Solution-polymerized Styrene Butadiene Rubber Research Articles

Thermoplastic Vulcanizates with an Integration of High Wear-Resistant and Anti-Slip Properties Based on Styrene Ethylene Propylene Styrene Block Copolymer/Styrene Ethylene Butylene Styrene Block Copolymer/Solution-Polymerization Styrene-Butadiene Rubber

Distinguished from traditional vulcanized rubber, which is not reusable, thermoplastic elastomer (TPV) is a material that possesses both the excellent resilience of traditional vulcanized rubber and the recyclability of thermoplastic, and TPVs have been widely studied in both academia and industry because of their outstanding green properties. In this study, new thermoplastic elastomers based on solution polymerized styrene butadiene rubber (SSBR) and thermoplastic elastomers (SEPSs/SEBSs) were prepared by the first dynamic vulcanization process. The high slip resistance and abrasion resistance of SSBR are utilized to improve the poor slip resistance of SEPSs/SEBSs, which provides a direction for the recycling of shoe sole materials. In this paper, the effects of different ratios of the rubber/plastic phase (R/P) on the mechanical properties, rheological properties, micro-morphology, wear resistance, and anti-slip properties of SSBR/TPE TPVs are investigated. The results show that the SSBR/TPE TPVs have good mechanical properties. The tensile strength, tear strength, hardness, and resilience of the TPVs decrease slightly with an increasing R/P ratio. Still, TPVs have a tensile strength of 18.1 MPa when the ratio of R/P is 40/100, and this reaches the performance of the vulcanized rubber sole materials commonly used in the market. In addition, combined with microscopic morphology analysis (SEM), it was found that, with the increase in the R/P ratio, the size of the rubber particles gradually increased, forming a stronger crosslinking network, but the rheological properties of TPVs gradually decreased; crosslinking network enhancement led to the increase in the size of the rubber particles, and the increase in the size of rubber particles made the material in the abrasion of rubber particles fall easily, thus increasing its abrasion volume. Through dynamic mechanical analysis and anti-slip tests, when the R/P ratio was 40/100, the tan δ of TPVs at 0 °C was 0.35, which represents an ordinary vulcanized rubber sole material in the market. The viscoelasticity of TPVs increased with the increase in the R/P ratio, which improved the anti-slip performance of TPVs. SSBR/TPE TPVs are expected to be used in footwear and automotive fields due to their excellent abrasion resistance and anti-slip performance.

COMPATIBILITY STUDY OF HYDROCARBON RESINS WITH RUBBER COMPOUNDS FOR TIRE APPLICATIONS

ABSTRACT The addition of hydrocarbon resins to rubber compounds has a significant impact on their properties such as wet grip and rolling resistance. These performance characteristics have a strong correlation with the compatibility of the resin with the rubber matrix. Incompatible resins can cause excessive broadening of the damping curve, which results in poor rolling resistance. Compatibility, however, allows maximization of wet grip while minimizing the effect on rolling resistance. Compatibility is promoted by lower resin molecular weight and structural similarity to the polymers being blended. In this study, a method based on the Fox equation has been developed to quantitatively characterize the compatibility between resin and natural rubber (NR), a binary system. The dynamic shear rheometer (DSR), a tool new to the tire industry, is used to investigate the interaction between resin and two rubbers (i.e., a ternary system of NR–butadiene rubber [BR]–resin and solution polymerized styrene–butadiene rubber [SSBR]–butadiene rubber [BR]–resin), with a specific emphasis on resin partitioning among rubber blends. In addition, the DSR is applied to assess the Tg shift and tangent delta peak height, providing insight into the compatibility between rubbers and resin. A curve-fitting model was developed for the SSBR–BR–resin system to depict the relationship between these two parameters and the physical and chemical properties of resins, with the selection of resins featuring different degrees of aromaticity, Tg, and molecular weight. The findings indicated that higher Tg increased aromaticity and that lower molecular weight of the resin resulted in an elevated Tg shift in the blend, while lower molecular weight led to an increase in the tangent delta peak height. Our findings supply insight into the performance of rubber–resin blends and introduce a new screening tool for characterizing these blends in their green state.

