割口对胶料撕裂性能测定结果的影响

考察新月形和哑铃形试样及条形试样割口深度对胶料撅裂性能测试结果的影响。试验表明，新月形试样及条形试样小割口阶段(1mm)，胶料撅裂强度测定结果由大到小顺序为NR，SBR，BR；哑铃形试样及条形试样中割口阶段(2～5mm)，胶料撕裂强度测定结果由大到小的顺序为NR，BR，SBR；条形试样大割口阶段(6～9mm)，胶料撕裂强度测定结果由大到小的顺序为BR，SBR，NR。     

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。     

不同苯乙烯含量丁苯橡胶与天然橡胶并用的研究

将普通丁苯橡胶(SBR1,苯乙烯质量分数为0. 235)和高苯乙烯SBR(SBR2,苯乙烯质量分数为0. 68)分别与天然橡胶(NR)并用,研究NR/SBR并用比和SBR苯乙烯含量对并用胶硫化特性、物理性能和阻尼性能的影响。结果表明:随着SBR用量的增大,NR/SBR并用胶的硫化速度、拉伸强度和撕裂强度下降,NR/SBR1并用胶的滞后能量密度(HED)先增大后减小,NR/SBR2并用胶的HED增大;NR/SBR并用比相同时,NR/SBR2并用胶的硫化速度、拉伸强度、拉断伸长率和撕裂强度低于NR/SBR1并用胶;NR/SBR2并用胶的有效阻尼温域拓宽至高温区。     

石墨烯/橡胶复合材料在输送带胶料中的应用

研究石墨烯/丁苯橡胶(SBR)复合材料或石墨烯/天然橡胶(NR)复合材料在输送带胶料中的应用。结果表明:添加石墨烯可以显著提高SBR胶料和NR/SBR胶料的300%定伸应力、拉伸强度、撕裂强度和耐磨性能;石墨烯/SBR复合母胶或石墨烯/NR复合母胶(石墨烯质量分数为0. 1)用量为10～15份时,胶料的加工安全性、物理性能、耐磨性能和耐热老化性能较好;添加少量石墨烯即可提高输送带胶料的抗撕裂性能和耐磨性能,有利于延长输送带的使用寿命。     

硫化体系对天然橡胶性能的影响

研究普通硫化体系和半有效硫化体系对天然橡胶(NR)各项性能的影响。结果表明:与普通硫化体系NR胶料相比,半有效硫化体系NR胶料的硫化返原程度小,物理性能、压缩疲劳性能、耐磨性能和耐热老化性能好,且随着促进剂用量的增大性能更优,但耐切割性能变差;随着硫化时间的延长,普通硫化体系和半有效硫化体系NR胶料的压缩疲劳温升和磨耗量均增大,且普通硫化体系胶料增幅更大。     

熔体法制备有机黏土/橡胶纳米复合材料的结构及性能

将有机黏土(OC)分别加入到天然橡胶(NR)、丁苯橡胶(SBR)、丁基橡胶(IIR)和三元乙丙橡胶(EPDM)中,通过熔体法制备了纳米复合材料。探讨了橡胶黏度及其分子结构对OC在复合材料中分散状况的影响,研究了复合材料的力学性能。结果表明,在以NR为基体的复合材料中。OC片层分散均匀,且剥离程度较高;在SBR,IIR,EPDM中,OC以插层结构为主,且插层效果从大到小的顺序依次为SBR,IIR,EPDM。与相应的纯胶相比,OC／NR纳米复合材料的定伸应力提高,拉伸强度和扯断伸长率有所下降;OC／SBR,OC／IIR,OC／EPDM纳米复合材料的定伸应力变化不大,拉伸强度和扯断伸长率明显提高,且OC／SBR和OC／EPDM复合材料的撕裂强度提高。     

