blood level studies with rats, dosed with styrene monomer by various routes, illustrated uptake phenomena that were dependent on the dose and route of administration and were also affected by the vehicle used to convey the styrene monomer. PMID:1026397

Withey, J R

1976-01-01

440

Viscoelastic Properties, Ionic Conductivity, and Materials Design Considerations for Poly(styrene-b-ethylene oxide-b-styrene)-Based Ion Gel Electrolytes  

SciTech Connect

The viscoelastic properties and ionic conductivity of ion gels based on the self-assembly of a poly(styrene-b-ethylene oxide-b-styrene) (SOS) triblock copolymer (M{sub n,S} = 3 kDa, M{sub n,O} = 35 kDa) in the ionic liquid 1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)amide ([EMI][TFSA]) were investigated over the composition range of 10-50 wt % SOS and the temperature range of 25-160 C. The poly(styrene) (PS) end-blocks associate into micelles, whereas the poly(ethylene oxide) (PEO) midblocks are well-solvated by this ionic liquid. The ion gel with 10 wt % SOS melts at 54 C, with the longest relaxation time exhibiting a similar temperature dependence to that of the viscosity of bulk PS. However, the actual values of the gel relaxation time are more than 4 orders of magnitude larger than the relaxation time of bulk PS. This is attributed to the thermodynamic penalty of pulling PS end-blocks through the PEO/[EMI][TFSA] matrix. Ion gels with 20-50 wt % SOS do not melt and show two plateaus in the storage modulus over the temperature and frequency ranges measured. The one at higher frequencies is that of an entangled network of PEO strands with PS cross-links; the modulus displays a quadratic dependence on polymer weight fraction and agrees with the prediction of linear viscoelastic theory assuming half of the PEO chains are elastically effective. The frequency that separates the two plateaus, {omega}{sub c}, reflects the time scale of PS end-block pull-out. The other plateau at lower frequencies is that of a congested micelle solution with PS cores and PEO coronas, which has a power law dependence on domain spacing similar to diblock melts. The ionic conductivity of the ion gels is compared to PEO homopolymer solutions at similar polymer concentrations; the conductivity is reduced by a factor of 2.1 or less, decreases with increasing PS volume fraction, and follows predictions based on a simple obstruction model. Our collective results allow the formulation of basic design considerations for optimizing the mechanical properties, thermal stability, and ionic conductivity of these gels.

Zhang, Sipei; Lee, Keun Hyung; Sun, Jingru; Frisbie, C. Daniel; Lodge, Timothy P. (UMM)

2013-03-07

441

Anisotropic optical functions of ?-1,4,4-tetraphenyl-1,3-butadiene  

NASA Astrophysics Data System (ADS)

One of the known monoclinic polymorphs of 1,1,4,4-tetraphenyl-1,3-butadiene was grown by the floating-drop technique. This material is of interest for blue emitting devices and for fundamental studies on intermolecular interactions, excited states and vibronic coupling in the fields of chemical physics and materials science. Polarized UV-visible spectra are reported. The origin of the optical bands is resolved. The results give information on the intermolecular interactions and are compared with theoretical predictions and modeling. The full material dielectric tensor is provided, as deduced from generalized spectroscopic ellipsometry. Details on the use of this technique on strongly anisotropic and absorbing molecular materials are given. Some typical features of the optical spectra are also demonstrated to be very sensitive to the presence of misaligned domains, which, in our samples, are found to be rotated around the normal to the surface and whose amount is determined. The method allows discriminating among monocrystals, in-plane polycrystalline samples, layered samples formed by misaligned successive layers, or samples with both types of disorder. Two independent parameters giving the fraction of misaligned domains or layers are suggested for the characterization and optimization of the growth and deposition of molecular organic materials.

Tavazzi, Silvia; Mora, Stefano; Alessandrini, Laura; Silvestri, Leonardo

2011-01-01

442

The effect of distribution of monomer moiety on the pH response and mechanical properties of poly(acrylonitrile-co-acrylic acid) copolymers  

NASA Astrophysics Data System (ADS)

The pH response and mechanical properties of copolymer-based hydrogels such as poly(acrylonitrile-co-acrylic acid) are usually attributed to their chemical composition. In this study, it has been shown that the architecture of the polymer chains, i.e. the distribution of comonomers in the macromolecules, also plays a major role in controlling these properties. A series of four poly(acrylonitrile-co-acrylic acids) with fixed composition (i.e. ~30 mol% acrylic acid moieties) were synthesized, where the block lengths of both AN (acrylonitrile) and AAc (acrylic acid) moieties in the copolymers were varied by controlling the feeding pattern of the monomers during free radical copolymerization. These copolymers were then converted into fine fibers of the same dimensions. The monomer distribution in the four copolymers was estimated using quantitative carbon 13C nuclear magnetic resonance (NMR) and related to the mechanical and pH response properties of the resultant fibers. The pH response of the fibers with similar composition increased dramatically as the block length of the AAc moiety was increased, while the mechanical properties increased as a direct function of the block length of the AN moieties. The fiber's response at pH 10 in terms of the change in length increased by ~four times while its response rate increased by ~50 times with the increase in block length of the AAc moiety. On the other hand, the tensile properties and retractive stress increased by ~four times with the increase in the block length of the AN moiety.

Sahoo, Anasuya; Jassal, Manjeet; Agrawal, Ashwini K.

