Solution Styrene Butadiene Rubber Research Articles

Hybrid factors influencing wet grip and rolling resistance properties of solution styrene‐butadiene rubber composites

AbstractInfluencing factors on wet grip and rolling resistance properties of solution styrene − butadiene rubber (SBR) composites were investigated in terms of main hybrid components of the microstructure and crosslink density. Influence of the molecular weight and oil extension on the wet grip and rolling resistance properties was also examined. The styrene and 1,2‐unit contents of SBR affected the wet grip and rolling resistance properties. The influence of hybrid factors on the wet grip and rolling resistance properties was examined using 3D plots of the microstructure and crosslink density. The wet grip property was influenced by the hybrid microstructure of the styrene and 1,2‐unit as well as the crosslink density. The rolling resistance property was found to be mainly affected by not only the styrene content but also the crosslink density. It was found that SBR with appropriate styrene content (15 − 18 mol%), relatively high 1,2‐unit content (45 − 50 mol%) and relatively high crosslink density (over 1.5 × 10−4 mol cm−3) might be good for improvement of both the wet grip and rolling resistance properties. © 2017 Society of Chemical Industry

Preparation of nano‐silica loaded N‐cyclohexyl‐2‐benzothiazole sulphonamide and its application in solution styrene‐butadiene rubber/butadiene rubber composites

N-cyclohexyl-2-benzothiazole sulphonamide (rubber vulcanisation accelerator CZ) was grafted onto the surface of dispersible nano-silica (DNS) to obtain silica-loaded rubber vulcanisation accelerator CZ (DNS-CZ) through in-situ surface modification. A series of as-prepared DNS-CZ samples with different CZ loadings were used as the fillers to reinforce the composites made of solution styrene-butadiene rubber (SSBR) and butadiene rubber (BR). The effect of DNS-CZ fillers on the mechanical properties of the SSBR/BR composites was investigated in relation to the scanning electron microscopic observation of the filler dispersion in the rubber matrix. It was found that the CZ is chemically bonded onto the surface of nano-silica, thereby effectively reducing the polarity of the nano-silica and enhancing its compatibility with the rubber matrix. Therefore, the SSBR/BR composites filled with DNS-CZ exhibit greatly improved mechanical properties and Akron abrasion resistance than the counterparts filled with unloaded DNS. Particularly, when the loading amount of the CZ is set as 81.10 mmol/kg, the resultant SSBR/BR/DNS-CZ composite exhibits the best mechanical properties and Akron abrasion resistance, showing promising application for green tire tread.

Effect of the structural characteristics of solution styrene–butadiene rubber on the properties of rubber composites

ABSTRACTSolution‐polymerized styrene–butadiene rubber (SSBR) has been widely used in the high‐quality tire industry, and various brands of SSBR have been synthesized. Five kinds of SSBR were selected from multiple products to investigate the effects of different brands of SSBR on the comprehensive properties. Different characterization tools, such as Fourier transform infrared spectroscopy, 1H‐NMR, and differential scanning calorimetry, were used to characterize the microstructures of the SSBRs. The results show that the microstructures of the SSBRs distinctly affected the comprehensive properties of the SSBR composites, especially the properties of the “magic triangle.” For instance, the content of trans‐1,4‐butadiene positively corresponded to the Akron abrasion for the SSBR composites with different brands, and cis‐1,4‐butadiene could partly replace the influence of vinyl when the content of trans‐1,4‐butadiene was small. SSBR 2564S, SSBR 4526‐2, and SSBR 2535E were selected because of the excellent magic‐triangle properties. They were used to investigate the effects of different brands of SSBR with different ratios of natural rubber (NR) to SSBR on the comprehensive properties of the NR–SSBR rubber blend composites. The results indicate that the properties of magic triangle were distinctly enhanced. However, there was an optimized content of SSBR to enhance the wear resistance (≤15 phr). For SSBR 4526‐2, the Payne effect was negatively correlated to the content of SSBR, whereas for SSBR 2564S and SSBR 2535E, the Payne effect was positively correlated to the content of SSBR. On the basis of these results, the SSBR 2564S seemed to exhibit the best comprehensive properties to prepare a tire tread tailored for high‐performance tires. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018, 135, 45749.

