溶聚丁苯橡胶结构与性能研究

以正丁基锂（n-BuLi)为引发剂，环己烷为溶剂，HTF、2G及TMEDA为极性调节剂，SnCl4、DVB及DEAP为偶联剂合成溶聚丁苯橡胶（SSBR），研究了调节剂种类及用量对SSBR的微观结构及共聚物苯乙烯序列分布的影响，同时也研究了不同极性调节剂和偶联剂对SSBR偶联效果及性能的影响。结果表明，改变调节种类及用量，可改变共聚物中丁二烯分子链中1，2－结构含量，其调节能力为2G＞TMEDA≥THF；所选用的调节剂用量制得共聚物中苯乙烯的序列分布趋无规分布。比较不同体系下SSBR的偶联效果，物理机械性能及DMA的Tanδ值，发现以THF作调节剂用SnCl4作偶联剂时制备的SSBR综合性能最优。     

高性能SSBR的制备及性能研究

采用阴离子聚合方法,分别以环己烷和环戊烷为溶剂,以十二烷基苯磺酸钠(SDBS)及四氢呋喃(THF)为复合结构调节剂,以n-BuLi为引发剂,SnCl4为偶联剂,合成了性能优异的SSBR。考察了不同溶剂对聚合过程的影响、复合结构调节剂用量对SSBR结构及偶联效率的影响,采用T型关联度分析法对门尼粘度的影响因素进行了研究。并采用国标方法对SSBR的物理机械性能进行了测定。结果表明,环戊烷可用于合成SSBR,且对SSBR性能影响不大;当复合结构调节剂SDBS/THF与正丁基锂的摩尔比为4∶0.7∶1时,SSBR的无规化程度较好;当SDBS与THF的用量较小时,偶联效率可达51.3%;对SSBR门尼粘度影响较大的因素为丁苯共聚物的组成(共聚物单体配比)、聚合物分子量及聚合物分子量分布。     

结构调节剂对SSBR结构与性能的影响

研究结构调节剂四氢呋喃(THF)、二乙二醇二甲醚(2G)和N，N，N′，N′-四甲基乙烯基二胺(TMEDA)对溶聚丁苯橡胶(SSBR)结构和性能的影响。试验结果表明，随结构调节剂用量的增大和反应温度的降低，SSBR中1，2-结构质量分数增大；随结构调节剂用量的增大，SSBR中苯乙烯结构质量分数逐渐接近苯乙烯与丁二烯的投料比；结构调节剂品种对SSBR物理性能影响不大，以THF为结构调节剂合成的SSBR动态性能最好。     

极性调节剂对SSBR微观结构及聚合反应的影响

以正丁基锂为引发剂,以环己烷为溶剂,分别采用SDBS／THF、SDBS／PMDETA为复合调节剂,制备了溶聚丁苯橡胶（SSBR）;研究了极性调节剂对聚合反应速率和聚合物微观结构的影响。结果表明：复合调节剂可使聚合反应速率增加,并且使聚合物链中乙烯基含量和苯乙烯含量均匀分布,得到的产品是完全无规化的SSBR,相对分子质量分布大于1．6,从而对改善SSBR的性能起到了重要的作用。最终合成的SSBR具有良好的物理机械性能。     

极性调节剂对SSBR微观结构及性能的影响

以正丁基锂为引发剂,环己烷为溶剂,采用SDBS/THF为复合调节剂,制备了溶聚丁苯橡胶（SSBR）;研究了聚合物微观结构对聚合物性能的影响。结果表明：复合调节剂使聚合物链中乙烯基含量和苯乙烯含量均匀分布,得到的产品是完全无规化的SSBR,随着聚合物链中乙烯基含量和苯乙烯含量的增加,产品的玻璃化转变温度明显增加,产品的动态力学性能得到显著提高,分子质量分布大于1.6,合成的SSBR具有良好的物理机械性能。     

复合调节体系对合成SBS微观结构及反应速率的影响

通过活性阴离子聚合手段,以正丁基锂为引发剂、环己烷为溶剂,合成苯乙烯-丁二烯-苯乙烯三元嵌段共聚物(SBS).分别研究了单一调节剂四氢呋喃(THF)、复合调节体系四甲基乙烯基二胺(TMEDA)与THF、二乙二醇二甲醚(2G)与THF对SBS微观结构的影响.结果表明,在聚合温度为60℃,苯乙烯(St)与丁二烯(Bd)质量...     

