Self-adhesion of natural rubber modified with phosphorylated cashew nut shell liquid

The self-adhesion strength of natural rubber (NR) compounds modified with phosphorylated cashew nut shell liquid (PCNSL) prepolymer has been studied with respect to variations in contact time, contact pressure, storage time, and concentration of PCNSL. The self-adhesion strength of NR as measured from the 180° peel test showed a maximum at 10 phr of PCNSL. The adhesion between substrates containing various concentrations of PCNSL (from 0 to 20 phr) also reached a maximum at a PCNSL concentration of 10 phr in one of the substrates. An increase in self-adhesion strength with storage time was observed for the PCNSL-modified NR compounds, which is presumed to be due to the time-dependent interfacial diffusion.     

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。     

Physicomechanical properties of filled natural rubber vulcanizates modified with phosphorylated cashew nut shell liquid

Effect of fillers like carbon black, silica, and china clay on the cure characteristics and physicomechanical properties of natural rubber (NR) modified with phosphorylated cashew nut shell liquid (PCNSL) in various proportions has been studied. Prominent cure retardation has been observed with progressive increase in concentration of PCNSL from 0 to 20 phr. The softening effect of PCNSL on the vulcanizate has been displayed by the linear decrease in hardness and tensile modulus and the increase in elongation at break with the increase in concentration of PCNSL. The results on the tensile and tear strengths of the vulcanizates showed that the reinforcing effect of the fillers were maximized at concentrations of PCNSL ranging from 5 to 10 phr. Also, the PCNSL-modified NR vulcanizates showed improved resistance to thermo-oxidative ageing and decomposition, especially at the higher concentration of 20 phr. © 1998 John Wiley & Sons, Inc. J Appl Polym Sci 68: 1303–1311, 1998     

Co-compatibilising effect of carbon nanotubes and liquid isoprene rubber on carbon black filled natural rubber/polybutadiene rubber blend

Abstract

Bis-(triethoxysilylpropyl)-tetrasulfane functionalised carbon nanotubes (t-CNTs) were used as compatibiliser along with liquid isoprene rubber (LIR) in the natural rubber (NR)/polybutadiene rubber (BR) blend. Their reinforcing and compatibilising effects were evaluated by mechanical, fatigue crack growth resistance properties and blend homogeneity. Scanning electron microscope and transmission electron microscope showed enhanced interfacial adhesion between the binary rubber phases and improved dispersion of the minor phase in the rubber blend respectively with the co-existence of LIR and carbon nanotubes. The tensile strength of the carbon black (CB) filled NR/BR blend reached its optimum when 3 phr CB was replaced with an equal amount of t-CNTs in the presence of 7 phr LIR, while the fatigue crack growth resistance property achieved its maximum in the presence of 3 phr LIR. This interesting co-compatibilisation behaviour of t-CNTs and LIR suggests that t-CNTs have a better effect than CB with the assistance of LIR, which is an effective plasticiser in the NR/BR blend.     

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。     

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     

Formulation and morphology of kaolin-filled rubber composites

In the present work the formulation and morphology of novel kaolin-filled rubber composites were investigated. The kaolin-filled rubber composites were obtained by filling rubbers such as natural rubber (NR), styrene–butadiene rubber (SBR), polybutadiene rubber (ER), nitrile butadiene rubber (NBR), ethylene propylene diene monomer (EPDM), chloroprene rubber (CR) and methyl vinyl silicon rubber (MVQ). The best formulation of filled rubbers was determined by determining the mechanical and thermal properties of the composites. Structural characterization was carried out by using infrared spectroscopy (IR) and a polarizing light microscope (PLM). The kaolin/rubber composites have outstanding mechanical and thermal properties except elongation at break, and good compatibility. The best formulation of kaolin filled rubbers is respectively 40 parts per hundred rubber (phr), 40 phr, 50 phr, 40 phr, 50 phr, and 50 phr for NR, SBR, BR, NBR, EPDM and CR. Kaolin can replace silica in the specific rubber products, and is suitable to reinforce more steric rigid rubber.     