Effect of organosilane agents on the vulcanizate structure and physical properties of silica-filled solution styrene butadiene rubber compounds

Physical properties of rubber compounds are affected by the filler-rubber interaction, filler dispersion in the rubber matrix, and crosslink structure formed during vulcanization. Organosilane agents are essentially used in silica-rubber compounds to inhibit the formation of silica agglomerates and increase the formation of silica-rubber networks. Generally, organosilane agents have an alkoxysilyl alkyl sulfide structure and are classified into silane coupling and covering agents depending upon the presence of sulfur. Coupling agents have a sulfur moiety and serve as a sulfur donor during the vulcanization process, thus increasing the formation of filler-rubber and chemical crosslink networks. On the other hand, covering agents promote the hydrophobation of silica surfaces, decreasing the adsorption loss of vulcanization additives, which increases the formation of chemical crosslink networks. This implies that organosilane agents can affect the vulcanizate structure, which causes a variation in the properties of silica compounds. Therefore, in this study, the effect of coupling (bis(3-triethoxysilylpropyl)disulfide (TESPD) and bis(3-triethoxysilylpropyl)tetrasulfide (TESPT)) agents and a covering (triethoxy(octyl)silane) agent on the vulcanizate structure and properties of silica compounds was investigated and compared. In the comparative study of coupling and covering agents, the influence of sulfur donors on the formation of vulcanizate structures was investigated. In the case of the coupling agents, the effect of sulfur rank on the vulcanizate structure and properties of silica-rubber compounds was quantitatively analyzed through various characterization techniques.

Functionalized graphene‐reinforced rubber composite: Mechanical and tribological behavior study

ABSTRACTA functionalized graphene, fluorinated graphene nanosheets (FGS), and SiO2 nanoparticles as reinforcing fillers were employed to improve the mechanical properties of the solution styrene butadiene and butadiene rubber composites (SSBR‐BR). The results showed that the mechanical properties of SSBR‐BR composite filled with FGS were substantially improved than those of the unfilled and equivalent filler loaded graphene oxide (GO) and reduced graphene oxide (rGO) filled SSBR‐BR composites. It can be ascribed to the fact that the hydrophobic surface of FGS can be endowed the good dispersion in rubber matrix and stronger interfacial interaction between rubber and fillers. The tribological properties of these composites are also investigated. The results reveal that incorporation of GO, rGO, and FGS in SSBR‐BR composites can decrease antiwear properties because the existence of layered graphene promotes to tear and peel off. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017, 134, 44970.

Understanding the mechanical and tribological properties of solution styrene butadiene rubber composites based on partially graphene oxide

Poor dispersion of graphene in non-polar polymer matrices creates composites with limited applications. A method to improve the dispersion of graphene in solution styrene butadiene (SSBR) and butadiene rubber (BR) via grafting polystyrene (PS) or poly(styrene-co-isoprene) (PSI) on the surface of graphene oxide (GO) is examined. Composites of SSBR-BR with graphene as well as SSBR-BR with GO-PS (or GO-PSI) were prepared by open-mill mixing and vulcanization. Improved dispersion of GO in SSBR-BR composites substantially increases both the tensile strength and the wear resistance properties compared to neat SSBR-BR composites at low loads. More importantly, the wear test results and corresponding wear mechanisms of the all SSBR-BR composites were discussed at different loads.

Structure and Properties of Silicone Rubber/Styrene–Butadiene Rubber Blends with in Situ Interface Coupling by Thiol-ene Click Reaction

The low surface energy of silicone rubber (SiR) makes it difficult to blend SiR with conventional rubbers such as solution styrene−butadiene rubber (SSBR) and natural rubber. In this study, to enhance the interface interaction between SiR and SSBR, trimethylolpropane tris(3-mercaptopropionate) (TMPMP) was carefully chosen to couple SiR and SSBR by in situ thiol-ene click reactions between mercapto groups of TMPMP and vinyl groups of SiR and SSBR. The reaction of TMPMP with SiR and SSBR was characterized via torque–time curves, element analysis, and the dissolving–swelling test. Accordingly, a two-step strategy was proposed to prepare SiR/SSBR composites. Transmission electron microscopy indicated that the two-step strategy reduced the phase domain size of the blend. The composite exhibited higher mechanical properties and lower hysteresis. The results would extend SiR applications.