杂质对合成中乙烯基聚丁二烯橡胶的影响 Ⅳ.腈、醛、酮、醇和醚对聚合的影响

本工作以正丁基锂(n-BuLi)为引发剂,环己烧为溶剂,分别以四氢呋喃(THF)及二乙二醇二甲醚(以下简称 2 G)为结构调节剂,研究了聚合体系中的杂质乙腈、丙烯酸、甲乙酮、丙酮、异丁醇、呋喃等对合成中乙烯基聚丁二烯聚合转化率、聚合物微观结构及特性粘度的影响。     

用十二烷基苯磺酸钠／四氢呋喃二元体系调节聚丁二烯的1，2-结构

研究了十二烷基苯磺酸钠(SDBS)一元调节体系和SDBS/四氢呋喃(THF)二元调节体系对聚丁二烯微观结构的影响.实验表明,SDBS这一强极性调节剂可大幅度降低THF的用量,当SDBS/Li(摩尔比)为0.1～0.7、THF/Li(摩尔比)为2～8时,聚丁二烯1,2-结构的摩尔分数可控制在30%～55%.SDBS是一种对温度不敏感的调节剂,温度升高20℃,聚丁二烯的1,2-结构摩尔分数仅降低4%～6%.SDBS/THF二元调节体系同样具有温度不敏感性,温度升高20℃,聚丁二烯的1,2-结构摩尔分数仅降低6%～8%.     

杂质对合成中乙烯基聚丁二烯橡胶的影响 Ⅲ.丁二烯二聚体对聚合的影响

以正丁基锂为引发剂、环己烷为溶剂、采用四氢呋喃(THF)或二乙二醇二甲醚(2G)为结构调节剂,研究了聚合体系中丁二烯二聚体对合成中乙烯基聚丁二烯的聚合速度、转化率以及聚合物微观结构、[η]和分子量分布的影响。结果表明,丁二烯二聚体的存在,不影响聚合物微观结构(THF体系)、分子量分布和单体浓度的动力学反应级数,但影响转化率、聚合物微观结构(2G体系)、[η]和表观增长活化能。     

星形杂臂异戊二烯-丁二烯-苯乙烯橡胶的结构与性能

采用负离子溶液聚合法,以正丁基锂为引发剂、环己烷为溶剂、十二烷基苯磺酸钠/四甲基乙二胺为复合结构调节剂、二乙烯基苯为偶联剂制备了具有高抗湿滑性和低滚动阻力的星形杂臂异戊二烯-丁二烯-苯乙烯橡胶,考察了聚合温度及结构调节剂和偶联剂用量对聚合物微观结构、动态力学性能及力学性能的影响.结果表明,聚合物中非1,4-结构链节的含...     

星型SIBR合成中偶联反应的研究

以n-BuLi为引发剂,环乙烷为溶剂,SnCI4为偶联剂,在不同极性添加剂存在下合成了苯乙烯、异戊二烯和丁二烯的偶联星型无规共聚物SIBR。研究了聚合阶段不同极性添加剂（THF、THF－2G和2G)、偶联温度、偶联剂用量及偶联方式对偶联效果的影响。 研究结果表明适宜的工艺条件为：极性添加剂THF或THF－2G;偶联温度70℃;偶联剂用量n(SnCI4)/n(Li)=0.40-0.45(THF作极性添加剂）或0．35（THF－2G作极性添加剂）;二次偶联、偶联前加入适量极性添加剂及丁二烯戴帽,都可以提高偶联效果。     

