Showing papers on "Styrene-butadiene published in 2001"

Rheological and Thermodynamical Behavior of Styrene/Butadiene Rubber‐Organoclay Nanocomposites

Abstract: Organophilic layered silicate (montmorillonite type) was added up to 10 phr to a styrene/butadiene rubber (SBR) cured by an efficient vulcanization system. The compounds were characterized in respect to their curing, rheological and mechanical properties. In addition, attempt was made to consider some thermodynamical aspects of the resulting network. The crosslink density, assessed by the Flory-Rehner equation, increased with increasing organoclay content. This was traced to the accelerator role of the amine functionality of the trialkylamine intercalant used. The pronounced structural viscosity (i. e. viscosity decrease as a function of shear rate) and high elongation at break of the compounds caused by the incorporation of organoclay were opposed to the enhanced crosslinking and reinforcing effect of the clay supposed to be exfoliated. To solve the above contradiction a model was proposed according to which the silicate layers are intercalated/exfoliated and encapsulated by a highly crosslinked rubber layer and these “rubberized” platelets are embedded in the lightly crosslinked bulk.

Rapid FTIR method for quantification of styrene‐butadiene type copolymers in bitumen

Abstract: The mid-IR molar absorptivity for polystyrene (PS) and polybutadiene (PB) blocks were obtained for five styrene-butadiene-styrene (SBS) and SB copolymers, including linear, branched, and star copolymers, and their blends with bitumen. The average absorptivity for PS and PB blocks was 277 and 69 L mol−1 cm−1 and it was little affected by the S/B ratio or the copolymer architecture. In the presence of bitumen, Beer's law was obeyed but the respective PS and PB absorptivity was 242 and 68 L mol−1 cm−1, possibly because of weak interactions between the copolymer and bitumen. The absorptivity values were used to calculate the concentration of SB-type copolymers in blends with bitumen with an accuracy of 10% or better. The method can be used to probe the stability of bitumen–copolymer blends in storage at 165°C, to determine the copolymer concentration in commercial polymer modified bitumen (PMB), and to assess the resistance of PMB to weathering. © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 79: 1034–1041, 2001

Progress of synthesis and application of trans-1,4-polyisoprene

Abstract: A new technology to synthesize trans-1,4-polyisoprene (TPI) with bulk precipitation polymerization in the presence of a supported Ti catalysts was introduced. The termination of polymerization, stabilization of the polymer, and the adjustment of the molecular weight of TPI and its quality index are discussed. The blending and covulcanization of TPI with natural rubber (NR), styrene butadiene rubber (SBR), and butadiene rubber (BR) were studied. The blending compounds had outstanding dynamic mechanical properties, especially the rolling resistance, heat buildup, and wet skid resistance. Tread and sidewall compounds that contained TPI had a higher modulus, longer fatigue life, better abrasion resistance, lower rolling resistance, and lower buildup, which indicates that TPI is suitable for high-performance tire. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 82: 81–89, 2001

Improvement of properties of silica‐filled styrene–butadiene rubber compounds using acrylonitrile–butadiene rubber

Abstract: Since silica has strong filler-filler interactions and adsorbs polar materials, a silica-filled rubber compound has a poor dispersion of the filler and poor cure characteristics. Improvement of the properties of silica-filled styrene-butadiene rubber (SBR) compounds was studied using acrylonitrile-butadiene rubber (NBR). Viscosities and bound rubber contents of the compounds became lower by adding NBR to the compound. Cure characteristics of the compounds were improved by adding NBR. Physical properties such as modulus, tensile strength, heat buildup, abrasion, and crack resistance were also improved by adding NBR. Both wet traction and rolling resistance of the vulcanizates containing NBR were better than were those of the vulcanizate without NBR. The NBR effects in the silica-filled SBR compounds were compared with the carbon black-filled compounds.

