【作者】 史工昌；

【导师】 王玉荣； 廖明义； 梁爱民；

【作者基本信息】 大连理工大学 ， 材料学， 2006， 硕士

【摘要】 溶聚丁苯橡胶（SSBR）是合成橡胶的主要胶种之一。通过分子设计的手段,以烷基锂为引发剂,经阴离子溶液聚合,可以合成出汽车轮胎所需的低滚动阻力和高抗湿滑性的SSBR胎面用胶。近年来随着汽车工业和高速公路的不断发展,SSBR的需求比例持续增长。自溶聚丁苯实现工业化以来,国外越来越多的厂家采用了连续聚合法。与间歇法相比,连续法表现出了其独特的优点如:聚合物结构和质量均一、生产效率提高、工艺容易操作和调整等等。但是需要解决的一个主要问题是反应釜内凝胶的抑制。反应器中产生的凝胶,导致反应器的堵塞,从而过早地终止反应器的周期运行,凝胶的形成也严重影响聚合物的均一性、产品质量和生产效率,即阻碍了连续聚合的发展。抑凝剂的作用是通过链转移或链终止以减少可增长的大“活性”分子链的数目,以及凝胶的产生。 本文在建立丁二烯/苯乙烯阴离子连续溶液共聚合模试装置的基础上,对以正丁基锂（n-BuLi）,四氢呋喃(（THF）或四甲基乙二胺（TMEDA）和环己烷分别为引发剂、调节剂和溶剂的丁二烯/苯乙烯阴离子连续溶液共聚进行实验研究。详细考察了单体浓度,极性添加剂、物料平均停留时间及聚合温度等对共聚反应转化率、共聚产物微观结构、分子量及分子量分布的影响。在实验研究的基础上,采用了两种不同的方法线性回归法和非线性法建立了连续搅拌釜式反应器中丁二烯/苯乙烯阴离子溶液共聚合数学模型,并进行了模型的参数估计和模拟计算。利用三釜串联连续聚合模试转化率线性模型求得多级串联连续溶液聚合过程中不同引发剂浓度[n-BuLi](3.58×10^-4,6.72×10^-4,8.96×10^-4mol/1),不同聚合温度（50℃、60℃、70℃、80℃、90℃）,不同THF/Li（0、15、30、50、70、100）下的假一级表观增长反应速度常数K_B’、K_S’。利用非线性模型对三釜串联连续溶液聚合产品偶联SSBR-a的不同单体浓度,不同调节剂用量THF/Li,直链SSBR-b不同调节剂用量THF/Li,不同反应温度,SSBR-c的不同调节剂用量TMEDA/Li的动力学进行了研究,求取了各反应条件下的k_BB、k_ss、k_BS、k_SB,4个链增长表观反应速率常数,丁二烯表观竞聚率r_B,苯乙烯表观竞聚率r_S,结果表明随单体浓度的增大,调节剂用量的增大,反应温度的升高聚合反应达到稳态时所需的反应时间明显缩短,稳态时单体的相对转化率增大。并计算了各反应条件下苯乙烯结合量,共聚物组成分布,微观结构和链分布,并与实验值进行了比较,曲线基本吻合,说明所求取的参数准确性较高。对凝胶产生的机理以及抑制凝胶的机理进行了探讨。更多还原

【Abstract】 Solution polymerized styrene-butadiene rubber (SSBR) is one of the most important synthetic rubbers, and is synthesized via anionic solution polymerization process with taking alkyl-lithium as initiator. Tread stock with properties of low rolling resistance and high anti-wet skid, which are the primary features of superior quality automobile tires, can be prepared through the means of molecular design. In the recent years, the demand for SSBR in domestic and overseas market is continuously growing with the development of the automobile industry and construction of highway.Continuous polymerization of 1,3-butadiene and styrene of copolymers by organolithium initiation in solution polymerization systerms offers real production, advantages;such as more economic production, and more uniform compositions Process variables can be.readily adjusted in a continuous operation so as to optimize operations for a given polymerization recipe. Minor adjustments of monomer feed rates, initiator rates, randomizer rates, temperature control, pressure control, solvent usage, all can be readily made in a continuous process, in effect "fine tuning" so as to maintain relatively consistently a product with optimum properties. Continuous polymerization is more suitable for produce random copolymer of butadiene/styrene with relatively broader molecular weight distributionUnfortunately;continuous solution polymerization has the disadvantage of a tendency toward fouling and gel. Having to stop the entire process, clean the equipment, and then start up all over again, means attendant startup problems and necessity to again fine tune the operation. Gel, of course, adversely affects polymer uniformity and quality. Methods of reducing reactor fouling generally involve the addition of a gel inhibitor to the polymerization system.In this thesis, The anionic solution copolymerization of butadiene/styrene with n-butyllithium (n-BuLi),tetrahydrofuran(THF)or(TMEDA) modifier, and cyclohexane solvent was studied experimentally in three agitated tank reactors of 2 liters employing the continuous operation mode. The reaction conversion of comonomers, the molecular weight and molecular weight distribution of butadiene/styrene copolymer, and the micro-structure of the copolymer were analyzed by gas chromatograph, gel permeation chromatograph, and nuclear magnetic resonance, respectively. The effects of the mean residence time, the ratio of THF to n-BuLi(THF/n-BuLi), and the reaction temperature on the conversion, the molecular weight and molecular weight distribution, and the micro-structure of the copolymer were investigated. On the basis of the information of experimental study, models of comonomer conversion, and the molecular weight distribution under the condition of the maximummixednees in three continuous stirred tank reactor(CSTRS) were established. The parameters of the models were evaluated in terms of experimental data and the simulations of the models were carried out. The reaction rate constants(￡M > k^ ?> kgs ^ kSB) and The apparent reactivityratio(rB ,rs) were obtained in terms of the experimental results and the parameter evaluation.Modeling of dynamic equilibrium of different states of living polymer was studied. The simulated results were good agreeable to the experimental results. The polymerizing technics condition of anionic solution copolymerization SBR is determined by experimental data and the simulations of the models.The experimental results showed that the effects of THF/n-BuLi, comonomer concentration, reaction temperature on the propagation rate constants(￡BB > kss -. kBS ■> ￡SB)andThe apparent reactivity ratio(rB,rs) of the anionic continuous solution copolymerization ofbutadiene/styrene(includingSSBR-a,SSBR-b, SSBR-c),the content of combined styrene, the micro-structure of the randomized copolymer of butadiene/styrene(includingSSBR-a,SSBR-b, SSBR-c),and the percentage of produce nM, polystyrene chain were significant, The rate of the copolymerization increased obviously with increasing of THF/n-BuLi, comonomer concentration, reaction temperature. The conversions of comonomer and the average molecular weight increased with increase of the mean residence time. The dispersion index of molecular weight distribution was close to 2.更多还原