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1

Solid-State Microcellular Acrylonitrile-Butadiene-Styrene Foams Solid-StateMicrocellular  

E-print Network

Solid-State Microcellular Acrylonitrile-Butadiene-Styrene Foams Solid-StateMicrocellular Acrylonitrile-Butadiene-Styrene Foams Ross E. Murray, John E. Weller and Vipin Kumar* Department of Mechanical. INTRODUCTION ABS (Acrylonitrile-butadiene-styrene)has grown to become one of the most widely used thermoplastic

Kumar, Vipin

2

Mechanical behavior of acrylonitrile butadiene styrene fused deposition materials modeling  

Microsoft Academic Search

Analytical\\/Computational models for the fused deposition (FD) material stiffness and strength as a function of mesostructural parameters are developed. Effective elastic moduli are obtained using the strength of materials approach and an elasticity approach based on the asymptotic theory of homogenization. Theoretical predictions for unidirectional FD-acrylonitrile butadiene styrene materials are validated with experimentally determined values of moduli and strength. For

José F. Rodríguez; James P. Thomas; John E. Renaud

2003-01-01

3

Curing Characteristics and Mechanical and Morphological Properties of Styrene Butadiene Rubber\\/Virgin Acrylonitrile-Butadiene Rubber (SBR\\/vNBR) and Styrene Butadiene Rubber\\/Recycled Acrylonitrile-Butadiene Rubber (SBR\\/rNBR) Blends  

Microsoft Academic Search

Curing characteristics and mechanical and morphological properties of styrene butadiene rubber\\/virgin acrylonitrile-butadiene rubber (SBR\\/vNBR) and styrene butadiene rubber\\/recycled acrylonitrile-butadiene rubber (SBR\\/rNBR) were investigated. Results indicated that the curing characteristics, such as scorch time, t2, and cure time, t90, of SBR\\/vNBR and SBR\\/rNBR blends decreased with increasing vNBR and rNBR content. At similar blend ratios, particularly up to 15 phr, SBR\\/rNBR blends

N. Z. Noriman; H. Ismail; Azura Rashid

2008-01-01

4

Characterization of styrene butadiene rubber\\/recycled acrylonitrile-butadiene rubber (SBR\\/NBRr) blends: The effects of epoxidized natural rubber (ENR50) as a compatibilizer  

Microsoft Academic Search

The effects of epoxidized natural rubber (ENR-50) as a compatibilizer on the properties of styrene butadiene rubber\\/recycled acrylonitrile-butadiene rubber (SBR\\/NBRr) blends were studied. Styrene butadiene rubber\\/recycled acrylonitrile-butadiene rubber (SBR\\/NBRr) blends were prepared by two-roll mill with five different compositions (i.e., 85\\/5\\/10, 75\\/15\\/10, 65\\/25\\/10, 55\\/35\\/10 and 40\\/50\\/10), with the ENR-50 content fixed at 10 phr. Cure characteristics, mechanical properties, FTIR analysis, differential

N. Z. Noriman; H. Ismail; A. A. Rashid

2010-01-01

5

Natural Weathering Test of Styrene Butadiene Rubber and Recycled Acrylonitrile Butadiene Rubber (SBR\\/NBRr) Blends  

Microsoft Academic Search

The effect of recycled acrylonitrile butadiene rubber (NBRr) content of SBR\\/NBRr blends on natural weathering was studied. Three different size of NBRr (S1; 117–334 µm, S2; 0.85–15.0 mm and S3; direct sheeted form) were used and the blends were exposed to natural weathering for 3 and 6 months. The results indicated that the SBR\\/NBRr blends with smallest size of NBRr (S1) show

N. Z. Noriman; H. Ismail; A. A. Rashid

2010-01-01

6

Fire retardancy mechanisms of arylphosphates in polycarbonate (PC) and PC\\/acrylonitrile-butadiene-styrene  

Microsoft Academic Search

The pyrolysis of polycarbonate (PC) and PC\\/acrylonitrile-butadiene-styrene (PC\\/ABS) with and without arylphosphates (triphenylphosphate\\u000a TPP, resorcinol-bis(diphenyl phosphate) RDP and bisphenol A bis(diphenyl phosphate) BDP) is investigated by thermal analysis\\u000a as key to understanding the flame retardancy mechanisms and corresponding structure–property relationships. The correspondence\\u000a between the decomposition temperature range of arylphosphates and PC is pointed out as prerequisite for the occurrence of

Birgit Perret; Kristin H. Pawlowski; Bernhard Schartel

2009-01-01

7

The effects of electron beam irradiation on the thermal properties, fatigue life and natural weathering of styrene butadiene rubber\\/recycled acrylonitrile–butadiene rubber blends  

Microsoft Academic Search

The effects of electron beam (EB) irradiation on the thermal properties, fatigue life and natural weathering of styrene butadiene rubber\\/recycled acrylonitrile–butadiene rubber (SBR\\/NBRr) blends were investigated. The SBR\\/NBRr blends were prepared at 95\\/5, 85\\/15, 75\\/25, 65\\/35, or 50\\/50 blend ratios with and without the presence of a 3part per hundred rubber (phr) of polyfunctional monomer, trimethylolpropane triacrylate (TMPTA). Results indicate

N. Z. Noriman; H. Ismail

2011-01-01

8

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.

9

Effect of reactive compatibilization on the morphology and physical properties of bisphenol-A-polycarbonate/acrylonitrile-butadiene-styrene blends  

NASA Astrophysics Data System (ADS)

An amine functional styrene-acrylonitrile (SAN-amine) polymer is proposed as a reactive compatibilizer for bisphenol-A-polycarbonate/acrylonitrile-butadiene-styrene (PC/ABS) blends. This polymer is miscible with the styrene/acrylonitrile (SAN) copolymer matrix of ABS materials, and the pendant secondary amine groups react with PC at the carbonate linkage to form a SAN-g-PC copolymer. The graft copolymer molecules reside at the PC/ABS interface and provide improved morphological stability at elevated temperatures by suppressing phase coalescence. The synthesis of this reactive compatibilizer and its reaction with carbonate moieties is described. Characterization of this reaction was done by NMR and GPC using model secondary amine and carbonate containing compounds. A technique was developed for the quantitative measurement of the kinetics of dispersed phase particle coalescence in these blends; the morphology was examined using TEM. While uncompatibilized PC/SAN blends showed an increase in particle size from approximately 1 mum to 2 mum (depending on PC viscosity) in less than five minutes at 270sp°C; compatibilized blends containing as little as 1% SAN-amine exhibited no change in morphology after 20 minutes. The effects of dispersed phase concentration, viscosity ratio and interfacial compatibilization using the SAN-amine compatibilizer on the process induced morphology of PC/SAN blends were also examined. Dispersed phase particle size increased significantly with SAN concentration and, although the morphology of uncompatibilized PC/SAN blends mixed in a Brabender mixer, single and twin screw extruders were quite similar, the twin screw extruder produced significantly finer morphologies in blends containing SAN-amine. The average particle size for blends compatibilized with the SAN-amine polymer was approximately half that of uncompatibilized blends and was relatively independent of viscosity ratio and dispersed phase composition. The fracture of thin (3.18 mm) and thick (6.35 mm) specimens of PC, ABS and PC/ABS blends with both standard and sharp notches was examined by standard Izod and single edge notch three point bend (SEN3PB) instrumented drop tower tests. Load-deflection data were analyzed as a function of ligament length and fracture parameters were calculated using the theoretical framework of the essential work of fracture concept. The effects of blend composition, temperature, rubber concentration and reactive compatibilization on the fracture properties of these materials were examined.

Wildes, Gregg Stephen

1998-11-01

10

SISTER CHROMATID EXCHANGE AND CHROMOSOME ABERRATION ANALYSES IN MICE AFTER IN VIVO EXPOSURE TO ACRYLONITRILE, STYRENE, OR BUTADIENE MONOXIDE  

EPA Science Inventory

The use of polymers in plastic and rubber products has generated concern that monomers potentially active in biological systems may be eluted from these substances. The authors have evaluated two such monomers, acrylonitrile and styrene, for the induction of chromosome damage in ...

11

Bacterial colonization and endotoxin content of a new renal dialysis water system composed of acrylonitrile butadiene styrene.  

PubMed Central

We measured endotoxin and bacterial levels in tap water, in water purified by reverse osmosis, and in dialysate samples over a 4-month period in a new 10-bed renal dialysis unit. Water treated by reverse osmosis is conducted to the 10 stations through 111 m of piping composed of acrylonitrile butadiene styrene (ABS). All determinations were made prior to the opening of the unit and after the system was purged for 35 h with all bedside station taps open. Formaldehyde disinfection of the piping system was attempted with a recommended protocol after 11 weeks by feeding 2.5 liters of 37% formaldehyde (0.85%, vol/vol) into the delivery system. Prior to water purging, 24 ng of endotoxin per ml was detected. This level decreased to 2.0 ng of endotoxin after the purging. Levels of endotoxin remained below 1.0 ng of endotoxin per ml throughout the duration of the study. In contrast, the level of viable microorganisms recovered from the treated water was approximately 3.5 X 10(4) CFU/100 ml. Even after disinfection of the system, there was no significant decrease in culturable bacteria from the water even though endotoxin levels were lower. Species isolated from the renal dialysis system were predominately pseudomonads, whereas species isolated from the tap water were Bacillus and Flavobacterium species. ABS provides a surface suitable for long-term colonization and growth of bacteria. Currently recommended decontamination protocols are ineffective in removing potentially pathogenic bacteria from ABS pipes and thus constitute an increased risk to patients undergoing dialysis. Images PMID:3606109

du Moulin, G C; Coleman, E C; Hedley-Whyte, J

1987-01-01

12

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

...federal_regulations/ibr_locations.html. (c) Specifications. (1) Nitrogen...federal_regulations/ibr_locations.html. (3) Residual acrylonitrile monomer...federal_regulations/ibr_locations.html. (d) Extractives limitations....

2014-04-01

13

21 CFR 181.32 - Acrylonitrile copolymers and resins.  

Code of Federal Regulations, 2010 CFR

... (i) Acrylonitrile/butadiene/styrene copolymers—no restrictions. (ii...oleomargarine. (iv) Acrylonitrile/styrene copolymer—no restrictions. (2...copolymer or acrylonitrile/butadiene styrene copolymer mixed with neoprene,...

2010-04-01

14

21 CFR 181.32 - Acrylonitrile copolymers and resins.  

... (i) Acrylonitrile/butadiene/styrene copolymers—no restrictions. (ii...oleomargarine. (iv) Acrylonitrile/styrene copolymer—no restrictions. (2...copolymer or acrylonitrile/butadiene styrene copolymer mixed with neoprene,...

2014-04-01

15

21 CFR 181.32 - Acrylonitrile copolymers and resins.  

Code of Federal Regulations, 2013 CFR

... (i) Acrylonitrile/butadiene/styrene copolymers—no restrictions. (ii...oleomargarine. (iv) Acrylonitrile/styrene copolymer—no restrictions. (2...copolymer or acrylonitrile/butadiene styrene copolymer mixed with neoprene,...

2013-04-01

16

21 CFR 181.32 - Acrylonitrile copolymers and resins.  

Code of Federal Regulations, 2012 CFR

... (i) Acrylonitrile/butadiene/styrene copolymers—no restrictions. (ii...oleomargarine. (iv) Acrylonitrile/styrene copolymer—no restrictions. (2...copolymer or acrylonitrile/butadiene styrene copolymer mixed with neoprene,...

2012-04-01

17

21 CFR 181.32 - Acrylonitrile copolymers and resins.  

Code of Federal Regulations, 2011 CFR

... (i) Acrylonitrile/butadiene/styrene copolymers—no restrictions. (ii...oleomargarine. (iv) Acrylonitrile/styrene copolymer—no restrictions. (2...copolymer or acrylonitrile/butadiene styrene copolymer mixed with neoprene,...

2011-04-01

18

Co-recycling of acrylonitrile-butadiene-styrene waste plastic and nonmetal particles from waste printed circuit boards to manufacture reproduction composites.  

PubMed

This study investigated the feasibility of using acrylonitrile-butadiene-styrene (ABS) waste plastic and nonmetal particles from waste printed circuit boards (WPCB) to manufacture reproduction composites (RC), with the aim of co-recycling these two waste resources. The composites were prepared in a twin-crew extruder and investigated by means of mechanical testing, in situ flexural observation, thermogravimatric analysis, and dimensional stability evaluation. The results showed that the presence of nonmetal particles significantly improved the mechanical properties and the physical performance of the RC. A loading of 30 wt% nonmetal particles could achieve a flexural strength of 72.6 MPa, a flexural modulus of 3.57 GPa, and an impact strength of 15.5 kJ/m(2). Moreover, it was found that the application of maleic anhydride-grafted ABS as compatilizer could effectively promote the interfacial adhesion between the ABS plastic and the nonmetal particles. This research provides a novel method to reuse waste ABS and WPCB nonmetals for manufacturing high value-added product, which represents a promising way for waste recycling and resolving the environmental problem. PMID:25413110

Sun, Zhixing; Shen, Zhigang; Zhang, Xiaojing; Ma, Shulin

2015-01-01

19

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

20

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

21

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

22

Radiation effects on styrene butadiene styrene copolymer  

NASA Astrophysics Data System (ADS)

Styrene-butadiene-styrene copolymer (SBS) of different configuration and block ratio were irradiated by 60Co ?-rays at 20 °C and 120 °C. The gel fraction and thermal properties before and after irradiation were discussed. The gel fraction increased with both absorbed doses and temperature. This means higher crosslinking efficiency was obtained at higher temperature. The radiation chemical yields were calculated according to the Charlesby-Pinner equation. The DSC analysis indicated that the crosslinking had taken place in the polybutadiene (PB) block while the chain scission of polystyrene (PS) block was dominant when irradiated at elevated temperature.

Zhang, Yan; Zhao, Sufang; Li, Yintao; Xie, Leidong; Sheng, Kanglong

2008-08-01

23

Laser transmission welding of Acrylonitrile-Butadiene-Styrene (ABS) using a tailored high power diode-laser optical fiber coupled system  

NASA Astrophysics Data System (ADS)

Laser transmission welding (LTW) of polymers is a direct bonding technique which is already used in different industrial applications sectors such as automobile, microfluidic, electronic and biomedicine. This technique offers several advantages over conventional methods, especially when a local deposition of energy and minimum thermal distortions are required. In LTW one of the polymeric materials needs to be transparent to the laser wavelength and the second part needs to be designed to be absorbed in IR spectrum. This report presents a study of laser weldability of ABS (acrylonitrile/butadiene/styrene) filled with two different concentrations of carbon nanotubes (0.01% and 0.05% CNTs). These additives are used as infrared absorbing components in the laser welding process, affecting the thermal and optical properties of the material and, hence, the final quality of the weld seam. A tailored laser system has been designed to obtain high quality weld seams with widths between 0.4 and 1.0mm. It consists of two diode laser bars (50W per bar) coupled into an optical fiber using a non-imaging solution: equalization of the beam quality factor (M2) in the slow and fast axes by a pair of micro step-mirrors. The beam quality factor has been analyzed at different laser powers with the aim to guarantee a coupling efficiency to the multimode optical fiber. The power scaling is carried out by means of multiplexing polarization technique. The analysis of energy balance and beam quality is performed in two linked steps: first by means ray tracing simulations (ZEMAX®) and second, by validation. Quality of the weld seams is analyzed in terms of the process parameters (welding speed, laser power and clamping pressure) by visual and optical microscope inspections. The optimum laser power range for three different welding speeds is determinate meanwhile the clamping pressure is held constant. Additionally, the corresponding mechanical shear tests were carried out to analyze the mechanical properties of the weld seams. This work provides a detailed study concerning the effect of the material microstructure and laser beam quality on the final weld formation and surface integrity.

Rodríguez-Vidal, E.; Quintana, I.; Etxarri, J.; Otaduy, D.; González, F.; Moreno, F.

2012-06-01

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

Rheological characterization of styrene-butadiene-styrene copolymer modified bitumens  

Microsoft Academic Search

The rheological properties of styrene-butadiene-styrene copolymer (SBS) modified bitumens were studied. The modified binders were prepared using a laboratory mixer. Five types of bitumen from four sources were mixed with two SBS polymers at different polymer content levels. The rheological properties of the modified binders were characterized using dynamic mechanical analysis over wide ranges of temperatures and frequencies. It was

X. Lu; U. Isacsson

1997-01-01

26

Elastomeric nanofibers of styrene-butadiene-styrene triblock copolymer  

Microsoft Academic Search

Nanofibers of a commercial styrene- butadiene-styrene triblock copolymer were electrospun from solution, and collected either as a nonwoven elastomeric fabric, or on a layer of graphite that was evaporated onto a glass microscope slide. The resulting nanofibers were elastic, birefringent, and most had diameters around 100 nm. A few thin, beaded fibers were found among the smooth nanofibers. The diameter

Hao Fong; Darrell H. Reneker

1999-01-01

27

Rheological properties of styrene butadiene styrene polymer modified road bitumens  

Microsoft Academic Search

The use of polymers for the modification of bitumen in road paving applications has been growing rapidly over the last decade as government authorities and paving contractors seek to improve road life in the face of increased traffic. Currently, the most commonly used polymer for bitumen modification is the elastomer styrene butadiene styrene (SBS) followed by other polymers such as

Gordon D. Airey

2003-01-01

28

Three-dimensional study of cylindrical morphology in a styrene-butadiene-styrene  

E-print Network

Three-dimensional study of cylindrical morphology in a styrene-butadiene-styrene block copolymer electron microscopy (TEM), we have obtained projections ofa styrene-butadiene-styrene (SBS)copolymer (30wt component. Figure 1, for example, depicts for a styrene (S)-butadiene (B) triblock copolymer either

Agard, David

29

21 CFR 177.1020 - Acrylonitrile/butadiene/sty-rene co-polymer.  

Code of Federal Regulations, 2011 CFR

...Acrylonitrile/butadiene/sty-rene co-polymer. 177.1020 Section 177.1020 ...CONTINUED) INDIRECT FOOD ADDITIVES: POLYMERS Substances for Use as Basic Components...Acrylonitrile/butadiene/sty-rene co-polymer....

2011-04-01

30

21 CFR 177.1020 - Acrylonitrile/butadiene/sty-rene co-polymer.  

Code of Federal Regulations, 2010 CFR

...Acrylonitrile/butadiene/sty-rene co-polymer. 177.1020 Section 177.1020 ...CONTINUED) INDIRECT FOOD ADDITIVES: POLYMERS Substances for Use as Basic Components...Acrylonitrile/butadiene/sty-rene co-polymer....

2010-04-01

31

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

32

Macromolecules 1983, 16, 39-45 39 Entangled Chain Structure Trapped in a Styrene-Butadiene  

E-print Network

Macromolecules 1983, 16, 39-45 39 Entangled Chain Structure Trapped in a Styrene-Butadiene Random prepared by cross-linkinglinear styrene-butadiene random copolymer (67%styrene content)with y on a different polymer, a styrene-butadiene random copolymer with a styrene content of 67%. T

Granick, Steve

33

Comparison of Properties of Polypropylene (PP)\\/Virgin Acrylonitrile Butadiene Rubber (NBRv) and Polypropylene (PP)\\/Recycled Acrylonitrile Butadiene Rubber (NBRr) Blends  

Microsoft Academic Search

The comparison properties of polypropylene (PP)\\/recycled acrylonitrile butadiene rubber (NBRr) blends and polypropylene\\/virgin acrylonitrile butadiene rubber (NBRv) blends were investigated. The tensile properties such as tensile strength, tensile modulus and elongation at break of PP\\/NBRv blends are higher than PP\\/NBRr blends. However, PP\\/NBRv blends exhibit lower stabilization torque and higher swelling percentage than PP\\/NBRr blends. Based on SEM, a finer

H. Ismail; D. Galpaya; Z. Ahmad

2009-01-01

34

Degradation and stabilisation of styrene–ethylene–butadiene–styrene (SEBS) block copolymer  

Microsoft Academic Search

The degradation of hydrogenated poly[styrene-b-butadiene-b-styrene] or poly[styrene-b-(ethylene-co-butylene)-b-styrene], (SEBS) has been studied using a variety of analytical and spectroscopic methods including thermal analysis, UV, luminescence and FTIR spectroscopy coupled with crosslinking and hydroperoxide analysis in order to understand the nature of the processes involved. High temperature oxidation of non-commercial unstabilised material results in chain scission and severe crosslinking giving rise to

Norman S Allen; Michele Edge; Arthur Wilkinson; Cristopher M Liauw; Despina Mourelatou; Juan Barrio; Maria A Mart??nez-Zaporta

2000-01-01

35

Micromechanical modeling of the linear viscoelasticity of carbon-black filled styrene butadiene rubbers: the role  

E-print Network

Micromechanical modeling of the linear viscoelasticity of carbon-black filled styrene butadiene Micromechanics modeling of the linear viscoelasticity of carbon-black filled styrene butadiene rubbers (SBR styrene butadiene rubbers (L´eopold`es et al., 2004). According to Berriot et al.

Paris-Sud XI, Université de

36

Preparation and Characterization of Two Types of Cyanate Ester-epoxy Resin Interpenetrating Network Matrix\\/Butadiene-acrylonitrile Rubber Composites  

Microsoft Academic Search

Two types of butadiene-acrylonitrile rubbers (i.e., carboxyl randomized butadiene-acrylonitrile rubber (CRBN) and hydroxyl terminated butadiene-acrylonitrile rubber (HTBN)) have been used for modifying an interpenetrating network of cyanate ester (CE)\\/epoxy resin (EP) (70\\/30). The toughness of the matrix can be improved effectively with addition of rubbers. The values of impact strength (11.6 KJ\\/m) show a maximum for the CE\\/EP\\/HTBN (70\\/30\\/8) blend.

Zeng Minfeng; Lu Cuiyun; Qi Chenze

2010-01-01

37

Alder ene functionalization of polyisobutene oligomer and styrene-butadiene-styrene triblock copolymer  

Microsoft Academic Search

The Alder ene functionalization reaction of double bonds containing macromolecules such as polyisobutene oligomer (PIB) and a styrene-butadiene-styrene triblock copolymer (SBS) samples with maleic anhydride (MAH) or diethyl maleate (DEM) as enophiles is described. The analysis of the products by means of different techniques assesses the addition of the polar molecules to the reactive vinylidene units of the polymer with

Andrea Pucci; Chiara Barsocchi; Riccardo Rausa; Luigi D'Elia; Francesco Ciardelli

2005-01-01

38

DYNAMIC MODELLING OF LIVING ANIONIC SOLUTION POLYMERIZATION OF STYRENE/BUTADIENE/DIVINYLBENZENE  

E-print Network

DYNAMIC MODELLING OF LIVING ANIONIC SOLUTION POLYMERIZATION OF STYRENE model for the living anionic solution polymerization of styrene/butadiene/divinylbenzene in a continuous kinetic reactor model for the living anionic solution polymerization of styrene

Schittkowski, Klaus

39

The Utilization of Waste Latex Products in Styrene-Butadiene Rubber  

Microsoft Academic Search

Waste latex products are converted to a processable material by a novel economical process developed in our laboratory . It contains rubber hydro- carbonof very high quality and Is lightly cross-linked . Styrene-butadiene rubber is mixed with latex reclaim In different proportions . The mechanical properties are found to be improved up to 60 percent replacement of styrene-butadiene rubber by

Reena Susan George; Rani Joseph

1996-01-01

40

Voltage-assisted asperity formation in styrene butadiene at room temperature: Cross-linking at the nanoscale  

E-print Network

Voltage-assisted asperity formation in styrene butadiene at room temperature: Cross 5 August 2008 Nanoscale surface modification is reported for styrene butadiene rubber using of physi- cal factors, in this work we have selected styrene butadiene rubber SBR . SBR is a widely used

Paramonov, Pavel B.

41

The effects of using lime and styrene–butadiene–styrene on moisture sensitivity resistance of hot mix asphalt  

Microsoft Academic Search

This study focuses on determining the effects of styrene–butadiene–styrene (SBS) and using mineral filler with lime on various properties of hot mix asphalt especially moisture damage resistance. The asphalt cement was modified with 2%, 4% and 6% SBS. The lime treated mixtures containing 2% lime by weight of the total aggregate as filler. The physical and mechanical properties of polymer

Baha Vural Kok; Mehmet Yilmaz

2009-01-01

42

Disposition of styrene-acrylonitrile (SAN) trimer in female rats: Single dose intravenous and gavage studies  

Microsoft Academic Search

Styrene-acrylonitrile trimer (SAN Trimer), a mixture of six isomers (four isomers of 4-cyano-1,2,3,4-tetrahydro-alpha-methyl-1-naphthaleneacetonitrile [THAN] and two isomers of 4-cyano-1,2,3,4-tetrahydro-1-naphthaleneproprionitrile [THNP]), is a by-product of a specific production process of styrene-acrylonitrile polymer. Disposition studies in female rats were conducted to evaluate the pharmacokinetic behavior of [3H]SAN Trimer following a single intravenous administration (26mg\\/kg) to nonpregnant rats; a single gavage administration (nominal

Michael L. Gargas; Brad Collins; Timothy R. Fennell; Norman F. Gaudette; Lisa M. Sweeney

2008-01-01

43

Durability of styrene-butadiene latex modified concrete  

SciTech Connect

The durability of reinforced concrete structures represents a major concern to many investigators. The use of latex modified concrete (LMC) in construction has urged researchers to review and investigate its different properties. This study is part of a comprehensive investigation carried on the use of polymers in concrete. The main objective of this study to investigate and evaluate the main durability aspects of Styrene-Butadiene latex modified concrete (LMC) compared to those of conventional concrete. Also, the main microstructural characteristics of LMC were studied using a Scanning Electron Microscope (SEM). The SEM investigation of the LMC showed major differences in its microstructure compared to that of the conventional concrete. The LMC proved to be superior in its durability compared to the durability of conventional concrete especially its water tightness (measured by water penetration, absorption, and sorptivity tests), abrasion, corrosion, and sulphate resistance.

Shaker, F.A.; El-Dieb, A.S.; Reda, M.M. [Ain Shams Univ., Cairo (Egypt). Dept. of Structural Engineering] [Ain Shams Univ., Cairo (Egypt). Dept. of Structural Engineering

1997-05-01

44

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

E-print Network

test was conducted (all dimensions are in mm) ......................................97 46 The CBT1 and CBT2 specimen configurations...................................................98 47 The TERCO Twist and Bend testing machine used to conduct... of the part which is then translated into a file format usable by the manufacturing soft- ware which plans the machining operations to be performed to fabricate the part. A nu- merically controlled machine then manufactures the part based on the output...

Mamadapur, Monish Shivappa

2009-05-15

45

Non-isothermal kinetics of styrene—butadiene—styrene asphalt combustion  

NASA Astrophysics Data System (ADS)

The combustion characteristics of styrene—butadiene—styrene (SBS) asphalt are studied by thermogravimetric analysis (TG/DTG) at four different heating rates. According to the saturates/aromatics/resins/asphaltenes (SARA) fractionation method, the combustion process of SBS asphalt can be divided by Gaussian peak fitting into three main stages: oil content release, resin pyrolysis, and asphaltene and char combustion. When the heating rate increases, the mass losses of the oil content and resin pyrolysis increase, and less asphaltenes are formed at a higher temperature. The activation energy values are calculated by the Coats—Redfern method to be in the range 61.6 kJ/mol-142.9 kJ/mol. The Popescu method is used for the kinetic analysis, and the result shows that the three stages of asphalt combustion can be explained by the sphere phase boundary reaction model, the second order chemical reaction model, nucleation, and its subsequent growth model, respectively.

Wu, Ke; Zhu, Kai; Han, Jun; Wang, Jin-Chang; Huang, Zhi-Yi; Liang, Pei

2013-06-01

46

Diamino Telechelic Polybutadienes for Solventless Styrene-butadiene-styrene (SBS) Triblock Copolymer Formation  

PubMed Central

High molecular weight, high functionality diamino telechelic polybutadienes (TPBs) were synthesized by ring-opening metathesis polymerization (ROMP) of 1,5-cyclooctadiene (COD) in the presence of a chain transfer agent, 1,8-dicyano-4-octene, followed by lithium aluminum hydride reduction. Melt coupling of diamino TPB with anhydride-terminated polystyrene (PS-anh) resulted in the formation of styrene-butadiene-styrene (SBS) triblock copolymers; ca. 80% maximum conversion of PS-anh was achieved within 30 seconds. The results from SAXS, TEM, and rheological measurements of the coupling products confirmed the formation of SBS triblock copolymers having lamellar morphology. A fluororesent-labeled PS-anh was used to study the coupling kinetics by diluting the reactants by the addition of non-functional PS. PMID:19907636

Ji, Shengxiang; Hoye, Thomas R.; Macosko, Christopher W.

2008-01-01

47

Leukemia and cumulative exposure to butadiene, styrene and benzene among workers in the synthetic rubber industry  

Microsoft Academic Search

Retrospective, quantitative estimates of exposure to 1,3-butadiene, styrene and benzene were developed for a follow-up study of leukemia mortality among 16610 subjects employed at six North American styrene-butadiene rubber manufacturing plants (418846 person-years, 58 leukemia deaths). The estimation procedure entailed identifying work areas within each manufacturing process, historical changes in exposure potential and specific tasks involving exposure, and using mathematical

Maurizio Macaluso; Rodney Larson; Elizabeth Delzell; Nalini Sathiakumar; Mary Hovinga; Jim Julian; David Muir; Philip Cole

1996-01-01

48

Butadiene production process overview.  

PubMed

Over 95% of butadiene is produced as a by-product of ethylene production from steam crackers. The crude C4 stream isolated from the steam cracking process is fed to butadiene extraction units, where butadiene is separated from the other C4s by extractive distillation. The amount of crude C4s produced in steam cracking is dependent on the composition of the feed to the cracking unit. Heavier feeds, such as naphtha, yield higher amounts of C4s and butadiene than do lighter feeds. Crackers using light feeds typically produce low quantities of C4s and do not have butadiene extraction units. Overall butadiene capacity is determined by ethylene cracker operating rates, the type of feed being cracked, and availability of butadiene extraction capacity. Global butadiene capacity is approximately 10.5 million metric tons, and global production is approximately 9 million metric tons [Chemical Marketing Associates, Inc. (CMAI), 2005 World Butadiene Analysis, Chemical Marketing Associates, Inc. (CMAI), 2005]. Crude C4s are traded globally, with the United States being the only significant net importer. Finished butadiene is also traded globally, with the largest exporters being Canada, Western Europe, Saudi Arabia and Korea. The largest net importers are Mexico, the United States and China. The global demand for butadiene is approximately 9 million metric tons [Chemical Marketing Associates, Inc. (CMAI), 2005 World Butadiene Analysis, Chemical Marketing Associates, Inc. (CMAI), 2005]. Production of styrene-butadiene rubber and polybutadiene rubber accounts for about 54% of global butadiene demand, with tire production being the single most important end use of butadiene synthetic rubbers. Other major butadiene derivatives are acrylonitrile-butadiene-styrene (ABS) and styrene butadiene latex (about 24% of demand combined). PMID:17324391

White, Wm Claude

2007-03-20

49

Thermal hazard analysis of styrene monomer at Low temperature conditions during storage and transportation  

E-print Network

1 Thermal hazard analysis of styrene monomer at Low temperature conditions during storage Abstract Styrene Monomer (SM) has been widely used for producing polystyrene (PS), acrylonitrile-butadiene-styrene (ABS) and styrene-acryonitrile (SAN) in the petrochemical industry. From 1994 to 2001, several serious

Chen, Shu-Ching

50

Elongational viscosity of ABS polymer melts with soft or hard butadiene particles  

Microsoft Academic Search

The elongational viscosity of acrylonitrile-butadiene-styrene (ABS) polymer melts containing soft or hard butadiene particles has been investigated by using a Meissner-type uniaxial elongational rheometer. The influence of the hardness of the butadiene particles on the elongational viscosity is discussed for a series of ABS polymers having similar butadiene sizes and similar degrees of butadiene dispersion. The effect of the hardness

Tatsuhiro Takahashi; Weiguo Wu; Hideyuki Toda; Jun-ichi Takimoto; Takao Akatsuka; Kiyohito Koyama

1997-01-01

51

The compatibilizing effect of epoxy resin (EP) on polypropylene (PP)\\/recycled acrylonitrile butadiene rubber (NBRr) blends  

Microsoft Academic Search

A new method was used to prepare thermoplastic elastomers based on polypropylene (PP)\\/recycled acrylonitrile butadiene rubber (NBRr) with improved mechanical properties. An epoxy resin (EP) was used as a compatibilizing agent. The effect of EP on mechanical properties, swelling percentage and morphological characteristics of the blends was investigated with different blend compositions. The results showed that the incorporation of EP

H. Ismail; D. Galpaya; Z. Ahmad

2009-01-01

52

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

53

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

54

Atom transfer radical polymerization (ATRP) of styrene and acrylonitrile with monofunctional and bifunctional initiators  

Microsoft Academic Search

A bifunctional initiator (benzal bromide) was used to initiate the bulk atom transfer radical polymerization of styrene and acrylonitrile at 90°C with CuBr\\/2,2-bipyridyl. We compared these results with those of a monofunctional initiator of similar structure (1-bromoethyl benzene) under the same polymerization conditions. The monofunctional initiator worked better than the bifunctional initiator when both comonomers were added simultaneously at the

Mamdouh Al-Harthi; Amirpouyan Sardashti; João B. P. Soares; Leonardo C. Simon

2007-01-01

55

Recycling cycle of materials applied to acrylonitrile-butadiene-styrene/policarbonate blends with styrene-butadiene-styrene copolymer addition  

NASA Astrophysics Data System (ADS)

The scope of this research is the recycling of polymers from mobile phones hulls discarded and the performance evaluation when they are submitted to the Recycling Cycle of Materials (RCM). The studied material was the ABS/PC blend in a 70/30 proportion. Different compositions were evaluated adding virgin material, recycled material and using the copolymer SBS as impact modifier. In order to evaluate the properties of material's composition, the samples were characterized by TGA, FTIR, SEM, IZOD impact strength and tensile strength tests. At the first stage, the presented results suggest the composition containing 25% of recycled material and 5% of SBS combines good mechanical performance to the higher content of recycled material and lower content of impact modifier providing major benefits to recycling plans. Five cycles (RCM) were applied in the second stage; they evidenced a decrease trend considering the impact strength. At first and second cycle the impact strength was higher than reference material (ABS/PC blend) and from the fourth cycle it was lower. The superiority impact strength in the first and second cycles can be attributed to impact modifier effect. The thermal tests and the spectrometry didn't show the presence of degradation process in the material and the TGA curves demonstrated the process stability. The impact surface of each sample was observed at SEM. The microstructures are not homogeneous presenting voids and lamellar appearance, although the outer surface presents no defects, demonstrating good moldability. The present work aims to assess the life cycle of the material from the successive recycling processes.

Cândido, L. H. A.; Ferreira, D. B.; Júnior, W. Kindlein; Demori, R.; Mauler, R. S.

2014-05-01

56

Novel metallic materials constructed from epoxidized styrene-butadiene copolymers and cupric oxide  

Microsoft Academic Search

The functionalization of the insulator copolymer matrix star [styrene (30 tool%) butadiene] with epoxide groups leads to the development of a novel metallic conductor after mixing with cupric oxide (CuO), a poor electrical conductor. Conducting polymer materials are attracting research interest due to their wide range of present and possible future applications [1-6]. These polymers may be useful as microelectronic

E. Dalas; S. N. Koklas; E. Vitoratos; S. Sakkopoulos

1993-01-01

57

Morphology and Dynamic Mechanical Properties of Diglycidyl Ether of Bisphenol-A Toughened with Carboxyl-Terminated Butadiene-Acrylonitrile  

NASA Technical Reports Server (NTRS)

The fracture toughness of an incorporation of a carboxyl-terminated butadiene acrylonitrile (CTBN) elastomer in diglycidyl ether bisphenol A (DGEBA) resin was investigated. Measurements of dynamic mechanical properties, scanning electron microscopy and small-angle X-ray scattering were carried out to characterize the state of cure, morphology and particle size and size distribution of the neat resins and their graphite fiber reinforced composites.

Hong, S. D.; Chung, S. Y.; Fedors, R. F.; Moacanin, J.; Gupta, A.

1984-01-01

58

Study of styrene butadiene rubber and sodium methyl cellulose as binder for negative electrodes in lithium-ion batteries  

Microsoft Academic Search

Graphite and nano-silicon-based negative electrodes in lithium-ion batteries with low binder content were evaluated. The effectiveness of styrene butadiene rubber (SBR) and various types of cellulose containing electrodes were compared to standard electrodes containing PVdF as binder. The cycling performance of lithium-based half cells in EC:DMC (1:1), 1M LiPF6 shows that styrene butadiene rubber (SBR), sodium carboxymethyl cellulose (Na-CMC), or

H. Buqa; M. Holzapfel; F. Krumeich; C. Veit; P. Novák

2006-01-01

59

Nonisothermal degradation of poly(vinyl chloride)\\/methylmethacrylate-butadiene-styrene blends  

Microsoft Academic Search

The thermal degradation of poly(vinyl chloride)\\/methylmethacrylate-butadiene-styrene (PVC\\/MBS) blends was studied by nonisothermal thermogravimetry in nitrogen. Measurements were carried out in the temperature range 323–823K. The kinetic parameters were determined by applying Flynn–Wall–Ozawa and Kissinger’s methods. According to the compensation parameters the mechanism of degradation remains the same on adding the MBS; only the kinetics change. The thermal stability of the

B Andri?i?; T Kova?i?

1999-01-01

60

STUDY OF REDOX PROCESSES IN BUTADIENE-STYRENE COPOLYMER  

Microsoft Academic Search

The work presents the results of the study of thermoinitiated and photoinitiated oxidizing processes occurring in butodiene-styrene copolymer. The identification of the processes was made with the use of IR-spectroscopy and differential thermal analysis. It has been revealed, that the processes of thermo- and photooxidation of BS copolymer are similar. Irrespective of the way of initiation, oxidation proceeds on polybutadiene

Juriy G. Ivaschenko; Natalya N. Karpov; Olga V. Fedotova

61

Recent advances in R and D of commercial catalysts for acrylonitrile synthesis, styrene production and toluene disproportionation processes  

Microsoft Academic Search

This paper reports the progresses in R and D and commercial application of the industrial catalysts, developed and produced by SRIPT for acrylonitrile, styrene and toluene disproportionation processes.The research works of developing a unique method of catalyst preparation, adding proper amount of sodium ions to the Mo–Bi oxides system to improve catalytic activity and attrition resistance, and adding bromine ions

Qingling Chen; Xin Chen; Liansheng Mao; Wencai Cheng

1999-01-01

62

Disposition of styrene-acrylonitrile (SAN) trimer in female rats: single dose intravenous and gavage studies.  