Influence of the silanes on the crosslink density and crosslink structure of silica-filled solution styrene butadiene rubber compounds

The effects of three silane coupling agents, triethoxy(octyl)silane (TEOS), bis[3-(triethoxysilyl)propyl]disulfide (TESPD), and bis[3-(triethoxysilyl)propyl]tetrasulfide (TESPT) on the filler-rubber interaction, crosslink density and crosslink structure of the silica-filled solution styrene butadiene rubber (SSBR) vulcanizates were studied. High dispersion silica, 7000GR, was used as the filler, and the loading range was varied from 0 to 60 phr. Crosslink density was measured by the swelling method. Experimental results showed that Kraus plot can be applicable to the silica-filled SSBR vulcanizates to separate filler-rubber interaction from the measured swelling data. Filler-rubber interaction increased by increasing sulfur rank in the silane as TEOS < Silica without silanes < TESPD < TESPT. Sulfurless silane, i.e. TEOS, only worked as a covering agent for hydrophobating silica surface. Silica without silane show high filler-rubber interaction than TEOS system because chain-end functionalized SSBR was used in this study. Unfilled system showed similar amounts of poly, di, and mono-sulfidic crosslinks. On the contrary to this, all of the silica-filled vulcanizates showed high mono-sulfide contents due to longer cure time.

Influence of fillers dispersion on friction and wear performance of solution styrene butadiene rubber composites

ABSTRACTDevelopment of structure–properties relationships between the fillers/rubber matrix interface chemistry and the dispersion and interfacial adhesion properties of the rubber composites is critical to predict their bulk mechanical and tribological properties. In this paper, three solution styrene butadiene rubber (SSBR) composites containing various fillers with tailored interfacial chemistry were prepared via conventional mixing technique. Subsequently, thermal and structural features of filled SSBR composites were monitored by TG, DSC, XRD, XPS, FESEM and TEM, respectively. Sliding contact experiments were conducted to study tribological properties of styrene butadiene rubber composites under dry and wet conditions. It was shown that the SSBR filled with silicon dioxide nanoparticles significantly reduced both the friction coefficient and the wear against marble block. On the contrary, it exhibited an increased friction coefficient and wear under wet friction conditions due to the specific superior wet‐skid resistance of silicon dioxide nanopartilce filled rubber composites, a good dispersion of silicon dioxide nanopartilce in the rubber matrix and strong interfacial adhesion between nanoparticles and rubber matrix. In addition, the influence of fillers dispersion and interfacial adhesion on friction and wear of styrene butadiene rubber composites was evaluated employing theoretical calculation, and the predicted results were in agreement with the experimental observations. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016, 133, 43589.

Progress in the synthesis of high performance butadiene-based elastomer for green tires

