Showing papers on "Styrene-butadiene published in 2002"
TL;DR: In this paper, a simple and reproducible microbiological simulation procedure in combination with a chemical procedure was used to test concrete for its potential resistance against biogenic sulfuric acid, and it was shown that particularly the penetration of H2S inside the concrete crevices accelerated the corrosion process.
103 citations
TL;DR: In this article, variation of the bound rubber content with the storage time was studied using styrene-butadiene rubber (SBR) compounds filled with silica or carbon black.
92 citations
TL;DR: In this article, Clay-modified styrene-butadiene-styrene (SBS) rubber is used to toughen polypropylene (PP) matrix and it is found that rubber particle cavitation and matrix shear yielding are the main toughening mechanisms.
Abstract: Clay-modified styrene-butadiene-styrene (SBS) rubber is utilized to toughen polypropylene (PP). The SBS rubber is found to have good compatibility with clay particles. SBS rubber helps to finely disperse clay particles in PP matrix. Mode-I fracture mechanisms are investigated using optical microscopy and transmission electron microscopy techniques. Rubber particle cavitation and matrix shear yielding are found to be the main toughening mechanisms in PP/SBS system. In the case of PP/SBS/clay system, widespread rubber particle cavitation, which appears to be facilitated by the presence of clay particle inclusions inside the SBS rubber particles, takes place in the PP matrix. This, in turn, leads to the formation of a bigger shear yielded zone in PP matrix. As a result, an enhanced toughness is observed.
73 citations
TL;DR: In this article, the authors investigated the influence of temperature on the extraction of loosely bound rubber in styrene-butadiene rubber compounds filled with silica and/or carbon black.
Abstract: Formation of bound rubber is affected by the physical structure and surface chemistry of filler and the property of rubber Variation of the bound rubber formation in styrene-butadiene rubber compounds filled with silica and/or carbon black was studied Influence of temperature on extraction of loosely bound rubber was also investigated For the both silica and carbon black-filled compounds, the bound rubber content increases with increase in the silica content ratio The bound rubber content decreases with increasing the extracting temperature The loosely bound rubber content of the silica-filled compound is higher than that of the carbon black-filled one Activation energy for the extraction of the unbound and loosely bound rubbers becomes higher as the total filler content increases The activation energy of the silica-filled compound is higher (almost double the value) than for the carbon black-filled one Copyright© 2002 John Wiley & Sons, Ltd
73 citations
TL;DR: In this article, the authors investigated the influence of morphology on micromechanical deformation mechanisms and mechanical properties of star block copolymers by using transmission electron microscopy and tensile testing.
Abstract: Lamellae-forming styrene/butadiene star block copolymers are studied to investigate the influence of morphology on micromechanical deformation mechanisms and mechanical properties by using transmission electron microscopy and tensile testing. A large homogeneous plastic deformation of polystyrene (PS) lamellae is found in styrene/butadiene star block copolymers on the basis of the new mechanism called thin-layer yielding. This mechanism depends strongly on the thickness of the PS lamellae. At a critical thickness of PS lamellae of about 20 nm, a transition from thin-layer yielding mechanism to a crazelike deformation was observed. These new deformation zones are similar to crazes with respect to their propagation perpendicular to direction of external stress and similar to shear bands with respect to an internal shear deformation component of the lamellae in the deformation zones. As a result of our investigations, the mechanical properties of star block copolymers can be understood in correlation with morphology and micromechanical deformation mechanisms. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 85: 683–700, 2002
70 citations
TL;DR: In this article, poly(syndiotactic styrene-co-butadiene) (sPS−B) has been prepared using methylalumoxane (MAO) activated CpTiCl3 under a range of experimental conditions.