Filler-polymer interactions in both silica and carbon black-filled styrene-butadiene rubber compounds

Abstract: Bound rubber in a filled rubber compound is formed by physical adsorption and chemisorption between the rubber and the filler. Styrene–butadiene rubber (SBR) is composed of four components of styrene, cis-1,4-, trans-1,4-, and 1,2-units. Filler–polymer interactions in both silica and carbon black-filled SBR compounds were studied by analyzing microstructures of the bound rubbers with pyrolysis-gas chromatography. Differences in the filler–polymer interactions of the styrene, cis-1,4-, trans-1,4-, and 1,2-units were investigated. The filler–polymer interactions of the butadiene units were found to be stronger than that of the styrene unit. The interactions of the cis-1,4- and trans-1,4-units were stronger with carbon black than with silica, whereas the 1,2-unit interacted more strongly with silica than with carbon black. © 2001 John Wiley & Sons, Inc. J Polym Sci B: Polym Phys 39: 439–445, 2001

Recycled polymers for use as bitumen modifiers

Abstract: The volume of waste polymer being produced continues to rise. Disposal is difficult and waste exceeds acceptable levels. The purpose of this research is to examine the possibility of incorporating waste polymer into bitumen as a modifier. The aim was to find recycled polymer modified binders that would be similar to proven modified binders or that would augment the properties of 100 penetration grade bitumen. A wide range of recycled polymers were tested, including polyethylenes, polypropylenes, polyetherpolyurethane, ground rubber, and truck tire rubber. Tests included viscosity, penetration, softening point, aging, and rheology. Stiffness tests on samples of bituminous mixes made using a selection of binders also formed part of the research program. Although stability problems were evident with some recycled modified bitumen, some cases were found to be successful. The blend with 3% low density polyethylene substituted for 1% styrene butadiene styrene had similar properties to that of Polyflex 75, although it had lower stiffness. The most impressive was a combination of low density polyethylene, bitumen, and ethyl vinyl acetate.

Surface Modifications Produced by N2 and O2 RF Plasma Treatment on a Synthetic Vulcanized Styrene-Butadiene Rubber

Abstract: A low-pressure gas RF plasma-treatment has been used to improve the adhesion of a synthetic vulcanized rubber to polyurethane adhesive as an environmentally friendly alternative surface treatment to the conventional chemical treatments. A sulfur vulcanized styrene-butadiene rubber (R2) containing a noticeable amount of zinc stearate and paraffin wax (both providing a lack of adhesion) in its formulation was used. Two different gases (oxygen and nitrogen) were used to generate the RF plasma, which was performed at 50 Watt for 1–15 min. The modifications produced on the R2 rubber surface by the RF plasma treatments were assessed by using advancing and receding contact angle measurements, ATR-IR spectroscopy, X-ray Photoelectron Spectroscopy (XPS), Scanning Force Microscopy (SFM), and Scanning Electron Microscopy (SEM). Adhesion evaluation was obtained from T-peel tests of joints produced between plasma treated R2 rubber and a polyurethane adhesive. The plasma treatment produced a decrease in advancing and receding contact angle values on R2 rubber, irrespective to the gas used to generate the RF plasma. The treatment with RF plasma produced the partial removal of hydrocarbon moieties from the rubber surface and the generation of oxygen moieties. An increase in surface roughness was also produced. The degree of oxidation and the amount of hydrocarbon-rich layer removed from the R2 rubber surface was more important by treating with oxygen plasma. The treatment of rubber in oxygen plasma for 1 minute was enough to noticeably increase adhesion of R2 rubber to polyurethane adhesive. However, an extended treatment (15 min.) was needed when nitrogen plasma was applied to R2 rubber. The loci of failure in the joints produced between the plasma treated R2 rubber and the polyurethane adhesive was assessed by using ATR-IR spectroscopy. A mixed failure (partially adhesional and partially cohesive failure in the rubber) in the joints produced with plasma treated R2 rubber joints was always obtained.

Influence of the silica content on rheological behaviour and cure characteristics of silica‐filled styrene–butadiene rubber compounds

Abstract: Rheological behaviour and cure characteristics of silica-filled styrene–butadiene rubber (SBR) compounds and SBR compounds filled with both silica and carbon black with different silica contents were investigated. Rheocurves of the time versus the torque of the compounds showed specific trends with the silica content. For the compounds with low silica content (less than 50 phr), the torque decreased immediately after the steep increase at the initial point of the rheocurve and then increased very slowly. For the compounds with high silica content (more than 50 phr), the rheographs showed two minimum torque points; the torque decreased immediately after the steep increase at the start point of the rheocurve and then increased sharply before reaching the second minimum point. This can be explained by the strong filler–filler interaction of silica. The minimum torque of the compound increased slightly with an increase of the silica content up to 50 phr silica content and then increased appreciably. For the silica-filled compounds, cure times of the t02, t40, and t90 became shorter with an increase of the filler content. For the compounds filled with both silica and carbon black (total filler content of 80 phr), the cure times became longer with an increase of the silica content ratio. © 2001 Society of Chemical Industry

Depolymerization of Styrene−Butadiene Copolymer in Near-Critical and Supercritical Water

Abstract: Many conventional solvents do not sufficiently dissolve cross-linked polymers such as styrene−butadiene rubber (SBR) to allow efficient depolymerization. Supercritical and near-critical water provi...