2010-02-01

443

Vapor-liquid equilibria for copolymer+solvent systems: Effect of intramolecular repulsion  

SciTech Connect

Role of intramolecular interactions in blend miscibility is well documented for polymer+copolymer mixtures. Some copolymer+polymer mixtures are miscible although their corresponding homopolymers are not miscible; for example, over a range of acrylonitrile content, styrene/acrylonitrile copolymers are miscible with poly(methyl methacrylate) but neither polystyrene nor polyacrylonitrile is miscible with poly(methyl methacrylate). Similarly, over a composition range, butadiene/acrylonitrile copolymers are miscible with poly(vinyl chloride) while none of the binary combinations of the homopolymers [polybutadiene, polyacrylonitrile, and poly(vinyl chloride)] are miscible. This behavior has been attributed to ``intramolecular repulsion`` between unlike copolymer segments. We have observed similar behavior in vapor-liquid equilibria (VLE) of copolymer+solvent systems. We find that acrylonitrile/butadiene copolymers have higher affinity for acetonitrile solvent than do polyacrylonitrile or polybutadiene. We attribute this non-intuitive behavior to ``intramolecular repulsion`` between unlike segments of the copolymer. This repulsive interaction is weakened when acetonitrile molecules are in the vicinity of unlike copolymer segments, favoring copolymer+solvent miscibility. We find similar behavior when acetonitrile is replaced by methyl ethyl ketone. To best knowledge, this effect has not been reported previously for VLE. We have obtained VLE data for mixtures containing a solvent and a copolymer as a function of copolymer composition. It appears that, at a given solvent partial pressure, there may be copolymer composition that yields maximum absorption of the solvent. This highly non-ideal VLE phase behavior may be useful for optimum design of a membrane for a separation process.

Gupta, R.B.; Prausnitz, J.M.

1995-03-01

444

Nanoclustered palladium(0) supported on a gel-type poly-acrylonitrile– N, N-dimethylacrylamide–ethylenedimethacrylate resin: Nanostructural aspects and catalytic behaviour  

Microsoft Academic Search

Gel-type resin poly-acrylonitrile (30mol%)–N,N-dimethylacrylamide (66mol%)–ethylenedimethacrylate (4mol%) (ADE) is obtained in very high yield with ?-rays-sustained polymerisation in mass. Water-swollen ADE microparticles react readily with [PdCl42?] in water to give a macromolecular complex likely to be . The material undergoes facile reduction to a Pd0\\/ADE nanocomposite, in which a surprisingly non-homogeneous distribution of Pd0 nanoclusters suggests a remarkable inhomogeneity in the

L. De Zan; D. Gasparovicova; M. Kralik; P. Centomo; M. Carraro; S. Campestrini; K. Jerabek; B. Corain

2007-01-01

445

Study of poly(acrylonitrile-methyl methacrylate) as binder for graphite anode and LiMn 2O 4 cathode of Li-ion batteries  

Microsoft Academic Search

We evaluated poly(acrylonitrile-methyl methacrylate) (AMMA, AN\\/MMA=94:6) as a binder for the graphite anode and the LiMn2O4 cathode of Li-ion batteries by studying the cycling performance of lithium half-cells. The results showed that, using AMMA binder, both graphite and LiMn2O4 could be cycled well in 1m LiPF6 3:3:4 (weight) PC\\/EC\\/EMC electrolyte with less capacity fading. AMMA is chemically more stable than

S. S Zhang; T. R Jow

2002-01-01

446

Perturbations and Vibrational Energies in Acrylonitrile from Global Analysis of its Mm-Wave to Thz Rotational Spectrum  

NASA Astrophysics Data System (ADS)

The rotational spectrum of acrylonitrile has recently been studied in some detail up to THz frequencies. The perturbation between the ground state and v11=1 that was initially identified in the parent^a has also been observed in other isotopologues.^b The considerable energy difference between these states (228.29991(2) cm-1 in the parent) was, in all cases, determined entirely from perturbations in rotational transitions. Many other perturbations in rotational transitions have been identified, allowing the v15=1 level to be added to the analysis. We have now extended the broadband coverage of the rotational spectrum even further, and have been able to add the fourth vibrational state, v11=2, to the global analysis. The current coupled fit encompasses well over 12000 transition frequencies and delivers precise vibrational energy information entirely on the basis of many fitted perturbations in rotational transitions. The present work was used to further refine the features for identifying perturbations built into the AABS package for Assignment and Analysis of Broadband Spectra. Z.Kisiel, L.Pszcz??kowski, B.J.Drouin, C.S.Brauer, S.Yu, J.C.Pearson, J. Mol. Spectrosc., 258, 26 (2009). A. Krasnicki, Z.Kisiel, B.J.Drouin, J.C.Pearson, J. Mol. Struct., 1006, 20 (2011). Z.Kisiel et al., MH09, 66th OSU International Symposium on Molecular Spectroscopy (2011) Z.Kisiel, L.Pszczó?kowski, I.R.Medvedev, M.Winewisser, F.C.De Lucia, E.Herbst, J. Mol. Spectrosc., 233, 231 (2005).

Kisiel, Zbigniew; Pszczo?kowski, Lech; Drouin, Brian J.; Brauer, Carolyn S.; Yu, Shanshan; Pearson, John C.; Medvedev, Ivan R.; Fortman, Sarah; Neese, Christopher

2012-06-01

447

Solvent effect on post-irradiation grafting of styrene onto poly(ethylene-alt-tetrafluoroethylene) (ETFE) films  

NASA Astrophysics Data System (ADS)

Radiation-induced grafting of styrene onto ETFE films in different solvent was investigated after simultaneous irradiation (in post-irradiation condition) using a 60Co source. Grafting of styrene followed by sulfonation onto poly(ethylene-alt-tetrafluoroethylene) (ETFE) are currently studied for synthesis of ion exchange membranes. The ETFE films were immersed in styrene/toluene, styrene/methanol and styrene/isopropyl alcohol and irradiated at 20 and 100 kGy doses at room temperature. The post-irradiation time was established at 14 day and the grafting degree was evaluated. The grafted films were sulfonated using chlorosulfonic acid and 1,2-dichloroethane 20:80 (v/v) at room temperature for 5 h. The degree of grafting (DOG) was determined gravimetrically and physical or chemical changes were evaluated by differential scanning calorimeter analysis (DSC), thermogravimetric analysis (TGA) and scanning electron microscopy (SEM). The ion exchange capacity (IEC) values showed the best performance of sulfonation for ETFE membranes grafted in toluene solvent. Surface images of the grafted films by SEM technique have presented a strong effect of the solvents on the films morphology.