Abstract: Samples of poly(syndiotactic styrene-co-butadiene) (sPS−B) have been prepared using methylalumoxane (MAO) activated CpTiCl3 under a range of experimental conditions. Copolymerization activities were low (24−36 kg mol-1 of cat. h-1) and nearly constant over the range of polymerization temperatures investigated (25−70 °C). Eight sPS−B samples were synthesized at 25 °C with styrene molar fractions (xs) covering a full range of compositions (xs = 0.15−0.92). The copolymer samples were characterized by solution and solid state 13C NMR spectroscopy, X-ray powder diffraction analysis, and thermal (DSC) analysis. The 13C NMR analysis of the copolymer microstructure suggests that the butadiene homosequences are primarily cis-1,4 and the styrene segments are syndiotactic. However, some 1,2- and trans-1,4-butadiene units are occasionally formed during the polymerization process. The 13C NMR resonances diagnostic of the monomer triads comprising styrene units (SSB, SBS, BBS, BSB, and SSS) were assigned and the averag...
56 citations
TL;DR: In this article, a new method, pre-enveloping sand with polymer, was adopted to make polymer-modified cement mortar (PCM), and the experimental results of physical and mechanical tests showed that, at the same level of polymer cement ratio, the pre-encoding method was better than normal method regarding the performance of the resulted composite.
52 citations
TL;DR: In this article, the influence of modifier structure and compounding conditions on the extent of exfoliation/intercalation of the silicates was investigated by electron microscopy and dynamic mechanical analysis.
Abstract: Styrene butadiene rubber/layered silicate composites were prepared using clays modified with alkyl ammonium salts of different structure. The influence of modifier structure and compounding conditions on the extent of exfoliation/intercalation of the silicates was investigated by electron microscopy and dynamic mechanical analysis. With increasing exfoliation the glass transition temperature is lowered and the stability of the filler network is enhanced.
50 citations
TL;DR: A physically based diffusion model is used to evaluate the sink effect of diffusion-controlled indoor materials and to predict the transient contaminant concentration in indoor air in response to several time-varying contaminant sources.
Abstract: A physically based diffusion model is used to evaluate the sink effect of diffusion-controlled indoor materials and to predict the transient contaminant concentration in indoor air in response to several time-varying contaminant sources. For simplicity, it is assumed the predominant indoor material is a homogeneous slab, initially free of contaminant, and the air within the room is well mixed. The model enables transient volatile organic compound (VOC) concentrations to be predicted based on the material/air partition coefficient (K) and the material-phase diffusion coefficient (D) of the sink. Model predictions are made for three scenarios, each mimicking a realistic situation in a building. Styrene, phenol, and naphthalene are used as representative VOCs. A styrene butadiene rubber (SBR) backed carpet, vinyl flooring (VF), and a polyurethane foam (PUF) carpet cushion are considered as typical indoor sinks. In scenarios involving a sinusoidal VOC input and a double exponential decaying input, the model predicts the sink has a modest impact for SBR/styrene, but the effect increases for VF/phenol and PUF/naphthalene. In contrast, for an episodic chemical spill, SBR is predicted to reduce the peak styrene concentration considerably. A parametric study reveals for systems involving a large equilibrium constant (K), the kinetic constant (D) will govern the shape of the resulting gasphase concentration profile. On the other hand, for systems with a relaxed mass transfer resistance, K will dominate the profile.
46 citations
TL;DR: In this article, the effects of surface chemistry of silica particles on the mechanical properties were studied for silica filled styrene-butadiene rubber (SBR) systems, and the results indicated that the stress-strain behavior of filled vulcanizate is affected by the agglomerate of the fillers and the interactions between filler and rubber matrix.