顺丁橡胶和白炭黑对炭黑/天然橡胶复合材料性能的影响

试验研究顺丁橡胶(BR)和白炭黑对炭黑/天然橡胶(NR)复合材料性能的影响。结果表明:与炭黑/NR复合材料相比,炭黑/NR/BR胶料的焦烧时间略有缩短,交联程度增大,硫化胶的300%定伸应力增大,压缩生热降低,抗切割性能下降,耐磨性能提高,滚动阻力减小;炭黑/白炭黑/NR胶料的交联程度减小,硫化胶的拉断伸长率和撕裂强度明显增大,压缩生热略有升高,抗切割性能和耐磨性能提高,滚动阻力增大(须通过加入偶联剂予以改善)。     

天然橡胶/集成橡胶并用胶的相态结构及性能

研究了天然橡胶/集成橡胶(NR/SIBR)的并用比(质量比)对胶料的相态结构、力学性能、动态力学性能、耐切割性能、耐磨性能和压缩疲劳生热的影响。结果表明,NR/SIBR并用比为20/80时,并用胶的相态结构均匀;并用比为30/70和40/60时,并用胶呈现明显的相分离结构;NR/SIBR并用比为40/60时,表现出2个玻璃化转变温度。与纯SIBR相比,NR/SIBR并用胶的动态损耗峰变宽,拉伸强度和撕裂强度变化不大,但耐切割性能、耐磨性能有所降低,压缩疲劳生热有所增加。     

纳米碳酸钙的特点与应用

根据纳米碳酸钙的特点及填充补强机理,将白燕华CC填充于NR,SBR及BR胶料中,测试其补强填充效果。结果表明,随白燕华CC 用量的增大,BR 和SBR 胶料的拉伸强度明显上升,而NR 胶料则表现为先缓慢上升,在白燕华CC用量大于60份后明显下降;SBR和BR胶料的撕裂强度则不如NR胶料增长显著。在SBR和BR胶料中随白燕华CC用量的增大,硫化时间明显缩短。纳米碳酸钙可部分或大部分替代炭黑和白炭黑作补强填料,具有填充量大,补强、增白效果好等特点,适宜在浅色橡胶制品中应用。     

反式-1,4-聚异戊二烯的结晶性对丁苯橡胶/反式-1,4-聚异戊二烯共混硫化胶拉伸性能的影响

用X射线衍射仪分析了反式-1,4-聚异戊二烯(TPI)的拉伸结晶性能,研究了其对丁苯橡胶(SBR)/TPI共混硫化胶拉伸性能的影响。结果表明,TPI具有明显的拉伸诱导结晶特性。未填充炭黑的SBR/TPI共混硫化胶及TPI硫化胶的结晶衍射峰强度从大到小依次为预拉伸试样、拉断试样和原始试样,并且TPI用量越多相应试样的结晶衍射峰强度越大;炭黑填充SBR/TPI共混硫化胶的结晶度比相应的未填充试样低得多。炭黑填充SBR/TPI共混硫化胶的拉伸强度比未填充胶料明显提高,硬度随TPI用量增加而提高的幅度低于未填充者;未填充胶料的扯断伸长率先降低后升高,而填充胶料整体上呈现下降的趋势;未填充及填充胶料的100%定伸应力都随着TPI用量的增加而升高;炭黑填充胶料在50 mm/min拉伸速率下的拉伸强度比500 mm/min拉伸速率下测得结果的增长幅度以及预拉伸试样比原始试样拉伸强度的增长幅度都小于未填充胶料。     

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。     

Relationship between the material properties and fatigue crack‐growth characteristics of natural rubber filled with different carbon blacks