Ozone resistance of three natural antioxidants in solution polymerized styrene-butadiene rubber—Molecular simulation and experimental study

Rubbers containing a high number of unsaturated units face significant challenges due to ozone aging. In industrial production, p-phenylenediamines are commonly used as synthetic antiozonants to protect against ozone degradation. However, their potential adverse effects on human health and the environment are gradually being recognized. Experimentally selecting antioxidants is costly and subject to numerous restrictions. Consequently, developing a new strategy for efficiently screening eco-friendly antioxidants is crucial. This study involved a comparative analysis of three natural antioxidants and examined the factors influencing their ozone resistance through multi-scale molecular simulation methods. Subsequently, these antioxidants were incorporated into a solution polymerized styrene-butadiene rubber matrix. Their performance was experimentally validated and compared with the standard N-(1,3-dimethylbutyl)-N′-phenyl-p-phenylenediamine control. Analysis of the properties and microstructure in the experiments revealed the following order of ozone resistance: α-tocopherol > sinapic acid > gallic acid. This ranking aligns well with the predictions of the simulations. This study aims to augment the understanding of the anti-ozone actions of antioxidants and to propose a novel method for designing new antiozonants.

Structure and performance of silica/functionalized solution-polymerized styrene butadiene rubber/epoxidized butadiene rubber nanocomposites

Functionalized solution-polymerized styrene butadiene rubber (FSSBR) is extensively used in “green tires” tread, so it is very important to improve the phase distribution of silica in FSSBR blends. In this work, the butadiene rubber (BR) is epoxidized (EBR) and blended with FSSBR. The effect of epoxidation degree on the structure and performance of the silica in combination with bis-(γ-triethoxysilylpropyl) disulfide (TESPD) filled FSSBR/EBR nanocomposites (S/FSSBR/EBR) is investigated. S/FSSBR/EBR3 nanocomposite with epoxidation degree of 3% achieves the best dispersion and phase distribution of silica by ring-opening reaction between epoxy group of EBR and silanol group of silica. Compared with silica in combination with TESPD filled FSSBR/BR nanocomposite (S/FSSBR/BR), S/FSSBR/EBR3 has better abrasion resistance, 13% improvement in wet-skid resistance and 15% reduction in rolling resistance, which provides an excellent solution for the preparation of high-performance “green tires".

Research on the influencing factors of hysteresis heat of rubber roller in battery pole piece calendering

AbstractThe calendering process of pole piece is a key step affecting the performance of the power battery. In the calendaring process, rubber roller materials will produce hysteresis heat, resulting in rolling resistance, which will lead to energy loss. The thermo‐mechanical coupling model for calendering rubber roller has been established and the effects of materials, calendering speeds, and roller structure shape on the viscoelastic temperature rise of rubber roller were analyzed. Solution‐polymerized styrene–butadiene rubber (SSBR) materials with different fillers have the greatest impact on temperature rise, followed by the roller shape, and calendering speed is smaller. The loss modulus of SSBR filled with white carbon black studied was smaller, and the temperature rise at high speed was 14.5°C higher than that at low speed. The optimized roller shape has a temperature rise of 10.4°C lower than the original shape. The research results could provide reference for the calendering rubber roller design of pole piece and similar processing.Highlights A thermo‐mechanical coupling model of calendering rubber roller was established. The rubber roller made of SSBR‐VN3 has a lower temperature rise. Optimized structure reduced contact pressure by 28.1% and temperature rise by 10.4°C.

