共查询到18条相似文献,搜索用时 62 毫秒
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以自制的4种苯乙烯-异戊二烯-丁二烯橡胶(SIBR)为增韧组分,采用本体聚合工艺,以过氧化苯甲酰为引发剂进行苯乙烯接枝聚合以制备高抗冲聚苯乙烯,考察了用量、相对分子质量及分子链结构不同的SIBR对苯乙烯聚合速率的影响,并比较了用不同橡胶改性聚苯乙烯时的聚合动力学行为。结果表明,SIBR的用量越大聚合速率越小,相对分子质量越大则聚合速率越大;按SIBR分子链序列结构的不同聚合速率还呈现出从大到小依次为线型嵌段SIBR、线型无规SIBR、星形嵌段SIBR及星形无规SIBR的规律。用不同橡胶增韧聚苯乙烯时的聚合速率从大到小依次为SIBR、丁苯橡胶及顺丁橡胶。苯乙烯的表观接枝率随着SIBR用量或其相对分子质量的增大而减小,且远大于使用顺丁橡胶。 相似文献
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国外苯乙烯—异戊二烯—丁二烯橡胶的合成 总被引:3,自引:0,他引:3
苯乙烯-异戊二烯-丁二烯橡胶是一种理想的综合性能较佳的集成橡胶,滚动阻力和牵引性能达到良好的平衡,是极具希望的新型胎面胶种。 相似文献
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以n-BuLi为引发剂、乙基四氢糠基醚(ETE)和十二烷基苯磺酸钠(SDBS)二元复合调节体系为调节剂、己烷/环己烷为混合溶剂,在聚合温度为50 ℃时采用负离子聚合法进行苯乙烯-异戊二烯-丁二烯(SIBR)三元共聚合,考察了ETE/n-BuLi(摩尔比)和SDBS/n-BuLi(摩尔比)对SIBR微观结构含量和玻璃化转变温度(Tg)的影响。结果表明,当ETE/n-BuLi从0.5增加到2.0、SDBS/n-BuLi为0.1时,SIBR中聚丁二烯的1,2-结构质量分数和聚异戊二烯的3,4-结构质量分数分别增加了5.4和7.6个百分点,Tg上升了28.84 ℃左右;当SDBS/n-BuLi从0.1增加到0.8、ETE/n-BuLi为0.5时,SIBR中聚丁二烯的1,2-结构含量、聚异戊二烯的3,4-结构含量和Tg变化很小;ETE调节SIBR中聚丁二烯的1,2-结构和聚异戊二烯的3,4-结构的能力远远大于SDBS。 相似文献
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KANG Xin-he ZHAO Su-he WANG Ni-ni LIU Hui SUN Wen-juan XU Lin LI Chuan-qing YU Guo-zhu 《合成橡胶工业》2013,36(4)
SIBR is a new-style rubber with an excellent combination of low rolling resistance and high wet skid resistance,and could be applied to making high performance tires.2,2-di (tetrahydrofuran-2-yl) propane(DTHFP),as a new kind of polar modifier for terpolymerization of styrene(St),isoprene(Ip) and butadiene (Bd),has not been reported.In this paper,the anionic terpolymerization of St,Ip,Bd was conducted with DTHFP as polar modifier,n-BuLi as initiator,hexane/cyclohexane as solvent at different temperatures.The kinetics of anionic copolymerization of St,Ip,Bd was investigated using the method of gas chromatography. 相似文献
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以正丁基锂(n-BuLi)为引发剂,2G为调节剂,环己烷为溶剂,在50℃时考察丁二烯-异戊二烯共聚合。结果表明,当2G/n-BuLi(摩尔比)不大于0.5时,随着2G加入量的增多,聚合反应速率明显加快;当2G/n-BuLi(摩尔比)大于0.5时,随着2G加入量的增多,聚合反应速率略有增加。由K-T法求出丁二烯和异戊二烯共聚的竞聚率表明,随着2G/n-BuLi(摩尔比)增加,丁二烯单体竞聚率增大,而异戊二烯单体竞聚率减小。同时还考察了聚合物的微观结构。 相似文献
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常压下,以蓖麻油为原料,硫酸氢钠为催化剂,对合成共轭亚油酸的反应动力学进行了研究,分析了搅拌速度、反应时间、催化剂的用量对反应转化率的影响。结果表明,蓖麻油酸异构化反应为一级反应,反应活化能为18.060 kJ/mol,动力学方程为r C=35.943 e-18.060/RT C A。 相似文献
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In this study, the kinetics of isopropyl palmitate synthesis including the reaction mechanism was studied based on the two-step noncatalytic method. The liquid-phase diffusion effect on the reaction process was eliminated by adjusting the stirring rate. The results showed that the two-step reaction followed a tetrahedral mechanism and conformed to second-order reaction kinetics. Nucleophilic attack on the carbonyl carbon afforded an intermedi-ate, containing a tetrahedral carbon center. The intermediate ultimately decomposed by elimination of the leav-ing group, affording isopropyl palmitate. The experimental data were analyzed at different temperatures by the integral method. The kinetic equations of the each step were deduced, and the activation energy and frequency factor were obtained. Experiments were performed to verify the feasibility of kinetic equations, and the result showed that the kinetic equations were reliable. This study could be very significant to both industrial application and determining the continuous production of isopropyl palmitate. 相似文献
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油酸甲酯是一种重要的化工原料,因现行生产工艺存在污染环境、腐蚀设备、反应转化率较低等问题,使其生产受到了一定制约,为此,提出了一种无催化"两步法"合成油酸甲酯的工艺路线。文中在"两步法"工艺路线的基础上进一步研究了油酸甲酯合成反应动力学。采用积分法分析了在293,298,303,308,313 K下的实验数据,结果表明二步反应均符合二级反应特征,反应遵循四面体机理,并得到了不同温度下的动力学方程式。根据得到的不同温度下的反应速率常数确定了二步反应的活化能分别为121.6 kJ/mol和115.2 kJ/mol,频率因子为2.76×1019和4.03×1018。在实验293—313 K温度范围内,通过实验对得到的动力学方程进行验证,得到的实验值与动力学方程计算值相符合,说明得到的动力学方程是可靠的,为"两步法"合成油酸甲酯的工业放大提供了理论依据。 相似文献
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Hydrated silicas impart better physical properties to polar rubbers, compared to those of hydrocarbon rubbers. However, to achieve optimum properties silane coupling agents are crucial in such formulations. Epoxidized natural rubber (ENR) in small proportions is used as a reinforcement modifier for silica‐filled nitrile rubber (NBR). Two systems of cure were used: N‐cyclohexyl‐ 2‐benzthiazyl sulfenamide (CBS) alone and in combination with diphenyl guanidine (DPG). In the CBS accelerated system, incorporation of an optimum concentration of about 15% of ENR on total rubber was found to improve technological properties. Addition of a secondary accelerator further improves these properties. Comparable results are obtained with those containing coupling agent and NBR–ISAF. High bound rubber and volume fraction values indicate a high polymer–filler interaction and gel content resulting from the NBR–ENR interaction. Results of this study reveal that ENR could be used as a reinforcement modifier for the NBR–silica system. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 85: 292–306, 2002 相似文献