PubMed

Styrene-acrylonitrile trimer (SAN Trimer), a mixture of six isomers (four isomers of 4-cyano-1,2,3,4-tetrahydro-alpha-methyl-1-naphthaleneacetonitrile [THAN] and two isomers of 4-cyano-1,2,3,4-tetrahydro-1-naphthaleneproprionitrile [THNP]), is a by-product of a specific production process of styrene-acrylonitrile polymer. Disposition studies in female rats were conducted to evaluate the pharmacokinetic behavior of [3H]SAN Trimer following a single intravenous administration (26 mg/kg) to nonpregnant rats; a single gavage administration (nominal doses of 25 mg/kg, 75 mg/kg, or 200 mg/kg in corn oil) to nonpregnant rats; and a single gavage administration (nominal dose of 200 mg/kg in corn oil) to pregnant and lactating rats. SAN Trimer was rapidly eliminated from blood (T1/2 approximately 1h) following a single intravenous dose and following single oral doses (T1/2 approximately 3-4h). SAN Trimer was also rapidly excreted in the urine and feces following single oral doses, while total radioactivity was cleared more slowly. In pregnant rats, the concentrations of both radioactivity and SAN Trimer 2h after dosing were highest in the blood, followed by the placenta, with the lowest levels in the fetus. In lactating rats, the concentrations of both radioactivity and SAN Trimer were higher in milk than in maternal blood. Total radioactivity and SAN Trimer blood concentrations in nonpregnant, pregnant, and lactating rats were both higher in lactating rats compared to nonpregnant and pregnant rats. PMID:18384980

Gargas, Michael L; Collins, Brad; Fennell, Timothy R; Gaudette, Norman F; Sweeney, Lisa M

2008-04-21

63

Perinatal toxicity and carcinogenicity studies of styrene-acrylonitrile trimer, a ground water contaminant.  

PubMed

Styrene acrylonitrile (SAN) trimer is a by-product in the production of acrylonitrile styrene plastics. Following a report of a childhood cancer cluster in the Toms River section of Dover Township, New Jersey, SAN Trimer was identified as one of the groundwater contaminants at Reich Farm Superfund site in the township. The contaminants from the Reich Farm site's ground water plume impacted two wells at the Parkway well field. The National Toxicology Program (NTP) studied the toxicity and carcinogenicity of SAN Trimer in rats exposed during their perinatal developmental period and adulthood. The chronic toxicity and carcinogenicity studies in F344/N rats were preceded by 7- and 18-week perinatal toxicity studies to determine the exposure concentrations for the 2-year studies. Subsequently, Fisher 344 pregnant dams were exposed to SAN Trimer containing diet at 400, 800, or 1600ppm concentrations during gestation, nursing and weaning periods of offspring followed by two year of adult exposures to both male and female pups. There was no statistically significant evidence of carcinogenic activity following SAN-Trimer exposure; however, rare neoplasms in the brain and spinal cord were observed in males and to lesser extent in female rats. These incidences were considered within the range of historical background in the animal model used in the current studies. Therefore, the presence of a few rarely occurring CNS tumors in the treated groups were not judged to be associated with the SAN Trimer exposure. The major finding was a dose-related peripheral neuropathy associated with the sciatic nerves in females and spinal nerve roots in males and females thereby suggesting that SAN Trimer is potentially a nervous system toxicant. PMID:24060431

Behl, Mamta; Elmore, Susan A; Malarkey, David E; Hejtmancik, Milton R; Gerken, Diane K; Chhabra, Rajendra S

2013-12-01

64

High-concentration organic solutions of poly(styrene- co-butadiene- co-styrene)-modified graphene sheets exfoliated from graphite  

Microsoft Academic Search

A simple method is developed to produce high-concentration organic solutions of graphene sheets noncovalently modified with poly(styrene-co-butadiene-co-styrene) (SBS). Once exfoliated from natural graphite under sonication, the graphene sheets can be stabilized by SBS through the ?–? stacking with the PS chains. The PS–graphene interaction is confirmed by DSC, since the glass transition temperature of the PS blocks increases by ?8°C,

Yi-Tao Liu; Xu-Ming Xie; Xiong-Ying Ye

2011-01-01

65

21 CFR 177.1020 - Acrylonitrile/butadiene/sty-rene co-polymer.  

Code of Federal Regulations, 2012 CFR

...federal_regulations/ibr_locations.html. (c) Specifications. (1) Nitrogen...federal_regulations/ibr_locations.html. (d) Extractive limitations. ...federal_regulations/ibr_locations.html. (e) Acrylonitrile copolymers...

2012-04-01

66

21 CFR 177.1020 - Acrylonitrile/butadiene/sty-rene co-polymer.  

...federal_regulations/ibr_locations.html. (c) Specifications. (1) Nitrogen...federal_regulations/ibr_locations.html. (d) Extractive limitations. ...federal_regulations/ibr_locations.html. (e) Acrylonitrile copolymers...

2014-04-01

67

21 CFR 177.1020 - Acrylonitrile/butadiene/sty-rene co-polymer.  

Code of Federal Regulations, 2013 CFR

...federal_regulations/ibr_locations.html. (c) Specifications. (1) Nitrogen...federal_regulations/ibr_locations.html. (d) Extractive limitations. ...federal_regulations/ibr_locations.html. (e) Acrylonitrile copolymers...

2013-04-01

68

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

69

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

70

Droplet-cluster transition in sheared polyamide 6-poly(styrene-ethylene-butadiene-styrene)-polypropylene ternary blends.  

PubMed

We have used a Linkam CSS 450 stage equipped with an optical microscope to study online the evolution of the morphology and structure of polyamide 6 (PA6)-poly(styrene-ethylene-butadiene-styrene) (SEBS)-polypropylene (PP) ternary blends under shear flow. At a high shear rate (60?s(-1)), large drops of PA6 and SEBS broke up to form small randomly distributed PA6 droplets covered by SEBS in the PP matrix. These droplets aggregated into a well-ordered structure, i.e., parallel clusters, after decreasing the shear rate abruptly to within the range of 1.5-3.5?s(-1). Interestingly, these parallel clusters were aligned perpendicular to the direction of shear flow. An important feature of these parallel clusters is that they can be maintained for a long period of time (several tens of minutes) at the given shear rate or after cessation of flow; this feature allows us to freeze the structure by decreasing the temperature. PMID:21230101

Zhu, Yutian; Yang, Xiaodong; Yin, Jinghua; Jiang, Wei

2010-09-01

71

Droplet-cluster transition in sheared polyamide 6-poly(styrene-ethylene-butadiene-styrene)-polypropylene ternary blends  

NASA Astrophysics Data System (ADS)

We have used a Linkam CSS 450 stage equipped with an optical microscope to study online the evolution of the morphology and structure of polyamide 6 (PA6)-poly(styrene-ethylene-butadiene-styrene) (SEBS)-polypropylene (PP) ternary blends under shear flow. At a high shear rate (60s-1) , large drops of PA6 and SEBS broke up to form small randomly distributed PA6 droplets covered by SEBS in the PP matrix. These droplets aggregated into a well-ordered structure, i.e., parallel clusters, after decreasing the shear rate abruptly to within the range of 1.5-3.5s-1 . Interestingly, these parallel clusters were aligned perpendicular to the direction of shear flow. An important feature of these parallel clusters is that they can be maintained for a long period of time (several tens of minutes) at the given shear rate or after cessation of flow; this feature allows us to freeze the structure by decreasing the temperature.

Zhu, Yutian; Yang, Xiaodong; Yin, Jinghua; Jiang, Wei

2010-09-01

72

Styrene-butadiene-styrene copolymer compatibilized carbon black/polypropylene/polystyrene composites with tunable morphology, electrical conduction and rheological stabilities.  

PubMed

We report a facile kinetic strategy in combination with styrene-butadiene-styrene (SBS) copolymer compatibilizers for preparing carbon black (CB) filled immiscible polypropylene (PP)/polystyrene (PS) (1/1) blends with finely tuned morphologies and show the important role of location and migration of CB nanoparticles in determining the electrical conductivity and rheological behaviour of the composites. A novel method of mixing a SBS/CB (5/3) masterbatch with the polymers allowed producing composites with CB aggregates dispersed partially in the unfavorable PP phase and partially in the PP side of the interface to exhibit diverse phase connectivity and electrical conductivity depending on the compounding sequences. A cocontinuous morphology with CB enrichment along the interface was formed in the composite prepared by mixing the SBS/CB masterbatch with the premixed PP/PS blend, giving rise to a highest electrical conductivity and dynamic moduli at low frequencies. On the other hand, mixing the masterbatch with one and then with another polymer yielded droplet (PS)-in-matrix (filled PP) composites. The composites underwent phase coalescence and CB redistribution accompanied by marked dynamic electrical conduction and modulus percolations as a function of time during thermal annealing at 180 °C. The composites with the initial droplet-in-matrix morphology progressed anomalously into the cocontinuous morphology, reflecting a common mechanism being fairly nonspecific for understanding the processing of filled multicomponent composites with tailored performances of general concern. PMID:24647801

Song, Yihu; Xu, Chunfeng; Zheng, Qiang

2014-04-21

73

Evaluating corn starch and corn stover biochar as renewable filler in carboxylated styrene–butadiene rubber composites  

Microsoft Academic Search

Corn starch, corn flour, and corn stover biochar were evaluated as potential renewable substitutes for carbon black as filler in rubber composites using carboxylated styrene–butadiene as the rubber matrix. Previous work has shown that starch-based fillers have very good reinforcement properties at the expense of brittleness in the final rubber composite. In an attempt to alleviate this, starch was blended

Steven C. Peterson

2012-01-01

74

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

E-print Network

1 Trans-stereospecific polymerization of butadiene and random copolymerization with styrene using polymerization. In the presence of excesses of Mg co-catalyst, polymer chain transfer takes place between-4140" DOI : 10.1016/j.eurpolymj.2013.09.019 #12;2 Keywords Stereospecific polymerization, trans

Boyer, Edmond

75

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

76

The Effects of PP-g-MA on the Physical Properties and Morphology of Polypropylene (PP)\\/Recycled Acrylonitrile Butadiene Rubber (rNBR) Blends  

Microsoft Academic Search

Polypropylene-grafted maleic anhydride (PP-g-MA) was used to enhance the compatibility of polypropylene (PP) and recycled acrylonitrile butadiene rubber (rNBR) blends. The blends were prepared by melt mixing using a Haake Rheomix Polydrive R 600\\/610 mixer at 180°C. The processing torque was used to investigate the mixing process. The better mixing of compatibilized blends (PP\\/rNBR-MA) was evidence by the higher stabilization

Dilini Galpaya; Hanafi Ismail; Zulkifli Ahmad

2010-01-01

77

Effect of methyl methacrylate-butadiene-styrene copolymer on the thermooxidation and biodegradation of LDPE\\/plasticized starch blends  

Microsoft Academic Search

The effect of methyl methacrylate-butadiene-styrene copolymer (MBS) on the thermooxidative degradation and biodegradation of low-density polyethylene (LDPE)\\/plasticized starch (PLST) blends was examined. Ethylene-co-acrylic acid (EAA) was used as compatibilizer and cobalt stearate as pro-oxidant. The thermooxidative degradation was followed by means of Fourier transform infra-red spectroscopy, gravimetric measurements and mechanical properties during incubation of the blends in an air oven

D. Bikiaris; J. Prinos; C. Panayiotou

1997-01-01

78

Screening-level risk assessment for styrene-acrylonitrile (SAN) trimer detected in soil and groundwater.  

PubMed

A screening-level risk assessment was conducted for styrene-acrylonitrile (SAN) Trimer detected at the Reich Farm Superfund site in Toms River, NJ. Consistent with a screening-level approach, on-site and off-site exposure scenarios were evaluated using assumptions that are expected to overestimate actual exposures and hazards at the site. Environmental sampling data collected for soil and groundwater were used to estimate exposure point concentrations. Several exposure scenarios were evaluated to assess potential on-site and off-site exposures, using parameter values for exposures to soil (oral, inhalation of particulates, and dermal contact) and groundwater (oral, dermal contact) to reflect central tendency exposure (CTE) and reasonable maximum exposure (RME) conditions. Three reference dose (RfD) values were derived for SAN Trimer for short-term, subchronic, and chronic exposures, based upon its effects on the liver in exposed rats. Benchmark (BMD) methods were used to assess the relationship between exposure and response, and to characterize appropriate points of departure (POD) for each RfD. An uncertainty factor of 300 was applied to each POD to yield RfD values of 0.1, 0.04, and 0.03 mg/kg-d for short-term, subchronic, and chronic exposures, respectively. Because a chronic cancer bioassay for SAN Trimer in rats (NTP 2011a) does not provide evidence of carcinogenicity, a cancer risk assessment is not appropriate for this chemical. Potential health hazards to human health were assessed using a hazard index (HI) approach, which considers the ratio of exposure dose (i.e., average daily dose, mg/kg-d) to toxicity dose (RfD, mg/kg-d) for each scenario. All CTE and RME HI values are well below 1 (where the average daily dose is equivalent to the RfD), indicating that there is no concern for potential noncancer effects in exposed populations even under the conservative assumptions of this screening-level assessment. PMID:23030654

Kirman, C R; Gargas, M L; Collins, J J; Rowlands, J C

2012-01-01

79

Screening-Level Risk Assessment for Styrene-Acrylonitrile (SAN) Trimer Detected in Soil and Groundwater  

PubMed Central

A screening-level risk assessment was conducted for styrene-acrylonitrile (SAN) Trimer detected at the Reich Farm Superfund site in Toms River, NJ. Consistent with a screening-level approach, on-site and off-site exposure scenarios were evaluated using assumptions that are expected to overestimate actual exposures and hazards at the site. Environmental sampling data collected for soil and groundwater were used to estimate exposure point concentrations. Several exposure scenarios were evaluated to assess potential on-site and off-site exposures, using parameter values for exposures to soil (oral, inhalation of particulates, and dermal contact) and groundwater (oral, dermal contact) to reflect central tendency exposure (CTE) and reasonable maximum exposure (RME) conditions. Three reference dose (RfD) values were derived for SAN Trimer for short-term, subchronic, and chronic exposures, based upon its effects on the liver in exposed rats. Benchmark (BMD) methods were used to assess the relationship between exposure and response, and to characterize appropriate points of departure (POD) for each RfD. An uncertainty factor of 300 was applied to each POD to yield RfD values of 0.1, 0.04, and 0.03 mg/kg-d for short-term, subchronic, and chronic exposures, respectively. Because a chronic cancer bioassay for SAN Trimer in rats (NTP 2011a) does not provide evidence of carcinogenicity, a cancer risk assessment is not appropriate for this chemical. Potential health hazards to human health were assessed using a hazard index (HI) approach, which considers the ratio of exposure dose (i.e., average daily dose, mg/kg-d) to toxicity dose (RfD, mg/kg-d) for each scenario. All CTE and RME HI values are well below 1 (where the average daily dose is equivalent to the RfD), indicating that there is no concern for potential noncancer effects in exposed populations even under the conservative assumptions of this screening-level assessment. PMID:23030654

Kirman, C. R.; Gargas, M. L.; Collins, J. J.; Rowlands, J. C.

2012-01-01

80

Synthesis of Surface-Functionalized Poly(styrene-co-butadiene) Nanoparticles via Controlled\\/Living Radical Mini-emulsion Copolymerization Stabilized by Ammonolyzed Poly(styrene-alt-maleic anhydride) (SMA) RAFT Agent  

Microsoft Academic Search

A process for reversible addition-fragmentation chain transfer (RAFT) radical polymerization in a mini-emulsion system stabilized by ammnolyzed poly(styrene-alt- maleic anhydride) copolymer (SMA) as an amphiphilic macro RAFT agent has been applied to the copolymerization of styrene and butadiene to prepare nanoparticles. First, for the RAFT polymerization of styrene, the results of molecular weights (Mns) and polydispersity index (PDIs) determined by

Yitao Yu; Qinghua Zhang; Zhenxi Wang; Xiaoli Zhan; Ren He; Wentao Zhang; Fengqiu Chen

2012-01-01

81

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

82

Characterization of the mesostructure of fused-deposition acrylonitrile-butadiene-styrene materials  

Microsoft Academic Search

Fused-deposition (FD) is a robotically controlled “fiber” extrusion process that produces a new class of materials with a variety of controllable mesostructural features related to fiber layout and the presence of voids. Mesostructural features of importance to the stiffness and strength of unidirectionally extruded materials were characterized as a function of the processing variables. Samples were made using the Stratasys

Jose F. Rodriguez; James P. Thomas; John E. Renaud

2000-01-01

83

Mechanical behavior of acrylonitrile butadiene styrene (ABS) fused deposition materials. Experimental investigation  

Microsoft Academic Search

An experimental study of the mechanical behavior of fused-deposition (FD) ABS plastic materials is described. Elastic moduli and strength values are determined for the ABS monofilament feedstock and various unidirectional FD-ABS materials. The results show a reduction of 11 to 37 per cent in modulus and 22 to 57 per cent in strength for FD-ABS materials relative to the ABS

José F. Rodríguez; James P. Thomas; John E. Renaud

2001-01-01

84

Removal of Metallic Particles From Acrylonitrile Butadiene Styrene Wastes Using Electrostatic Separation Methods  

Microsoft Academic Search

Electrostatic separation techniques have been widely used in the recycling industry. The aim of this paper is to assess the possibility of employing them for the beneficiation of the newest and fastest growing category of wastes: the \\

Alexandru Iuga; Adrian Samuila; Vasile Neamtu; Roman Morar; Radu Beleca; Subhankar Das; Lucian Dascalescu

2011-01-01

85

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

...component of articles intended for use with food identified in table 1 of § 176.170(c) of this chapter as Type I, II, III, IVA, IVB, V, VIB, (except bottles intended to hold carbonated beverages), VIIA, VIIB, VIII and IX, under conditions...

2014-04-01

86

Radiation-induced copolymerization of styrene/ n-butyl acrylate in the presence of ultra-fine powdered styrene-butadiene rubber  

NASA Astrophysics Data System (ADS)

Styrene (St)/ n-butyl acrylate (BA) copolymers were prepared by two-stage polymerization: St/BA was pre-polymerized to a viscous state by bulk polymerization with initiation by benzoyl peroxide (BPO) followed by 60Co ?-ray radiation curing. The resultant copolymers had higher molecular weight and narrower molecular weight distribution than conventional methods. After incorporation of ultra-fine powdered styrene-butadiene rubber (UFSBR) with a particle size of 100 nm in the monomer, the glass transition temperature ( Tg) of St-BA copolymer increased at low rubber content. Both the St-BA copolymer and the St-BA copolymer/UFSBR composites had good transparency at BA content below 40%.

Yu, Haibo; Peng, Jing; Zhai, Maolin; Li, Jiuqiang; Wei, Genshuan; Qiao, Jinliang

2007-11-01

87

Genotoxicity of Styrene–Acrylonitrile Trimer in Brain, Liver, and Blood Cells of Weanling F344 Rats  

PubMed Central

Styrene–acrylonitrile Trimer (SAN Trimer), a by-product in production of acrylonitrile styrene plastics, was identified at a Superfund site in Dover Township, NJ, where childhood cancer incidence rates were elevated for a period of several years. SAN Trimer was therefore tested by the National Toxicology Program in a 2-year perinatal carcinogenicity study in F344/N rats and a bacterial mutagenicity assay; both studies gave negative results. To further characterize its genotoxicity, SAN Trimer was subsequently evaluated in a combined micronucleus (MN)/Comet assay in juvenile male and female F344 rats. SAN Trimer (37.5, 75, 150, or 300 mg/kg/day) was administered by gavage once daily for 4 days. Micronucleated reticulocyte (MN-RET) frequencies in blood were determined by flow cytometry, and DNA damage in blood, liver, and brain cells was assessed using the Comet assay. Highly significant dose-related increases (P < 0.0001) in MN-RET were measured in both male and female rats administered SAN Trimer. The RET population was reduced in high dose male rats, suggesting chemical-related bone marrow toxicity. Results of the Comet assay showed significant, dose-related increases in DNA damage in brain cells of male (P < 0.0074) and female (P < 0.0001) rats; increased levels of DNA damage were also measured in liver cells and leukocytes of treated rats. Chemical-related cytotoxicity was not indicated in any of the tissues examined for DNA damage. The results of this subacute MN/Comet assay indicate induction of significant genetic damage in multiple tissues of weanling F344 male and female rats after oral exposure to SAN Trimer. PMID:22351108

Hobbs, Cheryl A.; Chhabra, Rajendra S.; Recio, Leslie; Streicker, Michael; Witt, Kristine L.

2012-01-01

88

Genotoxicity of styrene-acrylonitrile trimer in brain, liver, and blood cells of weanling F344 rats.  

PubMed

Styrene-acrylonitrile Trimer (SAN Trimer), a by-product in production of acrylonitrile styrene plastics, was identified at a Superfund site in Dover Township, NJ, where childhood cancer incidence rates were elevated for a period of several years. SAN Trimer was therefore tested by the National Toxicology Program in a 2-year perinatal carcinogenicity study in F344/N rats and a bacterial mutagenicity assay; both studies gave negative results. To further characterize its genotoxicity, SAN Trimer was subsequently evaluated in a combined micronucleus (MN)/Comet assay in juvenile male and female F344 rats. SAN Trimer (37.5, 75, 150, or 300 mg/kg/day) was administered by gavage once daily for 4 days. Micronucleated reticulocyte (MN-RET) frequencies in blood were determined by flow cytometry, and DNA damage in blood, liver, and brain cells was assessed using the Comet assay. Highly significant dose-related increases (P < 0.0001) in MN-RET were measured in both male and female rats administered SAN Trimer. The RET population was reduced in high dose male rats, suggesting chemical-related bone marrow toxicity. Results of the Comet assay showed significant, dose-related increases in DNA damage in brain cells of male (P < 0.0074) and female (P < 0.0001) rats; increased levels of DNA damage were also measured in liver cells and leukocytes of treated rats. Chemical-related cytotoxicity was not indicated in any of the tissues examined for DNA damage. The results of this subacute MN/Comet assay indicate induction of significant genetic damage in multiple tissues of weanling F344 male and female rats after oral exposure to SAN Trimer. PMID:22351108

Hobbs, Cheryl A; Chhabra, Rajendra S; Recio, Leslie; Streicker, Michael; Witt, Kristine L

2012-04-01

89

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

90

Characteristics of styrene-butadiene rubber/silica/Nanoprene compounds for application in tire tread.  

PubMed

Nanoprene is made from chemically cross-linked rubber particles, and has many hydroxyl groups on the surface of the particles. It is speculated that the Nanoprene could reduce the silica-silica network formation by introducing hydrogen bonding between the silanol group of silica and the hydroxyl group of Nanoprene. In this study, the styrene-butadiene rubber (SBR)/silica compounds with two types of the Nanoprene (BM75OH, BM15OH) were evaluated and it could be well explained by the concept of the volume fraction of filler or the volume fraction of rubber. If the Nanoprene applied to the compound is considered as a kind of filler, the minimum torque values and bound rubber contents of the un-vulcanized compounds, the swelling ratio and the stress-strain relationship of the vulcanized compounds could be well explained by the volume fraction of filler (phi(F)). If Nanoprene is considered as a kind of rubber such as SBR, the properties such as peak tan delta, Payne effect, tan delta at 0 degrees C and 60 degrees C, and abrasion resistance could be well explained by the volume fraction of rubber (phi'(R)). However, the improvement of silica dispersion by addition of the Nanoprene particles in the compounds was not significant. The application of BM75OH as a polymer to the tread compound will be suitable for winter tires. In addition, the compound with BM15OH as an additive will be suitable as a tread compound for summer tires. PMID:23755663

Seo, Byeongho; Kang, Jonghyub; Jang, Sukhee; Kang, Yonggu; Kim, Wonho

2013-03-01

91

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

Code of Federal Regulations, 2011 CFR

...in the range of 17.7-19.8 percent. (2) Intrinsic viscosity of the matrix copolymer in butyrolactone is not less than 0...titled “Molecular Weight of Matrix Copolymer by Solution Viscosity,” which is incorporated by reference. Copies are...

2011-04-01

92

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

93

Effect of Applied Potential on the Electrochemical Deposition of Styrene-Butadiene Co-Polymer Based Conducting Polymer Composite  

NASA Astrophysics Data System (ADS)

Homogeneous conducting polymer composite films with improved electrical properties are synthesized via electrochemical polymerization of polyaniline on Styrene butadiene rubber coated steel electrode. The electrochemical polymerization is carried out by potentiostatic method using an aqueous solution of 0.2 M aniline and 1.5 M sulphuric acid as electrolyte in a single compartment electrochemical cell. The optical studies show successful incorporation of polyaniline into the matrix polymer film. The effect of applied potential on the electrodeposition of composite is studied by cyclic voltammetry and by impedance spectroscopic measurements.

Mathew, Anisha Mary; Neena, P.

2011-10-01

94

Analysis of recycled poly (styrene-co-butadiene) sulfonation: a new approach in solid catalysts for biodiesel production.  

PubMed

The disposal of solid waste is a serious problem worldwide that is made worse in developing countries due to inadequate planning and unsustainable solid waste management. In Mexico, only 2% of total urban solid waste is recycled. One non-recyclable material is poly (styrene-co-butadiene), which is commonly used in consumer products (like components of appliances and toys), in the automotive industry (in instrument panels) and in food services (e.g. hot and cold drinking cups and glasses). In this paper, a lab-scale strategy is proposed for recycling poly (styrene-co-butadiene) waste by sulfonation with fuming sulfuric acid. Tests of the sulfonation strategy were carried out at various reaction conditions. The results show that 75°C and 2.5 h are the operating conditions that maximize the sulfonation level expressed as number of acid sites. The modified resin is tested as a heterogeneous catalyst in the first step (known as esterification) of biodiesel production from a mixture containing tallow fat and canola oil with 59% of free fatty acids. The preliminary results show that esterification can reach 91% conversion in the presence of the sulfonated polymeric catalyst compared with 67% conversion when the reaction is performed without catalyst. PMID:24098857

Aguilar-Garnica, Efrén; Paredes-Casillas, Mario; Herrera-Larrasilla, Tito E; Rodríguez-Palomera, Felicia; Ramírez-Arreola, Daniel E

2013-01-01

95

Organic Semiconducting Materials in Film and Powder Forms from a Co-polymeric Elastomer-Styrene Butadiene Rubber  

NASA Astrophysics Data System (ADS)

Semiconducting materials in both film and powder forms are prepared by Antimony Pentachloride (SBCl5) doping in Styrene Butadiene Rubber (SBR). SBR is a synthetic co-polymeric elastomer, insulating in undoped state, is mainly used for manufacturing tires, tubes etc. Synthesized conducting materials are proposed to have tremendous application potentials in optoelectronic, electronic and electrical industries. For example conducting films can be used as active elements for fabrication of organic light emitting diodes, photovoltaic cells etc. Electrical and optical properties of prepared samples are studied by measuring electrical conductivity and analyzing spectroscopic data. Electrical conductivity of samples lies in the range of that of semi-conducting materials. Presence of conjugated sequences in the back bone of prepared conducting materials, which is regarded as pre-requisite condition for a polymer to conductive, is confirmed by studying UV/Vis spectra.

Santhamma, G.; Predeep, P.

2008-04-01

96

Industrial-hygiene survey report of Dow Chemical USA SB (styrene butadiene) Latex Facility, Freeport, Texas  

SciTech Connect

The purpose of the survey was to obtain information on the SB latex production process and assess the potential for occupational exposure to 1,3-butadiene at the SB latex facility. The information will be used in determining the suitability of including the plant in an in-depth survey.

Fajen, J.M.; Krishnan, E.R.

1986-03-01

97

Industrial-hygiene survey report of Dow Chemical USA SB (styrene butadiene) Latex Facility, Freeport, Texas  

Microsoft Academic Search

The purpose of the survey was to obtain information on the SB latex production process and assess the potential for occupational exposure to 1,3-butadiene at the SB latex facility. The information will be used in determining the suitability of including the plant in an in-depth survey.

J. M. Fajen; E. R. Krishnan

1986-01-01

98

Nanostructured poly(urethane)s and poly(urethane-urea)s from reactive solutions of poly[styrene- b-butadiene- b-(methyl methacrylate)]-triblock copolymers  

Microsoft Academic Search

Poly[Styrene-b-Butadiene-b-(Methyl Methacrylate)], SBM triblock copolymers have been incorporated in different polyurethane, PU formulations in order to prepare nanostructured materials. Macrodiols used for PU synthesis were based on a central bis-phenol A, BPA unit with two hydroxyl-terminated oligo(oxypropylene), BPA-POx or oligo(oxyethylene), BPA-EO chains with varying lengths. The initial solubility of the three blocks and the rheological behavior of the solutions in

Boris Jaffrennou; Julien Portal; Françoise Méchin; Jean-Pierre Pascault

2008-01-01

99

Degradation of carboxylated styrene butadiene rubber based water born paints: Part 2 – Models to predict UV stability and water absorption through central composite design  

Microsoft Academic Search

Central composite experimental design methods have been used to examine the simultaneous effects of talc (Viaton Viatalc® 30), titanium dioxide (modified Rutile, Tioxide® TR92) and additional hindered phenolic stabiliser (Aquanox® L, a 50% w\\/w aqueous dispersion of Winstay® L) on the water uptake and UV stability of composite films based on a carboxylated styrene butadiene rubber (c-SBR) latex. The talc

Elena Jubete; Christopher M. Liauw; Norman S. Allen

2007-01-01

100

Effect of silane coupling agent on vulcanization, network structure, polymer-filler interaction, physical properties and failure mode of mica-filled styrene-butadiene rubber  

Microsoft Academic Search

Physical properties of composites from mica and styrene-butadiene rubber (SBR) have been studied with special reference to the effect of silane coupling agent (A-174) in the compound. Tensile and tear properties increase with the addition of mica. The increase of tensile properties in more pronounced in the case of silane-treated mica. Silane treatment also raises the volume fraction of rubber

S. Debnath; S. K. De; D. Khastgir

1987-01-01

101

Kinetic analysis of the thermo-oxidative degradation of poly(vinyl chloride) in poly(vinyl chloride)\\/methyl methacrylate-butadiene-styrene blends1 Isothermal degradation  

Microsoft Academic Search

The thermal degradation of poly(vinyl chloride)\\/poly(methyl methacrylate-butadiene-styrene) (PVC\\/MBS) blends was investigated by means of isothermal thermogravimetry in air. During 120 min the main process in the blends is the dehydrochlorination of PVC. The reaction rate constants were determined by applying the Prout–Tompkins model, which assumes autocatalytic degradation. Their values are about three times higher in air than in nitrogen. MBS

Branka Andri?i?; Tonka Kova?i?; Ivka Klari?

2002-01-01

102

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

103

The Effects of Recycled Acrylonitrile Butadiene Rubber Content and Maleic Anhydride Modified Polypropylene (PPMAH) on the Mixing, Tensile Properties, Swelling Percentage and Morphology of Polypropylene\\/Recycled Acrylonitrile Butadiene Rubber\\/Rice Husk Powder (PP\\/NBRr\\/RHP) Composites  

Microsoft Academic Search

The effect of recycled acylonitrile butadiene rubber (NBRr) content and PPMAH as a compatibilizer on the properties of PP\\/NBRr\\/RHP composites were examined using a Haake Rheomix at 180°C, 60 rpm for 9 min. Results showed that higher stabilization torque, Young's modulus and tensile strength were obtained for PPMAH compatibilized composite as compared to uncompatibilized composites. However, for elongation at break (Eb) and

H. Ismail; S. Ragunathan; K. Hussin

2010-01-01

104

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

105

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

106

Degree of Mechanochemical Devulcanization of Model Styrene-Butadiene Rubber Compounds Containing Different Amount of Poly-, Di- and Monosulphidic Bonds  

NASA Astrophysics Data System (ADS)

There have been significant attempts to devulcanize waste elastomers to facilitate reusing these valuable resources in applications requiring the unique properties of rubber. The difficulty in recycling of elastomers has traditionally been with devulcanizing the elastomer without comprising its properties due to degradation of main chains. This research aimed to devulcanize model styrene-butadiene rubber (SBR) compounds, which had various amounts of poly-, di- and monosulfidic crosslinks using a mechanochemical process. Three model compounds were prepared using SBR using a laboratory two-roll mill. They were then vulcanized in a compression molding press at 140r C. The prepared vulcanized compounds were then ground and devulcanized in an internal mixer using a chemical mixture at a constant rotor speed and temperature. The crosslink density of the compounds before and after the devulcanization was calculated using volume-swelling measurements. The obtained data was used to establish the correlation between crosslink density of the compounds and the degree of devulcanization. The results showed that mechanochemical devulcanization caused a significant decrease in the crosslink density of the compounds by breaking the sulfidic linkages. The break up of polysulfidic crosslinks was predominant, meaning that mechanochemical process selectively affected different types of crosslinks.

Sangari, Samra; Anita, Hill; Dumitru, Pavel

2004-03-01

107

Biomonitoring of 1,3-butadiene and related compounds  

SciTech Connect

The 1990 Clean Air Act Amendments list several volatile organic chemicals as hazardous air pollutants, including ethylene oxide, butadiene, styrene, and acrylonitrile. The toxicology of many of these compounds shares several common elements such as carcinogenicity in laboratory animals, genotoxicity of the epoxide intermediates, involvement of cytochrome P450 for metabolic activation (except ethylene oxide), and involvement of at least two enzymes for detoxication of the epoxides (e.g., hydrolysis or conjugation with glutathione). These similarities facilitate research strategies for identifying and developing biomarkers of exposure. This article reviews the current knowledge about biomarkers of butadiene. Butadiene is carcinogenic in mice and rats, which raises concern for potential carcinogenicity in humans. 85 refs., 1 fig., 2 tabs.

Osterman-Golkar, S. [Stockholm Univ. (Sweden); Bond, J.A. [Chemical Industry Institute of Toxicology, Research Triangle Park, NC (United States)

1996-10-01

108

Lymphatic and haematopoietic cancer mortality in a population attending school adjacent to styrene-butadiene facilities, 1963-1993  

PubMed Central

STUDY OBJECTIVE: To evaluate the risk of mortality from lymphatic and haematopoietic cancers and other causes among students. DESIGN: The study used school records, yearbooks, and Texas Department of Health records for the school years 1963-64 to 1992-93 to construct a cohort of 15,403 students. Three mortality databases were searched to identify deaths, and mortality rates in the cohort were compared with mortality rates from the United States and Texas. Computed standardised mortality ratios and 95% confidence intervals were used. SETTING: Eastern Texas high school adjacent to facilities that have been producing synthetic styrene-butadiene since 1943. MAIN RESULTS: 338 deaths were identified. The all causes standardised mortality ratio was 0.84 (95% confidence intervals 0.74, 0.95) for men and 0.89 (0.73, 1.09) for women. The standardised mortality ratio for all lymphatic and haematopoietic cancers was 1.64 (95% confidence intervals 0.85, 2.87) for men and 0.47 (0.06, 1.70) for women. The slight male excess in lymphatic and haematopoietic cancers was stronger among men who attended school for two years or less. CONCLUSIONS: The overall mortality from lymphatic and haematopoietic cancer among the students was little different from that of the United States as a whole. A moderate excess for men, predominantly among the shorter-term students, was offset by a deficit among women. These variations are compatible with random fluctuations; the overall pattern is not indicative of an effect of environmental exposure sustained while attending the high school.   PMID:10396534

Loughlin, J. E.; Rothman, K. J.; Dreyer, N. A.

1999-01-01

109

Mechanical properties and electrical conductivity of carbon-nanotube filled polyamide-6 and its blends with acrylonitrile\\/butadiene\\/styrene  

Microsoft Academic Search

Composites of polyamide-6 and carbon nanotubes (NT) have been prepared on a corotating twinscrew extruder. It is shown by transmission electron microscopy (TEM) that the nanotubes are dispersed homogeneously in the polyamide-matrix. The electrical conductivity of these composites was analyzed and compared to carbon black filled polyamide-6. It is found that the NT-filled polyamide-6 shows an onset of the electrical

Olaf Meincke; Dirk Kaempfer; Hans Weickmann; Christian Friedrich; Marc Vathauer; Holger Warth

2004-01-01

110

The influence of stabilizing agents on the interaction between styrene/butadiene latex and calcium carbonate: a calorimetric and a dynamic electrokinetic study.  

PubMed

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 calcite surface. An electrostatic barrier is created and this decreases the attractive interactions between the latex and the negatively charged mineral surface. The total enthalpy change observed when an emulsion of styrene/butadiene particles substantially free from surfactant was added to the dispersed calcium carbonate could be described via a relatively complex path. The process included (i) an exothermic response from the association of the latex particles (adsorption process) with the dispersed calcium carbonate surface and (ii) an endothermic bulk phase effect due to the adsorption on the latex particles of dissolved species originating from the calcium carbonate. Stabilization of the latex particles with sodium dodecyl benzene sulfonate (SDBS) or a non-ionic fatty alcohol ethoxylate surfactant did not significantly change the enthalpy of interaction. It was further demonstrated that SDBS had a very weak affinity for the dispersed calcium carbonate particles and that dissolution of species, such as calcium ions, from the calcium carbonate surface, allows further adsorption of SDBS onto the latex particles. PMID:12702419

Backfolk, Kaj; Lagerge, Serge; Rosenholm, Jarl B

2002-10-01

111

Characterization of free volume during vulcanization of styrene butadiene rubber by means of positron annihilation lifetime spectroscopy and dynamic mechanical test  

NASA Astrophysics Data System (ADS)

An experimental investigation was performed to study the effect on the free volume of the advance of the cross-linking reaction in a copolymer of styrene butadiene rubber by sulfur vulcanization. The dynamic modulus and loss tangent were evaluated over samples cured for different times at 433 K by dynamic mechanical tests over a range of frequencies between 5 and 80 Hz at temperatures between 200 and 300 K. Using the William-Landel-Ferry relationship, master curves were obtained at a reference temperature of 298 K and the coefficients c01 and c02 were evaluated. From these parameters the dependence of the free volume on the cure time is obtained. Positron annihilation lifetime spectroscopy was also used to estimate the size and number density of free volume sites in the material. The spectra were analyzed in terms of continuous distributions of free volume size. The results suggest an increase of the lower free volume size when cross linking takes place. Both techniques give similar results for the dependence of free volume on the time of cure of the polymer.

Marzocca, A. J.; Cerveny, S.; Salgueiro, W.; Somoza, A.; Gonzalez, L.

2002-02-01

112

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

113

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...

114

Protective effect of the phenyl group in. gamma. -irradiated compatible blends of poly(methyl methacrylate) and poly(styrene-co-acrylonitrile)  

Microsoft Academic Search

The sensitivity to radiation of mixtures of poly(methyl methacrylate) (PMMA) and polystyrene-co-acrylonitrile (SAN) was studied over the entire range of composition. Polystyrene-co-acrylonitrile, like polystyrene, is highly resistant to ionizing radiation, having a small G\\/sub x\\/ value for crosslinking (0.077) and an even smaller G\\/sub s\\/ value for main chain scission (0.055). In contrast, PMMA degrades readily under irradiation (with G\\/sub

T. Q. Nguyen; H. H. Kausch

1984-01-01

115

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

116

Modeling the low-cycle fatigue behavior of visco-hyperelastic elastomeric materials using a new network alteration theory: Application to styrene-butadiene rubber  

NASA Astrophysics Data System (ADS)

Although several theories were more or less recently proposed to describe the Mullins effect, i.e. the stress-softening after the first load, the nonlinear equilibrium and non-equilibrium material response as well as the continuous stress-softening during fatigue loading need to be included in the analysis to propose a reliable design of rubber structures. This contribution presents for the first time a network alteration theory, based on physical interpretations of the stress-softening phenomenon, to capture the time-dependent mechanical response of elastomeric materials under fatigue loading, and this until failure. A successful physically based visco-hyperelastic model is revisited by introducing an evolution law for the physical material parameters affected by the network alteration. The general form of the model can be basically represented by two parallel networks: a nonlinear equilibrium response and a time-dependent deviation from equilibrium, in which the network parameters become functions of the damage rate (defined as the ratio of the applied cycle over the applied cycle to failure). The mechanical behavior of styrene-butadiene rubber was experimentally investigated, and the main features of the constitutive response under fatigue loading are highlighted. The experimental results demonstrate that the evolution of the normalized maximum stress only depends on the damage rate endured by the material during the fatigue loading history. The average chain length and the average chain density are then taken as functions of the damage rate in the proposed network alteration theory. The new model is found to adequately capture the important features of the observed stress-strain curves under loading-unloading for a large spectrum of strain and damage levels. The model capabilities to predict variable amplitude tests are critically discussed by comparisons with experiments.