An investigation of the influence of different types of carbon black on fatigue crack‐growth behavior was undertaken. Fatigue tests were carried out on edge‐notched specimens under cyclic tension loading. A power‐law dependency between the crack‐growth rate and tearing energy was obtained. Natural rubber (NR) filled with N330 (the mean diameter is 30 nm) carbon black possessed the lowest values of exponent b and constant B (the two crack growth parameters determined from cyclic crack growth testing), which denoted the strongest resistance to crack growth at a given tearing energy. Strain‐induced crystallization was investigated by the modified Mooney–Rivlin equation and showed the earliest appearance and strongest ability of the crystallization of the NR/N330 composite at the largest amount of bound rubber. The study on the viscoelastic properties by dynamic mechanical analysis confirmed that the NR/N330 composite had the largest viscoelastic contribution, which was attributed to the viscoelastic dissipation in the viscoelastic region in front of the crack tip. All of these results confirm the best crack‐propagation resistance of NR filled with N330. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

再生丁基橡胶与非极性不饱和橡胶共混物的性能研究

对再生丁基橡胶(RIIR)与非极性不饱和橡胶共混物的性能进行了研究。结果表明,RIIR易以填料的形式加入到非极性不饱和橡胶中使用,当RIIR以填料的形式加入到NR、BR及SBR中时,不仅使它们的耐热氧老化性及耐屈挠龟裂性得到明显改善,而且使NR及BR的撕裂强度及扯断伸长率提高;RIIR作为生胶与BR及NR共混,可改善BR的耐热氧老化性,提高NR的撕裂强度;SBR与RIIR共混,均使拉伸强度及撕裂强度降低;非极性不饱和二烯类橡胶与RIIR共混后,均使耐磨性降低。     

Effect of fatty acids on the strain‐induced crystallization of natural rubber detected by tear energy measurements

The strain‐induced crystallization of natural rubber (NR) was investigated by the measurement of the tear energy of a crosslinked blend consisting of NR and noncrystalline styrene–butadiene rubber (SBR). When NR was dispersed into the SBR matrix, the tear energy of SBR increased at various temperatures and tear rates. After the application of the principle of time–temperature superposition to the tear energy according to the Williams–Landel–Ferry equation, two distinct curves were found for the NR/SBR blend with respect to the reduced tear rate, despite the fact that the tear energy of SBR or the SBR/SBR blend gave its own single composite curve. When the fatty acid in the NR/SBR blend was removed by acetone extraction, the tear energy of the blend drew a single composite curve. The conversion of the two curves into the single composite curve for the NR/SBR blend suggested that the tear energy depended on the strain‐induced crystallization of NR dispersed in the SBR matrix, which was suppressed by the removal of the fatty acid. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 98: 613–619, 2005     

有机蒙脱土对天然橡胶/丁苯橡胶的补强及增容作用

采用机械混炼法制备了天然橡胶(NR)/丁苯橡胶(SBR)/有机蒙脱土(OMMT)纳米复合材料,采用TEM和XRD对复合材料的亚微观结构进行了表征,并对复合材料的表观交联密度、静态力学性能、动态力学性能和硫化热效应进行了研究。结果表明,复合材料为剥离型纳米复合材料;OMMT能够明显提高纳米复合材料的交联密度和静态力学性能;OMMT导致NR/SBR共混胶动态损耗因子降低,并且能够促使NR和SBR玻璃化转变温度更为接近,起到了增容作用;OMMT实现了NR和SBR两相的同步硫化。     

Fracture behavior of NR and SBR vulcanizates filled with ground rubber having uniform particle size

