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硫化胶的拉伸强度、扯断伸长率和撕裂强度明显减小,回弹性能提高,100%定伸应力、硬度和滚动阻力略有增大,压缩生热有所升高,耐磨和耐疲劳裂纹引发性能得到改善。用TOR改性NR/BR共混胶时的最佳用量为5份。     

国产丁戊橡胶与顺丁橡胶的加工应用性能对比研究

通过与BR的对比,研究了国产丁戊橡胶(BIR)的加工性能、硫化特性、物理性能,并探讨了BIR与BR在胎面胶中的加工应用性能差异。结果表明,BIR硫化速度快,门尼粘度低,加工性能好;BIR硫化胶撕裂强度高,压缩温升低,耐疲劳性好。NR/SBR/BIR并用体系胎面胶硫化速度快,加工性能好;硫化胶的撕裂强度、耐疲劳、抗湿滑等性能均优于NR/SBR/BR并用体系。     

环氧树脂增强天然橡胶/顺丁橡胶并用胶的性能

采用低相对分子质量的液体环氧树脂(EP)与固化剂混合作为增强体的前驱体,比较了其填充天然橡胶(NR)、顺丁橡胶(BR)及两者并用胶的物理机械性能,考察了EP用量对并用胶及炭黑增强并用胶物理机械性能的影响,并通过扫描电子显微镜表征了填充后的NR、BR及并用胶的微观相态结构。结果表明,EP的加入均可提高NR、BR、NR/BR并用胶的物理机械性能,其中并用胶的拉伸强度提高幅度最大;当EP用量约为24份时,NR/BR并用胶的综合性能最佳;EP可以提高炭黑增强NR/BR并用胶的物理机械性能,但提高幅度不大;EP在NR/BR并用胶中呈现规整的圆球形状,直径为1.0～2.5μm。     

甲基丙烯酸固态原位接枝改性炭黑对天然橡胶和顺丁橡胶性能的影响

考察了固态原位接枝改性制备的甲基丙烯酸接枝改性炭黑对天然橡胶(NR)和顺丁橡胶。(BR)静态力学性能、动态力学性能的影响。结果表明。甲基丙烯酸改性炭黑比普通商品炭黑填充的NR硫化胶具有更好的静态力学性能;甲基丙烯酸改性炭黑曼有利于降低NR和BR硫化胶的滚动阻力。同时,有利于提高NR硫化胶的抗湿滑性。     

改性Kevlar纳米纤维对羧基丁腈橡胶/丁苯橡胶共混胶力学性能的影响

采用环氧氯丙烷对Kevlar纳米纤维（KNFs）表面进行改性,制备了表面改性KNFs（m-KNFs）,考察了m-KNFs对羧基丁腈橡胶（XNBR）/丁苯橡胶（SBR）共混胶力学性能的影响。结果表明,m-KNFs可以增强XNBR/SBR共混胶的拉伸性能及撕裂性能,提高硫化胶的热稳定性和耐溶剂性能。添加5份m-KNFs后,共混胶的拉伸强度和撕裂强度分别提高102%和207%。     

Influences of trans‐polyoctylene rubber on the physical properties and phase morphology of natural rubber/acrylonitrile–butadiene rubber blends

The influence of trans‐polyoctylene rubber (TOR) on the mechanical properties, glass‐transition behavior, and phase morphology of natural rubber (NR)/acrylonitrile–butadiene rubber (NBR) blends was investigated. With an increased TOR level, hardness, tensile modulus, and resilience increased, whereas tensile strength and elongation at break tremendously decreased. According to differential scanning calorimetry and dynamic mechanical analysis, there were two distinct glass‐transition temperatures for a 50/50 NR/NBR blend, indicating the strongly incompatible nature of the blend. When the TOR level was increased, the glass transition of NBR was strongly suppressed. NBR droplets of a few micrometers were uniformly dispersed in the continuous NR phases in the NR/NBR blends. When TOR was added to a 50/50 NR/NBR blend, TOR tended to be located in the NR phase and in some cases was positioned at the interfaces between the NBR and NR phases. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 86: 125–134, 2002     