Correlation between morphology and mechanical properties of different styrene/butadiene triblock copolymers: a scanning force microscopy study*

Abstract: The morphology of different styrene/butadiene (SB) block copolymers with triblock architectures was investigated using tapping mode scanning force microscopy (SFM). Comparative analysis of the morphology of the samples at the polymer/substrate interface of solution-cast films and in bulk was performed. It was found that, besides the total phase volume ratio, the interfacial structure between the incompatible chains determines the phase morphology and mechanical properties of the investigated block copolymers. The asymmetric SBS triblock copolymer (φps( 74 vol%) forms, as expected, a cylindrical morphology with hexagonally packed polybutadiene (PB) cylinders in the polystyrene (PS) matrix. Depending on the interfacial structure, block configuration, and the hard/soft phase ratio, other triblock copolymers (φps( 74 vol% and 65 vol%) show lamellae and randomly distributed PS cylinders in a random styrene/butadiene copolymer S/B matrix, respectively. *Dedicated to Prof. Francisco J. Balta Calleja on the occas...

Production of elastomeric radiation protective material comprises mixing of high atomic weight metal powder with inorganic additive and incorporation into elastomer

Abstract: A process for the production of a radiation protective material comprising a polymer of a thermoplastic, vulcanizable elastomer and more than 80 wt.% of a radiation absorbing filler of a high atomic number metal or its compounds, comprises mixing of the high atomic weight metal powder (20-120 micro m particle size) with an inorganic additive and incorporation into the elastomer at below 180 deg C. A radiation protective material comprises a filled polymer of a synthetic, thermoplastic, vulcanizable elastomer such as natural rubber, polychloroprene, nitrile-butadiene, styrene butadiene, butadiene rubber, ethylene-propylene diene terpolymer, ethylene-propylene copolymer, polyurethane, isobutylene-isoprene rubber, silicon rubber and/or ethylene-vinyl acetate rubber or non-vulcanizable elastomers, preferably polypropylene/EPDM, styrene-ethylene-butylene-styrene, polyvinyl chloride-nitrile butadiene and/or ethylene-propylene copolymer and more than 80 wt.% of a radiation absorbing filler, with a powder of a high atomic number metal or its compound. Its production involves (A) mixing of the high atomic weight metal powder (20-120 mu m particle size) with magnesium-aluminum-silicate, zinc stearate, silicon resin powder, strontium carbonate, barium carbonate, barium sulfate,calcium-tungstate, gadolinium oxysulfide, tin oxide doped barium sulfate, zinc, antimony, lanthanides and/or actinides. (B) incorporating the mixed powder into the elastomer at below 180 deg C (C) cooling and further homogenization of the mixture using cooled rollers (D) cutting of the mixture into strips and passing through a screen (5-1000 (especially 15-35) micro m) (E) forming of the mixture into film by conventional processes, optionally after addition and vulcanization of necessary cross-linking agents.

Waterproof, durable products made from recycled rubber products

Abstract: Synthetic roofing products such as simulated slate and clay tile shingles, and other products, such as flower pots, floor coverings, plastic pallets and the like are compression molded from a mixture of ultra low density polyethylene binder and a filler which may comprise recycled rubber products such as E.D.P.M (ethylene propylene diene monomer) and S.B.R. (styrene butadiene rubber). Colorants may be added to the mixture prior to final molding. Many of the products, especially synthetic shingles, are less expensive, easier to handle, and more durable than the slate or clay tile shingle product simulated.