Napoleão Geraldes, Adriana; Augusto Zen, Heloísa; Ribeiro, Geise; Fernandes Parra, Duclerc; Benévolo Lugão, Ademar

2013-03-01

448

Adsorption of ethoxylated styrene oxide and polyacrylic acid and mixtures there of on organic pigment.  

PubMed

The adsorption of two polymeric surfactants on an organic pigment was investigated. As surfactants the anionic polyacrylic acid sodium salt (PANa, M(W)=15,000) and a non-ionic block copolymer surfactant based on styrene oxide (SO) and ethylene oxide (EO) (M(W)=1500) were used. The adsorption behavior was analyzed by size exclusion chromatography of the supernatant after centrifugation of the pigment dispersions. It was found that PANa has no affinity to the pigment, whereas SO-EO has a strong affinity to the pigment surface. Competitive adsorption of PANa and SO-EO was not observed. Addition of SO-EO yields stable dispersions. PMID:18771776

Wijting, W K; Laven, J; van Benthem, R A T M; de With, G

2008-11-01

449

Positronium Formation Of Glyeisdyl Methacrylic Acid (GMA)/Styrene Grafted On PVDF Membrane For Fuel Cells  

NASA Astrophysics Data System (ADS)

Simultaneous gamma irradiation was used effectively for grafting of glycidyl methacrylic acid and styrene onto Poly vinyldine fluoride (PVDF). Membranes were characterized by thermal gravimetric analysis (TGA) and scanning electron microscopy (SEM). The properties of the obtained membranes were evaluated in terms of proton conductivity, methanol permeability and positron annihilation lifetime (PALS) parameters. The high probability of Positronium formation enables the application of PALS to the study of free volume. Good property values approved the applicability of the membrane from the cost benefit point of view.

Abdel-Hady, E. E.; Eltonny, M. M.; Abdel-Hamed, M. O.

2011-06-01

450

Exposure-excretion relationship of styrene and acetone in factory workers: A comparison of a lipophilic solvent and a hydrophilic solvent  

Microsoft Academic Search

A factory survey was conducted in the second half of a working week on 41 exposed male workers, who were engaged in fiber-reinforced plastics work and exposed to the mixed vapors of styrene and acetone. Nonexposed workers, 20 men, were recruited from the same factory. Styrene and acetone in respiratory zone air were monitored for a 8-h shift with carbon

Kazunori Mizunuma; Tomojiro Yasugi; Toshio Kawai; Shun'ichi Horiguchi; Masayuki Ikeda

1993-01-01

451

Effect of preparation method and CuO promotion in the conversion of ethanol into 1,3-butadiene over SiO?-MgO catalysts.  

PubMed

Silica-magnesia (Si/Mg=1:1) catalysts were studied in the one-pot conversion of ethanol to butadiene. The catalyst synthesis method was found to greatly influence morphology and performance, with materials prepared through wet-kneading performing best both in terms of ethanol conversion and butadiene yield. Detailed characterization of the catalysts synthesized through co-precipitation or wet-kneading allowed correlation of activity and selectivity with morphology, textural properties, crystallinity, and acidity/basicity. The higher yields achieved with the wet-kneaded catalysts were attributed to a morphology consisting of SiO2 spheres embedded in a thin layer of MgO. The particle size of the SiO2 catalysts also influenced performance, with catalysts with smaller SiO2 spheres showing higher activity. Temperature-programmed desorption (TPD) measurements showed that best butadiene yields were obtained with SiO2-MgO catalysts characterized by an intermediate amount of acidic and basic sites. A Hammett indicator study showed the catalysts' pK(a) value to be inversely correlated with the amount of dehydration by-products formed. Butadiene yields could be further improved by the addition of 1?wt% of CuO as promoter to give butadiene yields and selectivities as high as 40% and 53%, respectively. The copper promoter boosts the production of the acetaldehyde intermediate changing the rate-determining step of the process. TEM-energy-dispersive X-ray (EDX) analyses showed CuO to be present on both the SiO2 and MgO components. UV/Vis spectra of promoted catalysts in turn pointed at the presence of cluster-like CuO species, which are proposed to be responsible for the increased butadiene production. PMID:25045112

Angelici, Carlo; Velthoen, Marjolein E Z; Weckhuysen, Bert M; Bruijnincx, Pieter C A

2014-09-01

452

Products of the gas-phase reactions of 1,3-butadiene with OH and NO{sub 3} radicals  

SciTech Connect

1,3-Butadiene is emitted into the atmosphere from a number of sources including combustion sources and is listed in the US as a hazardous air pollutant. In the atmosphere, 1,3-butadiene reacts with OH radicals, NO{sub 3} radicals, and O{sub 3} with the dominant tropospheric removal processes being daytime reaction with the OH radical and nighttime reaction with the NO{sub 3} radical. The authors have used gas chromatography, in situ Fourier transform infrared (FT-IR) absorption spectroscopy, and in situ atmospheric pressure ionization tandem mass spectrometry (API-MS) to identify and quantify the products formed from the reactions of 1,3-butadiene with OH radicals (in the presence of NO) and NO{sub 3} radicals. Acrolein, formaldehyde, and furan were identified and quantified from the OH radical-initiated reaction, with formation yields of 0.58 {+-} 0.04, 0.62 {+-} 0.05, and 0.03--0.04, respectively. Organic nitrates were observed by FT-IR spectroscopy with an estimated yield of 0.07 {+-} 0.03, and the API-MS analyses indicated that these organic nitrates are mainly the hydroxynitrate HOCH{sub 2}CH=CHCH{sub 2}ONO{sub 2} and/or its isomers. API-MS analyses showed the formation of a hydroxycarbonyl with the formula C{sub 4}H{sub 6}O{sub 2}, attributed to HOCH{sub 2}CH=CHCHO and/or its isomers. The major products of the NO{sub 3} radical-initiated reaction were organic nitrates; the API-MS analyses indicated the formation of acrolein, 1,2-epoxy-3-butene, and unsaturated C{sub 4}-hydroxycarbonyls, hydroxynitrates, carbonyl nitrates, and nitrooxyhydroperoxides. Acrolein, HCHO, and furan were again quantified by gas chromatographic and FT-IR analyses. The data is compared with previous literature studies, and detailed reaction mechanisms are presented and discussed.