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

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

Ethylene vinyl acetate as compatibilizer on cure characteristics and mechanical properties of (natural rubber)/(Recycled acrylonitrile‐butadiene rubber) blends

Ethylene vinyl acetate (EVA) has been used as a compatibilizer for (natural rubber)/(recycled acrylonitrile‐butadiene rubber) (NR/NBRr) blends, vulcanized by sulfur. EVA offers excellent heat, ozone, and weather resistance, whereas the vinyl acetate groups provide oil resistance to the blend. It exhibits good tear resistance and may be crosslinked. However, EVA exhibits poor low‐temperature flexibility. NBR gloves have excellent resistance to punctures, tears, and many types of chemicals, while NR has good physical and mechanical properties. NR/NBRr blends were prepared with various compositions with the EVA content fixed. Tensile properties, hardness, and swelling behavior tests were performed to determine the compatibility of NR/NBRr blends in the presence of EVA. Results indicated that incorporation of EVA into NR/NBRr blends improved tensile strength, modulus, and elongation at break compared with NR/NBRr blends without EVA. The improvement in hardness and reduction in resilience on compatibilization are due to an increase in crosslink density, which gives NR/NBRr blends better swelling resistance. Scanning electron microscopy of the fracture surfaces indicates that, with the addition of EVA in NR/NBRr blends, better adhesion between NR and NBRr was obtained, thus improving the compatibility of NR/NBRr blends. J. VINYL ADDIT. TECHNOL., 23:135–141, 2017. © 2015 Society of Plastics Engineers     

用于全钢子午线轮胎胎侧胶的反式-1,4-聚异戊二烯/天然橡胶/顺丁橡胶并用胶的性能

研究了不同反式-1,4-聚异戊二烯(TPI)用量对用于全钢子午线轮胎胎侧胶的TPI/天然橡胶(NR)/顺丁橡胶(BR)并用胶力学性能、动态力学性能和热老化性能的影响,并对并用胶进行了配方优化。结果表明,当TPI/NR/BR的并用比(质量比)为15.0/42.5/42.5时,混炼胶外表光滑,硬度适中;TPI/NR/BR并用胶的硫化特性与NR/BR并用胶相比变化不大,且在保持后者力学性能的基础上,动态力学性能明显提高;经配方优化后,并用胶耐屈挠性优异,滚动阻力、压缩生热降低,是一种较为理想的全钢子午线轮胎胎侧胶材料。     

Quantitative characterization of interfaces in rubber–rubber blends by means of modulated‐temperature DSC

Rubber–rubber blends are used widely in industry, for example, in tire manufacture. It is often difficult to characterize interfaces in such rubber–rubber blends quantitatively because of the similarity in the chemical structure of the component rubbers. Here, a new method was suggested for the measurement of the weight fraction of the interface in rubber–rubber blends using modulated‐temperature differential scanning calorimetry (M‐TDSC). Quantitative analysis using the differential of the heat capacity, dCp/dT, versus the temperature signal from M‐TDSC allows the weight fraction of the interface to be calculated. As examples, polybutadiene rubber (BR)–natural rubber (NR), BR–styrene‐co‐butadiene rubber (SBR), SBR–NR, and nitrile rubber (NBR)–NR blend systems were analyzed. The interfacial content in these blends was obtained. SBR is partially miscible with BR. The cis‐structure content in BR has an obvious effect on the extent of mixing in the SBR–BR blends. With increasing styrene content in the SBR in the SBR–BR blends, the interface content decreases. NR is partially miscible with both BR and SBR. The NBR used in this research is essentially immiscible with NR. The maximum amount of interface was found to be at the 50:50 blend composition in BR–NR, SBR–BR, and SBR–NR systems. Quantitative analysis of interfaces in these blend systems is reported for the first time. © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 76: 1791–1798, 2000     

Studies on coconut shell powder and crysnanoclay incorporated acrylonitrile‐butadiene rubber/ styrene butadiene rubber (NBR/SBR) green nanocomposites