Silica reinforced epoxidized solution-polymerized styrene butadiene rubber and epoxidized polybutadiene rubber nanocomposite as green tire tread

Solution-polymerized styrene butadiene rubber (SSBR) and high cis-polybutadiene rubber (BR) are usually used as matrix and silane coupling agent (SCA) modified silica as the filler in the conventional green tire tread. However, the SCA cannot achieve uniform distribution of silica, moreover the modification process generates volatile organic compounds. In this work, a novel silica reinforced epoxidized SSBR(ESSBR)/epoxidized BR (EBR) nanocomposite (S-ESSBR/EBR) without SCA is prepared. The ESSBR and EBR with different epoxidation degree are synthesized by an oxidant H2O2 and reaction-controlled phase-transfer catalyst CPC-PW4O16. The microstructure and performance of S-ESSBR/EBR nanocomposites are investigated and compared with the silica reinforced SSBR/BR nanocomposite (S-SSBR/BR-Si75) using Si75 as SCA. Silica nanoparticles transfer from ESSBR phase to EBR phase with increasing epoxidation degree of EBR, so the distribution of silica in two phases becomes homogeneous. The S-ESSBR/EBR nanocomposite exhibits high wet skid resistance, low rolling resistance and excellent abrasion resistance as green tire tread.

Enhancing silica dispersion and interfacial interaction in styrene butadiene/silica rubber composites by using epoxidized styrene butadiene rubber as interfacial compatibilizer

AbstractIt is usually desired but often challenging to improve the wet traction, and reduce the abrasion and rolling resistance simultaneously in tread rubber, which is referred to as “magic triangle” in tire industry. To fulfill this goal, the filler dispersion and interfacial interaction required to be improved, as they are two essential factors to concurrently govern the ultimate properties of rubber composites. Herein, we synthesized the epoxidized solution polymerized styrene butadiene rubber (ESSBR) with different epoxy level, and used them as interfacial compatibilizer to promote the silica dispersion and silica/rubber interfacial interaction. The epoxy of ESSBR would react with silanol on silica surface and co‐crosslink with SSBR simultaneously, therefore build a strong bridge between rubber matrix and filler. By incorporation of 20 phr of ESSBR‐15% (15% of double bonds on main chain was epoxidized), the wet grip was improved by 40%, and DIN abrasion and rolling resistance were reduced by 38% and 21%, respectively with hardly sacrifice the mechanical properties. We envisage that this study provides an approach for the fabrication of rubber composites with improved silica dispersion and strengthened interfacial interaction.

Microstructure and Performance of Green Tire Tread Based on Epoxidized Solution Polymerized Styrene Butadiene Rubber and Epoxidized Natural Rubber

Blending a solution of polymerized styrene–butadiene rubber (SSBR) with natural rubber (NR) as a matrix and silane coupling agent (SCA) modified silica as filler is widely used to prepare green tire tread. However, it is difficult to adjust the distribution of silica in different phases of a rubber blend by SCA. Moreover, the coupling reaction between silica and SCA emits volatile organic compounds. In this work, we use a new strategy to improve the distribution of silica in two phases without a SCA. Epoxidized SSBR (ESSBR) and epoxidized NR (ENR) are synthesized, and the performance of silica-filled ESSBR/ENR nanocomposite (S-ESSBR12/ENR) is investigated and compared with that of silica-filled SSBR/NR nanocomposite (S-Si75-SSBR/NR) using Si75 as the SCA. The S-ESSBR12/ENR nanocomposites have stronger interfacial interaction that results in better silica dispersion than the S-Si75-SSBR/NR nanocomposite. The epoxy groups can effectively adjust the phase selective distribution of silica. The S-ESSBR12/ENR18 nanocomposite shows homogeneous distribution, leading to the best performance. Compared with S-Si75-SSBR/NR nanocomposite, S-ESSBR12/ENR18 nanocomposite increases wet-skid resistance by 118%, reinforcing index by 38%, and abrasion resistance by 40% and decreases rolling resistance by 23%. Moreover, S-ESSBR12/ENR nanocomposites are eco-friendly and have potential application in the production of green tire treads.