Tuazon, E.C.; Alvarado, A.; Aschmann, S.M.; Atkinson, R.; Arey, J.

1999-10-15

453

Human physiologic factors in respiratory uptake of 1,3-butadiene.  

PubMed Central

1,3-Butadiene (BD), a suspected human carcinogen, is used as the raw material in industries to make synthetic butyl rubber and plastics. Simulation models using experimental animal data have shown that physiologic factors play an important role in the kinetic behavior of BD. However, human data are limited. The aim of this inhalation study was to identify influential human physiologic factors in the respiratory uptake of BD. We recruited 133 healthy volunteers in Boston, Massachusetts, into this study and tested them under an approved human subjects protocol. Each subject was exposed to 2 ppm (4.42 mg/m3) BD for 20 min, followed by purified air for another 40 min. Five exhaled breath samples collected during exposure were used to determine the respiratory uptake of BD, which was defined as absorbed BD (micrograms) per kilogram of body weight during exposure. Although subjects were given identical administered doses (40 ppm x min), there was a wide range of uptake, 0.6-4.9 microg/kg. Of the studied physiologic factors, the blood:air partition coefficient and alveolar ventilation were most significant in determining the respiratory uptake (p < 0.001 for each). In addition, in the multiple regression analysis, females had significantly higher respiratory uptake of BD than males on a weight basis. For all subjects, increasing age and cigarette smoking led to significantly decreased respiratory uptake of BD. The results of this human study are consistent with previous kinetic simulations and animal studies. The findings also suggest that interindividual variation in human physiologic factors that affect the exposure-internal dose relationship should be considered while also exploring exposure-disease associations in future epidemiologic research. PMID:11673121

Lin, Y S; Smith, T J; Kelsey, K T; Wypij, D

2001-01-01

454

Evaluation of frequencies of HPRT mutant lymphocytes in butadiene polymer workers in a Southeast Texas facility  

PubMed Central

We examined the frequency of mutant lymphocytes (VFs) in workers (n = 30) occupationally exposed to the petrochemical, 1,3-butadiene (BD), using the autoradiographic HPRT mutant lymphocyte assay. Current exposures were determined with organic vapor monitors that had a 12-hour method detection limit (MDL) of 2.5 parts per billion (ppb). HPRT VFs were analyzed with respect to current exposure estimates, age in years, and occupational longevity (OL; defined as years working in the BD industry at this facility). Current exposures were low (mean 93.5 ppb, median 2.5 ppb) with only one individual's estimate (1,683.5 ppb) exceeding the Occupational Safety and Health Administration's permissible exposure limit of 1,000 ppb. The majority (>50%) of current exposures were below the MDL. HPRT VFs were not significantly associated with current exposures (n = 29), and they were not significantly associated with age (n = 29). HPRT VFs were, however, significantly associated with OL (n = 29, R2 = 0.107, p < 0.046). This result suggests that chronic and/or past, high-level exposures might leave a mutagenic signature that is revealed by the HPRT assay, possibly through the retention of mutant, long-term memory T-cells. While it is encouraging that current occupational exposures to BD in this facility do not appear to be increasing the frequency of mutant T-lymphocytes, evidence from workers with a lengthy history in the industry (?30 years in this case) indicates that these individuals likely require additional biomonitoring for possible mutagenic effects resulting from chronic, past exposures. PMID:19107895

Wickliffe, Jeffrey K.; Ammenheuser, Marinel M.; Adler, P. Jene; Abdel-Rahman, Sherif Z.; Ward, Jonathan B.

2009-01-01

455

Membrane catalysts for partial hydrogenation of 1,3-butadiene: catalytic properties of palladium nanoclusters synthesized within diblock copolymer films  

Microsoft Academic Search

Palladium nanoclusters were synthesized within microphase-separated diblock copolymer films of [MTD]113[Pd(CpN)PA]50 (MTD=methyltetracyclododecene, CpN=endo-2-(cyclopentadienylmethyl)norborn-5-ene, PA=?3-1-phenylallyl). The organometallic repeat units were reduced by exposing the films to hydrogen at 100°C, leading to the formation of nearly monodisperse palladium nanoclusters. TEM was used to measure the cluster size. The nanocomposite films were active and selective catalysts for the gas phase hydrogenation of 1,3-butadiene.

Jane F Ciebien; Robert E Cohen; Alejandra Duran

1999-01-01

456

Dynamics of Radical Cation of Poly(styrene acrylate)-Based Chemically Amplified Resist for Extreme Ultraviolet and Electron Beam Lithography  

NASA Astrophysics Data System (ADS)

The dependence of the degree of copolymerization on the dynamics of radical cations of resist polymers was studied. The dynamics of radical cations was investigated in a chemically amplified resist polymer system. In this study, poly(styrene-ran-methyl methacrylate) [P(S-MMA)] was used as the base polymer of the resist model compound. It is suggested that radical cations of MMA are predominantly decomposed to be deprotonated immediately before the hole transfer to the styrene unit in P(S-MMA) at a lower styrene mole fraction (<50%). However, the acid yield of the P(S-MMA) decreases to that of PS with increasing styrene mole fraction (>70%). It is thus suggested that the hole transfer from the MMA to the multiple styrene units (n > 3) occurs in P(S-MMA).

