Effects of different interphases on the mechanical properties of cured silanized silica‐filled styrene–butadiene/polybutadiene rubber blends for use in passenger car tire treads

Polybutadiene (BR) and styrene–butadiene (SBR) rubbers containing the same loading of precipitated silica nanofiller were prepared. The silica surfaces were pretreated with bis(3‐triethoxysilylpropyl) tetrasulfide to chemically bond the silica to the rubber. The rubber compounds were mixed together for different times and at different temperatures to produce SBR/BR blends. The mass fraction and composition values of the interphases in the blends were subsequently determined with modulated‐temperature differential scanning calorimetry. These properties changed substantially as a function of mixing temperature and mixing time. The hardness, tensile strength, elongation at break, stored energy density at break, tear strength, modulus, abrasion resistance, heat buildup, and loss tangent of the cured blends were measured over a wide range of test conditions. Elongation at break, stored energy density at break, tearing energy, and abrasion resistance benefited from increases in the mass fraction of the interphase. The remaining properties were influenced mainly by the filler loading and mixing time of the two rubber compounds. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

Using a silanized silica nanofiller to reduce excessive amount of rubber curatives in styrene‐butadiene rubber

In recent years, the rubber industry has come under pressure to improve health and safety at work, minimize damage to the environment, reduce costs, and increase competitiveness. Rubber compounds contain additives including curing chemicals, which are hazardous and harmful. Reducing their use or eliminating them altogether will be beneficial to rubber compounders and manufacturers of rubber articles. A styrene‐butadiene rubber (SBR) was cured and reinforced with a high loading of precipitated amorphous white silica nanofiller. The silica surfaces were pretreated with bis(3‐triethoxysilylpropyl) tetrasulfide (TESPT), which is a sulfur‐bearing bifunctional organosilane to chemically adhere silica to the rubber. The chemical bonding between the filler and rubber was optimized via the tetrasulfane groups of TESPT by adding accelerator and activator. The rubbers were subsequently cured and their hardness, tensile strength, elongation at break, stored energy density at break, tearing energy, tensile modulus, Young's modulus, and bound rubber content were measured. This study showed that using the filler in combination with a sulfur‐donor accelerator was the most efficient method for curing and reinforcing the rubber. This led to a significant reduction in the use of the curing chemicals, a faster curing cycle, and very good mechanical properties for the rubber vulcanizate. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

Comparing effects of silanized silica nanofiller on the crosslinking and mechanical properties of natural rubber and synthetic polyisoprene

The effect of the same amount of precipitated silica nanofiller on the curing and mechanical properties of natural rubber and synthetic polyisoprene was investigated. The silica surfaces were pretreated with bis(3-triethoxysilylpropyl) tetrasulfide (TESPT) to chemically bond silica to rubber. The rubbers were primarily cured by using sulfur in TESPT, and the cure was optimized by the addition of accelerator and activator, which helped to form sulfur chemical bonds between the rubber and filler. Different amounts of accelerator and activator were needed to fully crosslink the filled rubbers. The hardness, tensile strength, elongation at break, stored energy density at break, tearing energy, and modulus of the vulcanizates improved substantially by the incorporation of the filler in the rubber. This was due to high level of rubber-filler adhesion and formation of chemical bonds between the rubber and TESPT. Interestingly, natural rubber benefited more from the filler than did synthetic polyisoprene. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

Novel technique for crosslinking and reinforcing high‐cis polybutadiene rubber using a silanized silica nanofiller

A large amount of a precipitated amorphous white silica nanofiller was mixed with a high‐cis polybutadiene rubber. The silica surfaces were pretreated with bis(3‐triethoxysilylpropyl)tetrasulfide (TESPT). TESPT is a sulfur‐containing bifunctional organosilane that chemically adheres silica to rubber. The rubber was cured primarily with sulfur in TESPT, and the cure was optimized by the addition of a sulfenamide accelerator, which helped to form sulfur chemical bonds between the rubber and the filler. The hardness, tensile properties, tear strength, abrasion resistance, modulus, and cyclic fatigue life of the cured rubber improved substantially when the filler was added. Interestingly, this new technique produced a rubber with good mechanical properties, and only one accelerator was needed to optimize the chemical bonding between the rubber and the filler and fully cure the rubber. As a result, a substantial reduction in the use of the curing chemicals was achieved. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2007     