Study on the phase structure and sound absorption properties of Eucommia ulmoides gum composites

Eucommia ulmoides gum (EUG) can be used as an underwater sound-absorbing material, but the effect of the phase structure of its composites on the sound absorption performance has not been fully investigated. EUG was blended with chloroprene rubber (CR) and solution-polymerized styrene butadiene rubber (SSBR), and then epoxidized natural rubber (ENR) was added to the EUG/CR composites. The results showed that when CR was supplemented with 20% EUG, the composite showed the sea-island structure, EUG existed mainly in β-crystal form, and the average sound absorption coefficient of the composite was 0.4 at 0 MPa pressure, which was twice as high as that of pure CR. However, the sound absorption performance of the EUG/SSBR composite obtained by the same method of EUG/CR composites was reduced. In addition, the average sound absorption coefficient improved to 0.62 with the addition of ENR based on EUG/CR composites, and the compression resistance was greatly improved. The key factors for EUG to improve the underwater sound absorption performance of rubber materials lie in the generation of well-dispersed sea-island structures while retaining its own crystals. This work will provide some reference for the preparation of EUG composite sound-absorbing materials that are resistant to high water pressure.

Using olefin metathesis reaction to modify solution polymerized styrene-butadiene rubber (SSBR) by for a more stable “green tire”

Using olefin metathesis reaction to modify solution polymerized styrene-butadiene rubber (SSBR) by for a more stable “green tire”

Research on Dynamic Mechanical Properties of Different Silane Coupling Agent In-situ Modified SSBR/Silica Composites

Hydroxyl density of silica surface will reduce and the compatibility of silica with rubber matrix will be improved through the modification of silica by silane coupling agent (SCAs). The silica-silica and silica-rubber interaction of silica filled solution polymerized styrene butadiene rubber (SSBR) in-situ modified by silane coupling agent TESPT and Si747 are studied by Dynamic Mechanical Analyzer (DMA). The effect of different types and loading amounts of SCAs on the dynamic mechanical properties of silica filled SSBR is investigated. The results show that the novel silane coupling agent Si747 has a more apparent effect on lessening the silica network than that of silane coupling agent TESPT, Hysteresis factor (tanδ) measured by DMA reduces, and the heat-built improves. It could also be found that Si747 modified composites have the lowest apparent activation energy, which is used to characterize the filler-rubber interaction, indicating the lowest temperature dependence.

Silica Masterbatches Produced with Liquid Phase Mixing; Part III. Quasi-Static Stress-Softening

The stress-softening effect of rubber-like materials is a phenomenon such that the stress required to attain a given elongation is less during the second cycle of deformation. In practice, stress-softening effects are used as a quantitative measure of strain energy loss. Both rubber reinforcement by fillers and the failure properties of vulcanizates, such as ultimate strength, tearing, cracking, abrasion, and fatigue, are closely related to the processes of energy dissipation during deformation. This paper reports the results of our research on the quasi-static stress-softening effect of vulcanizates of solution-polymerized styrene butadiene rubber (SSBR)/cis-polybutadiene rubber (BR)/silica masterbatches named Eco-Visco-Elastomer composite (EVEC) produced by a continuous liquid phase mixing, taking dry-mixed silica- and carbon black-filled vulcanizates as references. With this liquid phase mixing, the silanization efficiency of EVEC was greatly improved. Compared with the conventional silica filled vulcanizates, the stress softening effect of EVEC was significantly lower at low strain and rose more rapidly with increasing strain, which could be explained by the effects of filler agglomeration and polymer-filler interaction. The less energy dissipation at low strain is mainly due to fewer filler agglomerates, whereas at high strain, for EVEC, it is attributed to more rupture of polymer crosslinks and polymer chains in the matrix with increasing extension, due to higher polymer-filler interaction resulting in less slippage of polymer chains along the filler surfaces.