Tajima, Yasuharu; Okamoto, Kazumasa; Kozawa, Takahiro; Tagawa, Seiichi; Fujiyoshi, Ryoko; Sumiyoshi, Takashi

2011-06-01

457

Regional distribution of styrene analogues generated from polystyrene degradation along the coastlines of the North-East Pacific Ocean and Hawaii.  

PubMed

Beach sand and seawater taken from the coastlines of the North-East Pacific Ocean and Hawaii State were investigated to determine the causes of global chemical contamination from polystyrene (PS). All samples were found to contain styrene monomer (SM), styrene dimers (SD), and styrene trimers (ST) with a concentration distribution of styrene analogues in the order of ST > SD > SM. The contamination by styrene analogues along the West Coast proved more severe than in Alaska and other regions. The Western Coastlines of the USA seem be affected by both land- and ocean-based pollution sources, which might result from it being a heavily populated area as the data suggest a possible proportional relationship between PS pollution and population. Our results suggest the presence of new global chemical contaminants derived from PS in the ocean, and along coasts. PMID:24553245

Kwon, Bum Gun; Saido, Katsuhiko; Koizumi, Koshiro; Sato, Hideto; Ogawa, Naoto; Chung, Seon-Yong; Kusui, Takashi; Kodera, Yoichi; Kogure, Kazuhio

2014-05-01

458

Linear viscoelasticity of sulfonated styrene oligomers near the sol-gel transition  

NASA Astrophysics Data System (ADS)

Linear viscoelastic complex modulus (reported by Weiss and Zhao, 2009) of three ionomers, obtained through random sulfonation of oligomeric styrene at low ionic contents, p = 2.5, 4.8, and 6.5mol%, were analyzed using mean-field gelation theory with the fraction of repeat units that are sulfonated the effective extent of reaction p. Oligomeric styrene with low M = 4000 g/mol, having N = 38 repeat units, ensures absence of entanglement effects. The dynamics change in a complicated way with ion content p because the gel point p c = 1/( N-1) = 2.7 mol%. For ionomers having p = 2.5 mol%, the system is below but quite close to the gel point. The terminal relaxation is governed by the effective breakup of large clusters into subclusters of comparable sizes, as anticipated by Rubinstein and Semenov. The samples with p = 4.8 mol% and 6.5 mol%, are beyond the gel point and exhibit properties of reversible gels.

Chen, Quan; Colby, Ralph H.

2014-08-01

459

Conversion Characteristics and Production Evaluation of Styrene/o-Xylene Mixtures Removed by DBD Pretreatment.  

PubMed

The combination of chemical oxidation methods with biotechnology to removal recalcitrant VOCs is a promising technology. In this paper, the aim was to identify the role of key process parameters and biodegradability of the degradation products using a dielectric barrier discharge (DBD) reactor, which provided the fundamental data to evaluate the possibilities of the combined system. Effects of various technologic parameters like initial concentration of mixtures, residence time and relative humidity on the decomposition and the degradation products were examined and discussed. It was found that the removal efficiency of mixed VOCs decreased with increasing initial concentration. The removal efficiency reached the maximum value as relative humidity was approximately 40%-60%. Increasing the residence time resulted in increasing the removal efficiency and the order of destruction efficiency of VOCs followed the order styrene > o-xylene. Compared with the single compounds, the removal efficiency of styrene and o-xylene in the mixtures of VOCs decreased significantly and o-xylene decreased more rapidly. The degradation products were analyzed by gas chromatography and gas chromatography-mass spectrometry, and the main compounds detected were O3, COx and benzene ring derivatives. The biodegradability of mixed VOCs was improved and the products had positive effect on biomass during plasma application, and furthermore typical results indicated that the biodegradability and biotoxicity of gaseous pollutant were quite depending on the specific input energy (SIE). PMID:25629961

Jiang, Liying; Zhu, Runye; Mao, Yubo; Chen, Jianmeng; Zhang, Liang

2015-01-01

460

Study on radiation-induced grafting of styrene onto chitin and chitosan  

NASA Astrophysics Data System (ADS)

Radiation-induced grafting of styrene onto chitin and chitosan powder was performed at room temperature. The effect of various conditions such as absorbed dose, solvent and oxygen on grafting was investigated. The grafting yield increased with the increase in absorbed dose. At the same dose, the grafting yield of styrene on chitosan was higher than that on chitin. The grafting reaction was promoted in the presence of methanol, and oxygen delayed the grafting reaction but did not inhibit it completely. In order to study the mechanism of grafting reaction and analyze the grafted samples, the grafted products were extracted first by benzene, then they were hydrolyzed in the presence of acid and separated by thin layer chromatography (TLC). Three different kinds of polystyrene (PS), i.e. PS grafted onto chitin, PS embedded in chitin and PS in grafting solution were gained. The variation of their molecular weight (MW) and width index of molecular weight distribution ( Mw/ Mn) determined by gel permeation chromatography (GPC) at different grafting conditions is discussed.

Pengfei, Liu; Maolin, Zhai; Jilan, Wu

2001-05-01

461

Mechanical Properties of Composites Based on Low Styrene Emission Polyester Resins for Marine Applications  

NASA Astrophysics Data System (ADS)

Glass fibre reinforced polyester composites are used extensively for hulls and decks of pleasure boats. Boat-builders must optimise manufacturing technology, not only with respect to mechanical properties but also limiting volatile organic compounds (VOC) emissions. One way to achieve this is through modified polyester resin formulations such as low styrene content, low styrene emission or combinations of these. The resin matrix selection procedure is based on design specification (mechanical behaviour) but also manufacturing requirements and cost considerations. For this application post-cure is rarely used so it is important to optimise curing conditions. In this study the influence of the curing cycle on mechanical properties was examined first for two polyester resins. Then for one cycle (16 h at 40°C) the properties of eight resins have been determined. Significant differences in failure strain are observed, from 0.9% to 3.3%. The resins with improved VOC performance are the most brittle. The transverse tensile behaviour of these resins in composites with unidirectional glass fibre reinforcement and the limit of linearity for composites with glass mat both depend on these failure strains. These results are discussed in terms of admissible composite strains for boat design.

