Showing papers on "Styrene-butadiene published in 2003"

Structure and properties of fibrillar silicate/SBR composites by direct blend process

Abstract: Silicate attapulgite(AT)/Styrene Butadiene rubber (SBR) composites with excellent properties and low cost were first prepared from a direct blending process (including polymer melt blending and emulsion co-coagulation). The structure and properties of above composites were carefully investigated. It was found that most AT separated into dispersed units with diameters less than 100 nm in SBR by the direct blend process. However, a few dispersion units as large as 0.2–0.5 μm and a clear network structure of dispersion units in SBR was observed by TEM, SEM and RPA. AT can be purified, but purified AT cannot be easily dispersed in the rubber matrix by polymer melt blending. Siliane coupling agent Si69 can improve the dispersion of AT and enhance the chemical interfacial adhesion. At the same loading, AT (pretreated with Si69) was found to have better reinforcing effect on SBR than carbon black SRF with particle size 60–100 nm and even than N330 with particle size 26–30 nm to some extent. Meanwhile, the cost of AT/SBR composites is pretty low.

Effect of Chain Length of Amine and Nature and Loading of Clay on Styrene-Butadiene Rubber-Clay Nanocomposites

Abstract: Polymer nanocomposite is one of the highly discussed research topics in recent time. In this paper, we have reported the preparation and the properties of different nanoclays based on sodi...

Lithium secondary battery

Abstract: PROBLEM TO BE SOLVED: To provide a lithium secondary battery having a lead cover adhesive tape that does not cause voltage failure or the lowering of a battery capacity by micro short-circuiting even if a charge discharge cycle test or a high temperature storage test are carried out. SOLUTION: An adhesive tape 12 is composed of an adhesive agent containing a base material comprising a fluorine-based resin, and at least one of the adhesive materials selected from natural rubber, isobutyl rubber, and styrene butadiene rubber. A positive lead 2 is covered by the adhesive tape 12 so that the active material layer 18 of a positive electrode plate 1 does not contact thereto. One kind selected from among the group of an organic material comprising phthalocyanine, a metal powder or an oxide of titanium or aluinum is used as a pigment for coloring the adhesive tape 12.

Oil absorbents based on styrene–butadiene rubber

Abstract: Four oil absorbents based on styrene–butadiene (SBR)—pure SBR (PS), 4-tert-butylstyrene–SBR (PBS), EPDM–SBR network (PES), and 4-tert-butylstyrene-EPDM-SBR (PBES)—were produced from crosslinking polymerization of uncured styrene–butadiene rubber (SBR), 4-tert-butylstyrene (tBS), and ethylene–propylene–diene terpolymer (EPDM). The reaction took place in toluene using benzoyl peroxide (BPO) as an initiator. Uncured SBR was used as both a prepolymer and a crosslink agent in this work, and the crosslinked polymer was identified by IR spectroscopy. The oil absorbency of the crosslinked polymer was evaluated with ASTM method F726-81. The order of maximum oil absorbency was PBES > PBS > PES > PS. The maximum values of oil absorbency of PBES and PBS were 74.0 and 69.5 g/g, respectively. Gel fractions and swelling kinetic constants, however, had opposite sequences. The swelling kinetic constant of PS evaluated by an experimental equation was 49.97 × 10−2 h−1. The gel strength parameter, S, the relaxation exponent, n, and the fractal dimension, df, of the crosslinked polymer at the pseudo-critical gel state were determined from oscillatory shear measurements by a dynamic rheometer. The morphologies and light resistance properties of the crosslinked polymers were observed, respectively, with a scanning electron microscope (SEM) and a color difference meter.