The advantages of green tires in energy saving, environmental protection and safety make it become the trend of the tire. Neodymium-based high cis -polybutadiene rubber (Nd-BR) and solution styrene-butadiene rubber (SSBR) are two important raw materials for manufacturing green tire. Situation of green tire, progress in the synthesis of Nd-BR and butadiene-based copolymer, current status of some industrialized Nd-BR and development of rare earth catalysts have been reviewed, which is helpful for the production of high-performance synthetic rubber for green tire. The main Nd-BR producers are Lanxess, Versalis, ChiMei, Kumho, Japan Synthetic Rubber, Nizhnekamskneftekhim, Goodyear, Firestone, Sibur, Synthos and Karbochem. The commercial Nd-BR products are normally divided into three grades according to the various Mooney viscosity (ML1+4100°C) of around 45, 55 and 63. Furthermore, the effect of microstructure, composition and topology on processing property, mechanical properties and dynamic mechanical properties of Nd-BR and butadiene-based copolymer were introduced. Stereo-specificity is a key factor for the performance of Nd-BR product. The results of the characteristic relaxation time ( τ ), yield stress ( T y), 300% modulus ( T 300), and T 300/ T y for various Nd-BR indicated that the increase of cis -1,4 content was benefit for the improvement of processing properties. The decrease of Δ G ʹ with an increase in cis -1,4 content indicated that Nd-BR with high cis -1,4 content of around 98.5% behaved low Payne effect, which was mainly attributed to the strong interaction between polymer and filler. Excellent processing performance means that the addition of fillers to rubber compounds are easy to scatter. These can short the mixing time and produce the highest quality product with the lowest possible cost. Nd-BR products with higher cis -1,4 content possess the superior mechanical properties and dynamic mechanical properties of BR vulcanizates, such as modulus at 300%, tensile strength, abrasion resistance, heat build-up, compression properties and rolling resistance and wet-skid resistance. Nd-BR which possesses cis -1,4 content of more than 98% has more excellent mechanical properties, dynamic mechanical properties, and is suitable for green tire as raw materials for the excellent properties such as low heat build-up, rolling power loss, compression deformation, compression ratio and abrasion loss. Long chain branched Nd-BR possesses an improved cold flow resistance, processing performance and mixing performance with the filler. High cis -1,4 butadiene/styrene elastomer and stereospecfic butadiene/styrene copolymer combine excellent performance of Nd-BR and SBR. Both mechanical performance and skid resistance ability on ice road were increased, while rolling resistance was decreased for the vulcanizates. These excellent properties of the synthetic rubbers are beneficial for manufacture of high-performance green tires.

Filler Wetting in Miscible ESBR/SSBR Blends and Its Effect on Mechanical Properties

The selective wetting behavior of silica in emulsion styrene butadiene rubber (ESBR)/solution styrene butadiene rubber (SSBR) blends is characterized by the wetting concept, which is further developed for filled blends based on miscible rubbers. It is found that not only the chemical rubber–filler affinity but also the topology of the filler surface significantly influences the selective filler wetting in rubber blends. The nanopore structure of the silica surface has been recognized as the main reason for the difference in the wetting behavior of the branched ESBR molecules and linear SSBR molecules. However, the effect of nanopore structure becomes more significant in the presence of silane. It is discussed that the adsorption of silane on silica surface constricts the nanopore to some extent that hinders effectively the space filling of the nanopores by the branched ESBR molecules but not by the linear SSBR molecules. As a result, in silanized ESBR/SSBR blends the dominant wetting of silica surface by the tightly bonded layer of SSBR molecules causes a low-energy dissipation in the rubber–filler interphase. That imparts the low rolling resistance to the blends similar to that of a silica-filled SSBR compound, while the ESBR-rich matrix warrants the good tensile behavior, i.e., good abrasion and wear resistance of the blends.

Effects of silanization temperature and silica type on properties of silica‐filled solution styrene butadiene rubber (SSBR) for passenger car tire tread compounds

ABSTRACTInfluence of silanization temperature on properties of silica‐filled solution polymerized styrene butadiene rubber was investigated. Two types of silica, i.e., highly dispersible silica (HDSi) and conventional silica (CSi), were compared. Results show that the increased silanization temperature leads to the enhanced rubber–filler interaction, filler dispersion, and cross‐link density giving rise to the improvement in vulcanizate properties such as modulus, heat build‐up (HBU), and dynamic set, as well as tire performance, e.g., wet grip (WG), rolling resistance (RR), and abrasion resistance. Great care, however, must be taken to avoid the scorching phenomenon during the mixing process at too high temperature. Taken as a whole, the balanced properties are found at the silanization temperature of 140°C. Surprisingly, HDSi provides insignificant differences in degree of filler dispersion, WG, and RR, compared to CSi, despite its claimed greater dispersability. Probably, the relatively long mixing time used in this experiment may override the influence of silica type. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016, 133, 43342.

Improvement of mechanical performance of solution styrene butadiene rubber by controlling the concentration and the size of in situ derived sol–gel silica particles

The silica particles generated from alkoxide route are grown onto the styrene butadiene polymer chains and offer a direct rubber to filler interaction. As a result, superior mechanical performance of the elastomeric composites can be realised.