The development of commercially viable “green products” based on natural resources for both matrices and reinforcements for a wide range of applications is on the rise. This effort includes new pathways to produce natural polymers with better mechanical properties and thermal stability using nanotechnology and use of naturally occurring fillers such as lignocellulosic and hemicellulose to make biodegradable rubber composites. The blends of acrylonitrile butadiene rubber (NBR) and styrene butadiene rubber (SBR) with coconut shell powder (CSP) have been prepared by using a compounding technique in presence of different amounts of crysnanoclay (CN). The effect of CN loading on tensile properties, thermal properties, swelling behavior, and water uptake behavior were studied. Significant improvement of Young's modulus and tensile strength was observed as a result of addition of nanoclay to the rubber matrix especially at 10 wt% loading. Presence of CSP resulted in ahigher in water sorption but after incorporation of CN the water sorption tended to decrease. Thermal characteristics were performed using thermogravimetric analysis (TGA). TGA thermograms indicated that incorporation of CSP filler decreases the thermal stability of nanocomposites. The dispersion of CSP and CN in rubber matrix was analyzed from scanning electron microscopy. POLYM. COMPOS., 38:727–735, 2017. © 2015 Society of Plastics Engineers     

Kaolin modified with sodium salt of rubber seed oil as a reinforcing filler for blends of natural rubber,polybutadiene rubber and acrylonitrile–butadiene rubber

Blends of natural rubber (NR) and synthetic rubbers are widely used in the rubber industry to meet specific performance requirements. Further, the emerging field of organomodified clay/rubber nanocomposites could provide a host of novel materials having a unique combination of properties to meet various stringent service conditions. Previous studies have shown that at very low dosages, china clay (kaolin) modified with sodium salt of rubber seed oil (SRSO) improved the cure characteristics and physico‐mechanical properties of NR. Results of the present study show improved cure characteristics and physico‐mechanical properties for blends of NR with butadiene rubber and nitrile rubber containing 4 phr of SRSO‐modified kaolin as indicated by reduction in optimum cure time along with higher tensile strength, tensile modulus and elongation at break for their vulcanizates as compared to those containing unmodified kaolin. The SRSO‐modified kaolin/rubber nanocomposites showed improved flex resistance, reduced heat build‐up, tan delta and loss modulus and higher chemical crosslink density index, indicating a reinforcing effect of the SRSO‐modified kaolin, enabling the nanocomposites to have potential industrial applications. © 2015 Society of Chemical Industry     

纳米氧化锌在NR/BR并用胶及SBR胶料中的应用

研究纳米氧化锌替代普通氧化锌在天然橡胶(NR)/顺丁橡胶(BR)并用胶以及丁苯橡胶(SBR)胶料中的应用。结果表明,纳米氧化锌减量10%代替普通氧化锌,NR/BR并用胶及SBR胶料的加工性能和物理性能基本不变,质量减小,成本降低。     

Influence of rubber composition on change of crosslink density of rubber vulcanizates with EV cure system by thermal aging

Variation of the crosslink density of a rubber vulcanizate depending on the rubber composition after the thermal aging was studied with single rubber, biblend, and triblend vulcanizates of natural rubber (NR), butadiene rubber (BR), and styrene‐butadiene rubber (SBR). The efficient vulcanization (EV) system was employed to minimize the influence of free sulfur in the vulcanizate on the change of the crosslink density. Thermal aging was performed at 40, 60, and 80°C for 20 days with 5‐day intervals. The crosslink densities of the vulcanizates after the thermal aging increase. For the single rubber vulcanizates, variation of the crosslink density by the thermal aging has the order: SBR > BR > NR. For the biblend vulcanizates, variations of the crosslink densities of the NR/SBR and SBR/BR blends are larger than that of NR/BR blend. Variation of the crosslink density of the vulcanizate increases by increasing the SBR content in the vulcanizate. Variation of the crosslink density of the rubber vulcanizate depending on the rubber composition was explained by miscibility of the blends, combination reaction of the pendent groups, and mobility of the pendent group. © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 75: 1378–1384, 2000     