Correlation between Molecular Architecture, Morphology, and Deformation Behaviour of Styrene/Butadiene Block Copolymers

Abstract: The correlation between the molecular architecture, morphology, and micromechanical deformation behaviour of styrene/butadiene (SB) block copolymers with different architectures (linear and star block copolymers, total styrene content, Φ ST =0.74) was studied using dynamic mechanical analysis (DMA), uniaxial tensile testing, scanning force microscopy (SFM), and high voltage electron microscopy (HVEM). Deformation of the individual phases under uniaxial strain at the molecular level was monitored by Fourier transform infrared (FT-IR) spectroscopy. It was demonstrated that the morphology and deformation behaviour of these block copolymers are strongly influenced by their molecular topology, block symmetry, and the nature of the interface between the component blocks. While the cylindrical morphology (hexagonal polybutadiene (PB) cylinders in polystyrene (PS) matrix) was observed in a symmetric SBS triblock copolymer with Φ ST =0.74, a two-component three-phase morphology was found in an asymmetric star block copolymer having an equivalent chemical composition and an SBS arm structure. Likewise, an SBS triblock copolymer with a composition identical to the former ones but with highly asymmetric PS end blocks revealed a lamellar morphology. While no locally confined deformation zones were observed in the lamellar block copolymers, the cylindrical block copolymer was found to deform through the formation of highly localised craze-like deformation zones.

A Comparative Study on Processing, Mechanical Properties, Thermo-oxidative Aging, Water Absorption, and Morphology of Rice Husk Powder and Silica Fillers in Polystyrene/Styrene Butadiene Rubber Blends

Abstract: Rice husk powder (RHP) and silica-filled polystyrene (PS)/styrene butadiene rubber (SBR) composites were prepared by using the laboratory size internal mixer (Brabender Plasti-corder). The torque development, morphology, and mechanical properties such as tensile strength, elongation at break, Young modulus, and impact strength were studied. Water absorption and the effect of thermo-oxidative aging on tensile properties of composites were also examined. Filler loading and filler type influence the processibility of the composites in which RHP offers better processing advantage over silica. Tensile strength reduces with increasing filler loading for both RHP and silica composites. However, at 15 wt% the fillers act as reinforced materials to the composites. Young modulus also increases with increasing filler loading, whereas elongation at break shows no significant changes. Aging test results show that the tensile strength and elongation at break decrease and Young modulus increases with aging for RHP compo...

Dynamic mechanical properties of styrene‐butadiene rubber vulcanizate filled with electron beam modified surface‐treated dual‐phase filler

Abstract: The influence of the electron beam modification of a dual-phase filler on the dynamic mechanical properties of styrene-butadiene rubber (SBR) is investigated in the presence and absence of trimethylol propane triacrylate or triethoxysilylpropyltetrasulfide. Electron beam modification of the filler results in reduction of the tan δ at 70°C, a parameter for rolling resistance, and an increase in the tan δ at 0°C, a parameter for wet skid resistance of SBR vulcanizates. These modified fillers give significantly better overall performance in comparison with the control dual-phase filler. This variation in properties is explained in terms of filler parameters such as the filler structure that leads to rubber occlusion and filler networking. These results are further corroborated using the master curves obtained by the time–temperature superposition principle. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 88: 2992–3004, 2003

Effect of curing time and sulfur content on the dielectric relaxation of styrene butadiene rubber

Abstract: Dielectric investigations were carried out on styrene–butadiene rubber cured by an increase in either the sulfur content or curing time in a wide range of frequencies from 100 Hz up to 10 MHz and at room temperature (≈25°C). After subtraction, the losses due to the Maxwell–Wagner effect, the dielectric data showed deviation from the Debye formula but were found to be fitted in the frequency domain by the Havriliak–Nagami function, which is a combination of Cole–Cole and Cole–Davidson functions. This function describes the relaxation mechanisms of the aggregates caused by the movement of the main chain that were expected to be formed by the addition of the different ingredients to the investigated rubber. These mechanisms are also discussed in terms of the distribution function of Frohlich between two limiting values of relaxation times τ1 and τ2. The relaxation times obtained from both functions increased with an increase in either sulfur content or curing time. The data obtained are discussed in terms of the crosslinking density determined from the Flory–Rehner relation. The effect of thermal aging on such systems was also studied, and the data obtained were compared with those before aging. This investigation led us to conclude that to get an end product that is highly resistant to thermal aging, the system should be cured for a time greater than 30 min with the addition of more than 5 phr sulfur. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 88: 1613–1621, 2003