DETERMINATION OF FILLER STRUCTURE IN SILICA-FILLED SBR COMPOUNDS BY MEANS OF SAXS AND AFM

ABSTRACT The structure of the silica particles network in two different solution styrene–butadiene rubbers (S-SBRs) was studied by means of small-angle X-ray scattering (SAXS) and atomic force microscopy (AFM). S-SBR compounds with different silica contents were analyzed in comparison with their oil extended counterparts. A study into the application of SAXS experiments was defined to quantify the structures of silica primary particles and clusters in filled rubber compounds up to very high levels of filler content. We propose a modified structure model that is physically more sound than the widely used Beaucage model and that leads to more robust quantification of the silica structures. In addition, an independent characterization of the filler structure was performed by means of AFM. The cluster and particle sizes deduced from both techniques are in close agreement, supporting the proposed approach. The synergetic application of SAXS and AFM allows a consistent and robust characterization of primary particles and clusters in terms of size and structure. These results were compared and discussed in the framework of previously published works.

Influence of Extender Oil on Properties of Solution Styrene-Butadiene Rubber Composites

Crosslink density of a rubber vulcanizate determines the chemical and physical properties, while bound rubber is an important factor to estimate reinforcement of a filled rubber compound. Extender oil is added to a raw rubber with very high molecular weight for improving processability of a rubber composite. Influence of extender oil on crosslink density, bound rubber formation, and physical properties of solution styrene-butadiene rubber (SSBR) composites with differing microstructures was investigated. Crosslink densities of non-oil-extended SSBR (NO-SSBR) vulcanizates were higher than those of oil-extended SSBR (OE-SSBR) ones. Bound rubber contents of NO-SSBR compounds were also greater than those of OE-SSBR ones. The experimental results could be explained by interfering of extender oil. The OE-SSBR vulcanizates had low modulus but long elongation at break, whereas the NO-SSBR ones had high modulus but short elongation at break. It was found that the crosslink densities affected the physical properties more than the bound rubber contents. The moduli increased with increase in the crosslink density irrespective of extender oil, while the elongation at break decreased. Each variation of the tensile strengths of NO-SSBR and OE-SSBR vulcanizates with the crosslink density showed a decreasing trend. Tear strength of the OE-SSBR vulcanizate increased with increase in the crosslink density, whereas variation of the tear strength of NO-SSBR vulcanizate with the crosslink density showed a weak decreasing trend.

Construction of an Interconnected Nanostructured Carbon Black Network: Development of Highly Stretchable and Robust Elastomeric Conductors

In the present work, a strong filler–filler network of conductive carbon black was strategically established in an elastomer matrix, which leads to a unique combination of electrical and mechanical properties. The novelty of our composites was the development of a strong percolated morphology of nanostructured conducting carbon black particles by the incorporation of relatively large nonreinforcing spherical silica particles, inside the soft elastomer matrix. This technique allowed us to fabricate solution styrene butadiene rubber (S-SBR) composites with outstanding electrical conductivity of 40 S/m, tensile strength ∼10 MPa, and extensibility up to 200%. Furthermore, the electrical conductivity was strain-independent up to 50% elongation strain. The electrical conductivity was found to be unaltered after 2000 loading–unloading cycles. This is the first ever report of a robust elastomeric system with such high electrical conductivity where all the basic ingredients used were selected from well-known comme...

Analytical method for determination of microstructures of solution styrene-butadiene copolymers using 2-phenylpropene/styrene ratio of pyrolysis products

Raw and cured solution styrene-butadiene rubbers (S-SBRs) with different microstructures were pyrolyzed and the pyrolysis products were analyzed using gas chromatography/mass spectrometry. 2-Phenylpropene (2-PP) was newly found to be formed from butadiene-styrene heterosequence. Formations of 2-PP and styrene were competitive and their relative intensities varied depending on the microstructure. Intensity ratios of 2-PP/styrene were plotted as a function of the 1,2-unit, 1,4-unit and styrene contents in order to employ the 2-PP/styrene plots as calibration curves to determine microstructure of unknown S-SBR samples. The 2-PP/styrene plot as a function of the 1,2-unit content had better correlation coefficients than those of the styrene and 1,4-unit contents. Correlation coefficients of the 2-PP/styrene plots were improved by correction with the 1,2-unit mole fraction. Microstructures (1,2-unit, 1,4-unit, and styrene contents) of unknown S-SBR samples could be determined using the 2-PP/styrene calibration curves.