The use of recycled rubber including ground scrap vulcanizates in rubber compounds was studied. When ground rubber was incorporated into rubber compounds, the physical properties, especially the tensile strength, were deteriorated compared to the virgin rubber compound. Also, incorporating ground rubber caused a change of the cure behavior via migration of sulfur or an accelerator between the virgin rubber matrix and the ground rubber vulcanizate. In this study, the fracture behavior and abrasion property of carbon black‐filled SBR and NR compounds containing ground rubber vulcanizate were investigated. Also, the effect of the particle size or loading volume of ground rubber powder on those properties was studied. Four different sizes, 420–600, 177–250, 125–150, and 75–88 μm, of ambient ground rubber powder recycled from waste tire were selected and used in the compounding. The loading amounts of ground rubber powder were 10, 30, and 50 phr. The flex crack growth of SBR‐ and NR‐based compounds was altered by the addition of ground rubber particles. More delayed crack growth was observed with an increasing loading volume and decreasing particle size of the ground rubber powders, and this behavior was more prominent in SBR than in NR compounds. Tangent delta, a direct measure of internal energy dissipation, increased with an increasing loading volume of the ground rubber particles. The abrasion rate of ground rubber‐filled compounds was more dependent on the size of the abrasion pattern than on the loading level or particle size of the ground rubber powders. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 85: 2491–2500, 2002     

纳米碳酸钙的特点与应用

根据纳米碳酸钙的特点及填充补强机理,将白燕华ＣＣ填充于ＮＲ,ＳＢＲ及ＢＲ胶料中,测试其补强填充效果。结果表明,随白燕华ＣＣ用量的增大,ＢＲ和ＳＢＲ胶料的拉伸强度明显上升,而ＮＲ胶料则表现为先缓慢上升,在白燕华ＣＣ用量大于６０份后明显下降;ＳＢＲ和ＢＲ胶料的撕裂强度则不如ＮＲ胶料增长显著。在ＳＢＲ和ＢＲ胶料中随白燕华ＣＣ用量的增大,硫化时间明显缩短。纳米碳酸钙可部分或大部分替代炭黑和白炭黑作补强填料,具有填充量大,补强、增白效果好等特点,适宜在浅色橡胶制品中应用。     

Failure analysis of carbon black filled styrene butadiene rubber under fatigue loading conditions

Abstract

The present paper deals with the fatigue crack growth in a carbon black-filled styrene butadiene rubber (CB-SBR) under fully relaxing loading conditions. More precisely, it is devoted to the determination of the scenario of crack growth. For that purpose, an original ‘microcutting’ technique, previously applied by the authors on natural rubber (NR), is used to observe microscopic phenomena involved in fatigue crack growth thanks to scanning electron microscopy (SEM). Results show that the crack tip grows following a tearing line by generating ligaments; it explains the differences between fatigue responses of crystallisable and non-crystallisable rubbers during crack propagation. So, contrary to crystallisable elastomers such as NR, the microstructure of SBR is similar at crack tip and in the bulk material, and the crack tip does not resist crack propagation. Moreover, the morphology of fracture surfaces only depends on particles encountered by the fatigue crack during its propagation.     

Crack growth resistance of natural rubber reinforced with carbon nanotubes

Carbon nanotubes (CNTs)/natural rubber (NR) composites are prepared through ultrasonically assisted latex mixing combined with a two-roll mixing process, and their crack growth behavior is examined to evaluate their fatigue properties. CNTs/NR shows a reinforcement of crack growth resistance compared to unfilled NR. The measurements of the tearing energy and the hysteresis loss show that CNTs/NR exhibits more energy dissipation than NR. Also, strain-induced crystallization (SIC) around the crack tip of CNTs/NR and NR composite was examined at different fatigue strains. CNTs positioned at the crack tip led to a crack branching at low fatigue strain, which is responsible for the improvement of the crack growth resistance of CNTs/NR. However, the inclusion of CNTs renders NR higher crystallinity and larger crystallization zones in front of the crack tip at high fatigue strains, which allows more energy dissipation during crack growth. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2020 , 137, 48447.     

NR/SBR内胎胶配方的改进

对天然橡胶(NR)/丁苯橡胶(SBR)内胎胶配方进行调整:降低NR用量比例,调整补强体系和硫化体系。结果表明:NR/SBR并用比由60/40减小到50/50,胶料的门尼粘度较大,焦烧时间较长,加工安全性较好,热老化后性能下降率低,其他性能差异不大;成品内胎的耐热老化后性能明显改善,生产成本降低。