Ayoub, G.; Zaïri, F.; Naït-Abdelaziz, M.; Gloaguen, J. M.

2011-02-01

117

Assessment of 1,3-butadiene epidemiology studies  

Microsoft Academic Search

Positive carcinogenicity studies in mice and rats have led to concerns that 1,3-butadiene may be carcinogenic in humans under exposure conditions that have existed in occupational settings and perhaps exist today. The principal settings of interest are the styrene-butadiene rubber (SBR) manufacturing industry, which uses large quantities of 1,3-butadiene, and the 1,3-butadiene monomer industry. The potential for 1,3-butadiene exposure is

Ott

1990-01-01

118

Response of human cord blood cells to styrene exposure: evaluation of its effects on apoptosis and gene expression by genomic technology.  

PubMed

Styrene is one of the most important monomers produced worldwide, and it finds major use in the production of polystyrene, acrylonitrile-butadiene-styrene resins and unsaturated polystyrene resins. Epidemiological studies on styrene showed that the malignancies observed most frequently in humans after exposure are related to the lymphatic and haemopoietic system. IARC classified styrene a possible carcinogenic to humans (Group 2B). In this study, we evaluated the effect of styrene on gene expression profiles of human cord blood cells, as well as its activity on the apoptosis and bcl-2 related protein expression. Data demonstrated that, after 24 and 48 h of exposure, styrene (800 microM) induced an increase in the necrosis of mononuclear cord blood cells, whereas it did not cause any increase in the apoptotic process. Western blot analysis revealed a modified expression of Bax, BCl-2, c-Jun, c-Fos and Raf-1 proteins in the human cord blood cells after direct exposure to styrene, whereas p53 expression did not change. Furthermore, Macroarray analysis showed that styrene changed cord blood gene expression, inducing up-regulation of monocyte chemotactic protein 1 (MCP-1), and down-regulation of CC chemokine receptor type 1 (CCR-1) and SLP-76 tyrosine-phosphoprotein. PMID:15212811

Diodovich, Cristina; Bianchi, Marco Giorgio; Bowe, Gerard; Acquati, Francesco; Taramelli, Roberto; Parent-Massin, Dominique; Gribaldo, Laura

2004-08-01

119

21 CFR 177.1810 - Styrene block polymers.  

...3-butadiene, and subsequently hydrogenated. (b) Specifications: Styrene block polymers Molecular weight (minimum) Solubility Glass transition points Maximum extractable fraction in distilled water at specified temperatures, times, and...

2014-04-01

120

21 CFR 177.1810 - Styrene block polymers.  

Code of Federal Regulations, 2012 CFR

...3-butadiene, and subsequently hydrogenated. (b) Specifications: Styrene block polymers Molecular weight (minimum) Solubility Glass transition points Maximum extractable fraction in distilled water at specified temperatures, times, and...

2012-04-01

121

21 CFR 177.1810 - Styrene block polymers.  

Code of Federal Regulations, 2011 CFR

...3-butadiene, and subsequently hydrogenated. (b) Specifications: Styrene block polymers Molecular weight (minimum) Solubility Glass transition points Maximum extractable fraction in distilled water at specified temperatures, times, and...

2011-04-01

122

21 CFR 177.1810 - Styrene block polymers.  

Code of Federal Regulations, 2013 CFR

...3-butadiene, and subsequently hydrogenated. (b) Specifications: Styrene block polymers Molecular weight (minimum) Solubility Glass transition points Maximum extractable fraction in distilled water at specified temperatures, times, and...

2013-04-01

123

The Effect of Electron Beam (EB) Irradiation in Presence of TMPTA on Cure Characteristics and Mechanical Properties of Styrene Butadiene Rubber\\/Recycled Acrylonitrile-Butadiene Rubber (SBR\\/NBRr) Blends  

Microsoft Academic Search

The effect of electron beam (EB) irradiation on the cure characteristics and mechanical properties of unirradiated and irradiated SBR\\/NBRr blends were investigated. The SBR\\/NBRr blends were prepared at 95\\/5, 85\\/15, 75\\/25, 65\\/35, and 50\\/50 blend ratio with and without the presence of a polyfunctional monomer, trimethylolpropane triacrylate (TMPTA). Results indicated that the scorch time t2, cure time t90 and minimum

N. Z. Noriman; H. Ismail; C. T. Ratnam; A. A. Rashid

2010-01-01

124

SAMPLING AND ANALYSIS OF BUTADIENE AT A SYNTHETIC RUBBER PLANT  

EPA Science Inventory

Butadiene emission samples were collected from the process vent stream of a plant manufacturing synthetic rubber from styrene and butadiene. Samples were collected by modification of the evacuated container sampling procedure, outlined in Section 7.1.1 of EPA Method 18. On-site a...

125

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

126

21 CFR 177.1635 - Poly(p-methylstyrene) and rubber-modified poly(p-methyl-styrene).  

Code of Federal Regulations, 2011 CFR

...and rubber-modified poly(p-methyl-styrene). 177.1635 Section 177.1635...and rubber-modified poly(p-methyl-styrene). Poly(p -methylstyrene) and...33520-88-6) polymer produced by combining styrene-butadiene copolymer and/or...

2011-04-01

127

21 CFR 177.1635 - Poly(p-methylstyrene) and rubber-modified poly(p-methyl-styrene).  

...and rubber-modified poly(p-methyl-styrene). 177.1635 Section 177.1635...and rubber-modified poly(p-methyl-styrene). Poly(p -methylstyrene) and...33520-88-6) polymer produced by combining styrene-butadiene copolymer and/or...

2014-04-01

128

21 CFR 177.1635 - Poly(p-methylstyrene) and rubber-modified poly(p-methyl-styrene).  

Code of Federal Regulations, 2012 CFR

...and rubber-modified poly(p-methyl-styrene). 177.1635 Section 177.1635...and rubber-modified poly(p-methyl-styrene). Poly(p -methylstyrene) and...33520-88-6) polymer produced by combining styrene-butadiene copolymer and/or...

2012-04-01

129

21 CFR 177.1635 - Poly(p-methylstyrene) and rubber-modified poly(p-methyl-styrene).  

Code of Federal Regulations, 2013 CFR

...and rubber-modified poly(p-methyl-styrene). 177.1635 Section 177.1635...and rubber-modified poly(p-methyl-styrene). Poly(p -methylstyrene) and...33520-88-6) polymer produced by combining styrene-butadiene copolymer and/or...

2013-04-01

130

[Migrants from disposable gloves and residual acrylonitrile].  

PubMed

Disposable gloves made from polyvinyl chloride with and without di(2-ethylhexyl) phthalate (PVC-DEHP, PVC-NP), polyethylene (PE), natural rubber (NR) and nitrile-butadiene rubber (NBR) were investigated with respect to evaporation residue, migrated metals, migrants and residual acrylonitrile. The evaporation residue found in n-heptane was 870-1,300 ppm from PVC-DEHP and PVC-NP, which was due to the plasticizers. Most of the PE gloves had low evaporation residue levels and migrants, except for the glove designated as antibacterial, which released copper and zinc into 4% acetic acid. For the NR and NBR gloves, the evaporation residue found in 4% acetic acid was 29-180 ppm. They also released over 10 ppm of calcium and 6 ppm of zinc into 4% acetic acid, and 1.68-8.37 ppm of zinc di-ethyldithiocarbamate and zinc di-n-butyldithiocarbamate used as vulcanization accelerators into n-heptane. The acrylonitrile content was 0.40-0.94 ppm in NBR gloves. PMID:11775358

Wakui, C; Kawamura, Y; Maitani, T

2001-10-01

131

Butadiene production process overview  

Microsoft Academic Search

Over 95% of butadiene is produced as a by-product of ethylene production from steam crackers. The crude C4 stream isolated from the steam cracking process is fed to butadiene extraction units, where butadiene is separated from the other C4s by extractive distillation. The amount of crude C4s produced in steam cracking is dependent on the composition of the feed to

Wm. Claude White

2007-01-01

132

New modified hydrocarbon resins; An alternative to styrenated terpene resins in hot melts  

Microsoft Academic Search

This paper reports on the development of two hydrocarbon-based resin formulations that could be used with different thermoplastic block copolymers to formulate pressure-sensitive adhesives. Results are examined with one of these resins in formulations with styrene-isoprene-styrene (SIS) and styrene-butadiene (SB) compounds. The new modified hydrocarbon resin, with a softening point of 98° C, matches the adhesive performance of a terpene

Carper

1990-01-01

133

Industrial hygiene walk-through survey report of the Goodyear Tire and Rubber Company, Houston Chemical Plant, Houston, Texas  

Microsoft Academic Search

A walk-through survey was conducted at Goodyear Tire and Rubber Company, Houston, Texas in November, 1985. The purpose of the survey was to obtain information on production processes for styrene\\/butadiene rubber, styrene\\/butadiene latex and acrylonitrile\\/butadiene rubber, and to evaluate the potential for 1,3-butadiene exposure.

J. M. Fajen; L. J. Ungers

1986-01-01

134

Rheological properties characterization of styrene-isoprene-styrene block copolymers  

E-print Network

Rheological properties characterization of styrene-isoprene-styrene block copolymers using � Specific goal: characterization of complex, nanostructured materials: � Block copolymers: styrene-isoprene-styrene triblock� Block copolymers: styrene-isoprene-styrene triblock http

Petta, Jason

135

40 CFR 63.190 - Applicability and designation of source.  

Code of Federal Regulations, 2010 CFR

...resins (MBS) (iii) Butadiene-furfural cotrimer, (iv) Methylmethacrylate-acrylonitrile-butadiene-styrene (MABS) resins, and (v) Ethylidene norbornene. (7) The owner or operator of a plant site at which a process...

2010-07-01

136

Fundamental Scratch Behavior of Styrene-Acrylonitrile Random Copolymers  

E-print Network

Software ................................... 20 3.2 Model PP and PVC Systems ................................................................ 21 3.3 Scratch Testing and Analysis ............................................................... 22... of model PP and PVC. (Resolution = 300 dpi) ................................................................................ 24 3.2 Summary of critical load values for visibility and plowing for model PP and PVC...

Browning, Robert Lee

2011-10-21

137

HEALTH ASSESSMENT DOCUMENT FOR ACRYLONITRILE. FINAL REPORT  

EPA Science Inventory

Acute acrylonitrile intoxication in humans, like many volatile organic compounds, results in irritation of the eyes and nose, weakness, labored breathing, dizziness, impaired judgement, cyanosis, nausea, and convulsions. Unlike many of these other organics, acrylonitrile causes s...

138

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...

139

Dithiocarbamates as potential confounders in butadiene epidemiology.  

PubMed

Hematopoietic neoplasms associated with occupational exposure to 1,3-butadiene (BD) have been the subject of controversy. This has largely been due to the inconsistent results of epidemiology studies that have reported alternatively no or weak associations between exposure to BD and hematopoietic neoplasms. Moreover, the specificity of association of BD exposure with individual leukemia types remains unclear. In addition, a distinct difference in the pattern of leukemia risk has been observed between workers employed in BD monomer production and those involved in styrene-butadiene rubber (SBR) production: with no increase in leukemia risk observed for exposure to BD monomer alone. These observations are consistent with an increase in leukemia risk associated with the SBR process but not BD monomer and suggest the possibility that the increase may be the result of exposure to confounding factors previously not considered. In this regard, evidence is accumulating to suggest that SBR studies may be confounded by the presence of an important class of biologically active chemicals employed in the rubber industry, dithiocarbamates. The hematotoxicity and immunotoxicity of dithiocarbamates have been implicated in a wide range of clinical, animal and molecular studies, and an extremely high concordance exists between the risk of developing leukemia in SBR production and opportunity for exposure to this class of agents. Based on these findings additional studies on the epidemiology, carcinogenesis and molecular biology of dithiocarbamates are clearly warranted. PMID:9600335

Irons, R D; Pyatt, D W

1998-04-01

140

Occupational exposure to butadiene, isoprene and chloroprene.  

PubMed

Workers are exposed to butadiene, isoprene and chloroprene in the manufacture of these monomers and in their use in the production of various elastomers. These include styrene butadiene rubber, polybutadiene, polyisoprene, butyl rubber and neoprene. Monomer production and extraction are done in typical closed chemical process units where low background levels of the monomers are the result of minor leaks in valves and pumps. Occasionally, higher levels occur as a result of planned or unplanned events that cause releases. Polymer production is also a closed process, but the occasional clogging of pipes and equipment with polymer requiring maintenance operations where some release is likely occurs much more often than for monomer production. For this reason, exposure levels are generally higher on polymer production units. Polymer finishing is essentially an open process, but almost all monomer should have been stripped from the polymer before finishing. Where small amounts of solvents or monomers remain in the polymer and are volatilized in finishing, they are captured by vapor control systems. As a result, exposures in finishing are typically low. Measured levels of exposure in recent years are presented. In general, modern levels of exposure are well below OSHA, ACGIH and other applicable limits. Few measurements were made prior to the 1970s, but epidemiological estimates made by modeling suggest that levels could have been quite high in the 1940s and 1950s. In these years, manual reactor cleaning was common, and pumps often leaked. PMID:11397391

Lynch, J

2001-06-01

141

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

142

Terahertz spectroscopy of isotopic acrylonitrile  

NASA Astrophysics Data System (ADS)

Rotational spectra of four isotopically enriched, singly substituted species of acrylonitrile have been studied up to 1.2 THz. Extensive analysis of the spectra recorded for H 213C dbnd CHCN, H 2C dbnd CH 13CN, H 2C dbnd CHC 15N, and H 2C dbnd CDCN, revealed the presence of the same characteristic perturbations between the ground state and the v11 = 1 excited vibrational state, that have recently been identified in the parent molecule. For this reason transitions in v11 = 1 have also been assigned in each of the four isotopic species and a coupled state analysis of g.s. and v11 = 1 was performed on a total of around 3000 lines for each species. The derived precise values of E( v11 = 1) are found to be consistent with estimates from anharmonic force field calculations. In addition, transitions for six new doubly substituted isotopic species of acrylonitrile, H 213C dbnd 13CHCN, H 213C dbnd CH 13CN, H 2C dbnd 13CH 13CN, H 213C dbnd CHC 15N, H 2C dbnd 13CHC 15N, and H 2C dbnd CH 13C 15N, have been assigned, and their ground state spectroscopic constants have been determined. Rotational constants for all known isotopic species of acrylonitrile have been combined with ab initio calculation of vibration-rotation constants in the first evaluation of the reSE geometry of this molecule.

Kra?nicki, Adam; Kisiel, Zbigniew; Drouin, Brian J.; Pearson, John C.

2011-12-01

143

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...

144

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

145

Molecular Structure of Styrene  

NSDL National Science Digital Library

Styrene is a colorless to yellowish, oily liquid with a sweet, floral odor in the pure form but usually contains aldehydes that produce an extremely penetrating smell, that is sharp and unpleasant. The styrene monomer can be manufacture in many different techniques for commercial production but the most important are dehydrogenation of ethylbezene and the oxidation of ethylbenzene to ethylbenzene hydroperoxide. Styrene is used in the manufacture of plastics, synthetic rubber, polymer resins and protective coatings as insulators. Styrene is also used as a dilutant to reduce viscosity of uncured resin systems. In addition, it is used in dental fillings, as a component in agricultural products, as stabilizing agent and as a chemical intermediate. Styrene polymer is used in the manufacture of photocopier toner. Styrene will corrode copper and copper alloys.

2004-11-11

146

Optimize styrene units  

SciTech Connect

A simulation system is introduced to improve production on older EB reactors and styrene plants to compete with the latest styrene processes such as the Monsanto process. A simulation model of ethyl benzene styrene process flow was built and tested and is schematicized. Each tower, the EB reactor, the PEB recovery tower, and the benzene-toluene separator are specified. Sloppy design in the lumping of described components is eliminated. An integrated reactor fractionation system with EB reactor and styrene process units is created.

Huang, W.

1983-04-01

147

Fundamental Studies on Styrene-Butadiene-Styrene Polymer Modified Road Bitumens.  

National Technical Information Service (NTIS)

During the last two decades, road structures have deteriorated more rapidly than expected due to increases in traffic density, axle loading and tyre pressure and an insufficient degree of maintenance. To counteract the deterioration of road structures, th...

X. Lu

1996-01-01

148

24 CFR 3280.803 - Power supply.  

Code of Federal Regulations, 2010 CFR

...manufactured home floor. The raceway may be rigid conduit, electrical metallic tubing or polyethylene (PE), poly-vinylchloride (PVC) or acrylonitrile-butadiene-styrene (ABS) plastic tubing having a minimum wall thickness of nominal 1/8 inch....

2010-04-01

149

24 CFR 3280.803 - Power supply.  

Code of Federal Regulations, 2011 CFR

...manufactured home floor. The raceway may be rigid conduit, electrical metallic tubing or polyethylene (PE), poly-vinylchloride (PVC) or acrylonitrile-butadiene-styrene (ABS) plastic tubing having a minimum wall thickness of nominal 1/8 inch....

2011-04-01

150

24 CFR 3280.803 - Power supply.  

Code of Federal Regulations, 2013 CFR

...manufactured home floor. The raceway may be rigid conduit, electrical metallic tubing or polyethylene (PE), poly-vinylchloride (PVC) or acrylonitrile-butadiene-styrene (ABS) plastic tubing having a minimum wall thickness of nominal 1/8 inch....

2013-04-01

151

24 CFR 3280.803 - Power supply.  

Code of Federal Regulations, 2012 CFR

...manufactured home floor. The raceway may be rigid conduit, electrical metallic tubing or polyethylene (PE), poly-vinylchloride (PVC) or acrylonitrile-butadiene-styrene (ABS) plastic tubing having a minimum wall thickness of nominal 1/8 inch....

2012-04-01

152

24 CFR 3280.803 - Power supply.  

...manufactured home floor. The raceway may be rigid conduit, electrical metallic tubing or polyethylene (PE), poly-vinylchloride (PVC) or acrylonitrile-butadiene-styrene (ABS) plastic tubing having a minimum wall thickness of nominal 1/8 inch....

2014-04-01

153

29 CFR 1910.1045 - Acrylonitrile.  

...shown similar types of tumors in animals exposed to 80 ppm. In addition...Camden, S.C. In addition, the animal testing of acrylonitrile has resulted in...dizziness, and general weakness. The animal studies cited above suggest...

2014-07-01

154

Evaluate styrene production  

SciTech Connect

Improvements and innovations in styrene production since 1966 are outlined. Rigorous process models are attributed to the changes. Such models are used to evaluate the effects of changing raw material costs, utility costs, and available catalyst choices. The process model can also evaluate the best operating configuration and catalyst choice for a plant. All specified innovations are incorporated in the Mobil/Badger ethylbenzene and the Cosden/Badger styrene processes (both of which are schematicized). Badger's training programs are reviewed. Badger's Styrenics Business Team converts information into plant design basis. A reaction model with input derived from isothermal and adiabatic pilot plant units is at the heart of complete computer simulation of ethylbenzene and styrene processes.

Hagopian, C.R.; Lewis, P.J.; McDonald, J.J.

1983-02-01

155

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

E-print Network

. Polymerization Nechanisms The mechanisms which have been proposed for the monomers butadiene, isoprene and styrene -- are similar. For these monomers two bas. ic reaction mechanisms, stepwise addition or chain catalysis, have been proposed for 11th', us... of Polymerization The most genera]ly accepted reaction mechanism is by stepwise addition without any appreciable termination or chain transfer. Thus the over-all reaction rate i. s a combined sate of initiation and propagation. , qany of the early investigators...

Hasan, Sayeed

2012-06-07

156

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.

157

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

158

Metabolism and toxicity of styrene.  

PubMed Central

The absorption, blood levels, distribution, excretion, and biotransformation of styrene in man and experimental animals are briefly reviewed. The acute toxicity of styrene appears to be unrelated to its biotransformation. Reports of organ toxicity upon chronic exposure to styrene are rare; however, since the chief intermediate in styrene metabolism is an epoxide, hepatotoxicity due to covalent binding at the site of formation appears to be a possibility. PMID:809262

Leibman, K C

1975-01-01

159

SOURCE ASSESSMENT: ACRYLONITRILE MANUFACTURE (AIR EMISSIONS)  

EPA Science Inventory

The report gives results of an analysis of atmospheric emissions from propylene-based acrylonitrile manufacturing plants. Uncontrolled and controlled emission factors are given for each species emitted to the atmosphere from each source within a typical plant, based on field samp...

160

Evaluate styrene production  

Microsoft Academic Search

Improvements and innovations in styrene production since 1966 are outlined. Rigorous process models are attributed to the changes. Such models are used to evaluate the effects of changing raw material costs, utility costs, and available catalyst choices. The process model can also evaluate the best operating configuration and catalyst choice for a plant. All specified innovations are incorporated in the

C. R. Hagopian; P. J. Lewis; J. J. McDonald

1983-01-01

161

New modified hydrocarbon resins; An alternative to styrenated terpene resins in hot melts  

SciTech Connect

This paper reports on the development of two hydrocarbon-based resin formulations that could be used with different thermoplastic block copolymers to formulate pressure-sensitive adhesives. Results are examined with one of these resins in formulations with styrene-isoprene-styrene (SIS) and styrene-butadiene (SB) compounds. The new modified hydrocarbon resin, with a softening point of 98{degrees} C, matches the adhesive performance of a terpene resin with a softening point of 105{degrees} C. The resin performs as well as the modified terpene in SIS-, SB-, and EVA-based adhesives. The new hydrocarbon resin is especially well suited for hot-melt adhesives. It exhibits low volatility, good color stability, and excellent melt viscosity stability. Since the new resin is based on petroleum hydrocarbon feedstocks, it should be available at moderate, stable prices. The other hydrocarbon resin, with a softening point of 85{degrees} C, produced comparable results.

Carper, J.D. (Hercules Inc., Wilmington, DE (US))

1990-06-01

162

Growth of the black yeast Exophiala jeanselmei on styrene and styrene-related compounds  

Microsoft Academic Search

The black yeast Exophiala jeanselmei can grow on styrene as the sole source of carbon and energy in concentrations up to 0.36 mm. No growth is observed at higher styrene concentrations. Styrene oxidation is induced by styrene or styrene-related compounds, whereas glucose represses this styrene oxidation. E. jeanselmei shows a broad substrate specificity: various aromatic compounds are used as the

H. H. J. Cox; J. H. M. Houtman; H. J. Doddema; W. Harder

1993-01-01

163

An experimental system for the n-butyl-lithium initiated polymerization of styrene in a multi-sampled batch reactor  

E-print Network

attention. One of the interesting features of this class of anionic, step-wise addition polymerizations is the absence of termination reactions in some monofunctional vinylic monomers, notably styrene, isoprene and butadiene. This phenomenon can lead... to the production of extremely narrow polymer molecular weight distributions. There are several experimental quantities upon which kinetic models of these polymerization reactions can be based. These are monomer concentration, alkyllithium initiator...

Cox, James Harvey

2012-06-07

164

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...

165

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

166

Glass transition temperatures of copolymers from methyl methacrylate, styrene, and acrylonitrile: binary copolymers  

Microsoft Academic Search

By using a new theoretical glass transition temperature (T\\u000a g)–composition equation, T\\u000a g’s of statistic binary copolymers obtained from MMA, St and AN were investigated in this article. The copolymers were prepared\\u000a by bulk copolymerization using azo-bis-isobutyronitrile (AIBN) as initiator. The compositions and T\\u000a g’s were determined by NMR and DSC, respectively. The monomer reactivity ratios were obtained by nonlinear

Liubin Fan; Dongmei Zhao; Ce Bian; Yanli Wang; Guodong Liu

167

21 CFR 177.1040 - Acrylonitrile/styrene copoly-mer.  

Code of Federal Regulations, 2013 CFR

...federal_regulations/ibr_locations.html. 2 As determined by the method...federal_regulations/ibr_locations.html. 3 As determined on appropriately...federal_regulations/ibr_locations.html. (d) Interim listing....

2013-04-01

168

21 CFR 177.1040 - Acrylonitrile/styrene copoly-mer.  

...federal_regulations/ibr_locations.html. 2 As determined by the method...federal_regulations/ibr_locations.html. 3 As determined on appropriately...federal_regulations/ibr_locations.html. (d) Interim listing....

2014-04-01

169

21 CFR 177.1040 - Acrylonitrile/styrene copoly-mer.  

Code of Federal Regulations, 2012 CFR

...federal_regulations/ibr_locations.html. 2 As determined by the method...federal_regulations/ibr_locations.html. 3 As determined on appropriately...federal_regulations/ibr_locations.html. (d) Interim listing....

2012-04-01

170

Butadiene Complexes of Titanium(II) and Titanium(0): Synthesis, Butadiene Dimerization Catalysis, and Crystal  

E-print Network

in the catalytic dimerization of butadiene to the Diels-Alder dimer 4-vinylcyclohexene at rates of 5 turnovers of organic chemicals. For example, dimers of butadiene, such as 1,5-cyclooctadi- ene, 1,3,7-octatriene, and 4

Girolami, Gregory S.

171

Thermoplastic Resin Sales by Major Market (millions of pounds, dry weight basis)  

E-print Network

Thermoplastic Resin Sales by Major Market 2004-2008 (millions of pounds, dry weight basis) Major selected thermoplastic resins: Low-Density Polyethylene Polyvinyl Chloride Linear-Low-Density Polyethylene-Acrylonitrile Polystyrene Other Styrene-based Polymers Styrene Butadiene Latexes (SBL) Engineering Resins Thermoplastic

Laughlin, Robert B.

172

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

173

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

174

Rapid Modular Synthesis and Processing of Thiol-Ene Functionalized Styrene-Butadiene Block Copolymers  

E-print Network

difficult. Therefore, the development of facile and effective postpolymerization modification techniques of Chemistry and Materials Science, Food and Drug Administration, Silver Spring, Maryland 20993, United States. This technique described allows for the formation of nanopatterned block copolymer films with controlled

Rubloff, Gary W.

175

Mortality of workers exposed to acrylonitrile.  

PubMed

A retrospective cohort study was carried out in The Netherlands to investigate the potential carcinogenic effects in humans of occupational exposure to acrylonitrile (AN). The total study group consisted of 6803 workers "from eight chemical plants and one control plant" of whom 2842 had been exposed to AN between January 1, 1956 and July 1, 1979 for at least 6 months. All workers were employed by one of eight chemical companies. An extensive review of the available industrial hygiene data was conducted to assess the magnitude of past exposure to AN, occurrence of peak exposures, exposure to recognized potential human carcinogens, and respirator use. The total cohort was observed for mortality until January 1, 1988. In collaboration with the Central Bureau of Statistics, the causes of death were traced for the workers who died before 01-01-1988. In the exposed as well as in the nonexposed cohorts the total mortality was lower than expected, based on national mortality statistics. The observed cancer mortality in the exposed cohort was similar to the expected mortality. Specific analyses were carried out to investigate dose-response relationships and latency for total mortality and lung cancer mortality. Overall, no indications were found for a carcinogenic effect in this cohort of workers exposed to AN. PMID:1506938

Swaen, G M; Bloemen, L J; Twisk, J; Scheffers, T; Slangen, J J; Sturmans, F

1992-08-01

176

Bacterial degradation of styrene involving a novel flavin adenine dinucleotide-dependent styrene monooxygenase.  

PubMed Central

By using styrene as the sole source of carbon and energy in concentrations of 10 to 500 microM, 14 strains of aerobic bacteria and two strains of fungi were isolated from various soil and water samples. In cell extracts of 11 of the bacterial isolates, a novel flavin adenine dinucleotide-requiring styrene monooxygenase activity that oxidized styrene to styrene oxide (phenyl oxirane) was detected. In one bacterial strain (S5), styrene metabolism was studied in more detail. In addition to styrene monooxygenase, cell extracts from strain S5 contained styrene oxide isomerase and phenylacetaldehyde dehydrogenase activities. A pathway for styrene degradation via styrene oxide and phenylacetaldehyde to phenylacetic acid is proposed. PMID:2339888

Hartmans, S; van der Werf, M J; de Bont, J A

1990-01-01

177

46 CFR 154.1750 - Butadiene or vinyl chloride: Refrigeration system.  

Code of Federal Regulations, 2010 CFR

...2010-10-01 false Butadiene or vinyl chloride: Refrigeration system. 154.1750 Section 154.1750...154.1750 Butadiene or vinyl chloride: Refrigeration system. A refrigeration system for butadiene or vinyl chloride...

2010-10-01

178

The role of acrylonitrile in controlling the structure and properties of nanostructured ionomer films.  

PubMed

Ionomers are polymers which contain ionic groups that are covalently bound to the main chain. The presence of a small percentage of ionic groups strongly affects the polymer's mechanical properties. Here, we examine a new family of nanostructured ionomer films prepared from core-shell polymer nanoparticles containing acrylonitrile (AN), 1,3-butadiene (Bd) and methacrylic acid (MAA). Three new AN-containing dispersions were investigated in this study. The core-shell nanoparticles contained a PBd core. The shells contained copolymerised Bd, AN and MAA, i.e., PBd-AN-MAA. Three types of crosslinking were present in these films: covalent crosslinks (from Bd); strong physical crosslinks (involving ionic bonding of RCOO(-) and Zn(2+)) and weaker physical crosslinks (from AN). We examined and compared the roles of AN and ionic crosslinking (from added Zn(2+)) on the structure and mechanical properties of the films. The FTIR spectroscopy data showed evidence for RCOOH-nitrile hydrogen bonding with tetrahedral geometry. DMTA studies showed that AN copolymerised within the PBd-AN-MAA phase uniformly. Tensile stress-strain data showed that inclusion of AN increased elasticity and toughness. Analysis showed that about 33 AN groups were required to provide an elastically-effective chain. However, only 1.5 to 2 ionically bonded RCOO(-) groups were required to generate an elastically-effective chain. By contrast to ionic bonding, AN inclusion increased the modulus without compromising ductility. Our results show that AN is an attractive, versatile, monomer for increasing the toughness of nanostructured ionomers and this should also be the case for other nanostructured polymer elastomers. PMID:24852137

Tungchaiwattana, Somjit; Musa, Muhamad Sharan; Yan, Junfeng; Lovell, Peter A; Shaw, Peter; Saunders, Brian R

2014-07-14

179

Acrylonitrile butadiene rubber (NBR)/manganous tungstate (MnWO4) nanocomposites: Characterization, mechanical and electrical properties  

NASA Astrophysics Data System (ADS)

Nanocomposites of NBR with manganous-tungstate nanoparticles were prepared through vulcanization process. The extent of interaction of nanoparticles with the polymer was studied by FTIR, SEM, XRD, TGA and AC conductivity. FTIR and XRD ascertain the interaction of NBR with MnWO4 nanoparticles. SEM analysis established that the nanopartilces were well dispersed in the macromolecular chain of NBR. The mechanical properties of the nanocomposites were studied as a function of filler loading. The nanocomposites exhibited enhanced thermal stability as seen in TGA. Conductivity and dielectric properties of nanocomposites increase with increase in concentration of MnWO4 nanoparticles (7phr) and thereafter the value decreases.

Ramesan, M. T.; Abdu Raheem V., P.; Jayakrishnan, P.; Pradyumnan, P. P.

2014-10-01

180

Ab initio study of styrene and -methyl styrene in the ground and in the two lowest excited singlet states  

E-print Network

Ab initio study of styrene and -methyl styrene in the ground and in the two lowest excited singlet; accepted 28 March 1995 The structure and vibrational frequencies of styrene and trans- -methyl styrene treating molecules as large as styrene. High resolution fluorescence excitation and resonant en- hanced

Haas, Yehuda

181

Toxicity of acrylonitrile on human KB cells in culture  

SciTech Connect

Acrylonitrile is widely used in the manufacture of plastics, surface coatings, adhesives etc. The toxicity of this compound in vivo has been reported. Apparently the toxicity is related to the cyanide effects. The authors report here the in vitro toxicity of this compound using the KB cell culture systems.

Mochida, Kyo; Gomyoda, Manabu; Fujita, Tokio; Yamagata, Kei

1989-03-01

182

Lipase catalysed Michael addition of secondary amines to acrylonitrile.  

PubMed

A new enzymatic process is described. Different preparations of lipase B from Candida antarctica are able to catalyse Michael-type addition of secondary amines to acrylonitrile. This new reaction widens the applicability of these biocatalysts in organic synthesis. PMID:15278156

Torre, Oliver; Alfonso, Ignacio; Gotor, Vicente

2004-08-01

183

Photopolymerization of Acrylonitrile: Benzophenone-Isopropanol System as Initiator  

Microsoft Academic Search

Irradiation of benzophenone in the presence of a suitable hydrogen donor like alcohol leads to benzpinacol and the ketone as sole products. This reaction proceeds through ketyl radical intermediates. This photoredox system may be used for photopolymerization. Photopolymerization of acrylonitrile using isopropanol and benzophenone combination as initiator has been studied. The formation of the polymer is directly proportional to irradiation

C. P. Murthy; B. Sethuram; T. Navaneeth Rao

1984-01-01

184

Temporal Processing Disorder Associated with Styrene Exposure  

Microsoft Academic Search

Little evidence exists on the possible adverse effects of styrene on the central part of the auditory system. The present investigation aimed to study the possible association between styrene exposure and temporal processing abilities. Fifty-nine styrene-exposed subjects and 50 nonexposed control subjects were tested. Pure-tone audiometry (125–8000 Hz) and 3 temporal processing tests (gaps-in-noise, frequency pattern test and duration pattern

Ewa Zamyslowska-Szmytke; Adrian Fuente; Ewa Niebudek-Bogusz; Mariola Sliwinska-Kowalska

2009-01-01

185

Graft copolymerization of acrylonitrile onto bagasse and wood pulps  

SciTech Connect

Graft copolymerization of acrylonitrile onto bagasse and wood pulps has been studied using ceric ammonium nitrate as initiator. The effect of order of reactants addition on grafting was examined: three methods were studied. Addition of the pulp to a mixture of initiator and monomer (method A) resulted in more efficient grafting than the other two methods. The reaction produced more grafting at 50/sup 0/C than at 30/sup 0/C or at 40/sup 0/C. The results showed that the monomer and initiator concentrations are the major factors influencing the grafting rate of acrylonitrile. Increasing the acrylonitrile or initiator concentration was accompanied by a substantial increase in graft yields. Increasing the initiator concentration is more effective on polymerization rate than the increase in monomer concentration. The extent of grafting of this monomer can best be controlled by reaction time. Water swelling of pulps significantly affected the grafting rate of acrylonitrile as well as the ceric consumption during grafting. The reactivity of bagasse pulp towards grafting of acrylonitrile is higher than that of wood pulp due to a more open structure of cellulose in bagasse pulp as well as the presence of some lignin which accelerates grafting. Ceric consumption during grafting depends on the nature of the pulp as well as the monomer and initiator concentrations, time, temperature, and the method of grafting. More Ce(IV) is consumed during grafting than during oxidation of the pulps under identical reaction conditions, due to homopolymer formation which accompanied grafting. The ceric consumption by bagasse during grafting or oxidation is somewhat greater than that consumed by wood pulp under similar reaction conditions.

Heikal, S.O.; El-Kalyoubi, S.F.

1982-08-01

186

40 CFR 721.10151 - Modified styrene, divinylbenzene polymer (generic).  

Code of Federal Regulations, 2010 CFR

...false Modified styrene, divinylbenzene polymer (generic). 721.10151 Section...10151 Modified styrene, divinylbenzene polymer (generic). (a) Chemical substance...generically as modified styrene, divinylbenzene polymer (PMN P-07-642) is subject to...

2010-07-01

187

40 CFR 721.10151 - Modified styrene, divinylbenzene polymer (generic).  

Code of Federal Regulations, 2011 CFR

...false Modified styrene, divinylbenzene polymer (generic). 721.10151 Section...10151 Modified styrene, divinylbenzene polymer (generic). (a) Chemical substance...generically as modified styrene, divinylbenzene polymer (PMN P-07-642) is subject to...

2011-07-01

188

40 CFR 721.10151 - Modified styrene, divinylbenzene polymer (generic).  

Code of Federal Regulations, 2013 CFR

...2013-07-01 2013-07-01 false Modified styrene, divinylbenzene polymer (generic...Substances § 721.10151 Modified styrene, divinylbenzene polymer (generic...substance identified generically as modified styrene, divinylbenzene polymer (PMN...

2013-07-01

189

40 CFR 721.10151 - Modified styrene, divinylbenzene polymer (generic).  

Code of Federal Regulations, 2012 CFR

...2012-07-01 2012-07-01 false Modified styrene, divinylbenzene polymer (generic...Substances § 721.10151 Modified styrene, divinylbenzene polymer (generic...substance identified generically as modified styrene, divinylbenzene polymer (PMN...

2012-07-01

190

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...

191

Study of the inclusion processes of styrene and ?-methyl-styrene in ?-cyclodextrin  

NASA Astrophysics Data System (ADS)

The inclusion complexes of styrene and ?-methyl-styrene with ?-cyclodextrin (?-CD) were investigated by using [ 1H] NMR titration in solution and X-ray diffraction (XRD) analysis, thermo-gravimetric analysis (TGA), elemental analysis (EA) in the solid state. The inclusion process has been studied by using PM3 quantum-mechanical semi-empirical method. The calculated results are in agreed with the experimental data. All results show that ?-methyl-styrene has stronger interaction with ?-cyclodextrin than styrene does, so the complex of ?-CD-?-methyl-styrene is more stable.

Cao, Yujuan; Xiao, Xiaohua; Ji, Shengfu; Lu, Runhua; Guo, Qingxiang

2004-03-01

192

REDUCING STYRENE EMISSIONS FROM SPRAYED FILLED RESINS  

EPA Science Inventory

Styrene emissions are coming under increasing study as the U.S. Environmental Protection Agency (EPA) develops maximum achievable control technology standards. During the manufacture of fiber-reinforced plastics/composites products, styrene, a volatile organic compound and a haz...

193

Evidence for cellular protein covalent binding derived from styrene metabolite.  