Continuous ultrasonic devulcanization of unfilled butadiene rubber

The devulcanization of sulfur‐cured unfilled butadiene rubber (BR) with a grooved‐barrel ultrasonic reactor under various processing conditions was carried out. The experiments indicated that BR had a narrow devulcanization window. Outside this window, significant degradation or no devulcanization occurred. Gel permeation chromatography (GPC) measurements were carried out with the sol part of virgin and devulcanized samples to study the breakdown of the polymeric chains. The GPC data showed a significant molecular weight reduction and a broadening of the molecular weight distribution upon devulcanization, indicating that the devulcanization and degradation of BR occurred simultaneously. The rheological properties showed that devulcanized BR was more elastic than the virgin gum. The vulcanizates of the blends of virgin and devulcanized BR showed a considerable enhancement of the mechanical properties. The thermal behaviors of the virgin and devulcanized BR were found to be different. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 93: 1166–1174, 2004     

Nanomodified fillers in chloroprene‐rubber‐compatibilized natural rubber/acrylonitrile–butadiene rubber blends

Because of the structural dissimilarity, natural rubber (NR) and acrylonitrile–butadiene rubber (NBR) are immiscible, and compatibilizers are used during their blending. Neoprene or chloroprene rubber (CR) has a polar chlorine part and a nonpolar hydrocarbon part. Also, it has many advantageous properties, such as oil resistance, toughness, a dynamic flex life, and adhesion capacity. Hence, it is not less scientific to use CR as a compatibilizer in the blending of NBR with NR. Because many fewer studies on the use of neoprene as a compatibilizer in NR–NBR blend preparation are available, efforts were made to prepare 20:80 NR–NBR blends with CR with the aim of studying the effect of poly(ethylene oxide) (PEO)‐coated nano calcium silicate along with nano N‐benzylimine aminothioformamide and stearic acid coated nano zinc oxide in the sulfur vulcanization of the blends. The optimum dosage of the compatibilizer was derived by the determination of the tensile properties, tear resistance, abrasion resistance, compressions set, and swelling values. The tensile strength, tear resistance, and abrasion resistance of the gum vulcanizates of the blend were improved by the compatibilizing action of CR up to 5 parts per hundred parts of rubber (phr). In the case of the filled vulcanizates, the tear resistance, 300% modulus, hardness, and abrasion resistance increased with increasing dosage of nano calcium silicate. The elongation at break percentage decreased as expected when there was an increase in the modulus. Scanning electron microscopy was used to study the phase morphology of the blends. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012     

Effect of epoxidized natural rubber on thermal properties,fatigue life,and natural weathering test of styrene butadiene rubber/recycled acrylonitrile‐butadiene rubber (SBR/NBRr) blends

The utilization of waste rubber powder in polymer matrices provides an attractive strategy for polymer waste disposal. Addition of recycled acrylonitrile‐butadiene rubber (NBRr) in rubber compounds gives economic (lowering the cost of rubber compounds) as well as processing advantages. In this study, the properties of styrene butadiene rubber (SBR)/NBRr blends with and without epoxidized natural rubber (ENR‐50) as a compatibilizer were determined. The results such as thermal gravimetric analysis (TGA), fatigue life, and natural weathering test of SBR/NBRr blends with and without ENR‐50 were carried out. Results showed that TG thermograms of SBR/NBRr blends with ENR‐50 show lower thermal stability compared blends without ENR‐50. The incorporation of ENR‐50 into SBR/NBRr blends has reduced char residue compared SBR/NBRr blends without ENR‐50. The incorporation of ENR‐50 in SBR/NBRr blends has increased the rigidity of the blends thus lowering the fatigue life. The increment in tensile properties retention of SBR/NBRr blends with ENR‐50 indicated the enhancement on weathering resistant. The surfaces of SBR/NBRr blends with ENR‐50 after 6 months exposure showed a minimal severity of crack compared with SBR/NBRr blends without ENR‐50. It revealed that the scale of cracks has reduced indicating well‐retaining interfacial adhesion between SBR and NBRr with the presence of ENR‐50 as a compatibilizer. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