Comparing the dynamic behaviour of several rubbers filled with silanized silica nanofiller

BACKGROUND: The effect of the same amount of precipitated silica nanofiller on the curing and dynamic properties of different rubbers, including natural rubber (NR) without and with the addition of elemental sulfur (NR with S), synthetic polyisoprene (IR), polybutadiene (BR) and poly(styrene‐co‐butadiene) copolymer (SBR), was investigated. The silica surfaces were pre‐treated with bis(3‐triethoxysilylpropyl)tetrasulfane (TESPT) to chemically bond the silica to the rubber. The rubbers were primarily cured by using sulfur in TESPT with the addition of optimum accelerator (TBBS) and activator (ZnO), which helped to form sulfur chemical bonds between the rubber and filler. RESULTS: Cure properties, Mooney viscosity, glass transition temperature, bound rubber and crosslink density along with dynamic properties of the filled rubbers, including tan δ, loss modulus (G″) and storage modulus (G′), were measured as a function of double oscillation amplitude (DSA) from 15 to 1000 µm, temperature from ?130 to 100 °C and frequency from 1 to 100 Hz. The results with emphasis on potential for tyre tread applications are discussed. It emerged that SBR along with BR filled rubbers had the highest rolling resistance while IR filled rubber had the least. Moreover, it was found that SBR filled rubber had the best skid resistance and BR filled rubber the worst. CONCLUSION: Interestingly, the variation of G′ with DSA showed a complicated behaviour for different filled rubbers. It emerged that in some DSA ranges the Payne effect was observed, and in the remaining ranges increments of G′ with DSA were seen. Because the bound rubber of most of the filled rubbers was more than 92%, there should be another predominant mechanism in the systems studied rather than simply de‐agglomeration or filler network breakdown, which is proposed by the Payne model. In addition, the nanoscale of the filler may be effective for this behaviour. Copyright © 2008 Society of Chemical Industry     

Mechanical and aging properties of cross‐linked ethylene propylene diene rubber / styrene butadiene rubber blends

The mechanical properties and aging characteristics of blends of ethylene propylene diene monomer (EPDM) rubber and styrene butadiene rubber (SBR) were investigated with special reference to the effect of blend ratio and cross‐linking systems. Among the blends, the one with 80/20 EPDM/SBR has been found to exhibit the highest tensile, tear, and abrasion properties at ambient temperature. The observed changes in the mechanical properties of the blends have been correlated with the phase morphology, as attested by scanning electron micrographs (SEMs). The effects of three different cure systems, namely, sulfur (S), dicumyl peroxide (DCP), and a mixed system consisting of sulfur and peroxide (mixed) on the blend properties also were studied. The stress‐strain behavior, tensile strength, elongation at break, and tear strength of the blends were found to be better for the mixed system. The influence of fillers such as high‐abrasion furnace (HAF) black, general‐purpose furnace (GPF) black, silica, and clay on the mechanical properties of 90/10 EPDM/SBR blend was examined. The ozone and water aging studies also were conducted on the sulfur cured blends, to supplement the results from the mechanical properties investigation. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 93: 2606–2621, 2004     

Cure Characteristics and Mechanical Properties of Vinyltriethoxysilane Grafted Styrene-Butadiene Rubber/Silica Blends

Graft polymerization of vinyltriethoxysilane (VTES) onto styrene-butadiene rubber (SBR) was carried out in latex using potassium peroxydisulfate as an initiator. Then SBR-g-VTES/silica, SBR/TESPT/silica and SBR-g-VTES/TESPT/silica were prepared by mechanical mixing with different silica loading. The silica particles dispersed uniformly in the SBR-g-VTES networks. Among the three composites, the SBR-g-VTES/Silica blends show the highest of all. The t₉₀ of SBR-g-VTES/TESPT/Silica composites is the shortest of all. On the other hand, the SBR-g-VTES/TESPT/silica composites exhibit highest tensile strength and hardness of all. The SBR-g-VTES/silica composites show higher tensile strength and hardness than SBR/TESPT/silica. The tanδ value (loss tangent) at ?20-0°C of SBR-g-VTES/silica is slightly higher than that of SBR/TESPT/silica.     