Effect of styrene–isoprene–styrene, styrene–butadiene–styrene, and styrene–butadiene–rubber on the mechanical, thermal, rheological, and morphological properties of polypropylene/polystyrene blends

Abstract: The mechanical, thermal, rheological, and morphological properties of polypropylene (PP)/polystyrene (PS) blends compatibilized with styrene–isoprene–styrene (SIS), styrene–butadiene–styrene (SBS), and styrene–butadiene–rubber (SBR) were studied. The incompatible PP and PS phases were effectively dispersed by the addition of SIS, SBS, and SBR as compatibilizers. The PP/PS blends were mechanically evaluated in terms of the impact strength, ductility, and tensile yield stress to determine the influence of the compatibilizers on the performance properties of these materials. SIS- and SBS-compatibilized blends showed significantly improved impact strength and ductility in comparison with SBR-compatibilized blends over the entire range of compatibilizer concentrations. Differential scanning calorimetry indicated compatibility between the components upon the addition of SIS, SBS, and SBR by the appearance of shifts in the melt peak of PP toward the melting range of PS. The melt viscosity and storage modulus of the blends depended on the composition, type, and amount of compatibilizer. Scanning electron microscopy images confirmed the compatibility between the PP and PS components in the presence of SIS, SBS, and SBR by showing finer phase domains. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 88: 266–277, 2003

Effect of Styrene Butadiene Styrene Modifier on Cracking Resistance of Asphalt Mixture

Abstract: A laboratory investigation was conducted to evaluate the effects of styrene butadiene styrene (SBS) modification on the cracking resistance and healing characteristics of coarse-graded Superpave® mixtures. Four types of asphalt mixtures with 6.1% and 7.2% design asphalt contents using unmodified and SBS-modified asphalt cement were produced in the laboratory. Tests performed with the Superpave indirect tensile (IDT) test included repeated-load fracture and healing test, strength tests at two loading rates, and longer-term creep tests to failure. The test results showed that the benefit of SBS modifiers to mixture cracking resistance appeared to be primarily derived from a reduced rate of micro-damage accumulation. The reduced rate of damage accumulation was reflected in a lower m value without a reduction in fracture limit or healing rates. It was shown that the benefits of the SBS modifier were clearly identified by using the hot-mix asphalt fracture model, which accounts for the combined effects of m va...

Modification of styrene–butadiene rubber surfaces by plasma chlorination

Abstract: Chlorination with halogenating agents in organic solutions is a common surface treatment for styrene–butadiene rubber materials to improve their adhesion to polyurethane adhesives. An attempt to replace this wet chemical method with a clean plasma technique has been undertaken. Styrene–butadiene rubbers (both model elastomers, such as Finaprene 435 and Finaprene 507 and a typical composite vulcanised rubber) were exposed to the action of plasma generated in various reactive mixtures containing chlorine moieties. As chlorine precursors, trichloromethane (CHCl3), tetrachloromethane (CCl4), and chlorine (Cl2) were used. These compounds were supplied to the reactors as a pure agent or in a mixture with argon or oxygen. Pure argon and air were also tested. The process was performed both in RF (13.56 MHz) and AF (20 kHz) glow discharges, utilising electrode reactors working at low pressure. FTIR spectroscopy, contact angle measurements, and T-peel tests (before and after plasma treatment) characterised the elastomer surfaces. It has been found that for the pure CHCl3 and CCl4 plasmas with a relatively low power, the peel strength of the treated rubber surfaces is approximately 56% higher than that for the materials chemically chlorinated, and two to three times higher in comparison with the non-treated surfaces.