Effects of tetrahydrofuran as a structure modifier in preparation of SBS thermoplastic block copolymers in cyclohexane

Linear styrene-butadiene block copolymers of polyA-block-polyB-block-polyA type (SBS) were synthesized in the presence of varying amounts of THF functioning as the polar structure modifier. The efficiency of this modifier was studied by analyzing the microstructure of synthesized polymers using ¹³C-NMR, and the effect of THF on polymerization kinetics was determined by progressive buildup of the molecular weight measured by GPC. Polymerization at 4000 ppm THF concentration resulted in the highest styrene polymerization rate while a 1 wt % concentration gave the highest butadiene polymerization rate. The vinyl content increased from 20 to 64% with an increase in the amount of THF from 200 ppm to 1 wt % while the content of trans-1,4 and cis-1,4 units decreased. For SBS polymer synthesized via a sequential process, the use of THF as the structure modifier enhanced the crossover efficiency that would otherwise result in a skewed molecular weight distribution with a higher polydispersity. For SBS polymer made via a coupling process, the coupling efficiency decreased when the amount of THF exceeded a certain limit. The temperature dependence of the coupling efficiency was also investigated. © 1996 John Wiley & Sons, Inc.     

SOME THEORETICAL PROBLEMS OF ANIONIC POLYMERIZATION OF BUTADIENE——A Study on the Association Degree of n-BuLi and Polybutadienyl-Li

This paper determined the association degree of n-BuLi and polybutadinyllithium(PBLi)by UV spec-trometry and viscometry.The experimental results of UV spectrometric analysis showed that the associationdegree of n-BuLi as well as PBLi is dependent mainly on their concentration in solutions;there may be specieswith three and two degrees of association in cyclohexane solvent respectively for n-BuLi and PBLi,i.e.the asso-ciation degree for the former is equal to 2,4 and 6;and for the latter it equals to 2 and 4.Similarly,the experi-mental results obtained by viscometric measurement showed that the average association degree N of PBLiin cyclohexane changed from 2 to 4 with increasing of its concentration in solution and decreased with addi-tion of a small amount of polar additive into the above mentioned system.Furthermore,in pure polar solvent,such as dimethoxyethane(DME),tetrahydrofuran(THF)or dioxane(DOX),PBLi is completely dissociatedinto monomeric species;however,in pure diethyl ether,due to its weak polarity a part of associated species stillcan be found.Generally speaking,all of the above results were consistent with the results of kinetic studies in-vestigated by us before.     

结构调节剂对液体异戊二烯聚合的影响

采用锂系阴离子聚合工艺合成液体异戊二烯橡胶( LIR),在聚合过程中添加5种不同的结构调节剂,研究他们对LIR结构的影响。结果表明：非极性调节剂二硫化碳(CS₂)对LIR顺-1,4含量的影响不大;极性调节剂均可降低顺-1,4含量。其中二乙二醇二甲醚(2G)、四甲基乙二胺(TMEDA)对顺-1,4含量的调节作用较大;乙醚(Et₂O)对顺-1,4含量的调节作用较小;四氢呋喃(THF)作为结构调节剂效果最好。     

Synthesis of a difunctional organolithium compound as initiator for the polymerization of styrene‐butadiene/isoprene‐styrene triblock copolymer