Rubber and Carbon Black

Abstract: A process is provided for making a carbon-filled rubber having a uniform dispersion of nanometric-sized carbon black particles. Fluffy carbon black is received as a slurry in water and added to latex rubber before or during coagulation in an emulsion styrene butadiene rubber plant, or fluffy carbon black is similarly incorporated in rubber using a different type of rubber-manufacturing process. A uniform dispersion of smaller-than-usual carbon black particles in rubber is formed, which provides a black masterbatch rubber with superior mechanical and rheological properties. Ash and grit is removed from the fluffy carbon black slurry, which further improves the properties of the carbon-filled rubber by reducing defects in the rubber caused by the ash or grit.

Graft copolymerization of N‐isopropylacrylamide on styrene‐butadiene‐styrene block copolymer

Abstract: Graft polymerization of N-isopropylacrylamide (NIPAAm) onto styrene-butadiene-styrene (SBS) block copolymer using benzoyl peroxide was studied to improve the water absorptivity and thermosensitivity of SBS. The influence of various grafting reaction factors on the conversion of NIPAAm and the grafting percentage of SBS-g-NIPAAm were also investigated in the study. The experimental results showed that the conversion of SBS-g-NIPAAm was enhanced as the monomers of NIPAAm were increased. The maximum conversion of SBS-g-NIPAAm was observed when the molar ratio of NIPAAm to butadiene was 1.25. In addition, increasing the reaction time enhanced the conversion of SBS-g-NIPAAm; the maximum grafting percentage was obtained with a 4-h reaction. The optimal concentration of the initiator was 3 × 10−4 mol/20 mL of toluene, and the grafting reaction occurred at over 65°C. The test results of the hydrophilicity of the grafted membranes showed that the hydrophilicity and thermosensitivity were significantly enhanced by grafting NIPAAm onto SBS. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 82: 2641–2650, 2001

Pneumatic tire having a rubber component containing a block styrene butadiene copolymer

Abstract: There is disclosed a pneumatic tire having a rubber component comprising a sulfur cured rubber composition composed of, based on 100 parts by weight of rubber (phr): (a) 99 to 50 parts by weight of a first rubber containing olefinic unsaturation; and (b) 1 to 50 parts by weight of a second rubber which is different from said first rubber and which is an elastomeric block copolymer of (1) from 15 to 65 percent by weight, based on the total block copolymer, of butadiene, and (2) from 35 to 85 percent by weight, based on the total block copolymer, of styrene, which block copolymer has: (a) at least two blocks A which have polymerized units of styrene, a glass transition temperature Tg above 25° C. and forms a rigid phase, and (b) at least one elastomeric block which is composed of about 25 to 70 percent by weight of butadiene and 75 to 30 percent by weight of styrene, and which has polymerized B/A units of styrene and butadiene in a random structure; a glass transition temperature Tg from −50° C. to 25° C., and is located between two blocks A and forms a flexible phase, and the amount of the rigid phase accounts for 5 to 40 percent by volume.

Effect of a styrene–butadiene copolymer on the phase structure and impact strength of polyethylene/high‐impact polystyrene blends

Abstract: The effect of a styrene–butadiene block copolymer on the phase structure and impact strength of high-density and low-density polyethylene/high-impact polystyrene blends with various compositions was studied. For both the blends, the type of the phase structure was not affected by addition of a styrene–butadiene compatibilizer. The localization and structure of the compatibilizer in the blends were dependent on their composition. Addition of the compatibilizer improved impact strength of the blends in the whole concentration range. The improvement was the largest for blends with a low amount of the minor phase. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 81: 570–580, 2001

Interfacial adhesion in sisal fiber/SBR composites: an investigation by the restricted equilibrium swelling technique

Abstract: Short sisal fiber-reinforced styrene butadiene rubber (SBR) composites were prepared and characterized by the restricted solvent swelling technique. The solvent swelling characteristics of SBR composites containing untreated and bonding agent-added mixes were investigated in a series of aromatic solvents, such as benzene, toluene, and xylene. The diffusion experiments were conducted by the sorption gravimetric method. The adhesion between the rubber and short sisal fibers was evaluated from the restricted equilibrium swelling measurements. The anisotropy of swelling of the composite was confirmed by this study. The effect of fiber orientation in controlling the anisotropy of restricted swelling was also demonstrated. As the fiber content increased, the solvent uptake decreased, due to the increased hindrance and good fiber-rubber interactions. Bonding agent-added mixes showed enhanced restriction to swelling, due to the strong interfacial adhesion. The bonding system containing hexa-resorcinol in the mix ...