Abstract: The effects of surface chemistry of silica particles on the mechanical properties were studied for silica filled styrene–butadiene rubber (SBR) systems. The samples were prepared from different kinds of silicas and of silane coupling agents. The breakdown of the agglomerate formed by silica particles was successfully detected by transmission electron microscopy (TEM) observations when the strain was applied to silica filled vulcanizates. The degree of breakdown of the agglomerate of silica particles by the strain was more prominent in the larger one of which size was controlled by the number of silanol group per unit surface area of silica particles. The amount of entrapped rubber within the agglomerate seemed to be decreased with the decrease in the agglomerate size. Also, the initial agglomerate size and the change of agglomerate by the strain became small by the introduction of silane coupling agent, such as bis(3-triethoxysilylpropyl)tetrasulfane (TESPT). At a given degree of vulcanization, the initial modulus of silica filled vulcanizates was governed by the size of agglomerate formed by silica particles and the amount of entrapped rubber phase. On the other hand, at a larger strain, the tensile strength of the filled vulcanizates increased by the introduction of interfacial combination between silica particles and rubber matrix by TESPT. These results indicate that the stress-strain behavior of filled vulcanizate is affected by the agglomerate of the fillers and the interactions between filler and rubber matrix.
46 citations
TL;DR: In this paper, the effects of surface modification of silicas by plasma-polymerization coating, together with modification using a silane coupling agent for a comparison on the dispersion and physical properties of styrene butadiene rubber (SBR) are reported.
Abstract: The effects of surface modification of silicas by plasma-polymerization coating, together with modification using a silane coupling agent for a comparison on the dispersion and physical properties of styrene–butadiene rubber (SBR) are reported. The chemical compositions of the plasma-polymerization coating were characterized using FTIR and Auger spectrometer and it was found that the plasma coating was composed of CC and CH bonds. The surface modification of silica by either plasma polymerization or silane greatly improved the dispersion of silica particles in SBR vulcanizates. The plasma-polymerization modification of silica improved the tensile modulus of SBR vulcanizates without deterioration of important basic properties such as tensile strength and elongation at break.
© 2002 Society of Chemical Industry
TL;DR: In this paper, the pyrolysis patterns of styrene-butadiene rubbers with different microstructures were characterized with pyrolysgas chromatography, and the relative abundance of the styrene peak increased with an increase in styrene unit in SBRs.
TL;DR: In this article, the development of the dynamic glass transition in styrene-butadiene copolymers has been investigated by dielectric spectroscopy in the frequency range from 10-2 to 106 Hz.
Abstract: The development of the dynamic glass transition in styrene-butadiene copolymers has been investigated by dielectric spectroscopy in the frequency range from 10-2 to 106 Hz. Two processes were detected and attributed to the R- and ‚-relaxations. The R relaxation time has a non-Arrhenius temperature behavior that is highly dependent on styrene content while the ‚ relaxation time shows an Arrhenius behavior with an activation energy that is independent of styrene-content. Furthermore, the shape of the R-relaxation is strongly influenced by the styrene content while the shape of ‚-relaxation is not. We interpret these results as follows. The observed ‚-relaxation is primarily due to local motions of butadiene monomers and therefore not affected by the presence of styrene. The R-relaxation, on the other hand, is highly sensitive to the styrene content due to its cooperative character.
TL;DR: In this paper, the influence of the NBR type on the properties of silica-filled SBR compounds containing NBR was studied with NBRs of various acrylonitrile contents.
Abstract: Because silica has strong filler-filler interactions and adsorbs polar materials, a silica-filled rubber compound exhibits poor dispersion of the filler and poor cure characteristics in comparison with those of a carbon black-filled rubber compound. Acrylonitrile-butadiene rubber (NBR) improves filler dispersion in silica-filled styrene-butadiene rubber (SBR) compounds. The influence of the NBR type on the properties of silica-filled SBR compounds containing NBR was studied with NBRs of various acrylonitrile contents. The composition of the bound rubber was different from that of the compounded rubber. The NBR content of the bound rubber was higher than that of the compounded rubber; this became clearer for NBR with a higher acrylonitrile content. The Mooney scorch time and cure rate became faster as the acrylonitrile content in NBR increased. The modulus increased with an increase in the acrylonitrile content of NBR because the crosslink density increased. The experimental results could be explained by interactions of the nitrile group of NBR with silica.
TL;DR: In this article, the experimental results show that the mechanical properties, dynamic mechanical properties and optical properties of the Mg(MAA)2-reinforced SBR vulcanizates depend on the dicumyl peroxide (DCP) content, magnesium methacrylate (Mmm)2 content, and the mole ratio of MgO/MAA.