短切碳纤维对天然橡胶/顺丁橡胶复合材料性能的影响

以天然橡胶(NR)和顺丁橡胶(BR)为基料,以短切碳纤维(SCF)为添加剂,制备了SCF/NR/BR复合材料,考察了SCF用量对NR/BR的摩擦性能及力学性能的影响。结果表明,SCF可增强NR/BR基体的强度,增大其硬度。在NR/BR混合胶中加入15份SCF可以降低混合胶的摩擦系数,减少混合胶的磨损量,提高混合胶的耐磨性能。SCF增强的NR/BR在摩擦过程中发生了磨粒磨损和黏着磨损,形成了卷曲磨屑。     

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...     

纳米高岭土/橡胶复合材料的性能研究

研究纳米高岭土／橡胶（SBR，NR，BR和EPDM）复合材料的物理性能和热稳定性能，并用透射电子显微镜、X射线衍射、红外光谱和热重分析法对高岭土／橡胶复合材料进行分析。结果表明，与白炭黑／橡胶复合材料相比，纳米高岭土／橡胶复合材料回弹性、拉伸性能和热稳定性较好，撕裂强度和定伸应力稍差；高岭土片层厚度为纳米级、分散性良好、片状粒子与橡胶大分子在纳米尺度紧密结合以及纳米高岭土片层在橡胶基体中分离且定向平行排列，是复合材料具有优良物理性能和热稳定性的重要原因。     

Natural rubber and butadiene rubber blend using diblock copolymer of isoprene–butadiene as compatibilizer

Blends of natural rubber (NR) and butadiene rubber (BR) have been studied with or without diblock copolymers of isoprene–butadiene (BIR). It was found that NR/BR blends displayed the optimal properties at about 4 wt % of BIR from the tensile measurements of NR/BR blends. Increase of molecular weight of BIR resulted in the decrease of tensile properties, but had no significant effect on their hardness. Abrasion resistance of rubber blends containing BIR was about 30% higher than that without BIR. The molecular weight of BIR did not show a remarkable effect on the abrasion index. Differential scanning calorimetry and dynamic mechanical analyses of rubber blends suggested a two-phase structure even in the presence of BIR. © 1993 John Wiley & Sons, Inc.     

Study on the milling behavior of chloroprene rubber blends with ethylene–propylene–diene monomer rubber,polybutadiene rubber,and natural rubber

The viscoelastic properties of the blends of chloroprene rubber (CR) with ethylene–propylene–diene monomer rubber (EPDM), polybutadiene rubber (BR), and natural rubber (NR) at different temperature were studied using rubber processing analyzer (RPA). Mooney viscosities of compounds were measured and tight milling and sheeting appearance were observed on a two‐roll mill. The results showed that Mooney viscosities and the elastic modulus of the blends decreased with the increase of the temperature from 60 to 100°C. And the decreasing trends of pure CR, pure NR, and CR/NR blend compounds were more prominent than that of pure EPDM, pure BR, CR/EPDM, and CR/BR blend compounds. For CR/EPDM blend compounds, the decreasing trend became slower with the increase of EPDM ratio in the blend. Compared with pure CR, pure NR and CR/NR blend compounds, pure EPDM, pure BR compounds, and the blend compounds of CR/EPDM and CR/BR showed less sensibility to temperature and they were less sticky to the metal surface of rolls and could be kept in elastic state at higher temperature, easy to be milled up and sheeted. At the same blend ratio and temperature, the property of tight milling of the blends decreased in the sequence of CR/EPDM, CR/BR, and CR/NR. With the increase of EPDM, BR, or NR ratio in CR blends, its property of tight milling was improved. POLYM. COMPOS., 28:667–673, 2007. © 2007 Society of Plastics Engineers     

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。     

Effect of zinc oxide nanoparticles as cure activator on the properties of natural rubber and nitrile rubber