A study on mechanical and thermal properties of silicone rubber/EPDM damping materials

Silicone rubber (SR) and ethylene‐propylene‐diene monomer (EPDM) blends were prepared for damping application. The mechanical and thermal properties of the blends are studied. With the increasing content of EPDM, the tensile strength is decreased but elongation at break is increased. By blending with EPDM, tan δ (at 35 to 200°C) of SR is enhanced. However, thermogravimetric analysis results showed the decrease in thermal stability. Scanning electron microscopy study showed the good filler dispersion of the blends with some large silica particles. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

Mechanical aging behavior of styrene‐butadiene rubbers evaluated by abrasion test

The ring‐shaped styrene‐butadiene rubbers (SBRs) test pieces ran on a rotating stainless‐steel ring using an abrasion tester to evaluate the changes in the mechanical properties, such as the tensile storage modulus and tan δ values, the modulus at 300% elongation, and the strength and extension ratio at the breaking point, after a mechanical aging process. The surface of the SBR test pieces and the formed rubber debris after the running experiment was investigated using scanning electron microscopy. A change in the crosslinking density of the SBRs and the analysis of the isolated free polymers showed the occurrence of bond scission of the copolymer chains. On the other hand, the mechanical properties of whole SBR samples showed only a small change during the mechanical aging test. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

Developing ethylene‐propylene‐diene rubber compounds for industrial applications using a sulfur‐bearing silanized silica nanofiller

The loading of a sulfur‐bearing silanized silica nanofiller in ethylene‐propylene‐diene rubber with 4.5 wt% of ethylidene norbornene diene content was increased progressively to 60 parts per hundred rubber by weight. The rubber compounds were cured via the tetrasulfane groups of the silane by adding sulfenamide accelerator and zinc oxide. The hardness, tensile strength, elongation at break, stored energy density at break, tear strength, Young's modulus, M50–M300, compression set, cyclic fatigue life, and bound rubber content of the rubber vulcanizates were measured. With the exception of the elongation at break and compression set which deteriorated, the remaining properties improved and the rate of cure, optimum cure time, and cross‐link density benefited also when the loading of silica was increased in the rubber. The bound rubber content was unchanged, and the cyclic fatigue life of the rubber vulcanizate enhanced considerably when silica was added. Optimizing the chemical bonding between the rubber and filler via the tetrasulfane groups of bis(3‐triethoxysilylpropyl)‐tetrasulfide reduced the chemical curatives in the rubber. This was a major improvement in health, safety, and environment. POLYM. COMPOS., 34:2019–2025, 2013. © 2013 Society of Plastics Engineers     

炭黑/白炭黑共混比对BR/SBR性能的影响

研究了炭黑N234/白炭黑175Gr共混比对BR/SBR共混胶加工性能、物理机械性能和动态物理机械性能的影响。研究表明,当填料总用量不变时,炭黑/白炭黑共混能有效减弱填料网络的形成。当质量比为40/40时,共混胶佩恩效应最低,门尼粘度最小,物理机械性能最好;加入硅烷偶联剂可使白炭黑与橡胶产生化学结合,提高了化学交联密度,使硫化胶回弹性提高,动态损耗因子降低,有利于降低轮胎滚动阻力。     

The influence of in situ modification of silica on filler network and dynamic mechanical properties of silica‐filled solution styrene–butadiene rubber

The influence of in situ modification of silica with bis‐(3‐(triethoxysilyl)‐propyl)‐tetrasulfide (TESPT) on filler network in silica filled solution SBR compound was investigated. In situ modification greatly increased the bound rubber content. TEM observation of silica gel showed that bridging and interlocking of absorbed chains on the surface of silica particles formed the filler network. Rubber processing analyzer (RPA) was used to characterize the filler network and interaction between silica and rubber by strain and temperature sweeps. In situ modification improved the dispersion of silica, and in the meantime, the chemical bonds were formed between silica and rubber, which conferred the stability of silica dispersion during the processing. Compared to the compound without in situ modification, the compound with in situ modification of silica exhibited higher tan δ at low strains and lower tan δ at high strains, which can be explained in terms of filler network in the compounds. After in situ modification, DMTA results showed silica‐filled SSBR vulcanizate exhibited higher tan δ in the temperature range of ?30 to 10°C, and RPA results showed that it had lower tan δ at 60°C when the strain was more than 3%. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