Abstract: Through the neutralization of magnesium oxide (MgO) and methacrylic acid (MAA), magnesium methacrylate [Mg(MAA)2] was in situ prepared in styrene–butadiene rubber (SBR) and used to reinforce the SBR vulcanizates cured by dicumyl peroxide (DCP). The experimental results show that the mechanical properties, dynamic mechanical properties, optical properties, and crosslink structure of the Mg(MAA)2-reinforced SBR vulcanizates depend on the DCP content, Mg(MAA)2 content, and the mole ratio of MgO/MAA. The formulation containing DCP 0.6–0.9 phr, Mg(MAA)2 30–40 phr, and MgO/MAA mole ratio 0.50–0.75 is recommended for good mechanical properties of the SBR vulcanizates. The tensile strength of the SBR vulcanizates is up to 31.4 MPa when the DCP content is 0.6 phr and the Mg(MAA)2 content is 30 phr. The SBR vulcanizate have good aging resistance and limited retention of tensile strength at 100°C. The SBR vulcanizates are semitransparent, and have a good combination of high hardness, high tensile strength, and elongation at break. The Tg values of the SBR vulcanizates depend largely on the DCP content, but depend less on the Mg(MAA)2 content and the MgO/MAA mole ratio. The contents of DCP, Mg(MAA)2, and the MgO/MAA mole ratio have also great effects on the E′ values of the vulcanizates. The salt crosslink density is greatly affected by the Mg(MAA)2 content and MgO/MAA mole ratio, but less affected by the DCP content. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 85: 2667–2676, 2002
TL;DR: In this paper, the effect of surface treatment on silica agglomerate dispersibility was investigated by using a commercially available coupling agent Bis-(triethoxysilylpropyl)-tetrasulphane (TESPT) in a blender.
Abstract: The effect of surface treatment on silica agglomerate dispersibility was investigated. Precipitated silica powders were treated with a commercially available coupling agent Bis-(triethoxysilylpropyl)-tetrasulphane (TESPT) in a blender. Spherical agglomerates of known density were prepared and dispersed in styrene butadiene rubber (SBR) under controlled flow conditions. The erosion kinetics was monitored by measuring the reduction in size of parent agglomerate with time. Silica dispersibility was greatly enhanced upon surface treatment. The coupling agent used in surface treatment is known to reduce filler—filler interactions and therefore affects the intrinsic cohesivity of the powder. However powder surface treatment can also induce changes in agglomerate morphology and filler-liquid interactions. The work presented in this paper evidences such changes.
TL;DR: In this article, a new apparatus was designed to age modified binders as well as unmodified binders, which consists of a temperature-controlled vessel, a tube for introducing either nitrogen or air, a dispersing impeller for mixing the air and binder, and a condenser for collecting volatiles.
Abstract: Short-term aging procedures, either the thin-film oven test or the rolling thin-film oven test (RTFOT), are used to approximate the aging that occurs by asphalt binders during the hot-mix process. For unmodified binders, both of these procedures do a reasonable job of duplicating this aging not only with respect to physical property changes in the binder but also with respect to oxidation, as measured by changes in the infrared absorption spectrum. For modified binders, however, significant difficulties exist, among them surface skin formation and poor flow in the bottles. A new apparatus specifically designed to age modified binders as well as unmodified binders has been developed. This apparatus consists of a temperature-controlled vessel, a tube for introducing either nitrogen or air, a dispersing impeller for mixing the air and binder, and a condenser for collecting volatiles. Besides temperature, gas flow rate and mixing speed are controlled to desired values. The collection of volatiles allows a direct, rather than indirect, measure of volatiles loss. The required aging time of 30 min is less than the RTFOT's 85 min. Tests of the process with unmodified binders achieved excellent comparisons with RTFOT aging in both physical properties (dynamic shear rheometer) and oxidative aging (Fourier-transform infrared analysis). Trials with modified binders achieved uniform aging with no complications caused by the rheology of these materials. Modified binders studied included polymer-modified styrene butadiene diblock copolymer and styrene butadiene triblock copolymer materials.