High brightness coating compositions and related products

Abstract: The invention provides a coating composition that provides high brightness, high gloss and superior print quality The coated product comprises a substrate coated on at least one side with a coating composition comprising a pigment component and a binder component that is made of mixture of two binder resins Both binder resins are capable of film forming The first binder resin provides coating gloss and adhesion properties and the second binder resin enhances coating porosity, adhesion, and anti-static properties The first binder resin that is used at 60-95% by weight of the total binder resin blend is selected from the group consisting of vinyl acetate acrylate, styrene acrylate and styrene butadiene acrylic copolymers The second binder resin that is used at 5-40% by weight of the total binder resin blend is selected from the group consisting of anion type polystyrene derivatives, polyethylene glycol and polypropylene glycol

UV treatment of synthetic styrene-butadiene-styrene rubber

Abstract: The effectiveness of the treatment with ultraviolet light (UV) on several polymeric surfaces has previously been established. In this study, a low pressure mercury vapour lamp was used as a source of UV radiation for the surface treatment of a difficult-to-bond block styrenebutadiene-styrene rubber (S6), the treatment time ranging from 10 s to 30 min. The UV-treated S6 rubber surfaces were characterized by contact angle measurements (ethylene glycol, 25°C), ATR-IR spectroscopy, XPS, Scanning Electron Microscopy (SEM), and Atomic Force Microscopy (AFM). T-peel tests on UV-treated S6 rubber/polyurethane (PU) adhesive/ leather joints (before and after ageing) were carried out to quantify adhesion strengths. The UV treatment of S6 rubber produced improved wettability, the formation of C—O, C=O and COO- moieties, and ablation (removal of a thin rubber layer from the surface). The extent of these modifications increased with increasing treatment time. The extended UV treatment produced greater surface modificat...

Polyester Polyol-Based Polyurethane Adhesive; Effect of Treatment on Rubber Surface

Abstract: Polyester polyols were synthesized using vegetable oil fatty acids having different characteristics (mainly in terms of hydroxyl functionality) and epoxy resin, using triethylamine as a catalyst. Polyols were characterized by the FTIR spectroscopy. Polyurethane adhesives were synthesized from it and used in bonding rubber. Treatment of sulphuric acid on the non-polar styrene butadiene rubber (SBR) surface was studied for the bond strength improvement via an increase in wettability of the rubber surface. Wettability was found by measuring the contact angle using Goniometer. Bond strength was evaluated by a 180° T-peel test. The surface modification and mode of bond failure were studied by Scanning Electron Microscopy (SEM). The synthesized polyurethane adhesives were compared with the commercial adhesive.

Thermogravimetric Evaluation for Pyrolysis Kinetics of Styrene-Butadiene Rubber

Abstract: The pyrolysis kinetics of styrene-butadiene rubber (SBR) was studied by the kinetic model which accounts for the thermal degradation of polymer at any time. The kinetic analysis was performed by a conventional nonisothermal thermogravimetric (TG) technique at several heating rates between 10 and 50 K/min in a nitrogen atmosphere. To verify the effectiveness of the kinetic analysis method used in this work, the kinetic analysis results were compared with those of various analytical methods. The TG data were also compared with values calculated by using the kinetic parameters obtained from this work. It was found that the kinetic analysis method used in this work gave the reliable kinetic parameters of SBR pyrolysis.

Tire with component comprised of rubber composite of styrene/butadiene elastomer containing pendent silanol and/or siloxy groups