Baley, Christophe; Perrot, Y.; Davies, Peter; Bourmaud, A.; Grohens, Yves

2006-01-01

462

Phase Behavior of Hydrogenated Derivatives of Linear ABC Block-Random Copolymers of Styrene and Isoprene  

NASA Astrophysics Data System (ADS)

The capacity to synthesize block-random copolymers, block copolymers with one or more random copolymer blocks, allows for continuous tuning of the inter-block average segmental interaction parameter, ?, through the composition of the random copolymer without changes to system chemistry. By lithium-initiated anionic polymerization in a mixture of cyclohexane and triethylamine, we synthesized an asymmetric near-monodisperse linear ABC block-random copolymer of styrene and isoprene: S30-I12-SrI12, where SrI denotes a random copolymer block with 50 wt. % styrene, and block molecular weights are 30-12-12 kg/mol. Upon complete hydrogenation, the VCH-hI-VCHrhI triblock exhibits microphase separation into a well-ordered two-domain lamellar structure with an order-disorder transition between 180-185 C via small-angle x-ray scattering. This two-domain lamellar structure is confirmed using electron density modeling of the SAXS peak intensity and domain spacing arguments. A three-domain lamellar structure is expected in the diene-selective hydrogenated derivative, S-hI-SrhI, due to increased ? between the middle and end blocks. Additional S-I-SrI and S-SrI-I triblock copolymers are being synthesized and the effects of block sequence, end block molecular weight, and hydrogenation (S vs. VCH) on phase behavior are being explored.

Beckingham, Bryan; Register, Richard

2012-02-01

463

Simple and efficient immobilization of lipase B from Candida antarctica on porous styrene-divinylbenzene beads.  

PubMed

Two commercial porous styrene-divinylbenzene beads (Diaion HP20LX and MCI GEL CHP20P) have been evaluated as supports to immobilize lipase B from Candida antarctica (CALB). MCI GEL CHP20P rapidly immobilized the enzyme, permitting a very high loading capacity: around 110mgCALB/wetg of support compared to the 50mg obtained using decaoctyl Sepabeads. Although enzyme specificity of the enzyme immobilized on different supports was quite altered by the support used in the immobilization, specific activity of the enzyme immobilized on MCI GEL CHP20P was always higher than those found using decaoctyl Sepabeads for all assayed substrates. Thus, a CALB biocatalyst having 3-8 folds (depending on the substrate) higher activity/wet gram of support than the commercial Novozym 435 was obtained. Half-live of CAL-Diaion HP20LX at 60°C was 2-3 higher than the one of Novozym 435, it was 30-40 higher in the presence of 50% acetonitrile and it was around 100 folds greater in the presence of 10M hydrogen peroxide. Results indicate that styrene-divinylbenzene supports may be promising alternatives as supports to immobilize CALB. PMID:22112274

Hernandez, Karel; Garcia-Galan, Cristina; Fernandez-Lafuente, Roberto

2011-06-10

464

Photoionization studies of internally reactive small clusters: Van der Waals complexes of 1,3-butadiene with sulfur dioxide  

SciTech Connect

Efficiency functions for ions from the title complexes were measured using a photoionization mass spectrometer in which a molecular beam of target complexes, formed by a skimmed and recollimated free jet expansion of 1,3-butadiene + SO{sub 2}, was made to intersect a tunable VUV beam from Brookhaven's 750-MeV electron storage ring. The dissociation energies at 0 K of 1,3-C{sub 4}H{sub 6}{center dot}SO{sub 2} and (1,3-C{sub 4}H{sub 6}{center dot}SO{sub 2}){sup +} were measured to be 3.24 {plus minus} 0.48 and 3.00 {plus minus} 0.68 kcal mol{sup {minus}1}, respectively. For 3-sulfolene, the condensation product, the ionization potential was measured to be 10.073 {plus minus} 0.006 eV, while the appearance potential of its fragment C{sub 4}H{sub 6}{sup +} is 10.076 {plus minus} 0.029 eV, the same within the experimental uncertainty. However, the sulfolene parent ion is unstable with respect to disintegration into butadiene ion and sulfur dioxide by 0.38 {plus minus} 0.03 eV.

Grover, J.R.; Walters, E.A.; Newman, J.K.; White, M.G. (Brookhaven National Lab., Upton, NY (USA))

1990-08-29

465

Low-temperature 1 3-butadiene Hydrogenation over Supported Pt/3d/gamma-Al2O3 Bimetallic Catalysts  

SciTech Connect

Low-temperature 1,3-butadiene hydrogenation is used as a probe reaction to investigate the hydrogenation activity over several {gamma}-Al{sub 2}O{sub 3} supported Pt/3d (3d = Co, Ni, Cu) bimetallic catalysts. Batch and flow reactor studies are employed to quantify the kinetic activity and steady-state conversion, respectively, of each catalyst. Transmission electron microscopy (TEM) is utilized to characterize particle sizes and extended X-ray absorption fine structure (EXAFS) measurements are performed to verify the Pt-3d bimetallic bond formation. Pulse carbon monoxide chemisorption measurements are also performed to characterize the number of active sites. Additionally, density functional theory (DFT) calculations are included to determine the binding energies of 1,3-butadiene and atomic hydrogen on the corresponding model surfaces. The binding energies of the adsorbates are found to correlate with the hydrogenation activity, allowing for use of such correlation to potentially predict hydrogenation catalysts with enhanced activity based on the binding energies of the adsorbates of interest.