TL;DR: In this article, a carboxylic styrene-butadiene rubber latex was hydrogenated using hydrazine and hydrogen peroxide with ferrous sulfate as a catalyst without pressurized hydrogen and an organic solvent.
Abstract: Hydrogenation of carboxylic styrene–butadiene rubber latex was carried out using hydrazine and hydrogen peroxide with ferrous sulfate as a catalyst without pressurized hydrogen and an organic solvent. A mixed inhibitor was used during hydrogenation to prevent gel formation. Various hydrogenation conditions were studied. Ferrous sulfate is better than is cupric sulfate as a catalyst. The hydrogenation degree can reach over 90%. The hydrogenated product was characterized by IR and DSC. The hydrogenated products behave as a thermoplastic elastomer with excellent thermooxidation resistance, due to the absence of most double bonds and the presence of crystalline domains of polyethylene segments formed by the hydrogenation of polybutadiene segments. Ionomers were obtained by neutralization of the hydrogenated product with metallic ions and characterized by IR, DSC, and TEM. The ionomers also behave as thermoplastic elastomers with mechanical properties better than those of the hydrogenated product without neutralization, due to the existence of ionic domains besides the crystalline domains. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 83: 1375–1384, 2002
TL;DR: In this article, two styrene-butadiene triblock copolymers differing in the length of their styrene blocks (40S-60B-40S and 10S- 60B-10S) were used as compatibilizers for PS/PB and PS/PP (4/1) blends.
Abstract: Two styrene-butadiene triblock copolymers differing in the length of their styrene blocks (40S-60B-40S and 10S-60B-10S) were used as compatibilizers for PS/PB (4/1) and PS/PP (4/1) blends. The supramolecular structure of the copolymers determined by small-angle X-ray scattering (SAXS), morphology of the blends using transmission electron microscopy (TEM), and their tensile impact strength were chosen as criteria of the compatibilization efficiency of the copolymers used. Different mechanisms of compatibilization for “symmetrical” system (PS/PB/SBS) and “asymmetrical” system (PS/PP/SBS) were proved. While for the PS/PB blend, the 40S-60B-40S copolymer proved to be a good compatibilizer, for the PS/PP blend, surprisingly, the 10S-60B-10S copolymer is more efficient.
Patent•
14 May 2002TL;DR: In this article, a composition for rejuvenating asphalt pavement according to the present invention comprises an asphalt binder, water, a cationic surfactant, a recycling agent, and a coagglomerated styrene butadiene rubber latex, which includes sulfur and a vulcanizing agent.
Abstract: A composition for rejuvenating asphalt pavement according to the present invention comprises an asphalt binder, water, a cationic surfactant, a recycling agent, and a cationic, co-agglomerated styrene butadiene rubber latex, which includes sulfur and a vulcanizing agent. The composition is also useful as a scrub seal, fog seal, sand seal as well as for crack filling and the prevention of reflective cracking. The inventive composition may be used in emulsions with different setup times. The invention also includes a method for treatment of aged and cracked asphalt by application of the disclosed compositions.
TL;DR: In this paper, a novel surface modification of clay filler has been developed by coating this with an acrylate monomer, trimethylol propane triacrylate (TMPTA) or a silane coupling agent, triethoxy vinyl silane (TEVS) followed by electron beam irradiation.
TL;DR: In this article, a forced draft approach was used to reproduce field-ageing effects of bituminous bound layers in flexible pavements and the applicability of the method to ageing of porous asphalt mixtures was investigated using four bitumens: a 100 pen conventional and three polymer modified binders, including Styrene Butadiene Styrene (SBS) and Ethylene Vinyl Acetate (EVA) copolymers.