Abstract: The invention relates to a tire having at least one component (e.g. tread) of a rubber composition comprised of a styrene/butadiene elastomer composite comprised of a styrene/butadiene elastomer and a functionalized styrene/butadiene elastomer containing an internal silicon atom therein as a part of the elastomer, and at least one pendent silanol group and/or siloxy group from said silicon atom. Said elastomer composite is comprised of a significant polymodal (e.g. bimodal) molecular weight distribution between said styrene/butadiene elastomer and said functionalized styrene/butadiene elastomer. Said rubber composition contains synthetic, precipitated silica aggregates having hydroxyl groups on their surface which may be pre-treated (hydrophobated) to reduce hydroxyl groups contained on their surface prior to blending with said styrene/butadiene composite. Said rubber composition may contain a dispersion therein of a silica/plasticizer composite. Said rubber composition may be prepared by blending two bis(3-triethoxysilylpropyl) polysulfide coupling agents therewith, namely blending such polysulfide having an average of from 2 to 2.5 connecting sulfur atoms in its polysulfidic bridge in a non-productive mixing stage in the absence of addition of free sulfur and subsequently blending such polysulfide having an average of from 3.5 to 4 connecting sulfur atoms in its polysulfidic bridge in a productive mixing stage in combination with addition of free sulfur.

Tire with tread of CIS 1,4-polybutadiene rich rubber composition which contains a functional styrene/butadiene elastomer, silica and coupling agent

Abstract: The invention relates to a tire having a tread of a rubber composition comprised of a composite of styrene/butadiene elastomer and functionalized styrene/butadiene elastomer containing an internal silanol and/or siloxy group therein with pendent silanol and/or alkoxy groups of a polymodal (e.g. bimodal) molecular weight distribution, together with at least 30 phr of cis 1,4-polybutadiene rubber and a dispersion in said rubber composition of precipitated silica aggregates and a coupling agent as a bis (3-triethoxysilylpropyl) polysulfide having an average of from only 2 to 2.5 sulfur atoms in its polysulfidic bridge to the exclusion of a bis (3-trialkoxysilylalkyl) polysulfide having an average of greater than 2.5, and particularly greater than 3, sulfur atoms in its polysulfidic bridge. In one aspect, said silica aggregates may be pre-treated to reduce said hydroxyl groups on their surface prior to blending with said silanol and/or siloxy functionalized elastomer. In one aspect, a carbon black contained in the rubber composition may be an electrically conductive carbon black.

Mechanical and viscoelastic behavior of natural rubber and carboxylated styrene-butadiene rubber latex blends

Abstract: The morphology, mechanical and viscoelastic behavior of latex blends of unvulcanized natural rubber (NR) with carboxylated styrene-butadiene rubber (XSBR) were investigated, with special reference to the effect of the blend ratio, temperature, and frequency. Mechanical properties like tensile strength, modulus, and elongation at break were also studied. As the XSBR content increased, the tensile strength increased up to a 50:50 NR/XSBR ratio and then decreased as a result of the self-curing nature of XSBR. The dynamic mechanical properties of these latex blends were analyzed for loss tangent, storage modulus, and loss modulus. The entire blend yielded two glass-transition temperatures, which corresponded to the transitions of individual components, indicating that the system was immiscible. To determine the change in modulus with time, a master curve of 50:50 NR/XSBR blends was plotted. Time–temperature superposition and Cole–Cole analysis were done to understand the phase behavior of the latex blends. The experimental and theoretical values of storage modulus of blends were compared using the Kerner and Halpin–Tsai models. With the help of optical micrographs, attempts were made to correlate the morphology and viscoelastic behavior of these blends. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 88: 2639–2648, 2003

Molecular structure and gross melt fracture triggering

Abstract: We report in this paper rheological and rheo-optical experiments on a linear and a star-branched statistical copolymer of styrene butadiene rubber (SBR). The aim of this work is to study the influence of molecular structure on gross melt fracture defect. First, the rheological behavior in shear and in elongation of both materials are investigated. Then, the experimental results obtained by various rheological techniques enable us to compare the level of apparent shear rates and elongational stresses applied to each polymer at the onset of flow instabilities. The critical apparent shear rates and elongational stresses are found to be higher for the star-branched SBR copolymer. Moreover, the shear behavior of solutions of SBR copolymers in toluene is investigated using classical and optical rheometry. These results allow us to compute their stress optical coefficients. Birefringence experiments performed with a specific two-dimensional slit die corroborate axisymmetric observations. The level of the first normal stress difference along the flow axis is higher for the star-branched SBR copolymer than for the linear one before gross melt fracture occurrence. Thus, all experiments illustrate the dependence of gross melt fracture defect on molecular structure.