Improvement of the homogeneity of SBR/NBR blends using polyglycidylmethacrylate‐g‐butadiene rubber

Polyglycidylmethacrylate grafted butadiene rubber (PGMA‐g‐BR) was synthesized by a graft solution copolymerization technique. The PGMA content was determined through titration against HBr. The PGMA‐g‐BR was blended with styrene butadiene rubber/butadiene acrylonitrile rubber (SBR/NBR) blends with different blend ratios. The SBR/NBR (50/50) blend was selected to examine the compatibility of such blends. Compatibility was examined using scanning electron microscopy (SEM), differential scanning calorimetry (DSC), and viscosity measurements. The scanning electron micrographs illustrate the change of morphology of the SBR/NBR rubber blend as a result of the incorporation of PGMA‐g‐BR onto that blend. The T_gs of SBR and NBR in the blend get closer upon incorporation of PGMA‐g‐BR 10 phr, which indicates improvement in blend homogeneity. The intrinsic viscosity (η) versus blend ratio graph shows a straight‐line relationship, indicating some degree of compatibility. Thermal stability of the compatibilized and uncompatibilized rubber blend vulcanizates was investigated by determination of the physicomechanical properties before and after accelerated thermal aging. Of all the vulcanizates with different blend ratios under investigation, the SBR/NBR (25/75) compatibilized blend possessed the best thermal stability. However, the SBR/NBR (75/25) compatibilized blend possessed the best swelling performance in brake fluid. The effect of various combinations of inorganic fillers on the physicomechanical properties of that blend, before and after accelerated thermal aging, was studied in the presence and absence of PGMA‐g‐BR. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 99: 1559–1567, 2006     

Nanoclay distribution and its influence on the mechanical properties of rubber blends

The distribution of modified and unmodified nanoclays inside the rubber phases of immiscible rubber–rubber blends composed of nonpolar–polar natural rubber (NR)/epoxidized natural rubber (ENR) and nonpolar–nonpolar NR/polybutadiene rubber (BR) was investigated for the first time. The distribution of clays at various loadings in the blends was calculated from the viscoelastic properties of the blends. For example, in the 50 : 50 NR/ENR blend, 42% Cloisite 30B migrated to the NR phase, and 58% went to the ENR phase. However, in the same blend, only 7% Cloisite Na⁺ was found in the NR phase, and 93% was found in the ENR phase. Again, in the 50 : 50 NR/BR blends, the NR phase contained 85% Cloisite 30B, whereas 55% Cloisite Na⁺ migrated to the NR phase. All these observations were explained with the help of viscosity, X‐ray diffraction, and morphology analyses. The effect of the distribution of the clay on the mechanical properties was also discussed. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

Carbon black distribution driven by its concentration and its effect on physico-mechanical properties of styrene butadiene rubber and butadiene rubber miscible rubber blends

This paper discusses the influence of partitioning of carbon black (CB) with its increasing concentration (i.e., 10, 20, 30, 40, and 50 phr) on physical and static mechanical properties of Styrene Butadiene Rubber (SBR)/Butadiene Rubber (BR) rubber–rubber blends (RRB's) in 70SBR:30BR blend ratio. Partitioning of CB towards BR in CB-filled SBR/BR RRB's is quantitatively determined via dynamic mechanical analysis (DMA). DMA confirmed increased partitioning of CB towards BR phase with increasing CB. DMA data on the partitioning of CB towards BR were in good agreement with nuclear magnetic spectra obtained by solid-state nuclear magnetic resonance spectroscopy (SS-NMR spectroscopy). Curing properties, relative density, hardness, tensile test, tear test, and transmission electron microscopy (TEM) on CB filled SBR/BR RRB's were carried out to determine the effect of increasing concentration of CB on physical, mechanical, and dispersion characteristics in comparison to neat SBR/BR RRB's.