A difunctional organolithium compound was prepared by the addition of butyllithium (BuLi) to 1,4‐bis(4‐methyl‐1‐phenylethenyl)benzene (MPEB). The effects of the solvent, polar modifier (THF), butyl lithium structure, and reaction time on the formation of the difunctional organolithium compound were studied. Results showed that toluene as solvent was in favor of the addition reaction over cycohexane, in the absence of the polar modifier. However, cycohexane was a better option as solvent for the addition reaction, when polar modifier was employed. A small amount of polar modifier could efficiently accelerate the reaction rate and have no significant effect on the structure of the polydiene, which was initiated by the polar modifier containing organolithium compound. Results also showed that isobutyl lithium was more active in the addition reaction than n‐butyl lithium, because of inductive effect. The optimum molar ratio of THF/Li+ was determined as 4. The THF containing difunctional organolithium cyclohexane solution was sequentially used in the step‐wise polymerization of triblock thermoplastic copolymer SIBS. The so‐prepared SIBS shared the similar phase separation structure with SBS and exhibited excellent mechanic properties. As the content of the central polyisoprene block increases, the tensile strength of the copolymer is decreased, and the elongation at break is increased. The glass transition temperature T_g of the central block was correlated with its content as T_g = 0.33 × ?62.81, where × is the wt % of the central block, based on the triblock copolymer. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 100: 1395–1402, 2006     

对苯二甲酸直接酯化法合成PBT树脂的研究

讨论了酯化温度、催化剂种类和催化剂用量对酯化速度、酯化率、四氢呋喃生成量以及缩聚反应速度和树脂质量的影响。研究表明，钛锡复合催化剂能有效地提高酯化反应和缩聚反应速度，减少四氢呋喃生成量。采用钛锡复合催化剂，可使四氢呋喃生成量降到４６．２ｇ／ｋｇ树脂所得树脂特性粘数０．８９～１．０９ｄＬ／ｇ，羧基含量１２．３～１６．８μｅｑ／ｇ，熔点２２８～２３０℃。     

Morphology and properties of α-methylstyrene and butadiene diblock copolymers

Diblock copolymers of α-methylstyrene and butadiene were synthesized, using n-BuLi as initiator, toluene as solvent, and tetrahydrofuran (THF) as accelerator. The addition of a small amount of THF in polymerization solution would greatly increase the 1,2-addition of polybutadiene. However, this effect leveled off gradually as the amount of THF increased. Electron microscopic texture and viscoelasticity of diblock copolymer samples cast from THF, toluene, benzene and CCl₄ were examined. Two peaks were observed in the dynamic mechanical loss (tan δ) curve at ?27 and 145°C, corresponding to segmental motions of polybutadiene and poly-α-methylstyrene, respectively. This showed the microphase separation of the block copolymers. Different electron microscopic textures were observed for same sample cast from different solvents.     

Preparation and characterization of end-alkoxysilylated polystyrene and the grafting behaviors onto inorganic pigments. II. Utilization of 4-triethoxysilyl-α-methylstyrene

Novel polystyrene was prepared with triethoxysilyl (TES) groups at the end of the chain, and the grafting behaviors of the resulting polymer onto silica, alumina, and titania were studied. TES groups were introduced by the reaction between living polystyryl anion and 4-triethoxysilyl-α-methylstyrene (1) in THF at 195 K. The end-functional polymer was characterized by GPC, ¹H-NMR, and TLC. It was confirmed that the polymer had several units of 1 at the chain end and a fairly narrow molecular weight distribution. TES groups in the present polymer were found to be hydrolyzed with both acids and bases such as mono-n-butylphosphate (MBP) and tetrabutylammonium hydroxide (TBAH), respectively. The polymer was effectively grafted onto silica and alumina in toluene in the presence of MBP and TBAH, respectively. The amount of graft, estimated by thermogravimetry, changed with the selection of substrates and catalysts; about 2 mg/m² at the highest. The change in the amount of graft can be explained by the amount of effective acidic- or basic-hydroxyl groups on the substrate surfaces. However, titania received the largest amount of graft in the absence of catalyst. This may be because the strong acidic sites on the surface of titania act as a hydrolytic catalyst. The present polymer is expected to find wide application as a macromolecular dispersant for various types of inorganic pigments. © 1996 John Wiley & Sons, Inc.