PubMed

Styrene is one of the most important industrial intermediates consumed in the world. Human exposure to styrene occurs mainly in the reinforced plastics industry, particularly in developing countries. Styrene has been found to be hepatotoxic and pneumotoxic in humans and animals. The biochemical mechanisms of styrene-induced toxicities remain unknown. Albumin and hemoglobin adduction derived from styrene oxide, a major reactive metabolite of styrene, has been reported in blood samples obtained from styrene-exposed workers. The objectives of the current study focused on cellular protein covalent binding of styrene metabolite and its correlation with cytotoxicity induced by styrene. We found that radioactivity was bound to cellular proteins obtained from mouse airway trees after incubation with (14)C-styrene. Microsomal incubation studies showed that the observed protein covalent binding required the metabolic activation of styrene. The observed radioactivity binding in protein samples obtained from the cultured airways and microsomal incubations was significantly suppressed by co-incubation with disulfiram, a CYP2E1 inhibitor, although disulfiram apparently did not show a protective effect against the cytotoxicity of styrene. A 2-fold increase in radioactivity bound to cellular proteins was detected in cells stably transfected with CYP2E1 compared to the wild-type cells after (14)C-styrene exposure. With the polyclonal antibody developed in our lab, we detected cellular protein adduction derived from styrene oxide at cysteinyl residues in cells treated with styrene. Competitive immunoblot studies confirmed the modification of cysteine residues by styrene oxide. Cell culture studies showed that the styrene-induced protein modification and cell death increased with the increasing concentration of styrene exposure. In conclusion, we detected cellular protein covalent modification by styrene oxide in microsomal incubations, cultured cells, and mouse airways after exposure to styrene and found a good correlation between styrene-induced cytotoxicity and styrene oxide-derived cellular protein adduction. PMID:20470765

Yuan, Wei; Jin, Hua; Chung, Jou-Ku; Zheng, Jiang

2010-08-01

194

Perforation of ABS pipes by boring bivalve Martesia striata: a case study  

Microsoft Academic Search

Acrylonitrile butadiene styrene (ABS) pipes are considered to be immune for boring organisms. However, inspection of the offshore cooling water conduits of Lumut combined cycle power plant, Malaysia show that ABS pipes may not necessarily be immune for wood boring pholads, Martesia striata. M. striata caused heavy damage by drilling holes in ABS pipes used (about 5 years) for transportation

H. A. Jenner; S. Rajagopal; G. Van der Velde; M. S. Daud

2003-01-01

195

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

196

Pyrolysis of waste plastic crusts of televisions  

Microsoft Academic Search

The disposal of waste plastic crusts of televisions is an issue that is gaining increasing interest around the world. In this investigation, the pyrolysis and catalytic cracking of the waste television crusts mainly composed of acrylonitrile–butadiene–styrene copolymer was studied. Thermogravimetric analysis was used for initial characterization of the pyrolysis of the waste plastic, but most of the investigations were carried

Xinmin Liu; Zhen Wang; Dongyan Xu; Qingjie Guo

2012-01-01

197

Modeling of Bond Formation Between Polymer Filaments in the Fused Deposition Modeling Process  

Microsoft Academic Search

The bonding quality among polymer filaments in the fused deposition modeling (FDM) process determines the integrity and mechanical properties of resultant prototypes. This paper investigates the bond formation among extruded acrylonitrile butadiene styrene (ABS) filaments in the FDM process. Thermal analysis of the FDM process resulted in an estimation of the cooling profile of the extruded filaments. Sintering experiments were

Céline Bellehumeur; Longmei Li; Qian Sun; Peihua Gu

2004-01-01

198

Microbial community analysis of an aerobic nitrifying-denitrifying MBR treating ABS resin wastewater  

Microsoft Academic Search

A two-stage aerobic membrane bioreactor (MBR) system for treating acrylonitrile butadiene styrene (ABS) resin wastewater was carried out in this study to evaluate the system performance on nitrification. The results showed that nitrification of the aerobic MBR system was significant and the highest TKN removal of approximately 90% was obtained at hydraulic retention time (HRT) 18h. In addition, the result

Chia-Yuan Chang; Kulchaya Tanong; Jia Xu; Hokyong Shon

2011-01-01

199

An investigation into welding of engineering thermoplastics using focused microwave energy  

Microsoft Academic Search

Microwaves have been used for many years in industrial heating applications because of their ability to heat materials volumetrically. The dielectric properties of a material determine its ability to absorb microwave radiation. In this paper, the dielectric properties of engineering thermoplastic materials, which include ultra high molecular weight polyethylene (UHMW PE), polycarbonate (PC) and acrylonitrile-butadiene-styrene (ABS) polymers under room temperature

Prasad K. D. V Yarlagadda; Tan Chuan Chai

1998-01-01

200

Chromatography of Suspensions – An Experimental and Theoretical Investigation of Axial Dispersion Phenomena  

Microsoft Academic Search

Herein is reported an experimental and theoretical investigation of axial dispersion phenomena in the chromatography of spherical suspensions in the submicron range. Peak separation and broadening were measured for a number of particle suspensions (polystyrene, polyvinylacetate, styrene-acrylic acid copolymer, butadiene-acrylonitrile copolymer latices and silica particles) using different column combinations containing porous inorganic packing materials (Fractosils, Bioglass, Corning Glass) and over

A. E. Hamielec; S. Singh

1978-01-01

201

Study on Effective Microorganisms Bacteria for Acrylonitrile Wastewater Treatment  

Microsoft Academic Search

In this study, according to the specific characteristics of acrylonitrile wastewater, Effective Microorganisms (EM) was used as Contact oxidation strain. The optimum conditions of EM bacteria domestication and contact oxidation treatment, such as pH, concentration and temperature, was confirmed. In addition, the results of aerobic treatment of wastewater suggested that COD effluent reduced to below 100mg\\/L, the removal efficiency to

Zhou Guizhong; Sun Jing

2010-01-01

202

Effect of molecular weight between cross-links on the abrasion behavior of rubber by a blade abrader  

Microsoft Academic Search

The effect of molecular weight between cross-links on the abrasion behavior of rubber was investigated using acrylonitrile–butadiene rubber (NBR), styrene–butadiene rubber (SBR), and natural rubber (NR) with a blade abrader. The rate of abrasion was found to be almost constant irrespective of the cross-link density of rubber at low frictional input work, whereas it decreased to a minimum and increased

Kilwon Cho; Daeho Lee

2000-01-01

203

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

204

Simultaneous determination of aromatic acid metabolites of styrene and styrene-oxide in rat urine by gas chromatography -flame ionisation detection  

E-print Network

1 Simultaneous determination of aromatic acid metabolites of styrene and styrene-oxide in rat urine metabolites of styrene and styrene-oxide in rat urine: i.e. benzoic (BA), phenylacetic (PAA), mandelic (MA to quantitatively analyze styrene, styrene-oxide, ethylbenzene and toluene metabolites in urines samples from rats

Paris-Sud XI, Université de

205

HEALTH AND ENVIRONMENTAL EFFECTS PROFILE FOR STYRENE  

EPA Science Inventory

The Health and Environmental Effects Profile for styrene was prepared by the Office of Health and Environmental Assessment, Environmental Criteria and Assessment Office, Cincinnati, OH for the Office of Solid Waste and Emergency Response to support listings of hazardous constitue...

206

Cooxidation of styrene by horseradish peroxidase (HRP) and 4-methylphenol  

SciTech Connect

Styrene is cooxidized to styrene oxide in a system containing HRP/H/sub 2/O/sub 2/ and 4-methylphenol. Styrene oxide is not formed in the absence of any of these components, or if the reaction is run under anaerobic conditions. Styrene oxide formation is inhibited by ascorbic acid and catalase but not mannitol or superoxide dismutase. Incubation with /sup 18/O/sub 2/ resulted in more than 90% incorporation of label into styrene oxide. The epoxidation of trans-(1-/sup 2/H)styrene occurred with partial loss of stereochemistry. The products expected from addition of the phenoxy radical to styrene were synthesized and shown not to be formed. Finally, EPR evidence was obtained for formation of 4-methyl catechol in the presence, but not absence, of styrene. The results imply that a peroxy radical is formed by addition of oxygen to the HRP-generated 4-methylphenoxy radical, and that this peroxy radical then cooxidizes styrene.

Grab, L.A.; Ortiz, P.R.

1987-05-01

207

Aspects of the synthesis of poly(styrene-b-isobutylene-b-styrene) block copolymer  

SciTech Connect

Poly(styrene-b-isobutylene-b-styrene) block copolymers were synthesized by the addition of a solution of styrene to living polyisobutylene chains produced from a dicumyl chloride/TiCl{sub 4}/pyridine initiating system. The effect of the time of the styrene addition was investigated with respect to product polymer composition. Styrene addition at an isobutylene reaction time far exceeding the time necessary for complete isobutylene consumption was found to result in a very rapid polymerization of styrene, some of which was blocked properly and some of which was not. Conversely, premature addition of styrene (at intermediate isobutylene conversion) resulted in retardation of the polymerization and possible creation of a transitional random copolymer block. The appropriate time for styrene addition seems to be at an isobutylene conversion which corresponds to the point of departure from linearity of a plot of {minus}ln1{minus}(DP{sub n}[I]{sub o}/[M]{sub o}) vs time. Linearity of this plot ensures the absence of chain transfer and termination, and for the isobutylene polymerization system under investigation, the point of departure from linearity has been determined to be an approximately 90% conversion.

Storey, R.F.; Chisholm, B.J. [Univ. of Southern Mississippi, Hattiesburg, MI (United States)

1993-12-31

208

Radical Polymerization of Styrene and Styrene–Butylmethacrylate in a Counterrotating Twin Screw Extruder  

Microsoft Academic Search

This article describes the copolymerization of styrene-butylmethacrylate (St-BMA) and the homopolymerization of styrene (St) in a counterrotating twin screw extruder. The effect of prepolymerization on both the product properties and process was studied. It turned out that the process of reactive extrusion was strongly influenced by prepolymerization. Also, the product properties were altered by prepolymerization. When the polymerization of St

A. J. van der Goot; L. P. B. M. Janssen

1997-01-01

209

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

210

BIOMARKERS IN CZECH WORKERS EXPOSED TO 1,3-BUTADIENE: A TRANSITIONAL EPIDEMIOLOGIC STUDY  

EPA Science Inventory

All the biomarkers of exposure were correlated with the measurements of butadiene recorded by the air samplers. Although the correlation between hemoglobin adducts and exposure levels was strongest, urinary metabolites were also found to be very useful measures of butadiene...

211

Microbial transformation of styrene by anaerobic consortia.  

PubMed

Methanogenic microbial consortia, originally enriched from anaerobic sewage sludge with ferulic acid or styrene (vinylbenzene) as sole organic carbon and energy sources, were used to study transformation of styrene under strictly anaerobic conditions. Styrene, which was added as the substrate in a range of concentrations from 0.1 to 10 mmol/l, was extensively degraded but no methane production was observed during incubation for eight months. The addition of yeast extract during the enrichment stage completely inhibited degradation of styrene. Gas chromatography (GC), gas chromatography/mass spectrometry (GC/MS), high performance liquid chromatography (HPLC) analyses of the culture fluid, and GC analyses of the anaerobic headspace, indicated that the transformation of this arylalkene was initiated through an oxidation-reduction reaction and that the favoured mechanism was most likely the addition of water across the double bond in the alkenyl side-chain. The degradation proceeded through to carbon dioxide, the final product. Benzoic acid and phenol were transient compounds found in highest concentrations in the spent culture fluid and are suggested as the key intermediates of the transformation process. The tentative routes of anaerobic transformation partially overlap with those previously proposed for aromatic hydrocarbons such as toluene. Several pure cultures, which were tentatively identified as Clostridium spp. and Enterobacter spp., were isolated from the styrene-degrading consortia. Two of these cultures were demonstrated to grow on styrene as sole carbon and energy source. Additionally, a pure culture of Enterobacter cloacae DG-6 (ATCC 35929) which had been isolated previously from the ferulate-degrading consortium, was shown to degrade styrene through to carbon dioxide. PMID:2272946

Grbi?-Gali?, D; Churchman-Eisel, N; Mrakovi?, I

1990-08-01

212

Deuterium Kinetic Isotope Effects in Butadiene Epoxidation over Unpromoted and Cs-Promoted Silver Catalysts  

Microsoft Academic Search

Selectively deuterium-labeled isotopomers of 1,3-butadiene (CD2CDCDCD2, CD2CHCHCD2, and CH2CDCDCH2) have been used as feed reactants to study kinetic isotope effects (KIEs) in the epoxidation of butadiene over both unpromoted and Cs-promoted catalysts. On unpromoted catalysts, the rate of formation of the epoxide product, 3,4-epoxy-1-butene (EpB), is increased relative to that for unlabeled butadiene for the butadiene isotopomers labeled on the

J. Will Medlin; John R Monnier; Mark A Barteau

2001-01-01

213

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 ...

214

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

PubMed

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(-1) s(-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

2014-01-01

215

Purification process design in the production of styrene monomer  

Microsoft Academic Search

An economic study of two alternatives for styrene monomer purification based on equilibrium staged processes is presented. For this purpose, the solubility of t-butylcatechol (TBC) in styrene and the styrene–water liquid–liquid equilibrium were experimentally determined. In terms of economics, a combined process extraction–distillation shows worse results than a conventional distillation process, for the styrene purification, but this process could be

Ismael Díaz; Paul Langston; Gabriel Ovejero; María Dolores Romero; Eduardo Díez

2010-01-01

216

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

217

Surface Engineering of Styrene/PEGylated-Fluoroalkyl Styrene Block Copolymer Thin Films  

SciTech Connect

A series of diblock copolymers prepared from styrenic monomers was synthesized using atom transfer radical polymerization. One block was derived from styrene, whereas the second block was prepared from a styrene modified with an amphiphilic PEGylated-fluoroalkyl side chain. The surface properties of the resulting polymer films were carefully characterized using dynamic contact angle, XPS, and NEXAFS measurements. The polymer morphology was investigated using atomic force microscope and GISAXS studies. The block copolymers possess surfaces dominated by the fluorinated unit in the dry state and a distinct phase separated microstructure in the thin film. The microstructure of these polymers is strongly influenced by the thin film structure in which it is investigated.

Martinelle, E.; Menghetti, S; Galli, G; Glisenti, A; Krishnan, S; Paik, M; Ober, C; Smilgies, D; Fischer, D

2009-01-01

218

Rh-catalyzed linear hydroformylation of styrene.  

PubMed

Usually the Rh-catalyzed hydroformylation of styrene predominantly yields the branched, chiral aldehyde. An inversion of regioselectivity can be achieved using strong ?-acceptor ligands. Binaphthol-based diphosphite and bis(dipyrrolyl-phosphorodiamidite) ligands were applied in the Rh-catalyzed hydroformylation of styrene. High selectivities up to 83% of 3-phenylpropanal were obtained with 1,1-bi-2-naphthol-based bis(dipyrrolyl-phosphorodiamidite) with virtually no hydrogenation to ethyl benzene. The coordination chemistry of those ligands towards Rh(I) was investigated spectroscopically and structurally. PMID:23104326

Boymans, Evert; Janssen, Michèle; Müller, Christian; Lutz, Martin; Vogt, Dieter

2013-01-01

219

The Iodochlorination of Styrene: An Experiment that Makes a Difference  

ERIC Educational Resources Information Center

The iodochlorination of styrene, involving the addition of iodine monochloride to styrene, followed by the sodium methoxide-initiated dehydrohalogenation of the product results in a variable mixture of substituted styrenes by way of various substitution and elimination reaction mechanisms. As a result individual results are obtained for each…

Amiet, R. Gary; Urban, Sylvia

2008-01-01

220

Indigo formation by microorganisms expessing styrene monooxygenase activity  

Microsoft Academic Search

The transformation of indole to indigo by microorganisms expressing styrene monooxygenase (SMO) has been studied. Styrene and indole are structurally very similar, and thus we looked at a variety of styrene- degrading strains for indole transformation to indigo. Two strains, Pseudomonas putida S12 and CA-3, gave a blue color on solid media when grown in the presence of indole. Indole

K. E. O'Connor; ALAN D. W. DOBSON; SYBE HARTMANS

1997-01-01

221

Gender differences in the metabolism of 1,3-butadiene to butadiene diepoxide in Sprague-Dawley rats  

SciTech Connect

1,3-Butadiene (BD), a gaseous compound used in the production of rubber, is a potent carcinogen in mice and a weak carcinogen in rats. The mechanism of BD-induced carcinogenicity is thought to involve genotoxic effects of its reactive epoxide metabolites butadiene monoepoxide (BDO) and butadiene diepoxide (BDO{sub 2}). Studies in our laboratory have shown that levels of the epoxides, particularly BDO{sub 2}, are greater in mice-the more sensitive species-than rats. While both epoxides are genotoxic in a number of assays, BDO{sub 2} is mutagenic in TK6 human lymphoblastoid cells at concentrations approximately 100-fold lower than BDO. Species differences in carcinogenicity of BD have posed a dilemma to investigators deciding which animal model is most appropriate for BD risk assessment.

Thornton-Manning, J.R.; Dahl, A.R.; Bechtold, W.E. [and others

1995-12-01

222

Direct preparation of styrene carbonates from styrene using an ionic-liquid-based one-pot multistep synthetic process  

Microsoft Academic Search

One-pot synthesis of styrene carbonate from styrene is investigated using a multistep protocol in the presence of an ionic-liquid-based catalytic system that is consisted of MTO\\/UHP\\/Zn[EMIm]2Br4\\/[BMIm]BF4. Owing to the multistep operations and the compatibility of MTO and Zn[EMIm]2Br4 in ionic liquid, remarkable improvements of the reaction performance regarding the reaction of one-pot synthesis of styrene carbonate from styrene have been

Fumitaka Ono; Kun Qiao; Daisuke Tomida; Chiaki Yokoyama

2007-01-01

223

Pilot-scale production of (S)-styrene oxide from styrene by recombinant Escherichia coli synthesizing styrene monooxygenase.  

PubMed

Recombinant Escherichia coli JM101(pSPZ10) cells produce the styrene monooxygenase of Pseudomonas sp. strain VLB120, which catalyzes the oxidation of styrene to (S)-styrene oxide at an enantiomeric excess larger than 99%. This biocatalyst was used to produce 388 g of styrene oxide in a two-liquid phase 30-L fed-batch bioconversion. The average overall volumetric activity was 170 U per liter over a period of more than 10 h, equivalent to mass transfer rates of 10.2 mmoles per liter per hour at a phase ratio of 0.5. At this transfer rate, the biotransformation system appeared to be substrate mass-transfer limited. The reactor had an estimated power input in the order of 5 W. L(-1), which is close to values typically obtained with commercially operating units. The product could be easily purified by fractional distillation to a purity in excess of 97%. The process illustrates the feasibility of recombinant whole cell biotransformations in two-liquid phase systems with toxic substrates and products. PMID:12209784

Panke, Sven; Held, Martin; Wubbolts, Marcel G; Witholt, Bernard; Schmid, Andreas

2002-10-01

224

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

...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...

2014-04-01

225

Catalyst deactivation phenomena in styrene production  

Microsoft Academic Search

Catalyst deactivation in the styrene process occurs by several mechanisms such as coke deposition, migration, loss and redistribution of the potassium promoter, changes in the oxidation state of iron, and physical degradation. These changes are interrelated and occur simultaneously. Recent investigations in these areas and novel adaptations of the catalyst and process are discussed briefly in this review.

Garry R. Meima; P. Govind Menon

2001-01-01

226

Production of enantiopure styrene oxide by recombinant Escherichia coli synthesizing a two-component styrene monooxygenase.  

PubMed

A whole cell biocatalytic process was developed to enable the efficient oxidation of styrene to chiral (S)-styrene oxide with an enantiomeric excess better than 99%. Recombinant Escherichia coli cells were employed to express the genes styAB encoding the styrene monooxygenase of Pseudomonas sp. strain VLB120 from an expression plasmid utilizing the alk regulatory system of P. oleovorans GPo1. The strains reached specific activities of up to 70 U* (g cell dry weight)(-1) in shake-flask experiments with glucose as the carbon source. An efficient two-liquid phase fed-batch process was established for the production of (S)-styrene oxide with hexadecane as an apolar carrier solvent and a nutrient feed consisting of glucose, magnesium sulfate, and yeast extract. Engineering of the phase fraction and the composition of organic phase and feed led to a 2-L scale process with maximal volumetric productivities of 2.2 g (S)-styrene oxide per liter liquid volume per hour. This optimized process was based completely on defined medium and used bis(2-ethylhexyl)phthalate as the apolar carrier solvent, which together with substrate and inducer consisted of 50% of the total liquid volume. Using this system, we were able to produce per liter liquid volume 11 g of enantiopure (S)-styrene oxide in 10 h. PMID:10820335

Panke, S; Wubbolts, M G; Schmid, A; Witholt, B

2000-07-01

227

1,4-butyleneglycol and tetrahydrofuran production from butadiene  

SciTech Connect

New process for 1,4-butyleneglycol/tetrahydrofuran was developed and commercialized in 1982 by Mitsubishi Chemical Industries in Japan. The process consists of acetoxylation of butadiene, hydrogenation and hydrolysis/deacetoxycyclization. The process produces the two products at any ratio, and is highly economical and pollutionless.

Onoda, T.

1987-01-01

228

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

229

KINETIC MODELING OF COUNTERFLOW DIFFUSION FLAMES OF BUTADIENE. (R828193)  

EPA Science Inventory

A comprehensive, semi-detailed kinetic scheme was used to simulate the chemical structures of counterflow diffusion and fuel-rich premixed 1,3-butadiene flames, to better understand the formation of polycyclic aromatic hydrocarbons (PAH). The results showed that model predicti...

230

Rheological characterization of styrene-butadiene based medium and its finishing performance using rotational abrasive flow finishing process  

Microsoft Academic Search

Finishing of complex shaped components needs advanced finishing processes to produce nano level surface finish. Abrasive flow finishing (AFF) process uses abrasive mixed polymer as a medium to finish complex shapes. The medium should possess three basic properties i.e., better flow ability, self deformability and abrading ability to finish the given surface to nano scale. Various flow and deformation properties

M. Ravi Sankar; V. K. Jain; J. Ramkumar; Y. M. Joshi

2011-01-01

231

Efficient synthesis of styrene carbonate from CO 2 and styrene oxide using zinc catalysts immobilized on soluble imidazolium–styrene copolymers  

Microsoft Academic Search

Preparation of zinc catalysts (Zn\\/PS-IL[X], X=Br?, Cl?, BF4?, and PF6?) supported on imidazolium–styrene copolymers, as well as their catalytic use for the solvent-free synthesis of styrene carbonate from CO2 and styrene oxide, are described. Among the catalysts examined, Zn\\/PS-IL[Br] was proved to be the most efficient. When used in a homogeneous system during the reaction process, Zn\\/PS-IL[Br] gave a 97.5%

Kun Qiao; Fumitaka Ono; Quanxi Bao; Daisuke Tomida; Chiaki Yokoyama

2009-01-01

232

Possible regulatory role for nonaromatic carbon sources in styrene degradation by Pseudomonas putida CA3  

Microsoft Academic Search

Styrene metabolism in styrene-degrading Pseudomonas putida CA-3 cells has been shown to proceed via styreneoxide,phenylacetaldehyde,andphenylaceticacid.TheinitialstepinstyrenedegradationbystrainCA-3 is oxygen-dependent epoxidation of styrene to styrene oxide, which is subsequently isomerized to phenylacet- aldehyde. Phenylacetaldehyde is then oxidized to phenylacetic acid. Styrene, styrene oxide, and phenylacetal- dehyde induce the enzymes involved in the degradation of styrene to phenylacetic acid by P. putida CA-3. Phenylacetic

K. O'Connor; C. M. Buckley; S. Hartmans

1995-01-01

233

Cell sealant  

SciTech Connect

An electrochemical cell is described comprising an anode, a cathode and an electrolyte disposed within an open ended cylindrical metallic cell container, with an insulative cell top member being positioned within the open end of a sealant at the interface between the cell top member and the metallic cell container. The sealant is a mixture of a Type 2 BUR asphalt and an elastomeric material selected from the group consisting of (cis-1,4-polyisoprene), styrene-butadiene copolymer (SBR), cis-1,4-polybutadiene and styrene butadiene styrene (SBS), styrene isoprene styrene (SIS), neoprene (poly-chloprene), acrylonitrile-butadiene copolymer (NBR), ethylene-propylene elastomers (EPR), butyl rubber (copolymers of isobutylene), urethane, nitrile (polymers of butadiene and acrylonitrile), polysulfide, polyacrylate, silicone, chlorosulfonated polyethylene, and EPDM (terpolymers of ethylene, propylene and diene monomers), and mixtures thereof, and wherein the elastomeric material is substantially inert to the electrolyte and is present in an amount between 0.5% to 10% by weight of the asphalt.

Markin, C.; Book, R.J.; James, D.A.

1988-04-26

234

Photofragment Translational Spectroscopy of 1,3-Butadiene and 1,3-Butadiene-1,1,4,4-d4 at 193 nm  

E-print Network

Photofragment Translational Spectroscopy of 1,3-Butadiene and 1,3-Butadiene-1,1,4,4-d4 at 193 nm with photofragment translational spectroscopy coupled with product photoionization using tunable VUV synchrotron, and C2H4 + C2H2. The translational energy (P(ET)) distributions suggest that these channels result from

Neumark, Daniel M.

235

Penultimate effect in ethylene-styrene copolymerization and the discovery of highly active ethylene-styrene catalysts with increased styrene reactivity.  

PubMed

For the first time commercially relevant catalysts for the copolymerization of ethylene and styrene have been identified. The catalysts maintain very high copolymer efficiencies at relatively high reactor temperatures without sacrificing styrene comonomer reactivity. The observations which led to this discovery are based upon the kinetic analysis of ethylene-styrene copolymerization using constrained geometry catalyst (eta5-C5Me4)(SiMe2-N-t-Bu)TiMe2 (1). This analysis revealed a substantial styrene penultimate monomer effect. Inherent reactivity of 1 toward styrene is greatly improved when the penultimate monomer on the growing polymer chain is styrene rather than ethylene. The presence of a penultimate styrene effect led to the hypothesis that catalysts bearing aromatic moieties in close proximity to the active site could lead to enhancement of styrene reactivity for this catalyst family. This hypothesis was born out by two new constrained geometry catalysts, one having two phenyl substituents placed in the 3 and 3' positions of the Cp ring (2) and the other with a 2,2'-biphenyl fragment attached to the Cp ring (3). Both catalysts exhibit higher activity than that of 1 and, more importantly, much higher styrene reactivity leading to copolymers with substantially increased styrene content (21.5% for 2, 30.6% for 3) as compared to 1 (11%) under the same polymerization conditions. Analysis of the X-ray crystal structures of 2 and 3 shows no overriding structural arguments for the increased performance. Outstanding polymerization characteristics achieved with 3 make this catalyst a candidate for commercial production of ethylene-styrene resins in a solution process. PMID:17489593

Arriola, Daniel J; Bokota, Marilyn; Campbell, Richard E; Klosin, Jerzy; LaPointe, Robert E; Redwine, O David; Shankar, Ravi B; Timmers, Francis J; Abboud, Khalil A

2007-06-01

236

Differential gene expression by styrene in rat reproductive tissue.  

PubMed

Styrene is an important industrial chemical that is extensively used in the production of resins, rubbers and fiberglass-reinforced plastics. Exposing male rats to high doses of styrene may produce sperm abnormalities or infertility. To determine the mechanism underlying styrene-mediated toxicity in male reproductive organs, a reverse transcription-polymerase chain reaction (RT-PCR) technology was employed using annealing control primers (ACPs) to identify the differentially expressed genes following styrene treatment in isolated testis of male rats. By using 120 ACPs, a total of 6 expressed sequence tags (ESTs) of genes were differentially expressed in styrene-treated rats, as compared to untreated, which were cloned and sequenced. Of the genes analyzed, 5 genes (testis-specific expressed gene 101, protein kinase C, H+-ATPase isoform 2, peroxiredoxin 1, and aquaporin 9) were inducible and one gene expression (clusterin) was significantly suppressed by styrene. Regulation of each gene by styrene was confirmed by RT-PCR. It was shown that styrene decreased clusterin expression in a concentration-dependent manner and these effects occurred mainly in testis. Taken together, these results indicate that repression of clusterin gene expression by styrene may play an important role in styrene-mediated toxicities. PMID:17654243

Han, Jee Hye; Choi, Chang-Su; Kim, Mie Young; Chun, Young-Jin

2007-08-01

237

How new styrene unit is working  

SciTech Connect

A modern styrene unit will have utility requirements less than half of those for a 1940's unit. The byproduct formation will be less than a third. The process mechanism, steam dehydration of ethylbenzene, is primarily unchanged, but progressive improvements to the process make it a highly competitive system. Against this highly developed system, UOP and the Allied-Signal Engineered Materials Research Center developed some novel concepts and a catalyst to further improve the production of styrene. These were discovered and tested at the Research Center, and then demonstrated by Mitsubishi Petrochemical Co. (MPC), first in their laboratories at Yokkaichi, Japan, and later in a full-scale demonstration unit at Kashima, Japan.

Ward, D.J.; Black, S.M.; Imai, T.; Sato, Y.; Nakayama, N.; Tokano, H.; Egawa, K.

1987-03-01

238

Effect of mixing on polymerization of styrene  

E-print Network

Molecular Weight Distributions Calculated Degrees of Polymerization . Calculated Molecular Weight Distributions Streaking Observed in Reaction Medium During Continuous Polymerizations DISCUSSION Evaluation of 50 ml Glass Reactor Errors... Science. of segregation, if any, occurring in a bench scale laboratory reactor; and to evaluate the usefulness of reactor flow models based on micro- and macro-mixing in a constant-flow, stirred-tank reactor. Styrene was polymerized in a bench scale...

Treybig, Michael Norris

2012-06-07

239

Biotransformation of styrenes by a Pseudomonas putida  

Microsoft Academic Search

A strain of Pseudomonas putida was isolated from soil in the presence of a-methylstyrene, as the sole carbon and energy source. The analysis of the oxidation products from culture broth allowed the identification of 2-phenyl-2-propen-1-ol and 1,2-dihydroxy-3-isopropenyl-3-cyclohexene suggesting the existence of different initial steps in the metabolism of a-methylstyrene. The same strain also oxidized styrene and produced by initial oxidation

G. Bestetti; E. Galli; C. Benigni; F. Orsini; F. Pelizzoni

1989-01-01

240

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

241

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

242

Influence of styrene on the oxidative dehydrogenation of ethylbenzene  

Microsoft Academic Search

The influence of styrene and by-products of side reactions on the oxidative dehydrogenation of ethylbenzene into styrene with use of the vanadia-magnesia catalyst has been investigated. Notable slowing-down influence of styrene contained in the substrates on the process has been ascertained, whereas the contamination with other products has not caused such an effect. The apparent activation energy and pre-exponential factor

Waldemar Oganowski; Roman Klimkievicz

1993-01-01

243

40 CFR 721.9492 - Polymers of styrene, cyclohexyl methacrylate and substituted methacrylate.  

Code of Federal Regulations, 2010 CFR

...2010-07-01 2010-07-01 false Polymers of styrene, cyclohexyl methacrylate...Chemical Substances § 721.9492 Polymers of styrene, cyclohexyl methacrylate...chemical substances identified generically as polymers of styrene, cyclohexyl...

2010-07-01

244

40 CFR 721.9492 - Polymers of styrene, cyclohexyl methacrylate and substituted methacrylate.  

Code of Federal Regulations, 2011 CFR

...2011-07-01 2011-07-01 false Polymers of styrene, cyclohexyl methacrylate...Chemical Substances § 721.9492 Polymers of styrene, cyclohexyl methacrylate...chemical substances identified generically as polymers of styrene, cyclohexyl...

2011-07-01

245

40 CFR 721.9492 - Polymers of styrene, cyclohexyl methacrylate and substituted methacrylate.  

Code of Federal Regulations, 2013 CFR

... 2013-07-01 false Polymers of styrene, cyclohexyl methacrylate and substituted...Substances § 721.9492 Polymers of styrene, cyclohexyl methacrylate and substituted...substances identified generically as polymers of styrene, cyclohexyl methacrylate and...

2013-07-01

246

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

Code of Federal Regulations, 2013 CFR

...2013-07-01 2013-07-01 false Styrene, copolymer with acrylic acid, salt...Chemical Substances § 721.10389 Styrene, copolymer with acrylic acid, salt...chemical substance identified generically as styrene, copolymer with acrylic acid,...

2013-07-01

247

Abstract--Plasma polymerization of styrene is widely used to synthesize polymer membranes for various applications.  

E-print Network

Abstract-- Plasma polymerization of styrene is widely used to synthesize polymer membranes-- Plasma polymerization, styrene, nanoballs, low pressure. OLYSTYRENE nanoballs aroused interest can also be used. Plasma polystyrene polymer formation occurs when styrene vapour is injected

Boyer, Edmond

248

40 CFR 721.9492 - Polymers of styrene, cyclohexyl methacrylate and substituted methacrylate.  

Code of Federal Regulations, 2012 CFR

... 2012-07-01 false Polymers of styrene, cyclohexyl methacrylate and substituted...Substances § 721.9492 Polymers of styrene, cyclohexyl methacrylate and substituted...substances identified generically as polymers of styrene, cyclohexyl methacrylate and...

2012-07-01

249

21 CFR 173.70 - Chloromethylated aminated styrene-divinylbenzene resin.  

...2014-04-01 false Chloromethylated aminated styrene-divinylbenzene resin. 173.70 Section... § 173.70 Chloromethylated aminated styrene-divinylbenzene resin. Chloromethylated aminated styrene-divinylbenzene copolymer (CAS...

2014-04-01

250

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

251

Poly(acrylonitrile) encapsulated graphite as anode materials for lithium ion batteries  

NASA Astrophysics Data System (ADS)

Novel surface modification approach for graphite anode of lithium ion batteries was developed in this study. Poly(acrylonitrile) was in situ encapsulated on the surface of natural graphite (N-graphite) particles via radiation-initiated polymerization. The graphite obtained shows a large improvement in electrochemical performance such as initial Coulombic efficiency and cycleability compared with the original N-graphite. The structural stability of graphite surface is enhanced due to the fact that encapsulated poly(acrylonitrile) can depress the co-intercalation of solvated lithium ion.

Guo, Kunkun; Pan, Qinmin; Fang, Shibi

252

21 CFR 178.3790 - Polymer modifiers in semirigid and rigid vinyl chloride plastics.  

... Butadiene. a -Methylstyrene. Styrene. Vinylidene chloride. (iii...their polymerization with butadiene-styrene copolymers; provided that no chemical...polymer units derived from the butadiene-styrene copolymers. (b) The polymer...

2014-04-01

253

21 CFR 178.3790 - Polymer modifiers in semirigid and rigid vinyl chloride plastics.  

Code of Federal Regulations, 2013 CFR

... Butadiene. a -Methylstyrene. Styrene. Vinylidene chloride. (iii...their polymerization with butadiene-styrene copolymers; provided that no chemical...polymer units derived from the butadiene-styrene copolymers. (b) The polymer...

2013-04-01

254

21 CFR 178.3790 - Polymer modifiers in semirigid and rigid vinyl chloride plastics.  

Code of Federal Regulations, 2012 CFR

... Butadiene. a -Methylstyrene. Styrene. Vinylidene chloride. (iii...their polymerization with butadiene-styrene copolymers; provided that no chemical...polymer units derived from the butadiene-styrene copolymers. (b) The polymer...

2012-04-01

255

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

256

Effects of Dynamic Vulcanization on Tensile Properties, Morphology and Natural Weathering of Polypropylene\\/Recycled Acrylonitrile Butadiene Rubber (PP\\/NBRr) Blends  

Microsoft Academic Search

The effect of dynamic vulcanization on properties of PP\\/NBRr blends has been investigated. Natural weathering has been carried out for period of 3 months and 6 months. It has been observed that tensile properties and oil resistance of the blends improved by dynamic vulcanization. SEM results indicate that dynamic vulcanization can be employed as a technique to get finer and

H. Ismail; D. Galpaya; Z. Ahmad

2009-01-01

257

Otoacoustic emission sensitivity to exposure to styrene and noise.  

PubMed

The ototoxic effect of the exposure to styrene is evaluated, also in the presence of simultaneous exposure to noise, using otoacoustic emissions as biomarkers of mild cochlear damage. Transient-evoked and distortion product otoacoustic emissions were recorded and analyzed in a sample of workers (15 subjects) exposed to styrene and noise in a fiberglass manufacturing facility and in a control group of 13 non-exposed subjects. Individual exposure monitoring of the airborne styrene concentrations was performed, as well as biological monitoring, based on the urinary concentration of two styrene metabolites, the Mandelic and Phenylglyoxylic acids. Noise exposure was evaluated using wearable phonometers, and hearing loss with pure tone audiometry. Due to their different job tasks, one group of workers was exposed to high noise and low styrene levels, another group to higher styrene levels, close to the limit of 20?ppm, and to low noise levels. A significant negative correlation was found between the otoacoustic emission levels and the concentration of the styrene urinary metabolites. Otoacoustic emissions, and particularly distortion products, were able to discriminate the exposed workers from the controls, providing also a rough estimate of the slope of the dose-response relation between otoacoustic levels and styrene exposure. PMID:24180784

Sisto, R; Cerini, L; Gatto, M P; Gherardi, M; Gordiani, A; Sanjust, F; Paci, E; Tranfo, G; Moleti, A

2013-11-01

258

DRINKING WATER CRITERIA DOCUMENT FOR STYRENE (FINAL DRAFT)  

EPA Science Inventory

The Office of Drinking Water (ODW), U.S. Environmental Protection Agency has prepared a Drinking Water Criteria Document on styrene. The Criteria Document is an extensive review of the following topics: Physical and chemical properties of styrene, Toxicokinetics and human exposur...

259

Product property and production rate control of styrene polymerization  

Microsoft Academic Search

A multivariable multi-rate nonlinear model predictive control (NMPC) strategy is applied to styrene polymerization. The NMPC algorithm incorporates a multi-rate Extended Kalman Filter (EKF) to handle state variable and parameter estimation. A fundamental model is developed for the styrene polymerization CSTR, and control of polymer properties such as number average molecular weight (NAMW) and polydispersity is considered. These properties characterize

Vinay Prasad; Matthias Schley; Louis P. Russo; B. Wayne Bequette

2002-01-01

260

Addition of acetic acid to styrene catalyzed by ion exchanger  

Microsoft Academic Search

The possibility of preparation of 1-phenylethyl acetate by direct addition of acetic acid to styrene catalyzed by Ostion KS in the acid cycle has been investigated. The reaction is accompanied by the formation of higher molecular compounds. The effect of temperature, mole ratio of the starting compounds, stabilization of styrene, amount of the catalyst and of its repeated use on

L. ?ervený; A. Marhoul; J. Kozel

1988-01-01

261

Natural formation of styrene by cinnamon mold flora.  