W Lonergan; X Xing; R Zheng; S Qi; B Huang; J Chen

2011-12-31

466

Steady-State Performance of an Activated Carbon Biofilter Degrading Styrene: Effects of Residence Time and Inlet Concentration  

Microsoft Academic Search

A granular-activated-carbon-packed biofilter receiving a constant loading rate of styrene was subjected to changes in residence time and concentration, and the effects on performance characteristics and the composition of biofilm along the bed height in the biofilter were studied. This study was carried out during the last 3 months of the entire biofilter operation of 16 months. The total bed

Jan Paca; Martin Halecky; Mark Fitch; Thomas Spencer; Daniel Carder; Mridul Gautam; Nigel Clark; Thomas Balon; Paul Moynihan; Meng Yao; Qiong Zhang; David Hand; David Perram; Roy Taylor; Joshua Fu; David Streets; Carey Jang; Jiming Hao; Kebin He; Litao Wang; Qiang Zhang; David Williams; William Potter; William Clarkson; Dee Sanders; John Stevens; Hazem El-Zanan; Barbara Zielinska; Lynn Mazzoleni; D. Hansen; Hyun-Sun Kim; Seung-Muk Yi; Eric Edgerton; Gary Casuccio; Rick Saylor; Traci Lersch; Benjamin Hartsell; John Jansen; Roger Wayson; Gregg Fleming; Ralph Iovinelli; Hans Grimm; Delbert Eatough

2009-01-01

467

21 CFR 177.1635 - Poly(p-methylstyrene) and rubber-modified poly(p-methyl-styrene).  

...2014-04-01 2014-04-01 false Poly(p-methylstyrene) and rubber-modified poly(p-methyl-styrene). 177.1635 Section 177...Use Food Contact Surfaces § 177.1635 Poly(p-methylstyrene) and rubber-modified...

2014-04-01

468

21 CFR 177.1635 - Poly(p-methylstyrene) and rubber-modified poly(p-methyl-styrene).  

Code of Federal Regulations, 2011 CFR

...2011-04-01 2011-04-01 false Poly(p-methylstyrene) and rubber-modified poly(p-methyl-styrene). 177.1635 Section 177...Use Food Contact Surfaces § 177.1635 Poly(p-methylstyrene) and rubber-modified...

2011-04-01

469

21 CFR 177.1635 - Poly(p-methylstyrene) and rubber-modified poly(p-methyl-styrene).  

Code of Federal Regulations, 2010 CFR

...2010-04-01 2009-04-01 true Poly(p-methylstyrene) and rubber-modified poly(p-methyl-styrene). 177.1635 Section 177...Use Food Contact Surfaces § 177.1635 Poly(p-methylstyrene) and rubber-modified...

2010-04-01

470

21 CFR 177.1635 - Poly(p-methylstyrene) and rubber-modified poly(p-methyl-styrene).  

Code of Federal Regulations, 2013 CFR

...2013-04-01 2013-04-01 false Poly(p-methylstyrene) and rubber-modified poly(p-methyl-styrene). 177.1635 Section 177...Use Food Contact Surfaces § 177.1635 Poly(p-methylstyrene) and rubber-modified...

2013-04-01

471

21 CFR 177.1635 - Poly(p-methylstyrene) and rubber-modified poly(p-methyl-styrene).  

Code of Federal Regulations, 2012 CFR

...2012-04-01 2012-04-01 false Poly(p-methylstyrene) and rubber-modified poly(p-methyl-styrene). 177.1635 Section 177...Use Food Contact Surfaces § 177.1635 Poly(p-methylstyrene) and rubber-modified...

2012-04-01

472

Preparation and drug-loading properties of Fe3O4/Poly(styrene-co-acrylic acid) magnetic polymer nanocomposites  

NASA Astrophysics Data System (ADS)

Fe3O4/poly(styrene-co-acrylic acid) magnetic polymer nanocomposites were synthesized by the dispersion polymerization method using styrene as hard monomer, acrylic acid as functional monomer, Fe3O4 nanoparticles modified with oleic acid as core, and poly(styrene-co-acrylic acid) as shell. Drug-loading properties of magnetic polymer nanocomposites with curcumin as a model drug were also studied. The results indicated that magnetic polymer nanocomposites with monodisperse were obtained, the particle size distribution was 50-120 nm, and the average size was about 100 nm. The contents of poly(styrene-co-acrylic acid) and Fe3O4 nanoparticles in magnetic polymer nanocomposites were 74? and 24.7?, respectively. The drug-loading capacity and entrapment efficiency were 2.5% and 44.4%, respectively. The saturation magnetization of magnetic polymer nanocomposites at 300 K was 20.2 emu/g without coercivity and remanence. The as-prepared magnetic polymer nanocomposites have not only lots of functional carboxyl groups but also stronger magnetic response, which might have potential applications in drug carrier and targeted drug release.

Lu, Wensheng; Shen, Yuhua; Xie, Anjian; Zhang, Weiqiang

2013-11-01

473

EVALUATION OF POLLUTION PREVENTION OPTIONS TO REDUCE STYRENE EMISSIONS FROM FIBER-REINFORCED PLASTIC OPEN MOLDING PROCESSES  

EPA Science Inventory

Pollution prevention (P2) options to reduce styrene emissions, such as new materials, and application equipment, are commercially available to the operators of open molding processes. However, information is lacking on the emissions reduction that these options can achieve. To me...

474

Porous graphene-based material as an efficient metal free catalyst for the oxidative dehydrogenation of ethylbenzene to styrene.  

PubMed

Reduced porous graphene oxide as a metal free catalyst was selected for the oxidative dehydrogenation of ethylbenzene to styrene. It showed the best catalytic performance compared with other carbon materials (routinely reduced graphene oxide, graphite powder and oxidized carbon nanotubes) and commercial iron oxide. PMID:25625943

Diao, Jiangyong; Liu, Hongyang; Wang, Jia; Feng, Zhenbao; Chen, Tong; Miao, Changxi; Yang, Weimin; Su, Dang Sheng

2015-02-10

475

[The use of biological monitoring in the assessment of occupational exposure to styrene in fiberglass-reinforced plastics industry].  