Zinc oxide (ZnO) nanoparticles were synthesized by homogeneous precipitation and calcination method and were then characterized by transmission electron microscopy and X‐ray diffraction analysis. Synthesized ZnO was found to have no impurity and had a dimension ranging from 30–70 nm with an average of 50 nm. The effect of these ZnO nanoparticles as cure activator was studied for the first time in natural rubber (NR) and nitrile rubber (NBR) and compared with conventional rubber grade ZnO with special reference to mechanical and dynamic mechanical properties. From the rheograph, the maximum torque value was found to increase for both NR and NBR compounds containing ZnO nanoparticles. ZnO nanoparticles were found to be more uniformly dispersed in the rubber matrix in comparison with the conventional rubber grade ZnO as evident from scanning electron microscopy/X‐ray dot mapping analysis. The tensile strength was observed to improve by 80% for NR when ZnO nanoparticles were used as cure activator instead of conventional rubber grade ZnO. An improvement of 70% was observed in the case of NBR. The glass transition temperature (T_g) showed a positive shift by 6°C for both NR and NBR nanocomposites, which indicated an increase in crosslinking density. The swelling ratio was found to decrease in the case of both NR and NBR, and volume fraction of rubber in swollen gel was observed to increase, which supported the improvement in mechanical and dynamic mechanical properties. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2007     

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     

均匀剂在橡胶加工过程中的应用效果

研究了3种国外均匀剂产品40MS,60NS和M40和NR／BR及NR／BR／SBR共混体系中的应用效果。试验结果表明,均匀剂可改善胶料的加工流动性,降低胶料的门尼粘度和混炼功耗,提高混炼胶的相态均匀性,缩短炭黑的混入时间,对硫化胶的物理性能影响不大,相对而言,均匀剂M40对NR／BR和NR／BR／SBR共混体系的综合性能影响效果最好,当用量为3份时可达到加工性能和使用性能的最佳平衡。     

聚苯胺改性蒙脱土/天然橡胶纳米复合材料的制备与性能

采用原位聚合法制备了聚苯胺质量分数为20% 的聚苯胺改性蒙脱土,并以此作为增强剂利用机械混炼法制备了聚苯胺改性蒙脱土( PANI － MMT) /天然橡胶( NR) 纳米复合材料。使用X 射线衍射仪、傅里叶变换红外光谱仪及扫描电镜等对PANI － MMT 和PANI － MMT/NR 复合材料的结构进行了表征,并考察了PANI － MMT/NR 复合材料的力学性能。结果表明,PANI － MMT/NR 复合材料形成了插层型纳米结构; 与普通的有机蒙脱土/NR 复合材料相比,PANI － MMT/NR 复合材料的力学性能明显提高,PANI － MMT 添加质量为20 份时其力学性能达到最好,并超过了添加40 份炭黑N 660 的NR 的力学性能。     

改性炭黑对天然橡胶/顺丁橡胶并用胶性能的影响

采用3种方法对传统炭黑进行表面改性,考察了改性前后炭黑表面形貌及结构的变化,并采用改性炭黑填充天然橡胶（NR）/顺丁橡胶（BR）并用胶,考察了改性炭黑对并用胶力学性能、硫化特性及动态力学性能等的影响。结果表明,与未改性炭黑相比,细化粒径、调高pH值及木质素改性处理后,炭黑表面的粗糙程度增加;且细化改性炭黑具有更高的比表面积,调高pH值改性炭黑具有更多疏松的二次结构,木质素改性炭黑粒径略有增加。对于炭黑填充NR/BR,用细化粒径及调高pH值方法处理的炭黑进行填充,NR/BR硫化胶的力学性能、耐磨性能及抗湿滑性均得到明显改善,但硫化延迟效应明显;木质素改性后,炭黑填充胶的力学性能、耐磨性能均出现不同程度的降低。     

Organomodified kaolin as a reinforcing filler for natural rubber

China clay (kaolin) has been modified with sodium salt of rubber seed oil (SRSO). SRSO was characterized using X‐ray diffraction (XRD), infrared spectroscopy (FTIR), and differential thermal analysis (DTA). XRD of the unmodified and SRSO‐modified kaolins showed an increase in the d‐(001) spacing of kaolin platelets from 7.15 to 14 Å. FTIR spectroscopy indicated possible grafting of the organic moiety of rubber seed oil (RSO) onto the clay surface. DTA of the SRSO‐modified kaolin indicated that the SRSO is more strongly bound in a constraint environment within the lamellae of kaolin. Natural rubber (NR) mix containing 10 phr of SRSO‐modified kaolin was found to cure faster than that of a similar mix containing unmodified kaolin. NR vulcanizates containing SRSO‐modified kaolin showed considerable increase in tensile modulus, tensile strength, and elongation at break indicating its potential as an organomodified nanofiller. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

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