PubMed

Tests on 106 dried pure cinnamon samples of diverse origins showed that some samples were naturally contaminated with high levels of styrene, up to 524 microg/g. Styrene taint can be associated with high water activity levels and thus with microorganism growth. The mold flora of a Korintji cinnamon sample in which styrene had been found at a 50 microg/g concentration was analyzed and 5 species of mold were isolated. An investigation into the ability of the 5 species of mold to produce styrene showed that 3 of them--namely, Penicillium citrinum, Penicillium oxalicum, Aspergillus niger--produced styrene in vitro in buffered peptone water at 25 degrees C within 5 d in the presence of several natural cinnamon volatile constituents containing the styrene structure. The conversion of these compounds into styrene by these 3 cinnamon fungal species has never been previously reported. A standardized inoculation with the 3 mold species was carried out on 10 g cinnamon samples of various origins followed by a 10-d incubation and highlighting styrene production except for Sri Lanka origin. PMID:19723212

Lafeuille, J-L; Buniak, M-L; Vioujas, M-C; Lefevre, S

2009-08-01

262

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

263

40 CFR 721.10280 - Benzene ethenyl-, polymer with 1,3-butadiene, brominated.  

Code of Federal Regulations, 2013 CFR

...2013-07-01 2013-07-01 false Benzene ethenyl-, polymer with 1,3-butadiene...Chemical Substances § 721.10280 Benzene ethenyl-, polymer with 1,3-butadiene...The chemical substance identified as benzene ethenyl-, polymer with...

2013-07-01

264

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

265

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...

266

Oxidation of styrene using a silent discharge plasma  

SciTech Connect

A cylindrically symmetrical dielectric barrier discharge was constructed to study the oxidation of styrene in the gas phase. Several operating parameters were varied to find the optimum conditions for styrene destruction. An argon/oxygen mix was used to generate the non-thermal plasma with oxygen concentrations ranging from 2--8%. The styrene concentrations ranged from 1,000 ppm to 6,000 ppm and energy densities of the SDP cell ranged from .5--3 kJ/liter. The temperature of the SDP cell was varied from 200 C to 450 C. The concentrations of styrene and its partial oxidation products were monitored by a GC-MS and the concentrations of CO{sub 2} and CO were measured by FTIR. Destruction efficiencies of styrene up to 99.9% were measured.

Anderson, G.K.; Coogan, J.J.; Snyder, H.R. [Los Alamos National Lab., NM (United States). Chemical Science and Technology Div.

1997-12-31

267

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

268

75 FR 9438 - Americas Styrenics, LLC-Marietta Plant a Subsidiary of Americas Styrenics, LLLC Formerly Known as...  

Federal Register 2010, 2011, 2012, 2013

...LLC-Marietta Plant a Subsidiary of Americas...Chevron Phillips Chemical Co. LP Including...Styrenics LLC-Marietta Plant was formerly known as Chevron Phillips Chemical Co. LP. Some workers...Styrenics LLC-Marietta Plant, a subsidiary of...Chevron Phillips Chemical Co LP,...

2010-03-02

269

Determination of potentially carcinogenic compounds in food : trace analysis of vinylchloride, vinylidenechloride, acrylonitrile, epichlorohydrin and diethylpyrocarbonate  

Microsoft Academic Search

Toxicological evidence shows that some monomers present in packaging materials may be carcinogenic. These monomers, notably vinylchloride, vinylidenechloride, acrylonitrile and epichlorohydrin, may migrate from the packaging material into the food. Therefore, severe limits are set to the contents of these compounds. Very sensitive and specific methods are required for determining such contents. Moreover, a Food Inspection Service must be able

Lierop van J. B. H

1979-01-01

270

Radiation Grafting of Acrylonitrile onto Polyester Fiber as the Reinforcing Filler for Poly (Vinyl Chloride).  

National Technical Information Service (NTIS)

Studies have been carried out on radiation-induced grafting of acrylonitrile onto polyester fiber and on the properties of the grafted fiber in an attempt to increase the strength of polyester fiber reinforced soft poly (vinyl chloride) (PVC) sheet by imp...

K. Kaji, I. Ando

1985-01-01

271

The effects of antimony(III) oxide and basic iron(III) oxide on the flammability and thermal stability of a tertiary polymer blend  

Microsoft Academic Search

The effects of antimony(III) oxide (flame retardant) and basic iron(III) oxide (smoke suppressant) on the thermal stability of a tertiary blend containing ABS (acrylonitrile-butadiene-styrene), PVC (poly(vinyl chloride)) and PP (poly(propylene)) have been investigated.As found in earlier work on a two-component system of ABS and PVC, the basic oxide of iron has a marked stabilizing effect on the thermal degradation of

S. White

1995-01-01

272

Short fiber reinforced composites for fused deposition modeling  

Microsoft Academic Search

Addressed in this paper are critical material property issues related to the short fiber reinforced composite used in rapid prototyping and manufacturing (RP&M). Acrylonitrile–butadiene–styrene (ABS) copolymer has been a popular choice of material used in fused deposition modeling (FDM), a commonly used RP&M process. However, conventional ABS polymers in the filamentary form for FDM are known to be of low

Weihong Zhong; Fan Li; Zuoguang Zhang; Lulu Song; Zhimin Li

2001-01-01

273

Studies on profile error and extruding aperture for the RP parts using the fused deposition modeling process  

Microsoft Academic Search

Fused deposition modeling (FDM) is one of the leading rapid prototyping processes for producing acrylonitrile butadiene styrene\\u000a prototypes. However, the extruding accuracy in part fabrication is subject to transmission machinery and filament diameter.\\u000a The parts cannot be filled up completely. Therefore, profile error and extruding apertures are two substantial quality characteristics\\u000a to be considered. This study proposed an original image

Dar-Yuan Chang; Bao-Han Huang

2011-01-01

274

Thermomechanical properties of a highly filled polymeric composites for Fused Deposition Modeling  

Microsoft Academic Search

This paper presents an investigation on thermal and mechanical properties of new metal-particle filled Acrylonitrile Butadiene Styrene (ABS) composites for applications in Fused Deposition Modeling rapid prototyping process. Test samples of Iron\\/ABS and Copper\\/ABS composites involving metal content up to 40% by volume have been made by controlled centrifugal mixing, thermally compounded through a single-screw extruder and compression moulding. Dynamic

M. Nikzad; S. H. Masood; I. Sbarski

2011-01-01

275

Toxicity of Pyrolysis Gases from Elastomers  

NASA Technical Reports Server (NTRS)

The toxicity of the pyrolysis gases from six elastomers was investigated. The elastomers were polyisoprene (natural rubber), styrene-butadiene rubber (SBR), ethylene propylene diene terpolymer (EPDM), acrylonitrile rubber, chlorosulfonated polyethylene rubber, and polychloroprene. The rising temperature and fixed temperature programs produced exactly the same rank order of materials based on time to death. Acryltonitrile rubber exhibited the greatest toxicity under these test conditions; carbon monoxide was not found in sufficient concentrations to be the primary cause of death.

Hilado, Carlos J.; Kosola, Kay L.; Solis, Alida N.; Kourtides, Demetrius A.; Parker, John A.

1977-01-01

276

Studies on the runaway reaction of ABS polymerization process  

Microsoft Academic Search

Taiwan has the largest acrylonitrile–butadiene–styrene (ABS) copolymer production in the world. Preventing on unexpected exothermic reactions and related emergency relief hazard is essential in the safety control of ABS emulsion polymerization. A VSP2 (Vent Sizing Package 2) apparatus is capable of studying both normal and abnormal conditions (e.g., cooling failure, mischarge, etc.) of industrial process. In this study, the scenarios

Kwan-Hua Hu; Chen-Shan Kao; Yih-Shing Duh

2008-01-01

277

Characteristics of thermoplastics containing electrically conducting asymmetric particles - anisotropic electrical conductivity of injection molded parts and extrusion behavior  

Microsoft Academic Search

The characteristics of compounds of acrylonitrile-butadiene-styrene and high impact polystyrene resins filled with carbon fibers, steel fibers, carbon black, and aluminum flakes have been investigated with special emphasis on electrical conductivity and flow behavior in a capillary rheometer. Compression- and injection-molded compounds were found to be highly electrically anisotropic. The components of the electrical conductivity tensor, were measured. Generally, kappa-11,

Jan Martinsson; James L. White

1986-01-01

278

Tungsten carbide coatings deposited by high-velocity oxy-fuel spraying on a metallized polymeric substrate  

Microsoft Academic Search

A triplex system consisting of WC(Co) hard coating, metallic bond layers (Ni\\/Cu\\/Ni), and acrylonitrile-butadiene-styrene as substrate, was investigated. The WC (88 wt.%)-Co (12 wt.%) coating was deposited by the high-velocity oxy-fuel spraying technique modified by the addition of CO2 gas flows. The microstructure, the composition, and the phases present in the coating were studied by means of transmission and scanning

I. Grimberg; K. Soifer; B. Bouaifi; U. Draugelates; B. Z. Weiss

1997-01-01

279

Carbon black self-networking induced co-continuity of immiscible polymer blends  

Microsoft Academic Search

This work aims to clarify the mechanism of nanoparticle-induced co-continuity in immiscible polymer blends. An industrially relevant system, carbon black (CB)-filled acrylonitrile-butadiene-styrene (ABS)\\/polyamide 6 (PA6) blends, is investigated via scanning electron microscopy, selective extraction tests, dynamic mechanical analysis, and electrical conductivity measurements. The CB particles are found to be preferentially localized in the PA6 phase, and with an increase in

Guozhang Wu; Bingpeng Li; Jiandi Jiang

2010-01-01

280

Effect of heating rate on toxicity of pyrolysis gases from some elastomers  

NASA Technical Reports Server (NTRS)

The effect of heating rate on the toxicity of the pyrolysis gases from six elastomers was investigated, using a screening test method. The elastomers were polyisoprene (natural rubber), styrene-butadiene rubber (SBR), ethylene propylene diene terpolymer (EPDM), acrylonitrile rubber, chlorosulfonated polyethylene rubber, and polychloroprene. The rising temperature and fixed temperature programs produced exactly the same rank order of materials based on time to death. Acrylonitrile rubber exhibited the greatest toxicity under these test conditions, and carbon monoxide was not found in sufficient concentrations to be the primary cause of death.

Hilado, C. J.; Kosola, K. L.; Solis, A. N.

1977-01-01

281

Atomic and electronic structure of styrene on Ge(100) Do Hwan Kim a  

E-print Network

Atomic and electronic structure of styrene on Ge(100) Do Hwan Kim a , Yun Jeong Hwang b , Junga: Styrene Ge(100) Adsorption DFT calculations STM Coverage-dependent adsorption structures of styrene favorable configuration at room temperature is that the two styrene molecules are bound to two Ge dimers

Kim, Sehun

282

S0S1 transition of trans--methyl styrene: Vibronic structure and dynamics  

E-print Network

S0S1 transition of trans- -methyl styrene: Vibronic structure and dynamics Y. Haas, S. Kendler, E; accepted 28 March 1995 The fluorescence excitation and emission spectra of trans- -methyl styrene have been of styrene and of trans- -methyl styrene BMS is reported. The BMS molecule is calculated to be essentially

Haas, Yehuda

283

Sulfonated Styrene-(ethylene-co-butylene)-styrene/Montmorillonite Clay Nanocomposites: Synthesis, Morphology, and Properties  

PubMed Central

Sulfonated styrene-(ethylene-butylene)-styrene triblock copolymer (SSEBS) was synthesized by reaction of acetyl sulfate with SEBS. SSESB-clay nanocomposites were then prepared from hydrophilic Na-montmorillonite (MT) and organically (quaternary amine) modified hydrophobic nanoclay (OMT) at very low loading. SEBS did not show improvement in properties with MT-based nanocomposites. On sulfonation (3 and 6 weight%) of SEBS, hydrophilic MT clay-based nanocomposites exhibited better mechanical, dynamic mechanical, and thermal properties, and also controlled water–methanol mixture uptake and permeation and AC resistance. Microstructure determined by X-ray diffraction, atomic force microscopy, and transmission electron microscopy due to better dispersion of MT nanoclay particles and interaction of MT with SSEBS matrix was responsible for this effect. The resulting nanocomposites have potential as proton transfer membranes for Fuel Cell applications.

2008-01-01

284

Somatosensory evoked potentials in workers exposed to toluene and styrene.  

PubMed Central

Somatosensory evoked potentials (SEPs) were used to evaluate possible subclinical impairment of the nervous system due to occupational exposure to toluene and styrene. A group of 36 rotogravure printers with severe exposure to toluene, 20 workers with severe exposure to styrene in a glass laminate manufacturing plant, and a comparison group of healthy subjects were studied. The severity of exposure was documented by measurements of toluene and styrene concentrations in breathing zone air, by hippuric acid concentration in urine in the group exposed to toluene, and by urinary mandelic acid concentration in the group exposed to styrene. Somatosensory evoked potentials were measured by stimulation of the median nerve at the wrist and the tibial nerve at the ankle. Peripheral conduction velocities (CVs) in both extremities and central conduction time (CCT) after tibial nerve stimulation were significantly decreased in both exposed groups. Significantly prolonged latencies of peripheral and cortical SEPs to median nerve stimulation as well as cortical SEPs to tibial nerve stimulation were found in workers exposed to styrene. Some abnormalities in SEPs at peripheral or spinal and cortical levels were found in eight workers exposed to toluene and six workers exposed to styrene. Of these, in three workers exposed to toluene and two to styrene increased CCT and delayed latencies of cortical responses at normal conduction values in the periphery were found. A trend for increased frequency of abnormal SEPs with duration of exposure to toluene and styrene and alcohol abuse was found. Abnormalities in SEPs in the exposed groups are most probably of multifactorial origin. Central SEP abnormalities in both exposed groups could indicate early signs of subclinical dysfunction at spinal and cortical levels and could be due to toluene or styrene exposure probably potentiated by alcohol consumption in the group exposed to toluene. PMID:8329318

St?tkárová, I; Urban, P; Procházka, B; Lukás, E

1993-01-01

285

Clinical studies of styrene workers: initial findings.  

PubMed Central

Styrene monomer is a high volume chemical used chiefly in production of polystyrene. A clinical survey of 493 production workers was undertaken at the oldest and largest monomer production, polymerization, and extrusion facility in the U.S. Relative exposure durations and levels were obtained from occupational histories. Significant differences between the high and low exposure groups were found with regard to history of acute prenarcotic symptoms, acute lower respiratory symptoms, prevalence of FEV 1/FV less than 75 per cent, and elevated GCTP. Other liver function tests, chest x-ray, FVC less than 80 per cent, and hematological parameters showed no distinct pattern. A concomitant mortality study has been mounted and is in progress. PMID:1026403

Lorimer, W V; Lilis, R; Nicholson, W J; Anderson, H; Fischbein, A; Daum, S; Rom, W; Rice, C; Selikoff, I J

1976-01-01

286

Azobenzene Elastomers for Mechanically Tunable Diffraction Gratings Shuying Bai and Yue Zhao*  

E-print Network

-chain liquid crystalline polymers (SCLCPs) were grafted onto a styrene-butadiene-styrene (SBS) triblock preparation method,11 an azobenzene SCLCP was grafted onto a styrene-butadiene-styrene (SBS) triblock

Zhao, Yue

287

Inhalation toxicity studies with 1,3-butadiene -- 1. Atmosphere generation and control.  

PubMed

1,3-butadiene, which is used extensively in the synthetic rubber industry, is a highly reactive, potentially explosive compound, presenting particular problems for the design and execution of inhalation toxicity studies. Before undertaking inhalation studies with butadiene, it was necessary to develop safe systems for the generation and control of stable exposure chamber atmospheres. Infrared and gas chromatographic analytical methods were adapted for monitoring the concentration and distribution of butadiene in exposure chambers, and for analysis of known impurities, particularly, t-butyl catechol and 4-vinyl-1-cyclohexene, in atmospheres generated for inhalation tests. PMID:517437

Pullinger, D H; Crouch, C N; Dare, P R

1979-09-01

288

78 FR 6213 - Styrene-2-Ethylhexyl Acrylate Copolymer; Tolerance Exemption  

Federal Register 2010, 2011, 2012, 2013

...2-propenoic acid, 2-ethylhexyl ester, polymer with ethenylbenzene; also known as styrene-2-ethylhexyl...2-propenoic acid, 2-Ethylhexyl Ester, Polymer with Ethenylbenzene on food or feed commodities...2-propenoic acid, 2-ethylhexyl ester, polymer with ethenylbenzene; CAS No....

2013-01-30

289

Living cationic polymerisation of styrene in an ionic liquid.  

PubMed

For the first time, living cationic polymerisation of styrene has been carried out in room temperature ionic liquids under mild reaction conditions and using mild acid catalysts (e.g. organoborate acids) to obtain polymers of narrow polydispersity. PMID:15010788

Vijayaraghavan, R; MacFarlane, D R

2004-03-21

290

Styrene-Terminated Polysulfone Oligomers As Matrix Materials  

NASA Technical Reports Server (NTRS)

Report summarizes preliminary experimental study and evaluation of styrene-terminated polysulfone oligomers as matrix materials in graphite-fiber/matrix composites. Composites evaluated in terms of methods of fabrication and of mechanical properties.

Bowles, Kenneth J.; Vannucci, Raymond D.

1993-01-01

291

Vinylpyridinium Ionomers. 2. Styrene-Based ABA Block Copolymers,  

National Technical Information Service (NTIS)

The thermal and dynamic mechanical behavior of styrene-4-vinylpyridinium ABA block ionomers was investigated as a function of ion content and method of preparation. Only one tg, associated with the glass transition of the polystyrene phase, was observed i...

S. Gauthier, A. Eisenberg

1987-01-01

292

Sustainable bio-production of styrene from forest waste.  

PubMed

A strain of Penicillium expansum was studied for the production of styrene using forest waste biomass as a feeding substrate. The fungal strain was cultivated on bark of various trees supplemented with yeast extract and the volatiles produced were collected on Tenax TA and analyzed by gas chromatography-mass spectrometry. Fungus cultured on grated soft bark of pine (Pinus sylvestris) stems (GPB) and mature bark of oak (Quercus robur) supplemented with yeast extract produced relatively the highest amounts of styrene. The maximum styrene production rate was 52.5 ?g/h, 41 ?g/h and 27 ?g/h from fungus cultivated on 50 mL liquid media with 10 g GPB or mature bark of oak and potato dextrose broth respectively. These promising results suggest that the fungal strain could be used to produce "green" styrene plastics using renewable forest waste biomass. PMID:23899574

Azeem, Muhammad; Borg-Karlson, Anna Karin; Rajarao, Gunaratna Kuttuva

2013-09-01

293

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

294

Measurement of worker's exposure to styrene. Final report  

Microsoft Academic Search

Studies were conducted to determine the effectiveness of personal samplers in the work place by documenting the magnitude of the variability in breathing-zone concentrations of styrene within the reinforced-plastics industry, determining factors that contribute to breathing-zone concentrations, and investigating the stability of styrene samples taken with charcoal tubes. Measurements were taken at a facility for manufacturing boats where the production

B. S. Cohen; R. Malek

1988-01-01

295

Thermal characterisation of Boc-aminostyrene\\/styrene copolymers latexes  

Microsoft Academic Search

Microspheres based on funcionalized polystyrene are used as supports for immunological reactions. New styrene\\/Boc-aminostyrene (St\\/BocAmSt) copolymers and the corresponding styrene–aminostyrene (St\\/AmSt) copolymers obtained as microspheres under dispersion polymerization conditions and successive deblocking reaction respectively, were characterized by thermogravimetry (TG) and differential scanning calorimetry (DSC). Thermal stability was found to be dependent on copolymer molecular weight and composition. The St\\/AmSt copolymers

V. L Covolan; E. G Fernandes; S D’Antone; E Chiellini

1999-01-01

296

Synaptic contacts impaired by styrene-7,8-oxide toxicity  

SciTech Connect

Styrene-7,8-oxide (SO), a chemical compound widely used in industrial applications, is a potential hazard for humans, particularly in occupational settings. Neurobehavioral changes are consistently observed in occupationally exposed individuals and alterations of neurotransmitters associated with neuronal loss have been reported in animal models. Although the toxic effects of styrene have been extensively documented, the molecular mechanisms responsible for SO-induced neurotoxicity are still unclear. A possible dopamine-mediated effect of styrene neurotoxicity has been previously demonstrated, since styrene oxide alters dopamine neurotransmission in the brain. Thus, the present study hypothesizes that styrene neurotoxicity may involve synaptic contacts. Primary striatal neurons were exposed to styrene oxide at different concentrations (0.1-1 mM) for different time periods (8, 16, and 24 h) to evaluate the dose able to induce synaptic impairments. The expression of proteins crucial for synaptic transmission such as Synapsin, Synaptophysin, and RAC-1 were considered. The levels of Synaptophysin and RAC-1 decreased in a dose-dependent manner. Accordingly, morphological alterations, observed at the ultrastructural level, primarily involved the pre-synaptic compartment. In SO-exposed cultures, the biochemical cascade of caspases was activated affecting the cytoskeleton components as their target. Thus the impairments in synaptic contacts observed in SO-exposed cultures might reflect a primarily morphological alteration of neuronal cytoskeleton. In addition, our data support the hypothesis developed by previous authors of reactive oxygen species (ROS) initiating events of SO cytotoxicity.

Corsi, P. [Dip. di Farmacologia e Fisiologia Umana, Facolta di Medicina e Chirurgia, Universita degli Studi di Bari, 70124 Italy (Italy)], E-mail: pcorsi@fisiol.uniba.it; D'Aprile, A. [Dip. di Medicina Interna e Pubblica, Facolta di Medicina e Chirurgia, Universita di Bari (Italy); Nico, B. [Dip. di Anatomia Umana e Istologia, Facolta di Medicina e Chirurgia, Universita di Bari (Italy); Costa, G.L. [Dip. di Anatomia, Farmacologia e Scienze Medico Forensi, Facolta di Medicina e Chirurgia, Universita di Parma (Italy); Assennato, G. [Dip. di Medicina Interna e Pubblica, Facolta di Medicina e Chirurgia, Universita di Bari (Italy)

2007-10-01

297

Urinary excretion of the acrylonitrile metabolite 2-cyanoethylmercapturic acid is correlated with a variety of biomarkers of tobacco smoke exposure and consumption  

PubMed Central

Acrylonitrile is an IARC class 2B carcinogen present in cigarette smoke. Urinary 2-cyanoethylmercapturic acid (CEMA) is an acrylonitrile metabolite and a potential biomarker for acrylonitrile exposure. The objective of this work was to study the dose response of CEMA in urine of non-smokers and smokers of different ISO tar yield cigarettes. We observed that smokers excreted >100-fold higher amounts of urinary CEMA than non-smokers. The CEMA levels in smokers were significantly correlated with ISO tar yield, daily cigarette consumption, and urinary biomarkers of smoke exposure. In conclusion, urinary CEMA is a suitable biomarker for assessing smoking-related exposure to acrylonitrile. PMID:21108560

Minet, Emmanuel; Cheung, Francis; Errington, Graham; Sterz, Katharina; Scherer, Gerhard

2011-01-01

298

Transport Properties of Sulfonated Poly(styrene- b -isobutylene- b -styrene) Triblock Copolymers at High Ion-Exchange Capacities  

Microsoft Academic Search

Transport properties of sulfonated poly(styrene-b-isobutylene-b-styrene) (S-SIBS) triblock copoly- mers were examined as a function of ion-exchange capacity (IEC), specifically at high IECs (up to 2 mequiv\\/ g). The proton conductivity of S-SIBS was 1 order of magnitude higher than sulfonated polystyrene at similar IECs and 3-fold higher than Nafion 117 at an IEC of 2 mequiv\\/g. However, all polymers in

Yossef A. Elabd; Eugene Napadensky; Charles W. Walker; Karen I. Winey

2006-01-01

299

Synthesis of Styrene Carbonate from Carbon Dioxide and Styrene Oxide with Various Zinc Halide-Based Ionic Liquids  

Microsoft Academic Search

\\u000a Abstract  Various zinc halide-based ionic liquids were prepared from zinc halides and onium halides as catalysts for the synthesis of\\u000a styrene carbonate (SC) from styrene oxide and carbon dioxide. The effects of the ionic liquid catalyst composition (types\\u000a of onium cation and halide, onium cation\\/zinc ratio) and CO2 pressure on the reaction were investigated. The effectiveness of the onium cation as

Shin-ichiro Fujita; Masahiro Nishiura; Masahiko Arai

2010-01-01

300

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

301

Cyanoethylation of cyclopentadiene: Isolation of penta- and hexa(?-cyanoethyl)cyclopentadiene and an unexpected acrylonitrile polymer  

Microsoft Academic Search

The cyanoethylation of cyclopentadiene was examined under a variety of reaction conditions. Approximately 9% of cyclopentadiene was converted to the desired hexa(ß-cyanoethyl)cyclopentadiene when the amount of acrylonitrile to cyclopentadiene was increased from 2 to 7 equivalents under phase transfer conditions. The low conversion is due to competitive formation of various unreactive side-products. For example, termination leading to less-highly substituted products

Lon J. Mathias; Christopher C. Roberts; Jeno Muthiah

1992-01-01

302

Extent-of-exposure study: 1,3-butadiene monomer production industry  

Microsoft Academic Search

A new sampling and analytical method developed by NIOSH was used to assess exposure to 1,3-butadiene; the method is not susceptible to interference from four other carbon compounds and has a lower quantitation limit of 0.02 parts per million (ppm). Walk-through surveys were conducted at ten 1,3-butadiene monomer-production facilities, followed by in-depth surveys at four of the facilities. For all

E. R. Krishnan; L. J. Ungers; P. A. Morelli-Schroth; J. M. Fajen

1987-01-01

303

Review of old chemistry and new catalytic advances in the on-purpose synthesis of butadiene.  

PubMed

Increasing demand for renewable feedstock-based chemicals is driving the interest of both academic and industrial research to substitute petrochemicals with renewable chemicals from biomass-derived resources. The search towards novel platform chemicals is challenging and rewarding, but the main research activities are concentrated on finding efficient pathways to produce familiar drop-in chemicals and polymer building blocks. A diversity of industrially important monomers like alkenes, conjugated dienes, unsaturated carboxylic acids and aromatic compounds are thus targeted from renewable feedstock. In this context, on-purpose production of 1,3-butadiene from biomass-derived feedstock is an interesting example as its production is under pressure by uncertainty of the conventional fossil feedstock. Ethanol, obtained via fermentation or (biomass-generated) syngas, can be converted to butadiene, although there is no large commercial activity today. Though practised on a large scale in the beginning of the 20th century, there is a growing worldwide renewed interest in the butadiene-from-ethanol route. An alternative route to produce butadiene from biomass is through direct carbohydrate and gas fermentation or indirectly via the dehydration of butanediols. This review starts with a brief discussion on the different feedstock possibilities to produce butadiene, followed by a comprehensive summary of the current state of knowledge regarding advances and achievements in the field of the chemocatalytic conversion of ethanol and butanediols to butadiene, including thermodynamics and kinetic aspects of the reactions with discussions on the reaction pathways and the type of catalysts developed. PMID:24993100

Makshina, Ekaterina V; Dusselier, Michiel; Janssens, Wout; Degrève, Jan; Jacobs, Pierre A; Sels, Bert F

2014-10-20

304

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

Code of Federal Regulations, 2011 CFR

...Distillates (petroleum), C(3-6), polymers with styrene and mixed terpenes (generic...Distillates (petroleum), C(3-6), polymers with styrene and mixed terpenes (generic...distillates (petroleum), C(3-6), polymers with styrene and mixed terpenes...

2011-07-01

305

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

Code of Federal Regulations, 2010 CFR

...Distillates (petroleum), C(3-6), polymers with styrene and mixed terpenes (generic...Distillates (petroleum), C(3-6), polymers with styrene and mixed terpenes (generic...distillates (petroleum), C(3-6), polymers with styrene and mixed terpenes...

2010-07-01

306

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

307

Morphological and physical characterization of poly(styrene-isobutylene-styrene) block copolymers and ionomers thereof  

NASA Astrophysics Data System (ADS)

Poly(styrene-isobutylene-styrene) block copolymers made by living cationic polymerization using a difunctional initiator and the sequential monomer addition technique were analyzed using curve-resolution software in conjunction with high-resolution GPC. Fractional precipitation and selective solvent extraction were applied to a representative sample in order to confirm the identity of contaminating species. The latter were found to be low molecular weight polystyrene homopolymer, diblock copolymer, and higher molecular weight segmented block copolymers formed by intermolecular electrophilic aromatic substitution linking reactions occurring late in the polymerization of the styrene outer blocks. Solvent-cast films of poly(styrene-isobutylene-styrene) (PS-PIB-PS) block copolymers and block ionomers were analyzed using small-angle X-ray scattering (SAXS) and transmission electron microscopy (TEM). Four block copolymer samples with center block molecular weights of 52,000 g/mol and PS volume fractions (o sbPS) ranging from 0.17 to 0.31 were studied. All samples exhibited hexagonally packed cylinders of PS within the PIB matrix. Cylinder spacing was in the range 32 to 36 nm for most samples, while cylinder diameters varied from 14 to 21 nm. Porod analysis of the scattering data indicated the presence of isolated phase mixing and sharp phase boundaries. PS-PIB-PS block copolymers and ionomers therefrom were analyzed using dynamic mechanical analysis (DMA) and tensile testing. The study encompassed five block copolymer samples with similar PIB center blocks with molecular weights of approx52,000 g/mol and PS weight fractions ranging from 0.127 to 0.337. Ionomers were prepared from two of these materials by lightly sulfonating the PS outer blocks. Sulfonation levels varied from 1.7 to 4.7 mol % and the sodium and potassium neutralized forms were compared to the parent block copolymers. Dynamic mechanical analysis (DMA) of the block copolymer films indicated the existence of a third phase attributed to PIB chains near the PS domain interface which experience reduced mobility due to their firm attachment to the hard PS domain. The relative amount of this phase decreased in samples with larger PS blocks, while the temperature of the associated transition increased. Tensile testing showed increased tensile strength but decreased elongation at break with larger PS blocks. DMA of the ionomers indicated improved dynamic modulus at temperatures above 100spcirc$C. Tensile testing of the ionomers indicated slight improvements in tensile strength with little loss in elongation at break. PS-PIB-PS block copolymer ionomer (BCP01, center block molecular weight = 53,000 g/mole; 25.5 wt % polystyrene, 4.7% sulfonation of phenyl units, 100% neutralized with KOH) was compounded with various organic and inorganic acid salts of 2-ethylhexyl-p-dimethyl aminobenzoate (ODAB) to explore the efficacy of these compounds as ionic plasticizers. (Abstract shortened by UMI.)

Baugh, Daniel Webster, III

308

Styrene emission abatement in a bathtub manufacturing plant  

SciTech Connect

EPA is moving forward on promulgating the National Emission Standard for Hazardous Air Pollutants (NESHAP-MACT) for the Reinforced Plastics/Composites Source Category which affects styrene emitters like the American Standard plant. While most composites manufacturers are taking a wait and see approach, American Standard realized the need to move foreward with the controls. Styrene has a reputation of being a difficult VOC to abate. Most adsorption technologies shy away from this monomer due to reactions that cause fires. Weatherly refined their treatment of styrene emissions with experience from installations at similar plants in Europe. Weatherly installed a 35,000 scfm concentrator/oxidation Polyad{trademark} system in 1996 at American Standard`s bathtub manufacturing plant in Salem, Ohio. The styrene emissions are captured in the spray booth exhaust and discharged to the Polyad{trademark} system. The system is achieving 93% removal efficiency on the styrene emissions. This paper will describe the Weatherly Polyad{trademark} VOC abatement system at American Standard`s Salem Ohio plant.

Niezgodski, D.M. [Weatherly Inc., Atlanta, GA (United States)

1997-12-31

309

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

Gu, Tingyue

310

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

E-print Network

The objective of this research is to investigate and evaluate the concentration levels of styrene emitted during the production of cultured marble building materials. The manufacture of styrene monomer is generally carried out in closed systems...

Bell, Lewis Ray

2012-06-07

311

Preparation of periodic mesoporous silica-included divacant Keggin units for the catalytic oxidation of styrene to synthesize styrene oxide  

NASA Astrophysics Data System (ADS)

Periodic mesoporous composite catalysts, [( n-C 4H 9) 4N] 4[?-SiW 10O 34(H 2O) 2]/SBA-15 (TBA-1*/SBA-15, where TBA-1* = [( n-C 4H 9) 4N] 4[?-SiW 10O 34(H 2O) 2]), with TBA-1* loadings of 4.3-14.8% were prepared by simultaneous hydrolysis and co-condensation of the tetraethoxysilane (TEOS) in the presence of divacant Keggin-type polyoxometalate and triblock copolymer surfactant (P123) followed by hydrothermal treatment process. Structure integrity of the Keggin unit in as-prepared composites was studied by Fourier transform infrared spectroscopy (FT-IR), Raman scattering spectra, and 29Si magic-angle spinning (MAS) NMR. Periodic mesoporous structure of the composites was evaluated by low-angle X-ray powder diffraction (LXRD) patterns, nitrogen porosimetry, and transmission electron microscope (TEM) measurements. As-prepared TBA-1*/SBA-15 was used as an heterogeneous oxidation catalyst for the styrene epoxidation reaction to synthesize styrene oxide in the presence of dilute H 2O 2 (30%), and influences of solvent, molar ratio of styrene to H 2O 2, TBA-1* loading on the styrene conversion, styrene oxide yield and selectivity were considered.

Yu, Xiaodan; Xu, Leilei; Yang, Xia; Guo, Yingna; Li, Kexin; Hu, Jianglei; Li, Wei; Ma, Fengyan; Guo, Yihang

2008-05-01

312

Radiation grafting of styrene on starch with high efficiency  

NASA Astrophysics Data System (ADS)

Wheat starch grafted with polystyrene (PS-g-starch) was synthesized via polymerization grafting of styrene on starch by gamma-ray. The effects of starch/styrene weight ratio, and amount of applied doses (5-40 kGy) on the percentage of grafting, G (%), were investigated. The results showed that G (%) increased with increasing starch content. The optimum condition, starch/styrene weight ratio 1/3 and the applied dose 10 kGy, led to 252.9% of grafting. The obtained graft copolymer was characterized by Fourier transform infrared spectroscopy, X-ray diffraction, thermal gravimetric analysis, and scanning electron microscopy. FTIR spectroscopy as well as the XRD analysis exhibited the changes in chemical and crystalline structure of starch after grafting reaction. TGA demonstrated the changes in thermal stability of PS-g-starch copolymer. SEM micrographs indicated porous patches of PS adhering on the starch.

Sheikh, N.; Akhavan, A.; Ataeivarjovi, E.

2013-04-01

313

Bacterial degradation of styrene in waste gases using a peat filter  

Microsoft Academic Search

A biofiltration process was developed for styrene-containing off-gases using peat as filter material. The average styrene\\u000a reduction ratio after 190 days of operation was 70% (max. 98%) and the mean styrene elimination capacity was 12?g m?3?h?1 (max. 30 g m?3?h?1). Efficient styrene degradation required addition of nutrients to the peat, adjustment of the pH?to a neutral level and efficient\\u000a control

M. Arnold; A. Reittu; A. von Wright; P. J. Martikainen; M.-L. Suihko

1997-01-01

314

Microemulsion polymerization of styrene initiated with gamma ray  

NASA Astrophysics Data System (ADS)

The styrene microemulsion with high monomer content was stabilized with a specially designed emulsifier with a branch in lipophilic head. In order to keep the microemulsion stable during polymerization, the microemulsion was initiated with gamma ray at room temperature. It was observed that there was an apparent plateau of polymerization rate during polymerization. It was the number of growing polymer particles instead of the total polymer particles being kept constant during the plateau. The polymerization kinetics showed some similarity to that in styrene microemulsion stabilized with SDS and n-pentanol.

Mangling, Xu; Xuewu, Ge; Zhicheng, Zhang; Zhichao, Wu; Manwei, Zhang

315

Microemulsion polymerization of styrene initiated with gamma ray  

NASA Astrophysics Data System (ADS)

The styrene microemulsion with high monomer content was stabilized with a specially designed emulsifier with a branch in lipophilic head. In order to keep the microemulsion stable during polymerization, the microemulsion was initiated with gamma ray at room temperature. It was observed that there was an apparent plateau of polymerization rate during polymerization. It was the number of growing polymer particles instead of the total polymer particles being kept constant during the plateau. The polymerization kinetics showed some similarity to that in styrene microemulsion stabilized with SDS and n-pentanol.

Xu, Xiangling; Ge, Xuewu; Zhang, Zhicheng; Wu, Zhichao; Zhang, Manwei

1997-04-01

316

Viscosity study in the reaction bath of the radical copolymerization of styrene divinylbenzene  

E-print Network

L-539 Viscosity study in the reaction bath of the radical copolymerization of styrene measurements taken during the copolymerization of Styrene Divinylbenzene in the reaction bath, near the gel the copolymerization of Styrene and Divinyl- benzene (DVB) at 60 oC, using AZO-2,2' isobutyro- nitrile (AIBN

Paris-Sud XI, Université de

317

Enantioselective Organo-Singly Occupied Molecular Orbital Catalysis: The Carbo-oxidation of Styrenes  

E-print Network

-oxidation of Styrenes Thomas H. Graham, Casey M. Jones, Nathan T. Jui, and David W. C. MacMillan* Merck Center this theme, we recently questioned whether feedstock olefins, such as styrenes, might be exploited disclose the first asymmetric SOMO-catalyzed carbo-oxidation of styrenes to provide -nitrate

MacMillan, David W. C.

318

Borohydrido rare earth complexes as precatalysts for the polymerisation of styrene  

E-print Network

Borohydrido rare earth complexes as precatalysts for the polymerisation of styrene Philippe Zinck Keywords: Catalysis, lanthanides, borohydrides, alkylmagnesium, styrene, polymerisation Abstract for the polymerisation of styrene. The reaction is quantitative at 50°C after several hours. Two growing chains per

Paris-Sud XI, Université de

319

Enhanced regioselectivity in palladium-catalysed asymmetric methoxycarbonylation of styrene using phosphetanes as chiral ligands  

E-print Network

1 Enhanced regioselectivity in palladium-catalysed asymmetric methoxycarbonylation of styrene using. ____________________________________________________________________________________________________________ The palladium-catalysed asymmetric methoxycarbonylation of styrene has been investigated for the first time%. ____________________________________________________________________________________________________________ Over the past two decades, the asymmetric methoxycarbonylation of styrene (equation 1) has been

Paris-Sud XI, Université de

320

Poly(4-(aminomethyl)styrene)-b-polystyrene: Synthesis and Unilamellar Vesicle Formation  

E-print Network

Notes Poly(4-(aminomethyl)styrene)-b-polystyrene: Synthesis and Unilamellar Vesicle Formation formation from new block copolymers of the composition poly(4-(aminomethyl)- styrene)-b-polystyrene [P4AMSn of the associated styrene and is essentially "amphiphilic". In addition, the amine groups provide the option

Zasadzinski, Joseph A.

321

Carbon Tetrachloride as Thermoporometry Liquid-probe to Study the Cross linking of Styrene Copolymer  

E-print Network

Carbon Tetrachloride as Thermoporometry Liquid-probe to Study the Cross linking of Styrene styrene copolymer networks have been measured by thermoporometry using CCl4 as a probe liquid. All of vinyl monomers bearing benzil pendant groups and their copolymerization with styrene has been described

Paris-Sud XI, Université de

322

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 YuanVersity of Washington, Seattle, Washington 98101 ReceiVed NoVember 28, 2006 Styrene is widely used as one of the most, and automobile parts. Inhaled styrene has been reported to produce respiratory toxicity in humans and animals

Hammock, Bruce D.