Pneumatic tire having a rubber component containing a rubber gel and starch composite

Abstract: A pneumatic tire having a rubber component comprised of (A) 100 parts by weight (phr) of a rubber containing olefinic unsaturation; (B) from 0 to 100 phr of a filler selected from carbon black and silica; and (C) from 5 to 50 phr of a starch/plasticizer composite and 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, wherein the weight ratio of starch/composite to rubber gel is from about 10:1 to about 1:10.

Sulphur Vulcanisation of Styrene Butadiene Rubber using New Binary Accelerator Systems

Abstract: The influence of the newly developed binary accelerator 1-phe- nyl-2,4-dithiobiuret (DTB) in combination with sulphenamides like DCBS, MBS, TBBS on the cure characteristics,mechanical properties,viscoelastic behaviour and network characteristics of styrene butadiene rubber (SBR) is studied. Kinetics of vulcanisation is followed at three different temperatures. Mechanical properties are found to be improved upon DTB addition. Attempts have been made to correlate the observed properties with extent of crosslinking of DTB. Effect of aging on tensile properties of the vulcanisates was also done. The extent of crosslinking was also improved with DTB cured vulcanisates. Dynamic

Improvement of properties of silica‐filled styrene‐butadiene rubber (SBR) compounds using acrylonitrile‐styrene‐butadiene rubber (NSBR)

Abstract: Since silica has strong filler–filler interactions and adsorbs polar materials, a silica-filled rubber compound wil have poor dispersion of the filler and a poor cure characteristic. Improvement of properties of silica-filled styrene-butadiene rubber (SBR) compounds has been studied using emulsion SBR-based acrylonitrile-styrene-butadiene rubber (NSBR). The silica dispersion is improved by adding NSBR to the compound. The bound rubber content increases with increase in the NSBR content. The scorch time and cure rate become faster as the NSBR content increases. The crosslink density also increases by increasing the NSBR content. The wear property is improved by adding the NSBR. Copyright © 2003 John Wiley & Sons, Ltd.

Polymer proton-conduction systems based on commercial polymers. I. Synthesis and characterization of hydrogenated styrene-butadiene block copolymer and isobutylene isoprene rubber systems

Abstract: This work describes the synthesis and characterization of two nonfluorinated proton-conducting polymer systems, one consisting of a hydrogenated styrene–butadiene rubber (HSBR) block copolymer and the other consisting of an HSBR blend with isobutylene isoprene rubber for the improved mechanical stability of the final product. The films obtained were crosslinked, sulfonated, and microstructurally and electrically characterized. In addition, water and methanol crossover was determined, the results being compared with those of Nafion 117. The properties measured in the different samples confirmed that these systems may constitute a valid alternative to commercial membranes, being low-cost and less polluting and having a lower methanol crossover. © 2003 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 41: 2809–2815, 2003

Influence of novel electron beam modified surface treated dual phase filler on rheometric and mechanical properties of styrene butadiene rubber vulcanizates

Abstract: Rheometric and mechanical properties, hysteresis and swelling behavior of the Styrene-Butadiene Rubber vulcanizates (SBR) filled with unmodified and novel electron beam modified surface treated dual phase fillers were investigated. Scorch time increases for these modified filler loaded vulcanizates due to introduction of quinone type oxygen on the surface. Electron beam modification of dual phase filler in the absence of trimethylol propanetriacrylate (TMPTA) or triethoxysilylpropyltetrasulphide (Si-69) significantly improves the modulus of the SBR vulcanizates, whereas the values of tensile strength and elongation at break drop. However, presence of TMPTA or silane slightly increases the modulus with significant improvement in tensile strength. This effect is more pronounced at higher loading of these modified fillers in SBR vulcanizates. These variations in modulus and tensile strength are explained by the equilibrium swelling data, Kraus plot and a new mathematical model interpreting the polym...