环保型溶聚丁苯橡胶/顺丁橡胶并用胶与白炭黑的相互作用研究

探讨了国产环保型溶聚丁苯橡胶SSBR2564S和端基硅偶联SSBR72612S在半钢子午胎胎面胶中的应用,研究了两种SSBR与BR并用对白炭黑分散性的影响,并进一步考查了各并用体系混炼胶和硫化胶的基本性能。结果表明：BR与白炭黑的相互作用较SSBR要弱,SSBR更利于白炭黑的分散,端基硅偶联SSBR与白炭黑的相互作用更强;BR能有效缩短并用胶的硫化时间,改善SSBR72612S的加工性能;随BR并用量的增加,硫化胶的耐磨性得到明显改善,断裂伸长率、撕裂强度和回弹均有所提升,而300%定伸应力降低。BR能降低SSBR2564S体系的滚动阻力,但使两种SSBR体系的抗湿滑性损失较大。     

Cure retardation of peroxide‐cured silica filled natural rubber influenced by organosilane

The influence of silane coupling agent on properties of silica‐filled compounds under peroxide curing was investigated. bis (triethoxysilylpropyl) tetrasulfide (TESPT) was selected in this study and its content was varied from 0 to 12% w/w of silica. It is found that with increasing TESPT content, bound rubber content, tensile strength, elongation at break and tear strength are enhanced. By contrast, magnitude of Payne's effect, modulus at 100% elongation (M₁₀₀) and heat build‐up are decreased. The changes of such properties are attributed to the reduction of crosslink density in conjunction with the improvements of both rubber–filler interaction and degree of filler dispersion with increasing TESPT content in the peroxide curing system. POLYM. ENG. SCI., 59:42–48, 2019. © 2018 Society of Plastics Engineers     

反式聚辛烯橡胶改性天然橡胶/顺丁橡胶共混胶的性能

研究了反式聚辛烯橡胶(TOR)改性天然橡胶(NR)/顺丁橡胶(BR)(二者质量比80/20)共混胶的性能.结果表明,采用5～15份(质量,下同)TOR改性NR/BR混炼胶的门尼黏度逐渐降低、Payne效应基本不变,共混胶的焦烧时间和工艺正硫化时间延长、硫化速率减慢.相比NR/BR硫化胶,NR/BR/TOR硫化胶的拉伸强...     

DMA analysis of the damping of ethylene–vinyl acetate/acrylonitrile butadiene rubber blends

The mechanical and damping properties of blends of ethylene–vinyl acetate rubber (VA content > 40% wt) (EVM)/acrylonitrile butadiene rubber (NBR), with 1.4 phr BIPB [bis (tert‐butyl peroxy isopropyl) benzene] as curing agent, were investigated by DMA and DSC. The effect of chlorinated polyvinyl chloride (CPVC), silica, carbon black, and phenolic resin (PF) as a substitute curing agent, on the damping and mechanical properties of EVM/NBR blends were studied. The results showed that 10 phr CPVC did not contribute to the damping of EVM700/NBR blends; Silica could dramatically improve the damping of EVM700/NBR blends because of the formation of bound rubber between EVM700/NBR and silica, which appeared as a shoulder tan δ peak between 20 and 70°C proved by DMA and DSC. This shoulder tan δ peak increased as the increase of the content of EVM in EVM/NBR blends. The tensile strength, modulus at 100% and tear strength of the blend with SiO₂ increased while the elongation at break and hardness decreased comparing with the blend with CB. PF, partly replacing BIPB as the curing agent, could significantly improve the damping of EVM700/NBR to have an effective damping temperature range of over 100°C and reasonable mechanical properties. Among EVM600, EVM700, and EVM800/NBR/silica blend system, EVM800/NBR/silica blend had the best damping properties. The EVM700/NBR = 80/10 blend had a better damping property than EVM700/NBR = 70/20. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012     

鞘氨醇单胞菌脱硫丁苯橡胶胶粉填充丁苯橡胶性能的研究

利用鞘氨醇单胞菌对丁苯橡胶(SBR)胶粉进行脱硫,对比研究SBR胶粉和脱硫SBR胶粉填充SBR胶料的性能。结果表明:鞘氨醇单胞菌不仅可使硫交联键断裂,也可使橡胶主链上的部分碳-碳双键断裂。与SBR胶粉填充的SBR胶料相比,脱硫SBR胶粉填充SBR胶料的转矩和表观交联密度减小,拉伸强度和拉断伸长率增大,邵尔A型硬度和撕裂强度保持不变,阿克隆磨耗量减小,脱硫SBR胶粉与SBR基体结合较紧密,动态滞后损失较小。     