323

Dynamic light scattering study of the radical copolymerization of styrene-meta divinylbenzene  

E-print Network

L-73 Dynamic light scattering study of the radical copolymerization of styrene-meta divinylbenzene scattering study of a system undergoing irreversible gelation (styrene of styrene and m-divinylbenzene at 60 ~C in benzenic solution. The AZO-2,2' isobutyronitrile (AIBN) was used

Paris-Sud XI, Université de

324

Enantioconvergent Production of (R)-1-Phenyl-1,2-Ethanediol From Styrene  

E-print Network

Enantioconvergent Production of (R)-1-Phenyl-1,2-Ethanediol From Styrene Oxide by Combining radiobacter AD1, EchA-I219F, were pur- ified for the enantioconvergent hydrolysis of racemic styrene oxideA-I219F has enhanced enantioselec- tivity (enantiomeric ratio of 91 based on products) for converting (R)-styrene

Chen, Wilfred

325

Composites of Single-Walled Carbon Nanotubes and Styrene-Isoprene  

E-print Network

Composites of Single-Walled Carbon Nanotubes and Styrene-Isoprene Copolymer Latices Mai L. P. Ha are an excellent material to incorporate with polymers. There have been an Full Paper Composites of a styrene, as well as by mixing dispersed SWNTs with a styrene-isoprene copolymer latex after polymerization

Resasco, Daniel

326

Styrene Clusters in a Supersonic Jet: Reactive and Nonreactive Systems S. Kendler and Y. Haas*  

E-print Network

Styrene Clusters in a Supersonic Jet: Reactive and Nonreactive Systems S. Kendler and Y. Haas of styrene with several atoms and small molecules were prepared and studied in a supersonic jet by laser) by recording the excess energy at which fluorescence from the cluster disappears and styrene fluorescence

Haas, Yehuda

327

POTENTIAL FOR REDUCING STYRENE EXPOSURES FROM COPIED PAPER THROUGH USE OF LOW-EMITTING TONERS  

EPA Science Inventory

The paper reports results of tests, conducted using 53-L chambers to determine styrene emission rates from freshly copied paper produced on a single photocopier using two toners manufactured for the copier having different styrene contents. Copied-paper styrene emissions with bot...

328

(Z)-3-(1H-Indol-3-yl)-2-(3,4,5-tri­methoxy­phen­yl)acrylonitrile  

PubMed Central

In the title compound, C20H18N2O3, the C=C bond of the acrylonitrile group that links the indole and the 3,4,5-trimeth­oxy­phenyl rings has Z geometry, with dihedral angles between the plane of the acrylonitrile unit and the planes of the benzene and indole ring systems of 21.96?(5) and 38.94?(7)°, respectively. The acrylonitrile group is planar (r.m.s. deviation from planarity = 0.037?Å). Mol­ecules are linked into head-to-tail chains that propagate along the b-axis direction by bifurcated N—H?O inter­molecular hydrogen bonds, which form an R 1 2(5) motif between the indole NH group and the two meth­oxy O atoms furthest from the nitrile group. PMID:22412611

Penthala, Narsimha Reddy; Parkin, Sean; Crooks, Peter A.

2012-01-01

329

(Z)-3-(1-Benzofuran-2-yl)-2-(3,4,5-tri­meth­oxy­phen­yl)acrylonitrile  

PubMed Central

In the title compound, C20H17NO4, the double bond of the acrylonitrile group separating the 1-benzofuran moiety from the 3,4,5-trimeth­oxy­phenyl ring has Z geometry. The 1-benzofuran groups are ?–? stacked with inversion-related counterparts such that the furan ring centroid–centroid distance is 3.804?(5)?Å. The dihedral angle between the planes of the trimeth­oxy­phenyl ring and the acrylonitrile group is 24.2?(2)°. PMID:22412613

Penthala, Narsimha Reddy; Parkin, Sean; Crooks, Peter A.

2012-01-01

330

Selective hydrogenation of 1,3-butadiene in mixture with isobutene on a Pd\\/ ? -alumina catalyst in a semi-batch reactor  

Microsoft Academic Search

Butene isomers (C4) are obtained in the refinery as by-products of the steam cracking of naphtha and light gas oil. The C4 isomers contain a large fraction of butadiene. Butadiene is separated from this fraction by extractive distillation to produce a raffinate stream. However, the raffinate stream contains traces of butadiene (up to approximately 1%). For this stream to be

Deepyaman Seth; Amitava Sarkar; Flora T. T. Ng; Garry L. Rempel

2007-01-01

331

The use of non-tumor data in cancer risk assessment: reflections on butadiene, vinyl chloride, and benzeneq  

E-print Network

The use of non-tumor data in cancer risk assessment: reflections on butadiene, vinyl chloride of tumors in humans and/or experimental animals. Increasingly, however, other kinds of data (non-tumor data to characterize the pertinent non-tumor data available for 1,3- butadiene, benzene, and vinyl chloride

California at Berkeley, University of

332

Towards a Biocatalyst for (S)Styrene Oxide Production: Characterization of the Styrene Degradation Pathway of Pseudomonas sp. Strain VLB120  

Microsoft Academic Search

In order to design a biocatalyst for the production of optically pure styrene oxide, an important building block in organic synthesis, the metabolic pathway and molecular biology of styrene degradation in Pseudomonas sp. strain VLB120 was investigated. A 5.7-kb XhoI fragment, which contained on the same strand of DNA six genes involved in styrene degradation, was isolated from a gene

SVEN PANKE; BERNARD WITHOLT; ANDREAS SCHMID; MARCEL G. WUBBOLTS

1998-01-01

333

Rotary concentrator followed by thermal or catalytic oxidation - a hybrid approach to economical styrene abatement  

SciTech Connect

There are varied challenges in deciding appropriate technology for styrene abatement. Due to high costs of using RTOs for styrene abatement the small businesses, which form the bulk of styrene emitters, are faced with economically difficult choices. The proposed Rotary Concentrator technology can reduce operating cost up to six times and reduce CO{sub 2} and NO{sub x} emissions by more than half over the currently preferred RTO technology. It is also less expensive in capital expenditure and its viability for styrene abatement has been sufficiently demonstrated by pilot studies in the US and existing installations overseas. In both cases styrene destruction of more than 95% was achieved.

Gupta, A. [Duerr Industries, Inc., Plymouth, MI (United States)

1997-12-31

334

Cloning and characterization of styrene catabolism genes from Pseudomonas fluorescens ST  

SciTech Connect

Styrene is used in large quantities in the manufacturing of plastics, synthetic rubber, and resins. Styrene-utilizing microorganisms have been isolate in consideration of their potential applications as biocatalysts in the removal of styrene in industrial wastes. However, data conserving styrene catabolism in bacteria are not abundant. In this paper the isolated of the Pseudomonas fluorescens ST genes involved in the first steps of styrene degradation are reported as well as the identification of the intermediates accumulated by single recombinant clones. 33 refs., 5 figs., 1 tab.

Marconi, A.M.; Solinas, F. [La Sapienza Univ. of Rome (Italy); Galli, E.; Bestetti, G. [Univ. of Milan (Italy)] [and others

1996-01-01

335

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...

336

Kinetic and Dynamic Investigations of OH Reaction with Styrene.  

PubMed

The kinetics of hydroxyl radical reaction with styrene has been studied at 240-340 K and a total pressure of 1-3 Torr using the relative rate/discharge flow/mass spectrometry technique. In addition, the dynamics of the reaction was also studied using the ab initio molecular orbital method. The reaction was found to be essentially pressure independent over 1-3 Torr at both 298 and 340 K. At 298 K, the average rate constant was determined, using four different reference compounds, to be kstyrene+OH = (5.80 ± 0.49) × 10(-11) cm(3) molecule(-1) s(-1). At 240-340 K, the rate constant of this reaction was found to be negatively dependent on temperature with an Arrhenius expression determined to be kstyrene+OH = (1.02 ± 0.10) × 10(-11) exp[(532 ± 28)/T] cm(3) molecule(-1) s(-1). Observation of mass spectral evidence of adduct products and their respective fragment ions suggests that the reaction proceeds with addition of the OH to the vinyl carbons of the styrene molecule. Ab initio calculations of both the addition and the abstraction pathways predict that the addition pathways are more energetically favorable because of large exothermicity and essentially barrierless transition state associated with the additions, which is consistent with the experimental observations. Using the styrene + OH rate constant determined at 277 K in the present work, the atmospheric lifetime of styrene was estimated to be 4.9 h. PMID:25215459

Cho, Joeson; Roueintan, Masoud; Li, Zhuangjie

2014-10-01

337

Multiobjective differential evolution (MODE) for optimization of adiabatic styrene reactor  

Microsoft Academic Search

In this paper, a novel algorithm is proposed for solving multiobjective optimization problems. The proposed algorithm, multiobjective differential evolution (MODE), is applied to optimize industrial adiabatic styrene reactor considering productivity, selectivity and yield as the main objectives. Five combinations of the objectives are considered. Pareto set (a set of equally good solutions) obtained for all the cases is compared with

B. V. Babu; Pallavi G. Chakole; J. H. Syed Mubeen

2005-01-01

338

Styrene exposure and biologic monitoring in FRP boat production plants  

Microsoft Academic Search

A survey on styrene exposure was conducted in five small to medium-sized fiber-reinforced plastic (FRP) boat plants utilizing carbon felt dosimeters as personal and stationary samplers to measure 4 h (TWA) exposure during workday afternoons. The heaviest exposure, up to 256 ppm by personal sampling and 174 ppm by stationary sampling, took place during the lamination on a mold to

Masayuki Ikeda; Akio Koizumi; Michiko Miyasaka; Takao Watanabe

1982-01-01

339

Non-adiabatic radial-flow reactor for styrene production  

Microsoft Academic Search

A non-adiabatic radial reactor is proposed to carry out the dehydrogenation of ethylbenzene to styrene. Radial flow and continuous heating (using superheated steam) are the main features of the new design. Steam used as heating medium flows through tubes, which are radially installed in the catalyst bed. By means of steady-state simulations, this new design has been compared with two

A. A. Savoretti; D. O. Borio; V. Bucalá; J. A. Porras

1999-01-01

340

Ultrasonic degradation of poly (styrene-co-alkyl methacrylate) copolymers.  

PubMed

The ultrasonic degradation of poly (styrene-co-methyl methacrylate) (SMMA), poly (styrene-co-ethyl methacrylate) (SEMA) and poly (styrene-co-butyl methacrylate) (SBMA) copolymers of different compositions was studied. The copolymers were synthesized and NMR spectroscopy was used to determine the composition, and the glass transition temperatures were determined by DSC. The reactivity ratios were determined by the Kelen-Tudos method and it indicated that the copolymers were random. The effect of solvent, temperature and copolymer composition on the ultrasonic degradation rate of these copolymers was investigated. A model based on continuous distribution kinetics was employed to study the degradation kinetics. The degradation rate coefficients of the copolymers decreased with an increase in the styrene content in the copolymer. At any particular copolymer composition the rate of degradation follows the order: SBMA>SEMA>SMMA. Thermogravimetric analysis (TGA) of the copolymers was carried in order to assess their thermal stability. The same order of degradation was observed for the thermal degradation of the copolymers as that observed for ultrasonic degradation. PMID:20215041

Pasupuleti, Sasikiran; Madras, Giridhar

2010-06-01

341

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

342

Styrene vapor control systems in FRP yacht plants.  

PubMed

The production of large (greater than 25-ft) fiber-reinforced plastic (FRP) yachts has presented problems of styrene exposure in excess of the Occupational Safety and Health Administration permissible exposure level (OSHA PEL) of 100 ppm. Also, the National Institute for Occupational Safety and Health (NIOSH) is currently recommending a 10-hour workshift, 40-hour workweek time weighted average (TWA) of 50 ppm for styrene. Meeting this challenge will require a system of engineering, work practice, personal protective equipment, and monitoring control measures. NIOSH has performed a study of the engineering controls in three FRP yacht plants. Work practices and the use of personal protective equipment (PPE) were also considered in the evaluation. The three systems evaluated included a dilution system, a local ventilation system, and a push-pull ventilation system. The cost of constructing and operating these systems was not evaluated in this study. Study results indicated that each type of ventilation system can meet the present PEL of 100 ppm styrene; however, it is not certain that these systems can meet a lower PEL of 50 ppm styrene. PMID:4050803

Todd, W F

1985-01-01

343

Styrene vapor control systems in FRP yacht plants  

SciTech Connect

The production of large (greater than 25-ft) fiber-reinforced plastic (FRP) yachts has presented problems of styrene exposure in excess of the Occupational Safety and Health Administration permissible exposure level (OSHA PEL) of 100 ppm. Also, the National Institute for Occupational Safety and Health (NIOSH) is currently recommending a 10-hour workshift, 40-hour workweek time weighted average (TWA) of 50 ppm for styrene. Meeting this challenge will require a system of engineering, work practice, personal protective equipment, and monitoring control measures. NIOSH has performed a study of the engineering controls in three FRP yacht plants. Work practices and the use of personal protective equipment (PPE) were also considered in the evaluation. The three systems evaluated included a dilution system, a local ventilation system, and a push-pull ventilation system. The cost of constructing and operating these systems was not evaluated in this study. Study results indicated that each type of ventilation system can meet the present PEL of 100 ppm styrene; however, it is not certain that these systems can meet a lower PEL of 50 ppm styrene.

Todd, W.F.

1985-01-01

344

Styrene–Maleic Anhydride Copolymer Foam for Heat Resistant Packaging  

Microsoft Academic Search

Recent developments in direct injection foam processing using styrene–maleic anhydride (SMA) copolymer have resulted in a distinct and significant increase in the performance of foam packaging for food service applications. There are several problems that a consumer could experience when using a traditional polystyrene (PS) foam takeout container. To begin with, the heat of food at serving temperatures can cause

Robert D. Roberts; John C. Kwok

2007-01-01

345

Theoretical study of the Diels-Alder reactions of zirconium dimer with ethylene and butadiene  

SciTech Connect

A theoretical study of the symmetry concerted Diels-Alder analogue reactions of Zr{sub 2} with ethylene and 1,3-butadiene is carried out. The optimized structures of the complexes indicate breaking of one of the multiple bonds in Zr{sub 2} and 1,3-butadiene and the formation of a six-membered ring in agreement with symmetry concerted models. Thus the reaction of ethylene with Zr{sub 2} is thermally forbidden, while it is allowed for the butadiene case. This is explained based on the natural orbitals picture. The presented potential energy surfaces are useful for the interpretation of possible reactions in both ground and excited states. 26 refs., 7 figs., 3 tabs.

Roszak, S.; Balasubramanian, K. [Arizona State Univ., Tempe, AZ (United States)

1995-03-16

346

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

347

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

348

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

349

1,3-Butadiene: linking metabolism, dosimetry, and mutation induction.  

PubMed Central

There is increasing concern for the potential adverse health effects of human exposures to chemical mixtures. To better understand the complex interactions of chemicals within a mixture, it is essential to develop a research strategy which provides the basis for extrapolating data from single chemicals to their behavior within the chemical mixture. 1,3-Butadiene (BD) represents an interesting case study in which new data are emerging that are critical for understanding interspecies differences in carcinogenic/genotoxic response to BD. Knowledge regarding mechanisms of BD-induced carcinogenicity provides the basis for assessing the potential effects of mixtures containing BD. BD is a multisite carcinogen in B6C3F1 mice and Sprague-Dawley rats. Mice exhibit high sensitivity relative to the rat to BD-induced tumorigenesis. Since it is likely that BD requires metabolic activation to mutagenic reactive epoxides that ultimately play a role in carcinogenicity of the chemical, a quantitative understanding of the balance of activation and inactivation is essential for improving our understanding and assessment of human risk following exposure to BD and chemical mixtures containing BD. Transgenic mice exposed to 625 ppm BD for 6 hr/day for 5 days exhibited significant mutagenicity in the lung, a target organ for the carcinogenic effect of BD in mice. In vitro studies designed to assess interspecies differences in the activation of BD and inactivation of BD epoxides reveal that significant differences exist among mice, rats, and humans. In general, the overall activation/detoxication ratio for BD metabolism was approximately 10-fold higher in mice compared to rats or humans.(ABSTRACT TRUNCATED AT 250 WORDS) PMID:7698092

Bond, J A; Csanady, G A; Gargas, M L; Guengerich, F P; Leavens, T; Medinsky, M A; Recio, L

1994-01-01

350

1,3-Butadiene: Biomarkers and application to risk assessment.  

PubMed

1,3-Butadiene (BD) is a known rodent and human carcinogen that is metabolized mainly by P450 2E1 to three epoxides, 1,2-epoxy-3-butene (EB), 1,2:3,4-diepoxybutane (DEB) and 1,2-epoxy-3,4-butanediol (EB-diol). The individual epoxides vary up to 200-fold in their mutagenic potency, with DEB being the most mutagenic metabolite. It is important to understand the internal formation of the individual epoxides to assign the relative risk for each metabolite and to understand the molecular mechanisms responsible for major species differences in carcinogenicity. We have conducted extensive exposure-biomarker studies on mice, rats and humans. Using low exposures that range from current occupational levels to human exposures from tobacco smoke has provided evidence that mice are very different from humans, with mice forming ?200 times more DEB than humans at exposures of 0.1-1.5ppm BD. While no gender differences have been noted in mice and rats for globin adducts or N-7 guanine adducts, female rats and mice had 2-3-fold higher Hprt mutations and DNA-DNA cross-links, suggesting a gender difference in DNA repair. Numerous molecular epidemiology studies have evaluated globin adducts and Hprt mutations, SCEs and chromosomal abnormalities. None of the blinded studies have shown evidence of human genotoxicity at current occupational exposures and studies of globin adducts have shown similar or lower formation of adducts in females than males. If one calculates the EB dose-equivalents for the three species, mice clearly differ from rats and humans, being ?44 and 174 times greater than rats and humans, respectively. These data provide a scientific basis for improved risk assessment of BD. PMID:20974116

Swenberg, James A; Bordeerat, Narisa K; Boysen, Gunnar; Carro, Sujey; Georgieva, Nadia I; Nakamura, Jun; Troutman, John M; Upton, Patricia B; Albertini, Richard J; Vacek, Pamela M; Walker, Vernon E; Sram, Radim J; Goggin, Melissa; Tretyakova, Natalia

2011-06-30

351

Diels-alder reactions of allene with benzene and butadiene: concerted, stepwise, and ambimodal transition States.  

PubMed

Multiconfigurational complete active space methods (CASSCF and CASPT2) have been used to investigate the (4 + 2) cycloadditions of allene with butadiene and with benzene. Both concerted and stepwise radical pathways were examined to determine the mechanism of the Diels-Alder reactions with an allene dienophile. Reaction with butadiene occurs via a single ambimodal transition state that can lead to either the concerted or stepwise trajectories along the potential energy surface, while reaction with benzene involves two separate transition states and favors the concerted mechanism relative to the stepwise mechanism via a diradical intermediate. PMID:25216056

Pham, Hung V; Houk, K N

2014-10-01

352

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

353

Resonant Auger electron-photoion coincidence study of the fragmentation dynamics of an acrylonitrile molecule  

NASA Astrophysics Data System (ADS)

Monochromatic synchrotron radiation was used to promote K-shell electrons of nitrogen and carbon from the cyano group (C ? N) of gaseous acrylonitrile (C2H3-CN) to the unoccupied antibonding ?*C ? N orbital. Photofragmentation of acrylonitrile molecules following selective resonant core excitations of carbon and nitrogen core electrons to the ?*C ? N orbital was investigated using the electron-energy-resolved photoelecton-photoion coincidence technique. The fragment ion mass spectra were recorded in coincidence with the resonant Auger electrons, emitted in the decay process of the core-excited states. Singly and triply deuterated samples were used for fragment identification. The results showed the initial core-hole localization to be of minor importance in determining the dissociation pattern of the molecular cation. The participator and spectator Auger transitions produce entirely different fragmentation patterns and the latter indicates that complex nuclear rearrangements take place. It is suggested that the calculated kinetic energy releases are caused by the existence of metastable states, which appear with the opening of the spectator Auger channels.

Kooser, K.; Ha, D. T.; Granroth, S.; Itälä, E.; Partanen, L.; Nõmmiste, E.; Aksela, H.; Kukk, E.

2010-12-01

354

New sulfonated polystyrene and styrene-ethylene/butylene-styrene block copolymers for applications in electrodialysis.  

PubMed

In this study we prepared blends of polystyrene (PS) and high-impact polystyrene (HIPS) with poly(styrene-ethylene-butylene) (SEBS) triblock copolymer. After sulfonation, blends were used to fabricate ion-exchange membranes by solvent-casting and subsequent thermal treatment to obtain homogeneous packing densities. The morphology and structure of the blends were investigated by scanning electron microscopy, atomic force microscopy, and FTIR spectroscopy. Furthermore, the thermal transitions and stability of all the blends were characterized using calorimetric techniques and compared with those of the individual polymers. Analyses of the physical properties (i.e., ionic conductivity, ion-exchange capacity, water uptake, dimensional stability, mechanical properties, etc.) showed that the performance of the PS-containing membranes is, in general, higher than that of the HIPS containing one. Furthermore, the highest sulfonation degree was also found for the PS/SEBS membranes. The capabilities of the membranes were tested by investigating the extraction of Na(+) by electrodyalisis. Comparison of the percentage of extracted ions indicates that the incorporation of SEBS results in a significant improvement with respect to membranes made of individual polymers. PMID:22991943

Müller, Franciélli; Ferreira, Carlos A; Franco, Lourdes; Puiggalí, Jordi; Alemán, Carlos; Armelin, Elaine

2012-09-27

355

Mechanical Properties and Vulcanization Characteristics of Styrene-Butadiene Rubber (sbr) Based Compounds Filled with Eggshell Powder as a Bio-Filler  

NASA Astrophysics Data System (ADS)

Egg shell is an ordered bioceramic composite with five different layers [1, 2]. In this study, the effect of using various types of eggshell powder including after and before hatching eggshell and boiled eggshell on the mechanical properties and vulcanization characteristics of SBR compounds has been investigated. The obtained results were compared with calcium carbonate filled compounds. Evaluation of mechanical properties exhibited that incorporation of eggshell increased almost all of the mechanical properties of the compounds. BET test demonstrated higher specific area of eggshell powders compare with calcium carbonate. Some of the observed results attributed to higher specific area of eggshell powder. However, there is no definitive reason for some other results at this time. Vulcanization characteristics of the compounds showed that incorporation of eggshell powder had no considerable effect on curing time. The results of this research showed that all kinds of eggshell powders can be used in SBR based compounds successfully.

Saeb, Mohammad Reza; Dakhel, Hadi Ramezani; Ghaffari, Akbar

2008-08-01

356

Radiation processed styrene-butadiene rubber\\/ethylene-propylene diene rubber\\/multiple walled carbon nanotubes nano-composites: Effect of MWNT addition on solvent permeability behavior  

Microsoft Academic Search

Different compositions of SBR\\/EPDM 50:50 blends containing multiple walled carbon nanotubes (MWNT) as nano-particulate fillers (0.5–10%) were evaluated for radiation sensitivity and solvent permeability. The efficiency of radiation crosslinking was analyzed by gel-content and Charlesby-Pinner parameter measurements. Gamma radiation induced crosslinking extent was found to increase with radiation dose and MWNT concentration, which was reflected in different extents of swelling.

C. V. Chaudhari; K. A. Dubey; Y. K. Bhardwaj; S. Sabharwal

2011-01-01

357

Synergetic effect of copper-plating wastewater as a catalyst for the destruction of acrylonitrile wastewater in supercritical water oxidation.  

PubMed

A new supercritical water oxidation process for the simultaneous treatment of mixed wastewater containing wastewater from acrylonitrile manufacturing processes and copper-plating processes was investigated using a continuous tubular reactor system. Experiments were carried out at temperatures ranging from 400 to 600 degrees C and a pressure of 25 MPa. The residence time was fixed at 2s by changing the flow rates of feeds, depending on reaction temperature. The initial total organic carbon (TOC) concentration of the wastewaters and the O(2) concentration at the reactor inlet were kept constant at 0.49 and 0.74 mol/L. It was confirmed that the copper-plating wastewater accelerated the TOC conversion of acrylonitrile wastewater from 17.6% to 67.3% at a temperature of 450 degrees C. Moreover, copper and copper oxide nanoparticles were generated in the process of supercritical water oxidation (SCWO) of mixed wastewater. 99.8% of copper in mixed wastewater was recovered as solid copper and copper oxides at a temperature of 600 degrees C, with their average sizes ranging from 150 to 160 nm. Our study showed that SCWO provides a synergetic effect for simultaneous treatment of acrylonitrile and copper-plating wastewater. During the reaction, the oxidation rate of acrylonitrile wastewater was enhanced due to the in situ formation of nano-catalysts of copper and/or copper oxides, while the exothermic decomposition of acrylonitrile wastewater supplied enough heat for the recovery of solid copper and copper oxides from copper-plating wastewater. The synergetic effect of wastewater treatment by the newly proposed SCWO process leads to full TOC conversion, color removal, detoxification, and odor elimination, as well as full recovery of copper. PMID:19231072

Shin, Young Ho; Lee, Hong-shik; Lee, Young-Ho; Kim, Jaehoon; Kim, Jae-Duck; Lee, Youn-Woo

2009-08-15

358

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

359

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

PubMed Central

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

2008-01-01

360

Quantitation of DNA Adducts Induced by 1,3-Butadiene  

NASA Astrophysics Data System (ADS)

Human exposure to 1,3-butadiene (BD) present in automobile exhaust, cigarette smoke, and forest fires is of great concern because of its potent carcinogenicity. The adverse health effects of BD are mediated by its epoxide metabolites such as 3,4-epoxy-1-butene (EB), which covalently modify genomic DNA to form promutagenic nucleobase adducts. Because of their direct role in cancer, BD-DNA adducts can be used as mechanism-based biomarkers of BD exposure. In the present work, a mass spectrometry-based methodology was developed for accurate, sensitive, and precise quantification of EB-induced N-7-(1-hydroxy-3-buten-2-yl) guanine (EB-GII) DNA adducts in vivo. In our approach, EB-GII adducts are selectively released from DNA backbone by neutral thermal hydrolysis, followed by ultrafiltration, offline HPLC purification, and isotope dilution nanoLC/ESI+-HRMS3 analysis on an Orbitrap Velos mass spectrometer. Following method validation, EB-GII lesions were quantified in human fibrosarcoma (HT1080) cells treated with micromolar concentrations of EB and in liver tissues of rats exposed to sub-ppm concentrations of BD (0.5-1.5 ppm). EB-GII concentrations increased linearly from 1.15 ± 0.23 to 10.11 ± 0.45 adducts per 106 nucleotides in HT1080 cells treated with 0.5-10 ?M DEB. EB-GII concentrations in DNA of laboratory rats exposed to 0.5, 1.0, and 1.5 ppm BD were 0.17 ± 0.05, 0.33 ± 0.08, and 0.50 ± 0.04 adducts per 106 nucleotides, respectively. We also used the new method to determine the in vivo half-life of EB-GII adducts in rat liver DNA (2.20 ± 0.12 d) and to detect EB-GII in human blood DNA. To our knowledge, this is the first application of nanoLC/ESI+-HRMS3 Orbitrap methodology to quantitative analysis of DNA adducts in vivo.

Sangaraju, Dewakar; Villalta, Peter W.; Wickramaratne, Susith; Swenberg, James; Tretyakova, Natalia

2014-07-01

361

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...

362

Broadly effective enantioselective Diels-Alder reactions of 1-amino-substituted-1,3-butadienes.  

PubMed

[reaction: see text] A broad range of substituted 1-amino-1,3-butadienes undergo enantioselective Diels-Alder reactions with methacrolein in the presence of 5 mol % of Cr(III)-salen complex 1. The reactions are carried out conveniently, at room temperature, and they afford the cycloadducts in high yields and excellent ee's. PMID:11922808

Huang, Yong; Iwama, Tetsuo; Rawal, Viresh H

2002-04-01

363

Sulfoxide-directed thermal intramolecular [4 + 2] cycloadditions between 2-sulfinyl butadienes and unactivated alkynes.  

PubMed

2-Sulfinyl butadienes tethered to unactivated alkynes undergo a facile thermal intramolecular Diels-Alder cycloaddition, often at room temperature, to produce cyclohexa-1,4-dienes with good selectivities, in high yields, and preserving the valuable vinyl sulfoxide functionality. PMID:14587739

Fernández de la Pradilla, Roberto; Baile, Raquel; Tortosa, Mariola

2003-10-01

364

Highly active catalysts for the telomerization of crude glycerol with 1,3-butadiene  

Microsoft Academic Search

The first description of a telomerization reaction came from Smutny in 1967 who was studying the oligomerization and dimerization of 1,3-butadiene and its reactions with nucleophiles. Since then, numerous studies have appeared concentrated on monofunctional alcohols and other simple nucleophiles such as ammonia.

Regina Palkovits; Ilenia Nieddu

2008-01-01

365

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

366

The singlettriplet spectroscopy of 1,3-butadiene using cavity ring-down spectroscopy  

E-print Network

. Robinson, Paul R. Winter, and Timothy S. Zwiera) Department of Chemistry, Purdue University, West Lafayette of gas-phase 1,3-butadiene (C4H6) has been investigated over the region from 20 500 to 23 000 cm 1 using studies have focused attention primarily on the planar C2h symmetry and twisted Cs symmetry minima

Zwier, Timothy S.

367

Humidity sensor using cross-linked poly(chloromethyl styrene)  

Microsoft Academic Search

A resistive-type humidity sensor was prepared using a poly(chloromethyl styrene) (PCMS) film which was simultaneously cross-linked and quaternized. The impedance dependence on humidity for samples with various reaction degrees was measured. The sorption isotherm curves of water vapor in the cross-linked films were obtained using the quartz crystal microbalance method for the various samples. It was found that the degree

Y. Sakai; M. Matsuguchi; T. Hurukawa

2000-01-01

368

Characterization of glucoamylase immobilized on magnetic poly(styrene) particles  

Microsoft Academic Search

Glucoamylase (EC 3.2.1.3. from Aspergillus niger) which is widely used in industry was immobilized directly in one step onto low-cost magnetic poly(styrene) particles including active groups. Glucoamylase in both free and immobilized forms was used to hydrolyze maltose. For both forms, the temperature of 50°C and pH 4.5 were found as the optimum conditions in the aspects of activity and

T Bahar; S. S Çelebi

1998-01-01

369

Combustion products of 1,3-butadiene are cytotoxic and genotoxic to human bronchial epithelial cells.  

PubMed Central

Adverse health effects of airborne toxicants, especially small respirable particles and their associated adsorbed chemicals, are of growing concern to health professionals, governmental agencies, and the general public. Areas rich in petrochemical processing facilities (e.g., eastern Texas and southern California) chronically have poor air quality. Atmospheric releases of products of incomplete combustion (e.g., soot) from these facilities are not subject to rigorous regulatory enforcement. Although soot can include respirable particles and carcinogens, the toxicologic and epidemiologic consequences of exposure to environmentally relevant complex soots have not been well investigated. Here we continue our physico-chemical analysis of butadiene soot and report effects of exposure to this soot on putative targets, normal human bronchial epithelial (NHBE) cells. We examined organic extracts of butadiene soot by gas chromatography-mass spectrometry (GC-MS), probe distillation MS, and liquid chromatography (LC)-MS-MS. Hundreds of aromatic hydrocarbons and polycyclic aromatic hydrocarbons with molecular mass as high as 1,000 atomic mass units were detected, including known and suspected human carcinogens (e.g., benzo(a)pyrene). Butadiene soot particles also had strong, solid-state free-radical character in electron spin resonance analysis. Spin-trapping studies indicated that fresh butadiene soot in a buffered aqueous solution containing dimethylsulfoxide (DMSO) oxidized the DMSO, leading to CH(3)* radical formation. Butadiene soot DMSO extract (BSDE)-exposed NHBE cells displayed extranuclear fluorescence within 4 hr of exposure. BSDE was cytotoxic to > 20% of the cells at 72 hr. Morphologic alterations, including cell swelling and membrane blebbing, were apparent within 24 hr of exposure. These alterations are characteristic of oncosis, an ischemia-induced form of cell death. BSDE treatment also produced significant genotoxicity, as indicated by binucleated cell formation. The combination of moderate cytotoxicity and genotoxicity, as occurred here, can be pro-carcinogenic. PMID:11673128

Catallo, W J; Kennedy, C H; Henk, W; Barker, S A; Grace, S C; Penn, A

2001-01-01

370

Measurement of worker's exposure to styrene. Final report  

SciTech Connect

Studies were conducted to determine the effectiveness of personal samplers in the work place by documenting the magnitude of the variability in breathing-zone concentrations of styrene within the reinforced-plastics industry, determining factors that contribute to breathing-zone concentrations, and investigating the stability of styrene samples taken with charcoal tubes. Measurements were taken at a facility for manufacturing boats where the production process included spraying a catalyzed resin solution along with chopped fiberglass onto a mold. The average background air concentration was 18mg/m/sup 3/. The personal exposure concentrations were: nose, 327mg/m/sup 3/; left lapel, 365mg/m/sup 3/; right lapel, 388mg/m/sup 3/; and chest, 430mg/m/sup 3/. Factors affecting the concentration in the breathing zone included air-flow patterns, the hood face velocity, and the position of the worker relative to the hood and relative to the spray gun. Styrene, being a volatile and reactive compound, may undergo physical and chemical changes such as vaporization, oxidation and polymerization, any of which would cause underestimation if they occurred following the sample collection. Samples collected on charcoal were stable up to 4 weeks in storage.

Cohen, B.S.; Malek, R.

1988-08-03

371

Thermal polymerization of uninhibited styrene investigated by using microcalorimetry.  

PubMed

Calorimetric studies on the bulk polymerization of uninhibited styrene monomer under low temperature conditions from 50 to 85 degrees C were reported. Various thermograms acquired by either dynamic scanning or isothermal ageing were characterized by differential scanning calorimetry (DSC) or thermal activity monitor (TAM). Isothermal curve demonstrating an autocatalytic phenomenon associated with a characteristic induction time was detected. Heat of thermal polymerization of styrene between 50 and 85 degrees C was measured to be 670+/-11 J g(-1). The findings of this study include: (1) Exothermic phenomenon of thermal-initiation and chain transfer steps in thermal polymerization were corroborated by using calorimetric investigation extended to the temperature as low as 50 degrees C; (2) activation energies in the steps of thermal-initiation and chain transfer were determined to be 125+/-6 and 60+/-5 kJ mol(-1) by using Arrhenius plot, respectively; (3) apparent activation energy was verified to be 84 kJ mol(-1) related to the individual steps of thermal-initiation and chain transfer conformed. These kinetic parameters work well in simulating the adiabatic runaway behaviors of uninhibited styrene and in good agreement with other studies. PMID:18835095

Chen, Chin-Chuan; Duh, Yih-Shing; Shu, Chi-Min

2009-04-30

372

Characterization of a Poly(styrene-block-methylacrylate-random-octadecylacrylate-block-styrene) Shape Memory ABA Triblock Copolymer  

NASA Astrophysics Data System (ADS)

A new ABA triblock copolymer of poly(styrene-block- methylacrylate-random-octadecylacrylate-block-styrene) (PS-b- PMA-r-PODA-b-PS) was synthesized by reversible addition fragmentation chain transfer polymerization. The triblock copolymer can generate a three-dimensional, physically crosslinked network by self-assembly, where the glassy PS domains physically crosslink the midblock chains. The side chain crystallization of the polyoctadecylacrylare (PODA) side chain generates a second reversible network enabling shape memory properties. Shape memory tests by uniaxial deformation and recovery of molded dog-bone shape samples demonstrate that shape fixities above 96% and shape recoveries above 98% were obtained for extensional strains up to 300%. An outstanding advantage of this shape memory material is that it can be very easily shaped and remolded by elevating the temperature to 140^ oC, and after remolding the initial shape memory properties are totally recovered by eliminating the defects introduced by the previous deformation cycling.

Fei, Pengzhan; Cavicchi, Kevin

2011-03-01

373

Dielectric Relaxation Behavior of Poly(acrylonitrile-co-methacrylonitrile) Microcapsules Dispersed in a Silicone Matrix  

NASA Technical Reports Server (NTRS)

The dielectric relaxation behavior of poly(acrylonitrile-co-methacrylonitrile) dispersed in a cured polydimethyl siloxane (PDMS) matrix as microcapsules was investigated over multiple thermal cycles and at varying concentrations. The copolymer microcapsules contained an isopentane core. In the PDMS matrix this copolymer displayed a pronounced relaxation signal at temperatures above the glass transition of the copolymers due to Maxwell-Wagner-Sillars (MWS) relaxation. The mechanism of MWS relaxation interpreted by the Havriliak-Negami and Kohlrausch-Williams-Watts relaxation functions was found to be very similar to previous studies of neat polyacrylonitrile and its copolymer. The activation energy of the relaxation decreased over successive thermal cycling coincident with a decreasing strength of the relaxation. These observations were attributed to the decreasing concentration of nitrile groups due to intramolecular cyclizations.

Park, Taigyoo; OBrien, Emmett; Lizotte, Jeremy R.; Glass, Thomas E.; Ward, Thomas C.; Long, Timothy E.; Leo, Donald J.

2006-01-01

374

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

PubMed

Nanotechnology is expected to open some new aspects to fight and prevent diseases using atomic-scale tailoring of materials. The main aim of this study is to biosynthesize silver nanoparticles (AgNPs) using Trichoderma viride (HQ438699); the metabolite of this fungus will help either in reduction of the silver nitrate-adding active materials which will be loaded on the surface of the produced AgNPs. Poly(acrylonitrile-co-methyl methacrylate) copolymer (poly (AN-co-MMA)) was grafted with the prepared AgNPs. The poly(AN-co-MMA)/AgNPs were examined against ten different pathogenic bacterial strains, and the result was compared with another four different generic antibiotics. The produced poly(AN-co-MMA)/AgNPs showed high antibacterial activity compared with the four standard antibiotics. Moreover, the grafting of these AgNPs into the copolymer has potential application in the biomedical field. PMID:23873643

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

2013-10-01

375

Autodetachment Dynamics of Acrylonitrile Anion Revealed by Two-Dimensional Electron Impact Spectra  

NASA Astrophysics Data System (ADS)

Two-dimensional electron energy-loss spectra of acrylonitrile are presented in the incident energy range 0.095-0.9 eV, where the incoming electron is temporarily captured in the lowest ?* orbital. The cross section is plotted as a function of the incident electron energy that determines which vibrational resonant anion state is populated, and of the electron energy loss, that shows into which final vibrational states each resonance decays. The striking result is that besides the expected horizontal (for given resonances) and vertical (for given final states) patterns of peaks, diagonal arrangements of peaks are observed. They reveal restrictive selectivity with respect to which vibrations are deexcited in the detachment process, with ?4 (C?N stretch) and ?7 (C?H rocking) dominating. Surprisingly, all spectral features could be assigned to vibrational levels of the valence ?* resonance, and none to dipole-bound vibrational Feshbach resonance, although the latter must also exist in this energy range.

Regeta, K.; Allan, M.

2013-05-01

376

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

377

General and practical one-pot synthesis of dihydrobenzosiloles from styrenes.  