Grafting silica onto reduced graphene oxide via hydrosilylation for comprehensive rubber applications: Molecular simulation and experimental study

AbstractThe development of multifunctional rubber composites and the dispersion of fillers are always a focus in the industrial field of tires. In this work, supported by predictions from molecular simulations, reduced graphene oxide grafted with silica (rGO‐g‐SiO2) is fabricated through hydrosilylation. Structural and morphological characterization shows that SiO2 is present at the rGO surface. rGO‐g‐SiO2 was subsequently applied to enhance the performance of solution polymerized styrene butadiene rubber (SSBR) composites. As predicted from simulations, the mechanical and thermal properties of rGO‐g‐SiO2/SSBR are found to be improved due to an enhanced interfacial interaction and higher degree of phonon matching. In particular, with a 1.5% weight percentage of rGO, the reinforcing index and thermal conductivity of 1.5%‐rGO‐g‐SiO2/SSBR are found to be 168.7% and 114.0% higher than that for 1.5%‐rGO/SiO2/SSBR (physical mixture), respectively. The reinforced integrated performance is promising for the potential application of rGO‐g‐SiO2 as a filler for rubber composites.

Enhanced cross-linking performances and carbon black (CB) dispersion in solution styrene butadiene rubber (SSBR) filled with triazine-based graphdiyne (TGDY)

The cross-linking density and filler dispersion have decisive impacts on the mechanical properties of rubber products. Developing nanofillers with dual functions of both cross-linking agent and filler dispersant is highly demanded yet challenging. Here we prepare triazine-based graphdiyne (TGDY), and incorporate it into the solution polymerized styrene butadiene rubber (SSBR) matrix filled with carbon black (CB). The results show that the TGDY can simultaneously promote the curing rate and cross-linking density of the rubber composites. The interactions between TGDY and sulfur (S) are confirmed by DSC and FTIR measurements. It reveals that the TGDY can accelerate the curing rate of SSBR composites by facilitating the S fission at lower temperature. Moreover, the cross-linking density of the SSBR composites can be further increased through interactions between sulfur and TGDY. In addition, thanks to the sheet structure of TGDY, the dispersion of CB in the SSBR matrix is improved. Finally, we find that the rubber composites filled with CB/TGDY demonstrate excellent mechanical properties, such as 300% modulus and low rolling resistance. In summary, this work provides broad prospects and new paths for the application of TGDY in fabricating rubber products with high performances.

Effect of Pyrolysis Carbon Black from Waste Tire on the Mechanical Properties of SSBR/BR Blend

AbstractPyrolysis carbon black (PCB) is a main product during the pyrolysis of waste tires. Using PCB to partially replace carbon black has drawn great attention. Herein, PCB is used to replace commercial carbon black N234 in a solution‐polymerized styrene‐butadiene rubber (SSBR)/butadiene rubber (BR)/silica compound used for tire treads. The influence of liquid polyisoprene (LIR) on the SSBR/BR/silica compound is studied. The scorch time of the compound is prolonged and the curing rate increases when N234 is partially replaced by PCB, and the processing performance of the compound is improved after the addition of LIR. As N234 is partially replaced by PCB, the addition of LIR can increase the tensile strength and elongation at break of SSBR/BR/silica vulcanizates, and improve their ageing resistance. When 50% N234 is replaced by PCB in the presence of LIR, the rolling resistance and wet grip of SSBR/BR/silica vulcanizate are improved, while the abrasion resistance slightly decreased. In the presence of liquid polyisoprene, PCB can be successfully used to partially replace common carbon black in tire rubber compounds without compromising properties.

Constructing Chemical Interface Layers by Using Ionic Liquid in Graphene Oxide/Rubber Composites to Achieve High-Wear Resistance in Environmental-Friendly Green Tires.