Abstract: Age hardening is related to progressive oxidation of all bituminous bound layers in flexible pavements. Excessive age hardening is of particular relevance to surface courses where it can cause premature breakdown; it is of major importance to engineers and scientists involved in the design, construction and maintenance of such pavements. This paper discusses the development of a new method for the accelerated ageing of bituminous mixtures, based on the use of a forced draft approach, to reproduce field-ageing effects in the laboratory. The applicability of the method to ageing of porous asphalt mixtures is investigated using four bitumens: a 100 pen conventional and three polymer modified binders, including Styrene Butadiene Styrene (SBS) and Ethylene Vinyl Acetate (EVA) copolymers. The new method is shown to be capable of ranking the mixtures in a reasonable order, emphasising the improved properties of polymer modified mixtures. A useful correlation has been established between the ageing resistance of ...
TL;DR: In this paper, a dual role of nano-silica nanofiller in styrene-butadiene rubber (SBR) has been investigated and a mechanistic scheme involving dual function of this nano-filler has been suggested.
Abstract: The use of ZnO and stearic acid is very well known in sulfenamide accelerated sulfur vulcanization of diene elastomers. Zn-ion coated nano filler has been developed and tested, in styrene-butadiene rubber (SBR) as sulfur vulcanizing activator cum reinforcing filler. In this study Zinc oxide has been replaced by the Zn-ion coated nano silica filler with an aim to study the dual role of this nanofiller in SBR. The presence of Zn-ion on the nano silica filler surface activates the sulfur vulcanization by involving Zn++ in to the sulfurating complex formed with thiazole from sulfenamide. The increase of Zn-ion, on the nanofiller, decrease the scorch safety of the elastomer compound but increase the tensile strength, state of cure and tear strength and attain maximum at its 10% level. The presence of stearic acid increases the rate of vulcanization. Replacement of stearic acid with mono-stearate, however, increases the vulcanization rate but decrease the ultimate state of cure. A mechanistic scheme involving dual function of this nanofiller has been suggested.
TL;DR: An experimental investigation 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 suggests an increase of the lower free volume size when cross linking takes place.
Abstract: 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 c(0)(1) and c(0)(2) 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.
TL;DR: In this article, the effect of the addition of 5 and 10 phr of unsaturated polyester resin (UPE) on the compatibility and physicomechanical properties of SBR and NBR rubber blends was studied.
Abstract: The effect of the addition of 5 and 10 phr of unsaturated polyester resin (UPE) on the compatibility and physicomechanical properties of styrene–butadiene (SBR) and acrylonitrile–butadiene (NBR) rubber blends was studied. Differential scanning calorimetry (DSC), scanning electron microscopy (SEM), electrical, and ultrasonic techniques were used to determine the degree of the compatibility (DC). The results obtained revealed that, by the addition of 10 parts per hundred parts of rubber (phr) UPE as a compatibilizer for SBR/NBR blends, the degree of compatibility was greatly enhanced. The rheological and mechanical properties of the blends were also improved. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 83: 2314–2321, 2002
TL;DR: A series of techniques were developed to quantitatively characterize the free water-soluble oligomers found in the aqueous phase in a model styrene/butadiene/acrylic acid (St/Bu/AA) batch emulsion terpolymerization process.
Abstract: A series of techniques were developed to quantitatively characterize the free water-soluble oligomers found in the aqueous phase in a model styrene/butadiene/acrylic acid (St/Bu/AA) batch emulsion terpolymerization process. Particular attention was paid to the early stages of the polymerization. Ultracentrifugation was used to accomplish the separation of the aqueous phase from the particle phase. 1H NMR, aqueous phase GPC, and GC techniques were used to determine the oligomer concentration as well as their composition and the surfactant concentration in the aqueous phase, the oligomer molecular weight, and the acrylic acid monomer conversion, respectively. The results were related to the overall conversion and the number of particles as a function of conversion. The oligomer concentration vs conversion curves for the model system show a maximum at around 12% conversion. However, the position of this maximum with respect to conversion is related to the surfactant concentration. The sharp decrease in the o...