Mechanical and dynamic mechanical properties of natural rubber blended with waste rubber powder modified by both microwave and sol–gel method

Waste rubber powder (WRP) was modified by microwave, sol–gel method, and both microwave and sol–gel method, respectively. The mechanical and dynamic mechanical properties of natural rubber (NR)/modified WRP composite were investigated. The influence of bis‐(3‐(triethoxysilyl)‐propyl)‐tetrasulfide (TESPT) content on curing characteristics and mechanical properties of vulcanizate was also studied. The results showed that NR/WRP modified by both microwave and sol–gel method composite owned the best mechanical properties. Rubber processing analyzer was used to characterize the interaction between silica and rubber chains and the dispersion of silica. With increase of TESPT content, the Payne effect decreased. Scanning electron microscopy indicated the coherency and homogeneity of in situ generated silica filled vulcanizate. Dynamic mechanical analyzer showed that NR/WRP modified by both microwave and sol–gel method composite with 5 phr TESPT exhibited the lower tan δ at temperature range of 50–80°C, compared with composite without TESPT and the higher tan δ at temperature of 0°C, compared with the conventional modification of WRP. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013     

Effect of triblock copolymers on homogeneity,mechanical properties and swelling behavior of IIR/SBR rubber blends

The present research concerns with the preparation and characterization of isobutylene isoprene/butadiene–styrene rubber (IIR/SBR) blends with different blend ratios, in the presence and absence of styrene–isoprene–styrene (SIS) and styrene–isobutylene–styrene (SiBS) triblock copolymers to be tested as compatibilizers. Effect of the triblock copolymers on the blend homogeneity was investigated with the aid of scanning electron microscopy (SEM) and differential scanning calorimetry (DSC) measurements. Characterization of the rubber blends was conducted by measuring the physico-mechanical properties after and before thermal aging, in presence and absence of the triblock copolymers. In addition, weight swell % in toluene, motor oil and brake fluid of the rubber blend vulcanizates was assessed. The incorporation of SIS and SiBS triblock copolymers improved the homogeneity of IIR/SBR blends as well as increased both tensile strength and elongation at break of the rubber blend vulcanizates. Of the entire blend ratios examined, IIR/SBR (25/75) blend containing SIS compatibilizer possessed the best physico-mechanical properties (12.6 MPa tensile strength and 425 % elongation at break) and (14 MPa tensile strength and 555 % elongation at break) after and before thermal aging, respectively. Utilization of SIS and SiBS triblock copolymers enhanced the thermal stability of IIR/SBR blend vulcanizates. Moreover, IIR/SBR blends of different blend ratios showed superior swelling resistance in the brake fluid. IIR/SBR (25/75) blend containing SIS compatibilizer and cured with CBS/ZDEC/S vulcanizing system possessed the best physico-mechanical properties (14.4 MPa tensile strength and 440 % elongation at break) and (16.5 MPa tensile strength and 610 % elongation at break) after and before thermal aging, respectively.     

Influence of phenolic curative on crosslink density and other related properties of dynamically cured NR/HDPE blends

Dynamically cured 60/40 NR/HDPE blends with various amounts of phenolic curative were prepared in an internal mixer at 160°C. A simple blend (i.e., the blend without curative) was also prepared using the same materials and blend proportion for comparison purposes. Mechanical, dynamic, and morphological properties; swelling resistance and crosslink density of the blends were investigated. It was found that the thermoplastic vulcanizates (TPVs) gave superior mechanical and dynamic properties than the simple blend. Furthermore, the mechanical properties in terms of elongation at break, modulus and tensile strength and elastic response in dynamic test in terms of storage modulus increased with increased loading amount of the curative. The complex viscosity also increased but the tan δ and tension set decreased with increased loading level of the curative. The crosslink density of the TPVs was estimated based on the elastic shear modulus. It was found that the crosslink density of the blends increased with increased loading levels of the curative while the degree of swelling decreased. This correlated well with the trend of mechanical and dynamic properties. SEM micrographs were used to confirm the level of mechanical and dynamic properties. It was found that the simple blend at a given blend ratio exhibited co‐continuous phase morphology. However, the TPVs showed micron scale of vulcanized rubber domains dispersed in a continuous HDPE matrix. The size of vulcanized rubber domains decreased with increasing amounts of the curative. This led to greater interfacial adhesion between the phase and hence superior mechanical and dynamic properties. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009