The harm caused by small rubber particles generated from tire abrasion to the atmosphere is receiving a continuing concern. For developing environmental-friendly tire tread materials with high wear resistance, building the strong interface between nano-fillers and rubber matrix is the primary challenge. Herein, ionic liquid (IL, 1-allyl-3-methylimidazole chloride) was used to modify graphene oxide (GO) by π-cation interaction and hydrogen bonding between IL and GO. Furthermore, an IL-GO/natural rubber (NR) masterbatch possessing fine dispersion of GO was prepared by the emulsion compounding method, and thereafter, a further compound with solution polymerized styrene butadiene rubber (SSBR) was fabricated for the tread rubber composite. Results showed that the double bond in the IL enhanced the cross-linking reaction during the vulcanization of rubber composites occurred at high temperature, leading to an elevated interfacial interaction between the IL-modified GO and the rubber macromolecules. Compared with silicon dioxide (SiO2)-filled NR/SSBR composites, the cross-link density, 300% modulus, and tear strength of the IL-GO/SiO2/NR/SSBR composites were increased by 10.2, 42.6, and 20.2%, respectively. Importantly, the wear resistance of the IL-GO/SiO2/NR/SSBR composites was improved by 17.3%, ascribing to the strong interface between IL-GO and rubber macromolecules.

Evaluation of the aging coefficient and the aging lifetime of carbon black-filled styrene-isoprene-butadiene rubber after thermal-oxidative aging

We investigated the changes in the mechanical properties of carbon-black-filled styrene-isoprene-butadiene rubber (SIBR-CB) during a thermal-oxidative aging process at 90–130 °C. By tracking the changes in the mechanical properties of SIBR-CB over time at different temperatures, we estimated the aging temperature coefficient and aging lifetime of the rubber. Using the same methods, we directly compared the aging behavior of SIBR-CB to that of carbon black filled solution–polymerized styrene-butadiene rubber and carbon-black-filled neodymium-catalyzed isoprene rubber. The SIBR-CB sample exhibited the highest aging temperature coefficient, with values spread over a wider range compared to those of the other two rubbers. We attributed this to the presence of polybutadiene and polyisoprene chains within the macromolecular structure of SIBR-CB, which were susceptible to cross-linking and chain scission, respectively, during the thermal-oxidative aging process. These two reactions competed with each other and, in the case of SIBR-CB, the cross-linking was the dominant reaction. Consequently, the SIBR-CB sample exhibited the longest aging lifetime among the three rubbers. In addition, we established a relationship between the aging temperature and the aging lifetime and derived an equation that enables the calculation of the aging lifetime depending on the aging conditions.

Synthesis of allyltrimethoxysilane end-capped solution polymerized styrene-butadiene rubber

Synthesis of allyltrimethoxysilane end-capped solution polymerized styrene-butadiene rubber

A study on hydrocarbon resins as an advanced material for performance enhancement of radial passenger tyre tread compound

AbstractAdvancement in radial passenger car tyre tread compound introduces performance resin as a potential ingredient to improve wet grip (WG) and rolling resistance (RR). In this direction, our approach is to investigate the effect of two types of performance resins as Resin‐1 (mixture of aliphatic and aromatic) and Resin‐2 (aliphatic hydrocarbon) in silica filled solution polymerized styrene butadiene rubber (SSBR)/butadiene rubber (BR) based tread cap compound. Resin‐1 and Resin‐2 replaced low poly cyclic aromatic (PCA) oil by 10 phr (partially) and 20 phr (completely) with respect to the reference compound. It was observed that Resin‐1 has improved WG by 18% and 52%, whereas Resin‐2 showed 33% and 54% improvement at 10 phr and 20 phr replacement, respectively. Microscopic analysis was carried out to identify the dispersion of silica after replacement of oil by resins. Abrasion and fatigue resistance were studied by Laboratory Abrasion Tester (LAT‐100) and Tear Fatigue Analyzer (TFA) to understand the wear and fracture behavior of the modified compounds. Resin‐2 displayed 54% improvements in WG keeping similar RR and fatigue resistance by complete replacement of oil, whereas partial replacement was not appreciated due to less impact in dynamic mechanical properties.

Preparation and properties of thiol-functionalized solution-polymerized styrene-butadiene rubber

Preparation and properties of thiol-functionalized solution-polymerized styrene-butadiene rubber