Effect of styrene-butadiene rubber with different macrostructures and functional groups on the dispersion of silica in the compounds

In this study, the effects of high vinyl solution styrene-butadiene rubber (SSBR) containing different macrostructures and chain-end functional groups were investigated with respect to the dispersion of silica in the compounds. The microstructures and functional groups of three polymers were analyzed by using 1H nuclear magnetic resonance (NMR). According to the 1H NMR analysis, the star-shaped SSBR-E has a relatively higher numbers of ethoxy group in the polymer chain. All compounds showed good silica dispersion based on transmission electron microscopy (TEM) observation. According to analysis of the Payne effect, longer mixing times showed better dispersion of silica in the rubber compounds, and functional group differences in the SSBR also had an effect on the degree of silica dispersion that led to a decrease in storage modulus. In particular, the compound with star-shaped polymer containing ethoxy silyl groups showed the lowest storage modulus due to a higher number of functional groups compared to the other polymers. The abrasion resistance was closely related to the silica dispersion as well as the filler-rubber interaction. The abrasion loss decreased slightly when the mixing time was extended; however, this significantly decreased when the number of functional groups in the polymer chain was increased. Accordingly, the star-shaped polymer containing higher numbers of the functional group contributed to a better dispersion of silica in the compound. Mixing time was also considered as an important parameter to improve dispersion of silica and for reduction of silica flocculation in the rubber compounds.

Novel test method to estimate bound rubber formation of silica-filled solution styrene-butadiene rubber compounds

Bound rubber formation was investigated in detail by applying various extraction temperatures (at room temperature, 90°C, and 180°C) and novel treatment methods (ammonia bubbling and sonication). Bound rubbers could be divided into three major components of core shell, primary layer including tightly primary layer and occluded rubber, and secondary layer including connecting filament. Bound rubber content of the core shell was measured by four successive procedures of extraction at room temperature, ammonia bubbling, extraction at 180°C and sonication. Bound rubber content of the tightly primary layer was measured by three successive procedures of extraction at 90°C, ammonia bubbling and sonication. Bound rubber content of the primary layer was measured by two successive procedures of extraction at 90°C and sonication.

Influence of Mixing Procedure on Properties of Silica Filled Epoxidised Natural Rubber Compounds

Since the introduction of the so-called Green Tyre concept, in the early 90ies, the use of silica as reinforcing fillers has spread and grown worldwide. The general advantages of silica as reinforcing filler over carbon black filler are better rolling resistance by achieving at least equal wet traction while tread wear should not be adversely affected. One way to obtain both low rolling resistance and high wet traction is indeed, to use precipitated silica together with solution polymers in tyre treads. The benefits of reinforcement by silane coupled silicas, in certain blends of solution styrene –butadiene rubber (SBR) and butadiene rubber (BR), were recognized by major tyre manufacturer. However, the use of silica compounds entails considerable disadvantages in terms of raw material costs and processability (before vulcanization). These difficulties include higher compound Mooney Viscosity (ML1+4) that increases upon storage, short scorch time and environmental problems related to alcohol evolution. The high viscosity and poor processability in silica filled rubber compounds are believed to be associated with silica reaggregation (self aggregation) after rubber compounding. The study has been made of the effect of increased mixing stage and dispersion agent in rubber on uncured properties of the Silica Filled Epoxidised Natural Rubber Compounds. In this experiment, two orders of mixing were considered (1) Two Stages Mixing and (2) Three Stages Mixing. Results showed that filler dispersion, Mooney Viscosity and Payne Effect was influenced by the degree of mixing. The incorporation of dispersion agents in the compounds also resultant in the similar manner. It is believed that the dispersion agent could coat the silica surfaces as they are being broken down during the mixing and then stabilize the dispersed structure by stearically preventing silica reagglomeration.