PubMed

A one-pot synthesis of dihydrobenzosiloles from styrenes has been developed. The reaction involves the nickel-catalyzed hydrosilylation of styrene with diphenylsilane, followed by the iridium-catalyzed dehydrogenative cyclization. This method is efficient for both electron-rich and -deficient styrenes and exhibits good functional group tolerance, as well as excellent regioselectivity. The forming dihydrobenzosiloles can be efficiently converted into valuable benzosiloles or 2-hydroxyphenethyl alcohols. PMID:22272663

Kuznetsov, Alexey; Gevorgyan, Vladimir

2012-02-01

378

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

379

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

Microsoft Academic Search

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, da- tabases and peer-reviewed papers. Only sources with descriptive statistics of personal measure- ments were accepted. The styrene exposure data cover personal air samples and biological

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

2008-01-01

380

Copolymer from the waste products of styrene and maleic acid production  

Microsoft Academic Search

Influence of the process conditions on the production of “STAM” copolymer from waste products formed at join producing of\\u000a styrene and propylene oxide, the acetophenone bottom residue at styrene rectification, with maleic acid. Effects of temperature,\\u000a copolymerization process duration, weight ratio of acetophenone bottom residue to maleic acid and styrene content in the bottom\\u000a residue are studied.

O. N. Filimonova

2007-01-01

381

Mass transport limitations in zeolite catalysts: the dehydration of 1-phenyl-ethanol to styrene  

Microsoft Academic Search

The dehydration of 1-phenyl-ethanol to styrene is a critical step in the styrene\\/propene oxide manufacturing process. An important challenge is to achieve deep dehydration while minimising the oligomerisation of styrene to heavy products that deactivate the catalyst. The present study shows that zeolite-based catalysts can meet the challenge when designed and operated such as to avoid diffusion limitations in the

Jean-Paul Lange; Carl M. A. M Mesters

2001-01-01

382

Blood concentrations of acrylonitrile in humans after oral administration extrapolated from in vivo rat pharmacokinetics, in vitro human metabolism, and physiologically based pharmacokinetic modeling.  

PubMed

The present study defined a simplified physiologically based pharmacokinetic (PBPK) model for acrylonitrile in humans based on in vitro metabolic parameters determined using relevant liver microsomes, coefficients derived in silico, physiological parameters derived from the literature, and a prior previously developed PBPK model in rats. The model basically consists of a chemical absorption compartment, a metabolizing compartment, and a central compartment for acrylonitrile. Evaluation of a previous rat model was performed by comparisons with experimental pharmacokinetic values from blood and urine obtained from rats in vivo after oral treatment with acrylonitrile (30 mg/kg, a no-observed-adverse-effect level) for 14 days. Elimination rates of acrylonitrile in vitro were established using data from rat liver microsomes and from pooled human liver microsomes. Acrylonitrile was expected to be absorbed and cleared rapidly from the body in silico, as was the case for rats confirmed experimentally in vivo with repeated low-dose treatments. These results indicate that the simplified PBPK model for acrylonitrile is useful for a forward dosimetry approach in humans. This model may also be useful for simulating blood concentrations of other related compounds resulting from exposure to low chemical doses. PMID:20600458

Takano, Ryohji; Murayama, Norie; Horiuchi, Kana; Kitajima, Masato; Kumamoto, Masatoshi; Shono, Fumiaki; Yamazaki, Hiroshi

2010-11-01

383

Cooperative effects for CYP2E1 differ between styrene and its metabolites  

PubMed Central

Cooperative interactions are frequently observed in the metabolism of drugs and pollutants by cytochrome P450s; nevertheless, the molecular determinants for cooperativity remain elusive. Previously, we demonstrated that steady-state styrene metabolism by CYP2E1 exhibits positive cooperativity.We hypothesized that styrene metabolites have lower affinity than styrene toward CYP2E1 and limited ability to induce cooperative effects during metabolism. To test the hypothesis, we determined the potency and mechanism of inhibition for styrene and its metabolites toward oxidation of 4-nitrophenol using CYP2E1 Supersomes® and human liver microsomes.Styrene inhibited the reaction through a mixed cooperative mechanism with high affinity for the catalytic site (67 ?M) and lower affinity for the cooperative site (1100 ?M), while increasing substrate turnover at high concentrations. Styrene oxide and 4-vinylphenol possessed similar affinity for CYP2E1. Styrene oxide behaved cooperatively like styrene, but 4-vinylphenol decreased turnover at high concentrations. Styrene glycol was a very poor competitive inhibitor. Among all compounds, there was a positive correlation with binding and hydrophobicity.Taken together, these findings for CYP2E1 further validate contributions of cooperative mechanisms to metabolic processes, demonstrate the role of molecular structure on those mechanisms and underscore the potential for heterotropic cooperative effects between different compounds. PMID:23327532

Hartman, Jessica H.; Boysen, Gunnar; Miller, Grover P.

2014-01-01

384

MICROBIAL REDUCTIVE DECHLORINATION OF HEXACHLORO-1,3-BUTADIENE IN A METHANOGENIC ENRICHMENT CULTURE. (R825513C007)  

EPA Science Inventory

Sequential reductive dechlorination of hexachloro-1,3-butadiene (HCBD) was achieved by a mixed, methanogenic culture enriched from a contaminated estuarine sediment. Both methanol and lactate served as carbon and electron sources. Methanol was stoichiometrically converted to m...

385

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

386

Vinyl Polymerization. 274. Polymerization of Acrylonitrile Initiated by the System Tetramethyl Tetrazene and Co(II) Chloride  

Microsoft Academic Search

The binary system of tetramethyl tetrazene (TMT) and Co(II) chloride was used as initiator of acrylonitrile (AN) in dimethylformamide. The initial rate of polymerization (Rp) was found to be expressed by Rp = k[TMT][Co(II) chloride] [AN] The polymerization was confirmed to proceed via a radical mechanism. The over-all activation energy for the polymerization was estimated as 15.1 kcal\\/mole. On the

Kazuo Sugiyama; Tadao Nakaya; Minoru Imoto

1971-01-01

387

Polymerization of Acrylonitrile Initiated by 1,4Dimethyl1,4-bis(p-nitrophenyl)-2-tetrazene  

Microsoft Academic Search

The polymerization of acrylonitrile (AN) initiated by 1,4-dimethyl-1,4-bis(p-nitrophenyl)-2-tetrazene (Ie) was studied in dimethylformamide (DMF) at high temperature. The polymerization proceeds by a radical mechanism. The rate of polymerization is proportional to [Ie] and [AN]. The overall activation energy for the polymerization is 21.5 kcal\\/mole within the temperature range of 115-130°C. The chain transfer of Ie was also undertaken over the

T. Oda; T. Maeshma; K. Sugiyama

1979-01-01

388

Surface modification of nanofibrous poly(acrylonitrile- co-acrylic acid) membrane with biomacromolecules for lipase immobilization  

Microsoft Academic Search

In this work, poly(acrylonitrile-co-acrylic acid) (PANCAA) was electrospun into nanofibers with a mean diameter of 180nm. To create a biofriendly microenvironment for enzyme immobilization, collagen or protein hydrolysate from egg skin (ES) was respectively tethered on the prepared nanofibrous membranes in the presence of 1-ethyl-3-(dimethyl-aminopropyl) carbodiamine (EDC)\\/N-hydroxyl succinimide (NHS). Confocal laser scanning microscopy (CLSM) was used to verify the surface

Xiao-Jun Huang; An-Guo Yu; Jun Jiang; Chao Pan; Jing-Wen Qian; Zhi-Kang Xu

2009-01-01

389

Effect of homogeneity on the thermal degradation of poly(vinyl chloride)\\/poly (?-methylstyrene-acrylonitrile-methylmethacrylate) blends  

Microsoft Academic Search

The thermal degradation of homogeneous and heterogeneous poly(vinyl chloride)\\/poly(?-methylstyrene-acrylonitrile-methylmethacrylate) (PVC\\/ MS-AN) blends were investigated by means of dynamic thermogravimetry. The blends were prepared by precipitation from solution in a common solvent (homogeneous PVC\\/MS-AN-MMA blend) and by pressing the mixture of solid polymers in a cold hydraulic press (heterogeneous PVC\\/MS-AN-MMA blend).From the thermogravimetric curves and by determining the kinetic parameters of

T. Kova?i?; B. Bari?; I. Klari?

1995-01-01

390

Vesicle Formation and Stability in Aqueous Mixtures of the Hydrolyzed Copolymer of Styrene-Maleic Anhydride and  

E-print Network

Vesicle Formation and Stability in Aqueous Mixtures of the Hydrolyzed Copolymer of Styrene of the hydrolyzed copolymer of styrene-maleic anhydride (HSMA) and a series of single-tailed cationic surfactants

Huang, Jianbin

391

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

392

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

393

Palladium-Catalyzed Telomerization of Butadiene with Polyols: From Mono to Polysaccharides  

NASA Astrophysics Data System (ADS)

The telomerization of butadiene with alcohols is an elegant way to synthesize ethers with minimal environmental impact since this reaction is 100% atom efficient. Besides telomerization of butadiene with methanol and water that is industrially developed, the modification of polyols is still under development. Recently, a series of new substrates has been involved in this reaction, including diols, pure or crude glycerol, protected or unprotected monosaccharides, as well as polysaccharides. This opens up the formation of new products having specific physicochemical properties. We will describe recent advances in this field, focusing on the reaction of renewable products and more specifically on saccharides. The efficient catalytic systems as well as the optimized reaction conditions will be described and some physicochemical properties of the products will be reported.

Bouquillon, Sandrine; Muzart, Jacques; Pinel, Catherine; Rataboul, Franck

394

Nickel-catalyzed reductive carboxylation of styrenes using CO2.  

PubMed

A nickel-catalyzed reductive carboxylation of styrenes using CO2 has been developed. The reaction proceeds under mild conditions using diethylzinc as the reductant. Preliminary data suggests the mechanism involves two discrete nickel-mediated catalytic cycles, the first involving a catalyzed hydrozincation of the alkene followed by a second, slower nickel-catalyzed carboxylation of the in situ formed organozinc reagent. Importantly, the catalyst system is very robust and will fixate CO2 in good yield even if exposed to only an equimolar amount introduced into the headspace above the reaction. PMID:18928253

Williams, Catherine M; Johnson, Jeffrey B; Rovis, Tomislav

2008-11-12

395

The acute toxic effects of hexachloro-1 : 3-butadiene on the rat kidney  

Microsoft Academic Search

A single intraperitoneal injection of hexachloro-1 : 3-butadiene (HCBD) at 100 mg\\/kg or above produced renal tubular necrosis in the rat by 24 h. Histological examination of the kidneys indicated damage to the straight portion of the proximal tubules. Urinary analysis showed diuresis, increased proteinuria and an increase in the excretion of N-acetyl-ß-d-glucosaminidase, and alkaline phosphatase at doses above 100

Edward A. Lock; John Ishmael

1979-01-01

396

Cooxidation of styrene by horseradish peroxidase and phenols. A biochemical model for protein-mediated cooxidation  

SciTech Connect

Styrene is oxidized to styrene oxide and benzaldehyde when incubated with horseradish peroxidase, H/sub 2/O/sub 2/, and 4-methylphenol. Styrene oxide is not formed in the absence of any of these reaction components or of molecular oxygen. The coupling products 2-(4-methylphenoxy)-1-phenylethane, 2-(4-methylphenoxy)-1-phenylethan-1-ol, and 2-(4-methylphenoxy)-2-phenylethan-1-ol are not formed, but the ortho-linked dimer of 4-methylphenol is a major product. The epoxide oxygen is labeled in the presence of /sup 18/O/sub 2/ but not H/sub 2/ /sup 18/O/sub 2/. Styrene oxide formation is not inhibited by mannitol or superoxide dismutase. The stereochemistry of trans-(1-/sup 2/H)styrene is partially scrambled in the epoxide product. EPR signals attributable to the 2,4-dihydroxyl-5-methylphenoxy radical, a product of the oxidation of 4-methylcatechol, are observed if Zn/sup 2 +/ is added to stabilize the radical. This radical is only detected in the presence of styrene. The results imply that styrene is epoxidized by the hydroperoxy radical generated by addition of molecular oxygen to the 4-methylphenoxy radical. The epoxidation mimics the chemistry proposed to occur in the protein-mediated cooxidation of styrene by hemoglobin and myoglobin.

Ortiz de Montellano, P.R.; Grab, L.A.

1987-08-25

397

The preparation and spectral characterisation of vinylferrocene–styrene copolymer latexes  

Microsoft Academic Search

A series of vinylferrocene–styrene copolymer latexes having different vinylferrocene to styrene ratios were prepared via a free radical mechanism. Theoretical DLVO calculations have been used to model the aggregation behaviour of the polymer latexes with respect to a change in particle zeta potential. It has been shown that a critical value of the zeta potential of approximately ?25 mV is

Huma Ahmad; Lisa Benee; Martin J Snowden; Michael J. K Thomas; Edward A Vidgeon

2001-01-01

398

EVALUATION OF TRICKLE-BED AIR BIOFILTER PERFORMANCE FOR STYRENE REMOVAL  

EPA Science Inventory

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 vol...

399

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

400

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

Microsoft Academic Search

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,

Hasnaa Jorio; Louise Bibeau; Michèle Heitz

2000-01-01

401

Physiological analysis of the expression of the styrene degradation gene cluster in Pseudomonas fluorescens ST  

SciTech Connect

The effects of different carbon sources on expression of the styrene catabolism genes in Pseudomonas fluorescens ST were analyzed by using a promoter probe vector, pPR9TT, which contains transcription terminators upstream and downstream of the {beta}-galactosidase reporter system. Expression of the promoter of the stySR operon, which codes for the styrene two-component regulatory system, was found to be constitutive and not subject to catabolite repression. This was confirmed by the results of an analysis of the stySR transcript in P. fluorescens ST cells grown on different carbon sources. The promoter of the operon of the upper pathway, designated PstyA, was induced by styrene and repressed to different extents by organic acids or carbohydrates. In particular, cells grown on succinate or lactate in the presence of styrene started to exhibit {beta}-galactosidase activity during the mid-exponential growth phase, before the preferred carbon sources were depleted, indicating that there is a threshold succinate and lactate concentration which allows induction of styrene catabolic genes. In contrast, cells grown on glucose, acetate, or glutamate and styrene exhibited a diauxic growth curve, and {beta}-galactosidase activity was detected only after the end of the exponential growth phase. In each experiment the reliability of the reporter system constructed was verified by comparing the {beta}-galactosidase activity and the activity of the styrene monooxygenase encoded by the first gene of the styrene catabolic operon.

Santos, P.M.; Blatny, J.M.; Di Bartolo, I.; Valla, S.; Zennaro, E.

2000-03-01

402

Comparison of mouse strains for susceptibility to styrene-induced hepatotoxicity and pneumotoxicity  

SciTech Connect

Styrene is known to cause both hepatotoxicity and pneumotoxicity in mice. Strain differences have been reported by other investigators suggesting that Swiss mice are less susceptible than non-Swiss mice to styrene-induced liver damage. In this study, All and C57BL16 mice were found to be similar to non-Swiss albino (NSA) mice in susceptibility whereas CD-1 (Swiss) mice were more resistant to hepatotoxicity as assessed by serum sorbitol dehydrogenase levels and pneumotoxicity as determined by gamma-glutamyltranspeptidase and lactate dehydrogenase measurements in bronchoalveolar ravage fluid. Styrene was hepatotoxic in CD-1 mice treated with pyridine to induce CYP2E1. CYP2E1 apoprotein levels and p-nitrophenol hydroxylase activities in control and pyridine-induced mice were similar in the two strains. Hepatic and pulmonary microsomal preparations from both strains metabolized styrene to styrene oxide at similar rates. CD-1 mice were as susceptible as the NSA mice to the effects of styrene oxide. The data suggest that there are no differences in the bioactivation of styrene to styrene oxide or innate susceptibility to the active metabolite that would account for the differences between the CD-1 and NSA mice. 26 refs., 6 tabs.

Carlson, G.P. [Purdue Univ., West Lafayette, IN (United States)] [Purdue Univ., West Lafayette, IN (United States)

1997-10-01

403

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

404

Mechanochemical polymerization of styrene initiated by the grinding of layered clay minerals  

Microsoft Academic Search

The polymerization of styrene mechanochemically initiated by the grinding of talc was performed by using a vibrating ball mill. Talc used was one of layered clay minerals as well as montmorillonite. The effect of the grinding of talc on the polymerization of the styrene was investigated by characterizing the polymer formed and talc ground. The results revealed that of all

Masahiro Hasegawa; Mitsumasa Kimata; Itsuo Takahashi

2007-01-01

405

POTENTIAL FOR REDUCING INDOOR STYRENE EXPOSURE FROM COPIED PAPER THROUGH USE OF LOW-EMITTING TONERS  

EPA Science Inventory

Tests were conducted, using 53-L dynamic chambers, to determine airborne styrene emission rates over time from freshly copied paper. Copies were produced on a single photocopier, using two toners manufactured for this copier but having different styrene contents. The resulting em...

406

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

407

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.

408

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

409

Inhalation developmental toxicology studies: Teratology study of 1,3-butadiene in mice: Final report  

SciTech Connect

Maternal toxicity, reproductive performance and developmental toxicology were evaluated in CD-1 mice following whole-body, inhalation exposures to 0, 40, 200 and 1000 ppM of 1,3-butadiene. The female mice, which had mated with unexposed males were exposed to the chemical for 6 hours/day on 6 through 15 dg and sacrificed on 18 dg. Maternal animals were weighed prior to mating and on 0, 6, 11 and 18 dg; the mice were observed for mortality, morbidity and signs of toxicity during exposure and examined for gross tissue abnormalities at necropsy. Live fetuses were weighed and subjected to external, visceral and skeletal examinations to detect growth retardation and morphologic anomalies. Significant concentration-related decreases were detected in a number of maternal body weight measures. There was a significant concentration-related depression of fetal body weights and placental weights. Body weights of male fetuses of all exposed groups were significantly lower than values for control fetuses; weights of female fetuses were significantly depressed in the mice exposed to 200 and 1000 ppM. In the 200- and 1000-ppM exposure groups, weights of placentas of male fetuses were significantly decreased, but placental weights of female fetuses were significantly affected only in litters exposed to the highest 1,3-butadiene concentration. This exposure regimen produced significant signs of maternal toxicity at concentrations of 200 and 1000 ppM 1,3-butadiene.

Hackett, P.L.; Sikov, M.R.; Mast, T.J.; Brown, M.G.; Buschbom, R.L.; Clark, M.L.; Decker, J.R.; Evanoff, J.J.; Rommereim, R.L.; Rowe, S.E.; Westerberg, R.B.

1987-11-01

410

The Effect of Maleic Anhydride Grafted Styrene-Ethylene-Butylene-Styrene on the Friction and Wear Properties of Polyamide6\\/Carbon Nanotube Composites  

Microsoft Academic Search

The friction and wear properties of polyamide6 (PA6), polyamide6\\/carbon nanotube (PA6\\/CNT) nanocomposites and PA6\\/maleic anhydride grafted Styrene-ethylene-butylene-styrene (SEBS-g-MA+CNT) nanocomposites was studied by means of a ring-on-block tribometer. The morphologies of the worn surfaces of specimens were observed with a scanning electron microscopy (SEM). All specimen wear increases with increasing load; meanwhile, the friction coefficient decreases. Wear of PA6\\/CNT is larger

J. G. Zhang; J. Deng

2011-01-01

411

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

412

Organocatalytic chemo- and regioselective oxyarylation of styrenes via a cascade reaction: remote activation of hydroxyl groups.  

PubMed

The first organocatalytic oxyarylation of styrenes has been established through a cascade of vinylogous Michael addition/alkoxyl transfer reactions of o- or p-hydroxylstyrenes with quinone imine ketals. The process leads to a highly chemo- and regioselective oxyarylation of styrenes and provides access to m-alkylated anilines in generally high yields and excellent diastereoselectivity (up to 99% yield, >95:5 dr). An investigation of the reaction pathway revealed that the existence and position of the hydroxyl group of styrene played crucial roles in the cascade reaction, suggesting that the two reactants were simultaneously activated by binaphthyl-derived phosphoric acid via hydrogen bonding interactions and long-distance conjugative effects. In addition, the activating group of the hydroxyl functionality in the products can be easily removed or transformed, demonstrating the applicability and utility of this strategy in styrene oxyarylation and in the synthesis of styrene-based compounds. PMID:24905240

Zhang, Yu-Chen; Jiang, Fei; Wang, Shu-Liang; Shi, Feng; Tu, Shu-Jiang

2014-07-01

413

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

414

Unprecedented insertion of styrene single units in polyisoprene using borohydrido rare earths / dialkylmagnesium catalysts : a new family of SBR rubbers.  

E-print Network

1 Unprecedented insertion of styrene single units in polyisoprene using borohydrido rare earths, stereospecific polymers, rubber. Introduction The introduction of functional groups such as styrene in the backbone of polydienes is of interest for many fields of applications. Styrene-dienes copolymers commonly

Paris-Sud XI, Université de

415

Surface Science Letters Initial oxidation stages of hydrogen-and styrene-terminated Si(100) surfaces: A  

E-print Network

Surface Science Letters Initial oxidation stages of hydrogen- and styrene-terminated Si(100- and styrene-terminated Si(100)-2Ã?1 films in O2 atmosphere at 500 K using molecular dynamics (MD) simulations of these reactions leads to increased amorphization of the surface as the oxidation proceeds. In the case of styrene

Ciobanu, Cristian

416

The nature of the exalted Kekule vibration of styrene and other benzene derivatives in the S1 state  

E-print Network

The nature of the exalted Kekule vibration of styrene and other benzene derivatives in the S1 state structures. In Platt's notation, the excited state is the 1 Lb one [20]. Styrene, with a double bond situated-photon spectrum of styrene [24] also show

Haas, Yehuda

417

High-Shear-Rate Behavior of Radial Hydrogenated Styrene-Isoprene and Block Ethylene-Propylene Copolymer  

E-print Network

High-Shear-Rate Behavior of Radial Hydrogenated Styrene-Isoprene and Block Ethylene additives (an ethylene-propylene block copolymer and a radial hydrogenated styrene-isoprene copolymer) in a hydrocarbon-based oil solution has been investigated. At mass concentrations of up to 2.0% for the styrene

Erickson, David

418

Role of interphase processes in styrene vapor removal from airflow under the action of a pulsed electron beam  

Microsoft Academic Search

The conversion of styrene vapor in airflow under the action of a pulsed electron beam has been studied. It is demonstrated that the main processes leading to the removal of styrene from airflow involve reactive oxygen species and yield styrene oxidation products, which are characterized by low vapor pressures and are removed from airflow in a condensed state. This experimental

Yu. N. Novoselov; I. E. Filatov

2009-01-01

419

Mortality study of workers employed in 1,3-butadiene production units identified from a large chemical workers cohort.  

PubMed

The IARC 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, a cohort mortality study was conducted 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 and Institute 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% confidence interval (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. A statistically non-significant excess of stomach cancer was observed in the overall cohort (five cases; SMR = 243; CI = 79-568) that was most pronounced among workers employed in the Rubber Reserve plant for 2 or more years (five cases; SMR = 657; CI = 213-1530). We conclude that the results of this study add to the weight of evidence suggesting that butadiene is carcinogenic in humans. PMID:8901895

Ward, E M; Fajen, J M; Ruder, A M; Rinsky, R A; Halperin, W E; Fessler-Flesch, C A

1996-10-28

420

Investigation on RF styrene plasma by emission spectroscopy  

NASA Astrophysics Data System (ADS)

In order to gain an insight into the process of RF styrene plasma, the gas phase plasmas were investigated by emission spectroscopy. The plasma reactor was a bell-jar-type chamber with two parallel plate electrodes. The measurement of plasma emission spectra was made with axial resolution. The correlations among the emission intensities of CH and C4H2(+) species, the polymer deposition rate, and the polymeric structure of the deposited films were studied. The proposed analysis showed that the gas flow pattern in the plasma reactor, and the difference in collisions between styrene monomer molecules and energetic free electrons occurring in plasma region and RF sheath, made the fragments and ions produced thereof change in the different regions, resulting in the change in polymeric structure and deposition rate of the polymer films. With the increase in distance between the substrate position and the lower electrode, the deposition rate and the concentration of phenyl groups both at the polymer surface and in the bulk decreased.

Chen, Meng; Yang, Tsin-Chi; Ma, Zhenguo

1995-04-01

421

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

422

Coupled-cluster calculations of the excitation energies of ethylene, butadiene, and cyclopentadiene  

NASA Astrophysics Data System (ADS)

The equation-of-motion coupled-cluster (EOM-CC) method has been used to calculate the vertical excitation energies of ethylene, trans-butadiene, cis-butadiene, and cyclopentadiene. The approximations used were the EOM-CC singles-and-doubles (EOM-CCSD) method and EOM-CCSD with a noniterative treatment of triple excitations, EOM-CCSD(T), EOM-CCSD(T˜). The basis sets were atomic natural orbital sets augmented with diffuse functions. Comparisons have been made with a series of complete active space second-order perturbation theory (CASPT2) results, which used the same basis sets and geometries, and experiment. For the Rydberg states the EOM-CCSD results were in good agreement with experiment and CASPT2. The results for the valence states show more variation. For ethylene CASPT2 exaggerates the Rydberg character of the V state, while EOM-CCSD provides a better description. For the valence states of the other molecules the EOM-CCSD excitation energies tend to be too high, but considerable improvements are given by EOM-CCSD(T˜). For the 1 1Bu/1 1B2 states of butadiene and cyclopentadiene EOM-CCSD(T˜) agrees well with experiment and CASPT2. The agreement for the 1 1Ag?2 1Ag and 1 1A1?2 1A1 transitions for trans-butadiene and cis-butadiene, which are not known experimentally, is not so good, with the EOM-CC results significantly higher than the CASPT2 ones. However, the EOM-CCSD(T˜) and CASPT2 energies for the 1 1A1?2 1A1 transition in cyclopentadiene are in quite close agreement and both agree well with experiment. EOM-CCSD(T˜) shows an average error in vertical excitation energies for all states of all molecules of 0.12 eV, and improves those for valence states from an error of 0.26 eV for EOM-CCSD to 0.13 eV.

Watts, John D.; Gwaltney, Steven R.; Bartlett, Rodney J.

1996-10-01

423

Dodecagonal Quasicrystalline Morphology in a Poly(styrene-b-isoprene-b-styrene-b-ethylene oxide) Tetrablock Terpolymer  

SciTech Connect

A dodecagonal quasicrystalline (QC) morphology is identified in a poly(styrene-b-isoprene-b-styrene-b-ethylene oxide) (SISO) tetrablock terpolymer based on evidence provided by transmission electron microscopy (TEM), small-angle X-ray scattering, and dynamic mechanical spectroscopy measurements. The QC state occurs at temperatures between those associated with simple hexagonal order (HEX) and the {sigma}-phase (P4{sub 2}/mnm), T{sub HEX} < T{sub QC} < T{sub {sigma}} < T{sub ODT}, where T{sub ODT} is the order-disorder transition temperature. All three morphologies are formed from spherical domains containing an O core surrounded by a shell of S that screens unfavorable segment-segment interactions with an I-rich matrix. TEM analysis reveals a QC morphology with 12-fold rotational symmetry but devoid of long-range translational order, along with locally coordinated structures consistent with dodecagonal quasicrystalline approximants. The SISO molecular architecture decouples control over the domain shape and interdomain interactions, leading to a multiplicity of packing symmetries.

Zhang, Jingwen; Bates, Frank S. (UMM)

2012-10-26

424

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

425

Determination of acrylonitrile in foods by headspace gas-liquid chromatography with nitrogen-phosphorus detection.  

PubMed

A general procedure is described for the determination of acrylonitrile (AN) in foods such as margarine, honey butter, cold-pack cheese, and peanut butter, which are likely to be packaged in AN-based plastic. The entire sample is blended with water and salt at less than 5 degrees C, aliquots are sealed in crimp-top vials, and the vials are equilibrated in a boiling water bath. The headspace is sampled by using a heated syringe, and AN is determined by gas chromatography with a nitrogen-phosphorus selective detector. The inclusion of propionitrile as an internal standard allows quantitation of AN with detection at 4,4, and 10 ppb for margarine, honey butter, and cold-pack cheese, respectively. A peak corresponding to about 5 ppb apparent AN in all non-AN-packaged peanut butter samples examined limits detection in peanut butter to about 15 ppb. The coefficients of variation at 20 ppb for margarine, honey butter, cold-pack cheese, and peanut butter were 7.5, 8.3, 7.3, and 10.2%, respectively. PMID:6630123

Page, B D; Charbonneau, C F

1983-09-01

426

Nanostructured Synthetic Carbons Obtained by Pyrolysis of Spherical Acrylonitrile/Divinylbenzene Copolymers  

PubMed Central

Novel carbon materials have been prepared by the carbonization of acrylonitrile (AN)/divinylbenzene (DVB) suspension porous copolymers having nominal crosslinking degrees in the range of 30–70% and obtained in the presence of various amounts of porogens. The carbons were obtained by pre-oxidation of AN/DVB copolymers at 250?350°C in air followed by pyrolysis at 850°C in an N2 atmosphere. Both processes were carried out in one furnace and the resulting material needed no further activation. Resulting materials were characterized by XPS and low temperature nitrogen adsorption/desorption. It was found that maximum pyrolysis yield was ca. 50% depending on the oxidation conditions but almost independent of the crosslinking degree of the polymers. Porous structure of the carbons was characterized for the presence of micropores and macropores, when obtained from highly crosslinked polymers or polymers oxidized at 350°C and meso- and macropores in all other cases. The latter pores are prevailing in the structure of carbons obtained from less porous AN/DVB resins. Specific surface area (BET) of polymer derived carbons can vary between 440 m2/g and 250 m2/g depending on the amount of porogen used in the synthesis of the AN/DVB polymeric precursors. PMID:22916245

Malik, Danish J.; Trochimczuk, Andrzej W.; Ronka, Sylwia

2012-01-01

427

Effects of acrylonitrile on lymphocyte lipid rafts and RAS/RAF/MAPK/ERK signaling pathways.  

PubMed

Acrylonitrile (ACN) is a widely used chemical in the production of plastics, resins, nitriles, acrylic fibers, and synthetic rubber. Previous epidemiological investigations and animal studies have confirmed that ACN affects the lymphocytes and spleen. However, the immune toxicity mechanism is unknown. Lipid rafts are cell membrane structures that are rich in cholesterol and involved in cell signal transduction. The B cell lymophoma-10 (Bcl10) protein is a joint protein that is important in lymphocyte development and signal pathways. This study was conducted to examine the in vitro effects of ACN. We separated lipid rafts, and analyzed Bcl10 protein and caveolin. Western blotting was used to detect mitogen-activated protein kinase (MAPK) and phosphorylated MAPK levels. The results indicated that with increasing ACN concentration, the total amount of Bcl10 remained stable, but was concentrated mainly in part 4 to part 11 in electrophoretic band district which is high density in gradient centrifugation. Caveolin-1 was evaluated as a lipid raft marker protein; caveolin-1 content and position were relatively unchanged. Western blotting showed that in a certain range, MAPK protein was secreted at a higher level. At some ACN exposure levels, MAPK protein secretion was significantly decreased compared to the control group (P < 0.05). These results indicate that ACN can cause immune toxicity by damaging lipid raft structures, causing Bcl10 protein and lipid raft separation and restraining Ras-Raf-MAPK-extracellular signal-regulated kinase signaling pathways. PMID:25299088

Li, X J; Li, B; Huang, J S; Shi, J M; Wang, P; Fan, W; Zhou, Y L

2014-01-01

428

Uptake of One and Two Molecules of 1,3-Butadiene by Platinum Bis(dithiolene): A Theoretical Study.  

PubMed

Platinum bis(dithiolene) complexes have reactivity toward alkenes like nickel bis(dithiolene) complexes. We examined the uptake of 1,3-butadiene by platinum bis(dithiolene) [Pt(tfd)2] (tfd = S2C2(CF3)2) via a density functional theory study; both 1,2- and 1,4-additions of 1,3-butadiene to the ligands of Pt(tfd)2 to form both interligand and intraligand adducts were studied. For single 1,3-butadiene addition, direct 1,4-addition on interligand S-S, 1,2-addition on intraligand S-S, and 1,4-addition on intraligand S-C are all feasible at room temperature and are controlled by the symmetry of the highest occupied molecular orbital of 1,3-butadiene and the lowest unoccupied molecular orbital of Pt(tfd)2. However, the formation of the interligand S-S adduct through 1,4-addition of one molecule of cis-1,3-butadiene is the most favorable route, with a reaction barrier of 9.3 kcal/mol. The other two addition processes cannot compete with this one due to both higher reaction barriers and unstable adducts. Other possible pathways, such as formation of cis-interligand S-S adduct from 1,2-addition of one molecule of 1,3-butadiene via a twisted trans-interligand S-S adduct, have higher barriers. Our calculated results show that 1,4-addition of a single molecule of 1,3-butadiene on the interligand S-S gives the kinetically stable product by a one-step pathway. But of at least equal importance is the apofacial 1,4-addition of two molecules of 1,3-butadiene on the intraligand S-C of the same ligand on Pt(tfd)2, which yields the thermodynamically stable product, obtained via a short lifetime intermediate, the 1:1 intraligand S-C adduct, being formed through several pathways. The calculated results in this study well explain the experimental observation that 1:1 interligand S-S adduct was formed in a short time, and the intraligand S-C adduct from two molecules of cis-1,3-butadiene was accumulated in 20 h at 50° and characterized by X-ray crystallography. PMID:25184506

Dang, Li; Ni, Shao Fei; Hall, Michael B; Brothers, Edward N

2014-09-15

429

Adsorption and thermal decomposition of ethylbenzene and styrene on Pt(111) studied by UPS and XPS  

NASA Astrophysics Data System (ADS)

The interaction of ethylbenzene (EB) and styrene with Pt(111) was studied by UPS and XPS for adsorption temperatures between 135 and 870 K. Below 350 K, styrene chemisorbs strongly and the work function decreases by more than 2 eV indicating strong polarization or charge transfer. This is accompanied by different bonding shifts of the ? and ? orbitals towards lower binding energy. After saturation of the chemisorbed layer, physisorption and finally condensation in the form of clusters is observed. The isosteric heats of adsorption for physisorbed and condensed styrene are 61 and 58.5 kJ mol -1, respectively. The first EB layer dissociates into chemisorbed styrene and hydrogen atoms. The subsequent physisorbed and condensed layers consist of undissociated EB. Upon annealing in an EB or styrene atmosphere, chemisorbed ?-styrene polymerizes at about 400 K with a saturation coverage slightly above one monolayer. Upon further annealing the layer starts to decompose and beyond 700 K it forms a graphitic coke layer. Annealing of a ?-styrene layer without further gas admission yields the same species but with lower coverages.

Ranke, W.; Weiss, W.

2000-10-01

430

Desorption and biodegradation of sorbed styrene in soil and aquifer solids  

SciTech Connect

Approximately 40 and 18% of styrene freshly added to Lima loam and aquifer solids, respectively, was mineralized in 50 d. Although measurements of equilibrium desorption under abiotic conditions showed that only 7.2 and 5.7% of sorbed styrene were present in aqueous solution at 150 h, 61.0 and 66.7% of the compound were desorbed from the soil and aquifer solids, respectively, in 16 d under nonequilibrium conditions. Much of the nondesorbed styrene freshly added to the environmental samples could be extracted with methanol. Approximately 20% of the freshly added styrene not removed from columns of soil that had been repeatedly leached with water was mineralized in 49 d. Styrene freshly added to a muck soil also was extensively mineralized. However, if the compound was in soil for increasingly long periods in the absence of microbial activity, the extent of biodegradation by subsequently added microorganisms became progressively lower until < 3% was mineralized in soils in which the chemical was present for four months. Most of the styrene freshly added to Lima loam and Edwards muck could be extracted with acetonitrile, but < 4% was extracted from soils containing the chemical for 123 d. The biodegradation of styrene that has been in natural environments for some time thus is probably different from the transformations that occur with the freshly added compound.

Fu, M.H.; Mayton, H.; Alexander, M. (Cornell Univ., Ithaca, NY (United States). Dept. of Soil, Crop and Atmospheric Sciences)

1994-05-01

431

Development of Enantioselective Polyclonal Antibodies to Detect Styrene Oxide Protein Adducts  

PubMed Central

Styrene has been reported to be pneumotoxic and hepatotoxic in humans and animals. Styrene oxide, a major reactive metabolite of styrene, has been found to form covalent binding with proteins, such as albumin and hemoglobin. Styrene oxide has two optical isomers and it was reported that the (R)-enantiomer was more toxic than the (S)-enantiomer. The purpose of this study was to develop polyclonal antibodies that can stereoselectively recognize proteins modified by styrene oxide enantiomers at cysteine residues. Immunogens were prepared by alkylation of thiolated keyhole limpet hemocyanin (KLH) with styrene oxide enantiomers. Polyclonal antibodies were raised by immunization of rabbits with the chiral immunogens. Titration tests showed all six rabbits generated high titers of antisera that recognize (R)- or (S)-coating antigens accordingly. No cross-reaction was observed toward the carrier protein (BSA). All three rabbits immunized with (R)-immunogen produced antibodies that show enantioselectivity to the corresponding antigen, while only one among the three rabbits immunized with (S)-immunogen generated antibodies with enantioselectivity of the recognition. The enantioselectivity was also observed in competitive ELISA and immunoblot analysis. Additionally, competitive ELISA tests showed that the immunorecognition required the hydroxyl group of the haptens. Immunoblot analysis demonstrated that the immunorecognition depended on the amount of protein adducts blotted and hapten loading in protein adducts. In summary, we successfully developed polyclonal antibodies to stereoselectively detect protein adducts modified by styrene oxide enantiomers. PMID:19245253

Shen, Shuijie; Zhang, Fan; Zeng, Su; Tian, Ye; Chai, Xiaojuan; Gee, Shirley; Hammock, Bruce D.; Zheng, Jiang

2012-01-01

432

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

433

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

434

Singlet oxygen production from the peroxidase catalyzed formation of styrene glutathione adducts.  

PubMed

Recently, Stock et al. (J. Biol. Chem. 261, 15915-15922 [1986]) described a model enzyme system composed of horseradish peroxidase, hydrogen peroxide, phenol, glutathione and styrene. This system forms glutathione-styrene conjugates. Glutathione radicals and carbon-centered radicals are intermediates in this process. In the present study, this model enzyme system was also shown to generate singlet oxygen, probably via a Russell mechanism. No singlet oxygen was generated in the absence of styrene. Thus, contrary to prior suggestions, the reaction of glutathione radical with oxygen to produce a thiyl peroxyl radical is not a significant source of singlet oxygen. PMID:2930550

Kanofsky, J R

1989-03-31

435

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

436

Racemic and asymmetric Diels-Alder reactions of 1-(2-oxazolidinon-3-yl)-3-siloxy-1,3-butadienes.  