TL;DR: In this paper, the electrical conductivity during vulcanization process was measured as a function of time for the system of TiC loaded styrene-butadiene rubber (SBR) composites.
Abstract: The electrical conductivity during vulcanization process was measured as a function of time for the system of TiC loaded styrene-butadiene rubber (SBR) composites. The phenomenon of negative and positive temperature coefficients of conductivity and its conduction mechanism were also studied for the SBR polymeric composites. The current-voltage characteristics of the polymeric composites were non-linear in high voltage and showed a switching effect. The effects of temperature on the thermal conductivity and effective dielectric constant were measured. The measured parameters were found to be dependent on TiC concentration. The electromagnetic wave shielding (EMS) of the SBR-TiC polymeric composite was also examined. The SBR filled with TiC could be expected to be promising novel smart polymeric composites for self-electrical heating, temperature sensor, time delay switching, and electromagnetic wave shielding effectiveness.
Patent•
30 Sep 2002
TL;DR: In this paper, a method for producing an aqueous styrene-butadiene polymer dispersion by the radical emulsion-polymerization of a monomer mixture M, containing: between 40 and 80 wt. % styrene as monomer M1; between 20 and 60 wt % butadiene as monomers M2 and between 0 and 40 wt.
Abstract: The invention relates to a method for producing an aqueous styrene-butadiene polymer dispersion by the radical aqueous emulsion-polymerisation of a monomer mixture M, containing: between 40 and 80 wt. % styrene as monomer M1; between 20 and 60 wt. % butadiene as monomer M2 and between 0 and 40 wt. %, (in relation to l00 wt. % monomers), of ethylenically unsaturated comonomers M3 that differ from styrene and butadiene, according to a monomer feed process in the presence of between 0.05 and 0.5 wt. %, (in relation to l00 wt. % monomers), of at least one hydrocarbon KW comprising between 6 and 20 C atoms, selected from compounds, which form a pentadienyl or a 1-phenylallyl radical during the abstraction of a hydrogen atom, or from α-methylstyrene dimers. Said method is characterised in that at least 30 % of the hydrocarbon KW is already present in the polymerisation vessel and the residual quantity of the hydrocarbon KW is fed to the polymerisation reaction during the course of the latter.
Patent•
08 Feb 2002
TL;DR: A pneumatic tire having a rubber component is defined as a vehicle having a component where the rubber in said component is comprised of (a) from 10 to 75 phr of a rubber gel selected from the group consisting of polybutadiene, styrene butadiene gel, acrylonitrile-butadienes gel, chloroprene gel, natural rubber gel, and mixtures thereof; (b) from 1 to 25 phr of syndiotactic 1,2-polybutadiENE; and (c) a rubber containing olefinic unsaturation
Abstract: A pneumatic tire having a rubber component where the rubber in said component is comprised of (A) from 10 to 75 phr of a rubber gel selected from the group consisting of polybutadiene gel, styrene butadiene gel, acrylonitrile-butadiene gel, chloroprene gel, natural rubber gel, and mixtures thereof; (B) from 1 to 25 phr of syndiotactic 1,2-polybutadiene; and (C) a rubber containing olefinic unsaturation.
TL;DR: In this article, the effects of block length and block number of linear styrene-butadiene (S-B) block copolymers on their compatibilization efficiency in blending polystyrene with poly butadiene were studied.
Abstract: The effects of the block length and block number of linear styrene–butadiene (S–B) block copolymers on their compatibilization efficiency in blending polystyrene with polybutadiene were studied. For this purpose, two sets of model S–B copolymers and both homopolymers were prepared by anionic polymerization. Diblocks, triblocks, or pentablocks of S–B copolymers were blended with these homopolymers, and the structures and some end-use properties of the blends were determined. The supramolecular structure (determined by small-angle X-ray scattering), morphology (determined by transmission and scanning electron microscopy), and stress-transfer characteristics (impact and tensile strengths) of the blends were chosen as criteria for the compatibilization efficiency of the copolymers used. © 2002 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 40: 2612–2623, 2002