High-resolution solid state NMR investigation of the filler-rubber interaction : Part III. Investigation on the structure and formation mechanism of carbon gel in the carbon black-filled styrene-butadiene rubber

Abstract: This investigation describes the elastomer—filler interaction and its formation mechanism using solid state high-resolution, high-speed 1H magic-angle spinning nuclear magnetic resonance (NMR) spectroscopy. Pulsed NMR measurements were carried out on pure styrene-butadiene rubber (SBR), and solvent extracted carbon gels from freshly prepared and storage matured master batches. The effects of filler loading, storage maturation, severity of extraction and experimental temperature on the elastomer-filler interaction were examined and discussed. High resolution in NMR was achieved by higher temperature/low spinning rate, room temperature/high spinning and combined rotation and multiple-pulse spectroscopy (CRAMPS) techniques. High-speed magic-angle spinning (MAS) was found to be the most suitable method to achieve high resolution. Proton spin—spin relaxation time, T2, was measured successfully for each of the principal resonance species present in the samples. These measurements reveal an insight into...

Rubber blockout for guard rail

Abstract: A rubber blockout is provided for use in mounting a guardrail to a post. The blockout comprises natural rubber, styrene butadiene rubber and recycled tire cord with a vertical cavity formed therethrough. Optimally, the blockout comprises 50-75% recycled tire cord.

Functionalization of styrene-butadiene-styrene (SBS) triblock copolymer with maleic anhydride

Abstract: The thermoplastic elastomers have been widely used in polymer blends to improve their mechanical properties. This work is about the study of chemical modification of styrene-butadiene-styrene (SBS) with maleic anhydride (MA) by radical reaction. The functionalization reaction was carried out in a mixer Haake Rheomix 600 and the torque variation was monitored during the process. The products were characterized by Infrared Spectroscopy (FTIR) and crosslinking was evaluated by extraction. A calibration curve was plotted to determine the functionality. The results showed that it is possible to accomplish the functionalization reaction avoiding the crosslinking.

Halogenated elastomeric compositions having improved stability and green strength

Abstract: The present invention is a composition and a method of forming a composition, the composition comprising at least a halogenated elastomer and an amine or phosphine. An additional rubber component may be present in the composition of the invention. Ine one embodiment, the halogenated elastomer is a isoolefin copolymer comprising a halomethylstyrene derived unit. The amine or phosphine compound is represented by the formula (R1R2R3)Q, wherein Q is a Group 15 element, and wherein R1 is either hydrogen or a C?4? to C30 hydrocarbyl group, R?2? is either hydrogen or a C?1? to C30 hydrocarbyl group; and R?3? is either hydrogren or a C?1? to C30 hydrocarbyl group provided that at least one of R?1, R2 and R3? is not hydrogen. The additional rubber is selected from butyl rubber, halogenated butyl rubbe, star-branched butyl rubber, halogenated star-branched butyl rubber, isobutylene homopolymer, butadiene rubber, neoprene, nitrile rubber, ethylene/propylene/diene terpolymers, ethylene/propylene copolymers, styrene butadiene rubbers, polybutadiene, polyisoprene, isoolefin/alkylstyrene copolymer, halogenated isoolefin/alkylstyrene copolymer, natural rubber, polypropylene, polyethylene, polyurethane, polyvinyl chloride, silicon rubber, propylene oxide polymer, and mixtures thereof.

Method of adding water insoluble organic chemicals to styrene-butadiene rubber latex dispersions and resulting styrene-butadiene rubber latex dispersions

Abstract: The present invention is a method of incorporating a water insoluble organic chemical into a styrene-butadiene rubber latex dispersion and the resulting styrene-butadiene rubber latex dispersion. A styrene-butadiene rubber latex dispersion is provided comprising an aqueous phase and a disperse phase, with the disperse phase including particles of styrene-butadiene rubber. An organic solvent that is miscible in water and the water insoluble organic chemical are added together to the styrene-butadiene rubber latex dispersion. The addition of the water-miscible organic solvent allows the water insoluble organic chemical to pass from the aqueous phase into the disperse phase thus limiting separation of the water insoluble organic chemical from the latex dispersion. The resulting SBR latex has increased properties over conventional latices that use the same amount of the water insoluble organic chemical but that do not include the water-miscible organic solvent.