PubMed

Achiral and chiral 1-(2-oxazolidinon-3-yl)-3-siloxy-1,3-butadienes were prepared from readily available starting materials. Although more stable than the parent 1-amino-3-siloxy dienes, the 1-(2-oxazolidinon-3-yl)-3-siloxy-1,3-butadienes are still very reactive in Diels-Alder reactions, somewhat more than 1,3-dialkoxy-1, 3-butadienes (e.g., Danishefsky's diene). The cycloadditions of the achiral and chiral dienes with several different dienophiles were examined. The reactions proceeded in good yield, with modest to high endo selectivity. The chiral dienes exhibited excellent facial selectivity in cycloadditions with alpha-substituted acroleins, maleic anhydride and N-phenylmaleimide. Upon reduction and hydrolysis of the cycloadducts, substituted cyclohexenones were obtained with ee's ranging from 22% to >98%. PMID:11149852

Janey, J M; Iwama, T; Kozmin, S A; Rawal, V H

2000-12-29

437

T H1-directed modulation of in vitro cytokine production in human peripheral blood mononuclear cells by styrene-7.8-oxide  

Microsoft Academic Search

Styrene and its chiral main metabolite styrene-7.8-oxide are well characterized regarding their cytotoxic, genotoxic and neurotoxic properties. To our knowledge, no data exist on the influence of styrene and styrene-7.8-oxide on immune reactions. Epidemiological studies suggest that exposure to environmental pollutants, specifically volatile organic compounds (VOCs), including styrene is one factor contributing to increasing prevalence rates of allergic diseases. In

Georg H. Merker; Gerhard Metzner; Ferdinand Raabe

2006-01-01

438

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

439

Mortality study of workers in 1,3-butadiene production units identified from a chemical workers cohort.  

PubMed

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

1995-06-01

440

Coexistence of 1,3-butadiene conformers in ionization energies and Dyson orbitals  

NASA Astrophysics Data System (ADS)

The minimum-energy structures on the torsional potential-energy surface of 1,3-butadiene have been studied quantum mechanically using a range of models including ab initio Hartree-Fock and second-order Møller-Plesset theories, outer valence Green's function, and density-functional theory with a hybrid functional and statistical average orbital potential model in order to understand the binding-energy (ionization energy) spectra and orbital cross sections observed by experiments. The unique full geometry optimization process locates the s-trans-1,3-butadiene as the global minimum structure and the s-gauche-1,3-butadiene as the local minimum structure. The latter possesses the dihedral angle of the central carbon bond of 32.81° in agreement with the range of 30°-41° obtained by other theoretical models. Ionization energies in the outer valence space of the conformer pair have been obtained using Hartree-Fock, outer valence Green's function, and density-functional (statistical average orbital potentials) models, respectively. The Hartree-Fock results indicate that electron correlation (and orbital relaxation) effects become more significant towards the inner shell. The spectroscopic pole strengths calculated in the Green's function model are in the range of 0.85-0.91, suggesting that the independent particle picture is a good approximation in the present study. The binding energies from the density-functional (statisticaly averaged orbital potential) model are in good agreement with photoelectron spectroscopy, and the simulated Dyson orbitals in momentum space approximated by the density-functional orbitals using plane-wave impulse approximation agree well with those from experimental electron momentum spectroscopy. The coexistence of the conformer pair under the experimental conditions is supported by the approximated experimental binding-energy spectra due to the split conformer orbital energies, as well as the orbital momentum distributions of the mixed conformer pair observed in the orbital cross sections of electron momentum spectroscopy.

Saha, Saumitra; Wang, Feng; Falzon, Chantal T.; Brunger, Michael J.

2005-09-01

441

Inhalation developmental toxicology studies of 1,3-butadiene in the rat: Final report  

SciTech Connect

Maternal toxicity, reproductive performance and developmental toxicology were evaluated in Sprague-Dawley-derived rats during and following 6 hours/day, whole-body, inhalation exposures to 0, 40, 200, and 1000 ppM of 1,3-butadiene. The female rats (Ns = 24 to 28), which had mated with unexposed males, were exposed to the chemical from 6 through 15 dg and sacrificed on 20 dg. Maternal animals were weighed prior to mating and on 0, 6, 11, 16 and 20 dg; the rats were observed for mortality, morbidity and signs of toxicity during exposure and examined for gross tissue abnormalities at necropsy. Live fetuses were weighed and subjected to external, visceral and skeletal examinations to detect growth retardation and morphologic anomalies. There were no significant differences among treatment groups in maternal body weights or extragestational weights of rats exposed to 1,3-butadiene concentrations of 40 or 200 ppM, but, in animals exposed to 1000 ppM, significantly depressed body weight gains were observed during the first 5 days of exposure and extragestational weight gains tended to be lower than control values. These results, and the absence of clinical signs of toxicity, were considered to indicate that there was no maternal toxicity at exposure levels of 200 ppM or lower. The percentage of pregnant animals and the number of litters with live fetuses were unaffected by treatment. Under the conditions of this exposure regimen, there was no evidence for a teratogenic response to 1,3-butadiene exposure.

Hackett, P.L.; Sikov, M.R.; Mast, T.J.; Brown, M.G.; Buschbom, R.L.; Clark, M.L.; Decker, J.R.; Evanoff, J.J.; Rommereim, R.L.; Rowe, S.E.; Westerberg, R.B.

1987-11-01

442

Ab initio density-functional study of the bridging addition of acrylonitrile on the Si(100) surface.  

PubMed

Acrylonitrile may react with the Si(100) surface in a number of ways. Fifteen different configurations have been identified. This study which complements an earlier study devoted to cycloadditions and bonds involving a single atom deals essentially with configurations involving cumulative double bonds. Factors affecting the relative stability of various mesomeric forms are shown to be the proximity to tetrahedral geometry and the compatibility of the dipole form with buckled structures. Tripods are shown to be a way to accommodate a priori unfavorable structures. PMID:16375555

Cobian, M; Boureau, G; Hafner, J; Kresse, G

2005-11-01

443

Biotechnology Letters 25: 12031207, 2003. 2003 Kluwer Academic Publishers. Printed in the Netherlands.  

E-print Network

(ethylene-co-vinyl acetate) or poly(styrene-co-butadiene)). After inoculation with Alcaligenes xylosoxidans, the remaining the characterization and use of two solid polymers, poly(ethylene-co-vinyl acetate), EVA, and poly(styrene diameters of 3.4 mm, and SB (28% styrene, styrene- butadiene-styrene triblock) cylinders (Aldrich) with #12

Daugulis, Andrew J.

444

Heat of Combustion of the Product Formed by the Reaction of Diborane with 1,3-Butadiene  

NASA Technical Reports Server (NTRS)

The net heat of combustion of the product formed by the reaction of diborane with 1,3-butadiene was found to be 18,700+/-150 Btu per pound for the reaction of liquid fuel to gaseous carbon dioxide, gaseous water, and solid boric oxide. The measurements were made in a Parr oxygen-bomb calorimeter, and the combustion was believed to be 98 percent complete. The estimated net heat of combustion for complete combustion would therefore be 19,075+/-150 Btu per pound. Since this value is approximately the same as the heat of combustion of butadiene, it seems certain that the material is partially oxidized.

Tannenbaum, Stanley; Allen, Harrison, Jr.

1953-01-01

445

Comparative disposition of acrylonitrile and methacrylonitrile: quantitative whole-body autoradiographic studies in rats.  

PubMed

Following intravenous administration of an equimolar (0.216 mmol/kg) radioactive dose of acrylonitrile (2-[14C]VCN, 11.5 mg/kg) or methacrylonitrile (2-[14C]MeVCN, 14.5 mg/kg), the tissue distribution, covalent interaction, and elimination were compared (at 5 min to 48 hr) in male Fischer 344 rats using whole-body autoradiography (WBA). Autoradiographs obtained from freeze-dried or acid-extracted sections of animals treated with 2-[14C]VCN showed that radioactivity accumulated in the liver, lung, bone marrow, adipose tissues, kidney, gastrointestinal tract, and spleen. In animals treated with 2-[14C]MeVCN, the respiratory tissues contained high levels of 14C at an early period (5 min), while the gastrointestinal mucosa, adrenal cortex, liver, and kidney contained high levels of radioactivity at later periods (8, 24, and 48 hr). Quantitatively, lower uptake and irreversible interactions of 14C were observed in autoradiographs of rats treated with 2-[14C]MeVCN compared with those treated with 2-[14C]VCN. Rats given 2-[14C]VCN eliminated only 27% of administered radioactivity (exhaled air, urine, and feces), whereas rats treated with 2-[14C]MeVCN eliminated, by all routes, 65% of the total radioactive dose. Both WBA and elimination studies indicated that 2-[14C]VCN and/or its metabolites were rapidly distributed, extensively bound, and slowly eliminated from tissues. 2-[14C]MeVCN and/or its metabolites, however, were rapidly distributed and eliminated, mostly via the lung. The study indicated that the substitution of a methyl group on the alpha-carbon of the alpha-beta unsaturated aliphatic nitrile VCN, to form MeVCN, imparted qualitative and quantitative differences in the disposition of these two compounds. PMID:8812221

Ahmed, A E; Jacob, S; Ghanayem, B I

1996-09-01

446

Dynamic and kinetic aspects of the adsorption of acrylonitrile on Si(001)-2x1  

SciTech Connect

Using scanning tunnelling microscopy (STM), photoelectron and photoabsorption spectroscopies, we have examined how acrylonitrile (H{sub 2}C=CH-C{identical_to}N) reacts with the Si(001)-2x1 surface for coverages ranging from {approx}10{sup 12} molecules/cm{sup 2} to {approx}10{sup 14} molecules/cm{sup 2}. At 300 K, in the very low coverage regime (below 10{sup 13} molecules/cm{sup 2}), filled- and empty-state STM images show that the molecule bridges, via its {beta} carbon and nitrogen ends, two silicon dangling bonds, across the trench separating two dimer rows. A cumulative-double-bond unit (C=C=N) is formed. The 300 K STM image results from the dynamic flipping of the molecule between two equivalent equilibrium positions, which can be seen when the molecular motion is slowed down at 80 K. For coverages larger than 10{sup 13} molecules/cm{sup 2}, for which STM does not show ordered adsorption any more, the adsorption kinetics were observed in real-time using valence band photoemission and resonant Auger yield, associated with N 1s x-ray absorption spectroscopy (NEXAFS). At 300 K, these techniques point to a situation more complex than the one explored by STM at very low coverage. Three species (cyano-bonded, vinyl-bonded, and cumulative-double-bond species) are detected. Their distribution does not vary with increasing coverage. All dimerization-related surface states are quenched at saturation. The uptake rates versus coverage relationship points to the presence of a mobile precursor. Finally, the paper discusses a possible mechanism leading to the formation of cross-trench C=C=N unit at low coverage, and the reasons why the product branching ratio changes with increasing coverage.

Rangan, S.; Kubsky, S.; Gallet, J.-J.; Bournel, F.; Le Guen, K.; Dufour, G.; Rochet, F.; Funke, R.; Kneppe, M.; Piaszenski, G.; Koehler, U.; Sirotti, F. [Laboratoire de Chimie Physique Matiere et Rayonnement, Universite Pierre et Marie Curie, 11 rue Pierre et Marie Curie, 75231 Paris Cedex 05 (France); Fakultaet fuer Physik und Astronomie, Institut fuer Experimentalphysik IV/AG Oberflaechenphysik, Ruhr-Universitaet Bochum, NB 4/166, D-44780 Bochum (Germany); Laboratoire pour l'Utilisation du Rayonnement Electromagnetique, Centre Universitaire Paris-Sud, Batiment 209D, 91405 Orsay Cedex (France)

2005-03-15

447

Design of poly(acrylonitrile)-based gel electrolytes for high-performance lithium ion batteries.  

PubMed

The use of polyacrylonitrile (PAN) as a host for gel polymer electrolytes (GPEs) commonly produces a strong dipole-dipole interaction with the polymer. This study presents a strategy for the application of PAN in GPEs for the production of high performance lithium ion batteries. The resulting gel electrolyte GPE-AVM comprises a poly(acrylonitrile-co-vinyl acetate) copolymer blending poly(methyl methacrylate) as a host, which is swelled using a liquid electrolyte (LE) of 1 M LiPF6 in carbonate solvent. Vinyl acetate and methacrylate groups segregate the PAN chains in the GPE, which produces high ionic conductivity (3.5 × 10 (-3) S cm(-1) at 30 °C) and a wide electrochemical voltage range (>6.5 V) as well as an excellent Li(+) transference number of 0.6. This study includes GPE-AVM in a full-cell battery comprising a LiFePO4 cathode and graphite anode to promote ion motion, which reduced resistance in the battery by 39% and increased the specific power by 110%, relative to the performance of batteries based on LE. The proposed GPE-based battery has a capacity of 140 mAh g(-1) at a discharge rate of 0.1 C and is able to deliver 67 mAh g(-1) of electricity at 17 C. The proposed GPE-AVM provides a robust interface with the electrodes in full-cell batteries, resulting in 93% capacity retention after 100 charge-discharge cycles at 17 C and 63% retention after 1000 cycles. PMID:25361495

Wang, Shih-Hong; Kuo, Ping-Lin; Hsieh, Chien-Te; Teng, Hsisheng

2014-11-12

448

The acute lethality of acrylonitrile is not due to brain metabolic arrest  

PubMed Central

Acrylonitrile (AN) is an organic compound produced in large quantities by the chemical industry and is acutely toxic. One mechanism proposed to explain the toxicity of AN is metabolism by P450 into cyanide (CN). Although blood and brain levels of CN in rats following an LD90 dose of AN are consistent with acute toxicity, blocking CN formation with P450 inhibitors does not prevent lethality. Another mechanism implicated in toxicity is covalent binding of AN to cysteine residues in tissue proteins. Previous work in our laboratory has shown that AN can irreversibly inactivate the catalytically active cysteine-149 in glyceraldehyde-3-phosphate dehydrogenase (GAPDH). Inactivation of GAPDH by AN would be expected to impair glycolytic ATP production and, when coupled to the inhibition of mitochondrial ATP synthesis by the AN metabolite CN, would result in metabolic arrest, particularly in brain. In this study we have measured the high energy metabolites Phosphocreatine (PCr), ATP, ADP and AMP by HPLC and compared their levels in the brains of rats treated with an LD90 dose of AN, when respiration ceased, vs. controls. Two methods of rapid brain freezing in liquid nitrogen were used: Funnel Freezing (FF) and Head Immersion (HI). AN administration resulted in large decreases in PCr of 74% (FF) and 80% (HI) but relatively minor decreases in ATP of 5% (FF) and 21% (HI) and Energy Charge of 6% (FF) and 10% (HI). Thus, although substantial depletion of PCr was observed, possibly due to inhibition of creatine kinase by AN, we found no evidence that brain ATP is depleted when respiration ceases in AN-intoxicated rats. PMID:18834918

Campian, E. Cristian; Benz, Frederick W.

2008-01-01

449

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

450

Selective synthesis of multiply substituted 7-norbornenone derivatives or Diels–Alder cycloadducts from 1,2,3,4-tetrasubstituted 1,3-butadienes and maleic anhydride with or without Lewis acids  

Microsoft Academic Search

Reactions of 1,2,3,4-tetrasubstituted 1,3-butadienes with maleic anhydride and other dienophiles were investigated with or without addition of Lewis acid. When the silylated 1,3-butadienes, such as 1,4-bis(trimethylsilyl)-1,3-butadienes or 1-trimethylsilyl-1,3-butadienes, were treated with maleic anhydride in the presence of 2equiv of AlCl3, multi-substituted 7-norbornenones of well-defined exo,exo-disubstituted patterns were produced by an unprecedented and synthetically useful tandem process. Although some tetrasubstituted 1,3-butadienes

Dongzhen Li; An Shi; Wen-Xiong Zhang; Guangzhen Liu; Zhenfeng Xi

2008-01-01

451

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

Code of Federal Regulations, 2011 CFR

...specifications: Component/property Limitation Inherent viscosity 1.0-1.6 deciliter per gram.1 Styrene moiety ...Arsenic 3 parts per million maximum. 1 Inherent viscosity of a 0.25 percent (weight/volume) solution in...

2011-04-01

452

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...

453

Preparation and characterization of emulsifier-free polyphenylsilsesquioxane-poly (styrene-butyl acrylate) hybrid particles  

NASA Astrophysics Data System (ADS)

The core-shell polyphenylsilsesquioxane-poly (styrene-butyl acrylate) hybrid latex paticles with polyphenylsilsesquioxane as core and poly (styrene-butyl acrylate) as shell were successfully synthesized by seeded emulsion polymerization using polyphenylsisesquioxane (PPSQ) latex particles as seeds. X-ray diffraction (XRD) indicated that the polyphenylsilsesquioxane (PPSQ) had ladder structure, and PPSQ had incorporated into the hybrid latex particles. Transmission electron microscopy (TEM) confirmed that the resultant hybrid latex particles had the core-shell structure. TEM and dynamic light scattering (DLS) analysis indicated that the polyphenylsisesquioxane latex particles and obtained core-shell hybrid latex particles were uniform and possessed narrow size distributions. X-ray photoelectron spectroscopy (XPS) analysis also indicated that the PPSQ core particles were enwrapped by the polymer shell. In addition, compared with pure poly (styrene-butyl acrylate) latex film, the polyphenylsilsesquioxane-poly (styrene-butyl acrylate) hybrid latex film exhibited lower water uptake, higher pencil hardness and better thermal stability.

Bai, Ruiqin; Qiu, Teng; Han, Feng; He, Lifan; Li, Xiaoyu

2013-10-01

454

Occupational styrene exposure for twelve product categories in the reinforced-plastics industry  

SciTech Connect

Approximately 1500 occupational styrene exposure values from 28 reinforced-plastic manufacturers were collected retrospectively from companies and state and federal agencies. This report describes the major types of manufacturing processes within the reinforced-plastics industry and reports on the availability, collection and analysis of historical exposure information. Average exposure to styrene in most open-mold companies (24-82 ppm) was generally 2-3 times the exposure in press-mold companies (11-26 ppm). Manufacturers of smaller boats had mean styrene exposures of 82 ppm as compared to 37 ppm for yacht companies. There was considerable overlap in styrene exposure among job titles classified as directly exposed within open- and press-mold processing.

Lemasters, G.K.; Carson, A.; Samuels, S.J.

1985-08-01

455

Occupational styrene exposure for twelve product categories in the reinforced-plastics industry.  

PubMed

Approximately 1500 occupational styrene exposure values from 28 reinforced-plastic manufacturers were collected retrospectively from companies and state and federal agencies. This report describes the major types of manufacturing processes within the reinforced-plastics industry and reports on the availability, collection and analysis of historical exposure information. Average exposure to styrene in most open-mold companies (24-82 ppm) was generally 2-3 times the exposure in press-mold companies (11-26 ppm). Manufacturers of smaller boats had mean styrene exposures of 82 ppm as compared to 37 ppm for yacht companies. There was considerable overlap in styrene exposure among job titles classified as directly exposed within open- and press-mold processing. PMID:4050680

Lemasters, G K; Carson, A; Samuels, S J

1985-08-01

456

Hybrid coating pigments of poly(styrene-co-maleimide)\\/kaolin\\/alumina trihydrate for paper coating  

Microsoft Academic Search

Novel organic–inorganic hybrid pigments were prepared by in situ imidization of poly(styrene-co-maleic anhydride) (SMA) aqueous dispersion with ammonia in the presence of inorganic pigments, i.e. kaolin (K) or a mixture of kaolin (K)\\/alumina trihydrate (ATH). The objective was to allow the organic nano-particles of poly(styrene-co-maleimide) (SMI) to precipitate during their formation onto the surface of the inorganic pigment(s) and to

Mia Ahokas; Carl-Eric Wilén

2011-01-01

457

Covalent attachment of microbial lipase onto microporous styrene–divinylbenzene copolymer by means of polyglutaraldehyde  

Microsoft Academic Search

A novel method for immobilization of Thermomyces lanuginosus lipase onto polyglutaraldehyde–activated poly(styrene–divinylbenzene) (STY–DVB), which is a hydrophobic microporous support has been successfully developed. The copolymer was prepared by the polymerization of the continuous phase of a high internal phase emulsion (polyHIPE). The concentrated emulsion consists of a mixture of styrene and divinylbenzene containing a suitable surfactant and an initiator as

Nadir Dizge; Bülent Keskinler; Aziz Tanriseven

2008-01-01

458

High efficiency styrene biodegradation in a biphasic organic\\/water continuous reactor  

Microsoft Academic Search

Styrene was degraded as sole source of carbon and energy by a selected bacterial community in a two-phase aqueous-organic medium (80%:20%, vol\\/vol). Silicone oil was used to solubilize styrene, which is sparingly soluble in water and to prevent its toxicity toward microorganisms. Preliminary studies with the mixed population in batch cultures indicate that the specific activity and the maximum growth

Samira El Aalam; André Pauss; Jean-Michel Lebeault

1993-01-01

459

Genetic and Functional Analysis of the Styrene Catabolic Cluster of Pseudomonas sp. Strain Y2  

Microsoft Academic Search

The chromosomal region of Pseudomonas sp. strain Y2 involved in the conversion of styrene to phenylacetate (upper catabolic pathway) has been cloned and sequenced. Four catabolic genes, styABCD, and two regulatory genes, stySR, were identified. This gene cluster when transferred to Escherichia coli W confers to this pheny- lacetate-degrading host the ability to grow on styrene as the sole carbon

ANA VELASCO; SERGIO ALONSO; J. PERERA; EDUARDO DIAZ

1998-01-01

460

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

461

Occupational Styrene Exposure for Twelve Product Categories in the Reinforced-Plastics Industry  

Microsoft Academic Search

Approximately 1500 occupational styrene exposure values from 28 reinforced-plastic manufacturers were collected retrospectively from companies and state and federal agencies. This report describes the major types of manufacturing processes within the reinforced-plastics industry and reports on the availability, collection and analysis of historical exposure information. Average exposure to styrene in most open-mold companies (24–82?ppm) was generally 2–3 times the exposure

GRACE K. LEMASTERS; ARCH CARSON; STEVEN J. SAMUELS

1985-01-01

462

Adhesion of L1210 cells to modified styrene copolymer surfaces in the presence of serum.  

PubMed

The static adhesion of living L1210 cells (in serum-containing medium) to the surface of (styrene/methylmethacrylate) copolymers differing in styrene content (from 5% to 50% of styrene units) was investigated. The examination of wettability of the copolymer surfaces showed that the contact angle of water on the hydrophobic surfaces is an increasing linear function of styrene content in the copolymer. Cell adhesion to the unwettable surfaces is low (within 2-4%). A novel method of modification of the styrene copolymer surfaces was used to render these surfaces suitable for cell attachment. The modification consists of sulfonation of the surfaces with sulfur trioxide at the gas/solid interface. The contact angle of sulfonated copolymer surfaces is a decreasing linear function of styrene content in the copolymer. The contact angle decreases due to the increased number of highly hydrophilic sulfonic groups bonded to styrene. By acetylation of the sulfonated surfaces it was shown that cell adhesion to acetylated surfaces is not diminished and is at the same level as cell adhesion to sulfonated copolymer surfaces. Thus, it can be concluded that sulfonation of copolymer surfaces does not form hydroxyl groups. Cell adhesion to substrata of high wettability stabilizes after 30s. The relative number of cells adhering to the sulfonated copolymer surfaces is a decreasing linear function of the contact angle. For the copolymer surfaces containing 50% of styrene units the contact angle decreases sevenfold, due to sulfonation, and the number of adhering cells increases 40-fold. The results obtained show that for cell-substratum adhesive interaction the presence of sulfonic groups at the substratum surface is important. PMID:1939372

Kowalczynska, H M; Kaminski, J

1991-07-01

463

Effects of peak concentrations on the neurotoxicity of styrene in volunteers  

Microsoft Academic Search

The manufacture of fibreglass reinforced plastic products may give rise to substantial peak exposures to styrene. Such exposure patterns need further consideration in terms of styrene neurotoxicity. The aim of this study was to evaluate the neurotoxic effects of short-term peak exposures in volunteers, at levels respecting the Quebec occupational exposure limits (8 hours time weighed average of 213 mg\\/m3

B Ska; A Vyskocil; R Tardif; G Carrier; R Thuot; K Muray; C Viau

2003-01-01

464

Sensitivity of styrene oxidation reaction to the catalyst structure of silver nanoparticles  

NASA Astrophysics Data System (ADS)

This study shows how different morphologies of silver nanoparticles affect the selective oxidation of styrene in the gas phase using oxygen as oxidant. Silver nanoparticles (nanowires and nanopolyhedra), prepared using the polyol process, were supported on ?-Al 2O 3. For comparison, a conventional catalyst obtained by wet impregnation was also prepared. Phenylacetaldehyde (Phe) and styrene oxide (SO) were the main products for nanoparticles catalysts. The promotion effect on the catalytic activity of potassium and cesium on the silver nanowires catalysts was also studied. At 573 K, the styrene conversion and selectivity to styrene oxide with the silver nanowires catalyst were 57.6 and 42.5%, respectively. Silver nanopolyhedra catalyst showed 57.5% conversion and 30.8% selectivity to styrene oxide. The promotion by cesium played an important role in improving the epoxidation of styrene. The samples were structurally characterized using X-ray diffraction (XRD), ultraviolet-visible spectroscopy (UV-vis), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). X-ray photoelectron spectroscopy (XPS) and temperature programmed reduction (TPR) were applied to characterize the oxygen species detected (O ?, O ?) on the silver surface.

Chimentão, R. J.; Kirm, I.; Medina, F.; Rodríguez, X.; Cesteros, Y.; Salagre, P.; Sueiras, J. E.; Fierro, J. L. G.

2005-10-01

465

[ICP-AES method for the determination of active components Mo and Bi in catalyst for acrylonitrile production].  

PubMed

An ICP-AES method for the determination of active components Mo and Bi in catalyst for acrylonitrile production was established and reported in this paper. 0.2 g of the sample was dissolved with 5 mL of aqua regia and 8 mL of HF at 75 degrees C on a water bath and evaporated till dry to expel SiF4. The residue was dissolved and made volume with 3% HCL up to 100 mL. The solution was prepared for Bi determnination. Successively diluted with 3% HCL for 10 times the solution was used for Mo determination. Spectral interferences were investigated in detail by means of profiling the analytical lines with wavelength scanning of the blank and coexisting elements in the vicinity of the lines. Three Mo lines, MoII 202.030, MoII 203.844 and MoII 204.598, and two Bi lines, BiII 190.241 and BiI 223.061 were selected as the analytical lines considered free of spectral interferences. Utilizing multiple lines in a full spectrum for simultaneous determination of one element is of benefit to the improvement of accuracy and precision of the analysis. The method has been successfully used for monitoring the activity of the catalyst in acrylonitrile production. PMID:15769025

Shi, Hui-fang

2004-02-01

466

An XRD, XPS, and EPR Study of Li\\/MgO Catalysts: Case of the Oxidative Methylation of Acetonitrile to Acrylonitrile with CH 4  

Microsoft Academic Search

The overall purpose of this study was to investigate the effects of the magnesium and lithium precursors and the catalyst surface properties on the catalytic performance in the oxidative methylation of acetonitrile. The performance of the catalysts for the oxidative methylation of acetonitrile to acrylonitrile was significantly affected by the Li precursor, where catalysts prepared with LiCl and LiOH on

Catherine L. Bothe-Almquist; Reddy P. Ettireddy; Albert Bobst; Panagiotis G. Smirniotis

2000-01-01

467

Synthesis and characterization of N-acetyl-L-cysteine S-conjugates of butadiene monoxide and their detection and quantitation in urine of rats and mice given butadiene monoxide  

SciTech Connect

Butadiene monoxide (BM), a mutagen and carcinogen, is the major metabolite of 1,3-butadiene in rats and mice. Because mercapturic acids (N-acetyl-L-cysteine S-conjugates) were expected in vivo metabolites of BM, reference BM-mercapturic acids were prepared by the reaction of racemic BM with N-acetyl-L-cysteine. When rats were given BM at a dose of 71.5 to 285 {mu}mol/kg, their urinary excretion of I and II within 8 h of BM administration exhibited linear relationships with the administered BM dose; the total amount of the BM dose excreted as combined I and II averaged 17 {plus_minus} 4% (mean {plus_minus}SD,n=15). No metabolites were detected in urine samples collected between 8 and 24 h after BM dosing. Mice, which are known to be more sensitive to 1,3-butadiene carcinogenicity than rats, excreted similar amounts of mercapturic acids (26 {plus_minus} 13%) at the 285 {mu}mol/kg BM dose within 24 h of BM administration, however, at the 143 and 71.5 {mu}mol/kg BM doses, they excreted only 7 {plus_minus} 3% and 9 {plus_minus} 3% of the BM dose as mercapturic acids, respectively. Thus, the ability of the rat to excrete higher levels of BM-mercapturic acids compared to the mouse at low BM doses may partially explain the lower sensitivity of the rat to 1,3-butadiene-induced carcinogenicity. Furthermore, the BM-mercapturic acid analysis method, which has limits of detection of 25 and 40 {mu}M in rat and mouse urine, respectively, may be used to assess human exposure to 1,3-butadiene. 27 refs., 9 figs., 1 tab.

Elfarra, A.A.; Sharer, J.E.; Duescher, R.J. [Univ. of Wisconsin, Madison (United States)

1995-01-01

468

Photofragment translational spectroscopy of 1,2-butadiene at 193 nm Jason C. Robinson, Weizhong Sun,a)  

E-print Network

Photofragment translational spectroscopy of 1,2-butadiene at 193 nm Jason C. Robinson, Weizhong Sun 23 August 2001 Photofragment translational spectroscopy has been used to investigate the dissociation photoionization efficiency curve, whereas the C4H5 product cannot be identified definitively. The translational

Neumark, Daniel M.

469

Structure and dynamics of a pentablock copolymer of polystyrene-polybutadiene in a butadiene-selective solvent  

E-print Network

Structure and dynamics of a pentablock copolymer of polystyrene-polybutadiene in a butadiene solutions of a polystyrene-polybutadiene pentablock copolymer in n-heptane, a strongly selective solvent by the association of w200 polystyrene blocks. Dynamic light scattering measurements on 8 and 9% samples showed three

470

Synthesis of Densely Substituted 1,3-Butadienes through Acid-Catalyzed Alkenylations of ?-Oxoketene Dithioacetals with Aldehydes.  

PubMed

Aldehydes were proved to be viable reagents for implementing alkenylation of ?-oxoketene dithioacetals. AlCl3 was found to be the best catalyst. The established reaction opened an avenue to access densely substituted 1,3-butadiene derivatives. The obtained product bears multiple reactive sites that can be converted into various valuable molecules. PMID:25247719

Liu, Changhui; Gu, Yanlong

2014-10-17

471

Quantifying heterogeneity in exposure-risk relationships using exhaled breath biomarkers for 1,3-butadiene exposures  

Microsoft Academic Search

The health effects of human exposure to 1,3-butadiene (BD) have been extensively studied using both epidemiological and animal toxicology approaches. However, various data and knowledge gaps remain, one of which is an understanding of the human heterogeneity in BD dosimetry. The objective of our study was to better understand the role of individual variability in delivered tissue dose. We designed

Thomas J. Smith; Frederic Y. Bois; Yu-Sheng Lin; Celine Brochot; Sandrine Micallef; David Kim; Karl T. Kelsey

2008-01-01

472

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.

473

Role of interphase processes in styrene vapor removal from airflow under the action of a pulsed electron beam  

Microsoft Academic Search

The conversion of styrene vapor in airflow under the action of a pulsed electron beam has been studied. It is demonstrated\\u000a that the main processes leading to the removal of styrene from airflow involve reactive oxygen species and yield styrene oxidation\\u000a products, which are characterized by low vapor pressures and are removed from airflow in a condensed state. This experimental

Yu. N. Novoselov; I. E. Filatov

2009-01-01

474

Surface nano-patterning through styrene adsorption on Si(100)  

E-print Network

We present an ab initio study of the structural and electronic properties of styrene molecules adsorbed on the dimerized Si(100) surface at different coverages, ranging from the single-molecule to the full monolayer. The adsorption mechanism primarily involves the vinyl group via a [2+2] cycloaddition process that leads to the formation of covalent Si-C bonds and a local surface derelaxation, while it leaves the phenyl group almost unperturbed. The investigation of the functionalized surface as a function of the coverage (e.g. 0.5 -- 1 ML) and of the substrate reconstruction reveals two major effects. The first results from Si dimer-vinyl interaction and concerns the controlled variation of the energy bandgap of the interface. The second is associated to phenyl-phenyl interactions, which gives rise to a regular pattern of electronic wires at surface, stemming from the pi-pi coupling. These findings suggest a rationale for tailoring the surface nano-patterning of the surface, in a controlled way.

A. Calzolari; A. Ruini; M. J. Caldas; E. Molinari

2005-07-27

475

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

2012-12-01

476

Development and validation of personal monitoring methods for low levels of acrylonitrile in workplace atmosphere. II. Thermal desorption and field validation  

SciTech Connect

Thermal desorption is a more sensitive alternative to solvent desorption for the determination of acrylonitrile in air. A dual-bed collection tube (Tenax GC and Carbosieve B) was developed for collecting and concentrating low levels of acrylonitrile. Two thermal desorption techniques were evaluated for the recovery of acrylonitrile collected on the dual-bed tubes over a concentration range from 0.05 to 5 ppm. A commercially-available system, the Century Programmable Thermal Desorption Unit, was easy to operate, allowed for multiple injections of the sample and had a recovery of 82 +/- 12% (RSD). Sampled were stored for up to two months without affecting the recovery and there was not an observable effect from humidity or from the presence of other organic compounds. This system was found to have limitations at acrylonitrile concentrations above 1 ppm. A field validation study tested the sampling and analytical methods developed for monitoring low levels of acrylonitrile in the workplace. Three methods employing Pittsburgh Coconut-Base activated charcoal, Ambersorb XE-348 and Tenax-GC and Carbosieve B sampling mediums were validated for concentrations ranging from 0.05 to 5 ppm and confirmed in the field from 0.02 to 3 ppm in tests conducted at plant sites. These field studies were run over varying humidity and temperature conditions. The overall absolute recoveries and relative standard deviations found for these methods found during the field trials are 90 +/- 18% for charcoal; 85 +/- 11% for Ambersorb XE-348; and 90 +/- 19% for the Century dual-bed sorbent. These values were in quite good agreement with the 91 +/- 10%, 88 +/- 8%, and 82 +/- 12% determined in laboratory studies.

Borders, R.A.; Gluck, S.J.; Sowle, W.F.; Melcher, R.G.

1986-03-01

477

Formation of styrene glutathione adducts catalyzed by prostaglandin H synthase. A possible new mechanism for the formation of glutathione conjugates  

SciTech Connect

The metabolism of styrene by prostaglandin hydroperoxidase and horseradish peroxidase was examined. Ram seminal vesicle microsomes in the presence of arachidonic acid or hydrogen peroxide and glutathione converted styrene to glutathione adducts. Neither styrene 7,8-oxide nor styrene glycol was detected as a product in the incubation. Also, the addition of styrene 7,8-oxide and glutathione to ram seminal vesicle microsomes did not yield styrene glutathione adducts. The peroxidase-generated styrene glutathione adducts were isolated by high pressure liquid chromatography and characterized by NMR and tandem mass spectrometry as a mixture of (2R)- and (2S)-S-(2-phenyl-2-hydroxyethyl)glutathione. (1R)- and (1S)-S-(1-phenyl-2-hydroxyethyl)glutathione were not formed by the peroxidase system. The addition of phenol or aminopyrine to incubations, which greatly enhances the oxidation of glutathione to a thiyl radical by peroxidases, increased the formation of styrene glutathione adducts. We propose a new mechanism for the formation of glutathione adducts that is independent of epoxide formation but dependent on the initial oxidation of glutathione to a thiyl radical by the peroxidase, and the subsequent reaction of the thiyl radical with a suitable substrate, such as styrene.

Stock, B.H.; Bend, J.R.; Eling, T.E.

1986-05-05

478

Structure and Reaction of Oxametallacycles Derived from Styrene Oxide on Ag(110).  

SciTech Connect

The research described in this product was performed in part in the Environmental Molecular Sciences Laboratory, a national scientific user facility sponsored by the Department of Energy's Office of Biological and Environmental Research and located at Pacific Northwest National Laboratory. Styrene oxide forms a strongly bound oxametallacycle intermediate via activated adsorption on the Ag(110) surface. The oxametallacycle species derived from styrene oxide on Ag(110) fits well with the family of oxametallacycles identified previously in studies of nonallylic epoxides with unsaturated substituent groups on silver. Temperature-programmed reaction experiments demonstrate that styrene oxide ring opens at the substituted carbon, and Density Functional Theory calculations indicate that the phenyl ring of the resulting oxametallacycle is oriented nearly parallel to the Ag(110) surface. Interaction of the phenyl group with the silver surface stabilizes this intermediate relative to that derived from the mono-olefin epoxide, ethylene oxide. During temperature-programmed reaction, the oxametallacycle undergoes ring-closure to reform styrene oxide and isomerization to phenylacetaldehyde at 505 K on Ag(11 0). Styrene oxide-derived oxametallacycles exhibit similar ring-closure behavior on the Ag(111) surface.

Lukaski, Adrienne C.; Enever, Michael C.; Barteau, Mark A.

2007-08-15

479

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

480

Styrene oxide isomerase of Rhodococcus opacus 1CP, a highly stable and considerably active enzyme.  

PubMed

Styrene oxide isomerase (SOI) is involved in peripheral styrene catabolism of bacteria and converts styrene oxide to phenylacetaldehyde. Here, we report on the identification, enrichment, and biochemical characterization of a novel representative from the actinobacterium Rhodococcus opacus 1CP. The enzyme, which is strongly induced during growth on styrene, was shown to be membrane integrated, and a convenient procedure was developed to highly enrich the protein in active form from the wild-type host. A specific activity of about 370 U mg(-1) represents the highest activity reported for this enzyme class so far. This, in combination with a wide pH and temperature tolerance, the independence from cofactors, and the ability to convert a spectrum of substituted styrene oxides, makes a biocatalytic application imaginable. First, semipreparative conversions were performed from which up to 760 ?mol of the pure phenylacetaldehyde could be obtained from 130 U of enriched SOI. Product concentrations of up to 76 mM were achieved. However, due to the high chemical reactivity of the aldehyde function, SOI was shown to be the subject of an irreversible product inhibition. A half-life of 15 min was determined at a phenylacetaldehyde concentration of about 55 mM, indicating substantial limitations of applicability and the need to modify the process. PMID:22504818

Oelschlägel, Michel; Gröning, Janosch A D; Tischler, Dirk; Kaschabek, Stefan R; Schlömann, Michael

2012-06-01

481

Efficient bulky phosphines for the selective telomerization of 1,3-butadiene with methanol.  

PubMed

A series of bulky phosphines containing substituted biphenyl, 2-methylnaphthyl, or 2,7-di-tert-butyl-9,9-dimethylxanthene moiety were prepared. They were used in the preparation of new monophosphine-palladium(0)-dvds complexes, which were employed as catalysts for the selective telomerization of 1,3-butadiene with methanol to obtain 1-methoxyocta-2,7-diene (1-MOD), the key intermediate in the Dow 1-octene process. Several ligands showed improved selectivity and yield compared to that of the benchmark ligand PPh(3). Especially 2,7-di-tert-butyl-9,9-dimethylxanthen-4-yl-diphenylphosphine (4, "mono-xantphos") stands out as an excellent ligand in terms of yield, selectivity, and stability. PMID:20405840

Tschan, Mathieu J-L; García-Suárez, Eduardo J; Freixa, Zoraida; Launay, Hélène; Hagen, Henk; Benet-Buchholz, Jordi; van Leeuwen, Piet W N M

2010-05-12

482