PubMed

A field study was carried out in order to investigate the effect of occupational exposure to styrene on the urinary excretion of mandelic and phenylglyoxylic acids (MA and PGA). Over a period of three years, 210 periodical, prophylactic examinations were performed on 66 fiberglass-reinforced plastics workers. The examinations embraced environmental and biological monitoring, which involved the measurement of styrene concentration in the air and the excretion rate of urinary MA and PGA. An eight-hour time-weighed average (MAC) exposure values ranged from 16.1 to 246 mg/m3 (mean: 76.1 mg/m3). The average urinary excretion rates of MA and PGA were 17.7 (1-202) and 28.8 (2-267) mg/h, respectively. The measurements of MA excretion rate were compared with the measurements of styrene concentration in the air. It seems advisable to investigate whether the recommended biological limits value of 16 mg/h for mandelic acid is not too high in view of the binding OEL value of 50 mg/m3 for styrene. PMID:9919603

Brygiert, H; Adamski, J; Buszewski, B

1998-01-01

476

A nanodiamond/CNT-SiC monolith as a novel metal free catalyst for ethylbenzene direct dehydrogenation to styrene.  

PubMed

A novel nanodiamond/CNT-SiC monolith catalyst has been prepared by a facile two-step approach. The as-synthesized monolith afforded high activity and stability for ethylbenzene direct dehydrogenation to styrene, showing its potential application as a metal free catalyst in gaseous catalytic reactions. PMID:24905905

Liu, Hongyang; Diao, Jiangyong; Wang, Qi; Gu, Songyuan; Chen, Tong; Miao, Changxi; Yang, Weimin; Su, Dangsheng

2014-07-25

477

EFFECT OF OXYGEN ADDITION ON POLYCYCLIC AROMATIC HYDROCARBON FORMATION IN 1,3 BUTADIENE COUNTER-FLOW DIFFUSION FLAMES. (R828193)  

EPA Science Inventory

The effect of 3% O2 addition to the fuel on detailed chemical structure of a 1,3 butadiene counter-flow diffusion flame has been investigated by using heated microprobe sampling and online gas chromatography mass spectrometry. Centerline gas temperature and species ...

478

Mesoscopic TiO2/CH3NH3PbI3 perovskite solar cells with new hole-transporting materials containing butadiene derivatives.  

PubMed

Two new triphenylamine-based hole-transporting materials (HTMs) containing butadiene derivatives are employed in CH3NH3PbI3 perovskite solar cells. Up to 11.63% of power conversion efficiency (PCE) has been achieved. Advantages such as easy synthesis, low cost and relatively good cell performance exhibit a possibility for commercial applications in the future. PMID:24841233

Lv, Songtao; Han, Liying; Xiao, Junyan; Zhu, Lifeng; Shi, Jiangjian; Wei, Huiyun; Xu, Yuzhuan; Dong, Juan; Xu, Xin; Li, Dongmei; Wang, Shirong; Luo, Yanhong; Meng, Qingbo; Li, Xianggao

2014-07-01

479

Effect of aluminum oxide on the properties of Cu-Mo catalyst in the oxidative dehydrogenation of butene-1 to butadiene  

Microsoft Academic Search

Copper molybdate catalysts show catalytic activity for the oxidative dehydrogenation of butene-1, giving butadiene and carbon dioxide as main products, but not for its isomerization to butene-2. The isomerization reaction is catalysed at the centers of acidic nature; thus, aluminum oxide and aluminum molybdate catalysts having such acidic properties may be active catalysts for the conversion of butene-1 to butene-2.

P. N. Tiwari; T. G. Alkhazov; K. U. Adzamov; A. K. Khanmamedova

1989-01-01

480

Morphology control and 2D self-assembly of poly(styrene-co-divinylbenzene) capsules.  

PubMed

In this paper, monodisperse poly(styrene-co-divinylbenzene) (PS-DVB) capsules with a bowl-like morphology were prepared controllably by regulating the content of DVB and dispersant. Using as-prepared PS-DVB capsules as building blocks, two-dimensional (2D) uniform hexagonal close-packed array with same orientation of each bowl was successfully fabricated by solvent evaporation. The size distribution showed that the capsules were still spherical in acetone before assembly and thus certified that the capsules caved in after self-assembly. Many factors including DVB content in capsules, experimental temperature and dispersants play important roles on regularity of orientation. Besides, "local self-assembly" array using multi-caved capsule as building blocks was obtained. More study proceeds with it, further advanced materials with complex functionalities or peculiar behavior could be expected. PMID:21463865

Yang, Qiuyan; Chen, Jiafu; Wang, Libin; Xu, Qun; He, Linghao

2011-06-15

481

Carbon nanotubes and carbon onions for modification of styrene-acrylate copolymer based nanocomposites  

NASA Astrophysics Data System (ADS)

Styrene acrylate polymer (SAC) nanocomposites with various carbon nanofillers (multiwalled carbon nanotubes MWCNTs and onion like carbon OLC) are manufactured by means of latex based routes. Concentration of the carbon nanofillers is changed in a broad interval starting from 0.01 up to 10 wt. %. Elastic, dielectric and electromagnetic properties of SAC nanocomposites are investigated. Elastic modulus, electrical conductivity and electromagnetic radiation absorption of the investigated SAC nanocomposites increase along with rising nanofiller content. The effect of the addition of anisometric MWCNTs on the elastic properties of the composite is higher than in the case of the addition of OLC. Higher electrical conductivity of the OLC containing nanocomposites is explained with the fact that reasonable agglomeration of the nanofiller can promote the development of electrically conductive network. Efficiency of the absorption of electromagnetic radiation depends on the development of conductive network within the SAC matrix.

Merijs-Meri, Remo; Zicans, Janis; Ivanova, Tatjana; Bitenieks, Juris; Kuzhir, Polina; Maksimenko, Sergey; Kuznetsov, Vladimir; Moseenkov, Sergey

2014-05-01

482