【作者】 张雪涛；

【导师】 李杨；

【作者基本信息】 大连理工大学 ， 高分子材料， 2009， 博士

【摘要】 高反式聚丁二烯（HTPB）及其共聚物具有低的压缩生热、优异的耐疲劳性、耐磨性、耐撕裂性以及低温性能,而且其粘着性和生胶强度也很突出,在轮胎工业中可用做配胶,用以提高轮胎的性能,是发展高性能子午线轮胎的理想胶料。合成高反式聚丁二烯及其共聚物的催化体系主要有Zigler-Natta体系和阴离子聚合体系,其中阴离子聚合因为具有活性可以对聚合物进行精细的分子结构设计,所以可以定制不同结构的聚合物,从而满足不同性能的需求。因此,本文综述了前人的研究成果并在其基础上进行了阴离子聚合制备高反式聚丁二烯及其共聚物的研究,通过分子设计合成了一系列含HTPB的结晶-非结晶嵌段聚合物。本文采用二乙二醇单乙醚基钡（BaDEGEE）、三异丁基铝（TIBA）和烷基锂（RLi）组成三元引发体系,合成了高反式聚丁二烯及其共聚物,重点考察了Al/Li对聚合物微观结构的影响。对丁二烯（Bd）、异戊二烯（Ip）和苯乙烯（St）进行了均聚合动力学的研究,并对Bd-Ip的共聚合动力学进行了研究。最后,采用上述引发体系合成了一系列含HTPB的结晶-非结晶嵌段聚合物,并对其结构和性能进行了研究。主要研究结果及结论如下:随着Al/Li的增加,聚丁二烯（PB）的反式结构含量从50%增加到89%;聚异戊二烯（PI）的反式-1,4-结构含量从24%增加到46%,并且其3,4结构含量也有所增加;聚苯乙烯（PS）的微观结构基本没有变化,为无规聚苯乙烯。聚合温度的降低有利于提高PB的反式结构,我们通过降低聚合温度得到了反式-1,4-结构含量为92.1%的高反式聚丁二烯。随着反式-1,4-结构含量的增加,聚丁二烯由无定形态经过中间过渡态（半结晶态）逐渐转变为结晶态。Al/Li对丁二烯、异戊二烯和苯乙烯的聚合动力学影响较为显著,尤其是对苯乙烯,当Al/Li大于1.0时阻滞作用尤其明显;而对于丁二烯和异戊二烯,当采用不同的烷基锂时影响规律又不尽相同。对于丁二烯-异戊二烯共聚合,竞聚率r_Bd＞r_Ip,随着温度的升高或者Al/Li的增加,r_Bd下降,r_Ip升高,它们的乘积r_Bdr_Ip逐渐增大并趋于恒定,说明共聚物的无规性变好;另外,通过降低聚合温度或者提高Al/Li,可以使共聚趋近恒比共聚。研究了二乙二醇单乙醚基钡/三异丁基铝/正丁基锂体系下苯乙烯的阴离子聚合,发现,当采用二乙二醇单乙醚基钡/聚苯乙烯基锂体系时,所得聚苯乙烯的分子量分布为双峰分布,据此提出了“同时促进-阻滞聚合”的假设:当0＜Ba/PSLi＜0.17时,聚合体系表现出“促进聚合”特性;当0.17≤Ba/PSLi＜0.33时,聚合体系表现出“同时促进-阻滞聚合”特性;当Ba/PSLi≥0.33时,聚合体系表现出“阻滞聚合”特性。通过分子设计,采用二乙二醇单乙醚基钡/三异丁基铝/烷基锂体系合成了非结晶-结晶立构两嵌段聚丁二烯（LCPB-b-HTPB）、结晶-非结晶-结晶对称立构三嵌段聚丁二烯（HTPB-b-LCPB-b-HTPB）和结晶-非结晶星型立构嵌段聚丁二烯（C-（LCBR-b-HTPB）n）,研究发现,三种类型的立构嵌段聚丁二烯均存在冷结晶现象,这是因为低顺聚丁二烯的柔顺性导致发生“润滑效应”,诱使结晶性的高反式聚丁二烯发生冷结晶。通过与异戊二烯或者苯乙烯共聚,合成了含高反式聚丁二烯的丁二烯-异戊二烯嵌段共聚物（包括HTPB-b-PI,C-（PI-b-HTPB）n,C-（HTPB-b-PI）n和PI-b-HTPB-b-PI）和丁二烯-苯乙烯嵌段共聚物（包括HTPB-b-PS,C-（PS-b-HTPB）n,C-（HTPB-b-PS）n和PS-b-HTPB-b-PS）,对嵌段共聚物的结构和性能进行了系统的研究。研究发现:对于丁二烯-异戊二烯嵌段共聚物,当聚异戊二烯嵌段达到一定链长时,高反式聚丁二烯嵌段出现冷结晶;对于丁二烯-苯乙烯嵌段共聚物,无冷结晶现象,当聚苯乙烯嵌段达到一定链长时,发生微观相分离,聚合物出现两个玻璃化转变温度,一个属于聚丁二烯相,一个属于聚苯乙烯相。综上所述,提出了含高反式聚丁二烯的结晶-非结晶嵌段聚合物产生冷结晶的条件:其一为嵌段具有一定的柔顺性;其二为嵌段达到一定的长度。由于聚苯乙烯嵌段为硬段,所以即使达到一定的长度也不会产生“润滑效应”而冷结晶;虽然聚异戊二烯嵌段具有一定的柔顺性,但是当其长度不够时,依然没有冷结晶产生,仅当聚异戊二烯嵌段达到一定长度时,才产生冷结晶。更多还原

【Abstract】 High trans-1,4-polybutadiene（HTPB） and its copolymers exhibit desirable dynamic properties,such as excellent antifatigue,low rolling resistance,low heat buildup,good green strength and low abrasion loss.These properties make HTPB and its copolymers the idea materials for the production of high performance tires.HTPB can be prepared with Ziegler-Natta catalysts of Ti,Ni,Co,V,or anionic polymerization initiators.Due to the living nature,anionic polymerization is able to well design the macromolecules to meet different requirements.Fully recognizing the significant advantages of anionic polymerization,the syntheses of HTPB and its copolymers by anionic polymerization are surveyed.The preparation of HTPB and its copolymers were investigated,a series of block copolymers containing HTPB were also designed and synthesized.The initiation system was composed of di（ethylene glycol） ethyl ether（BaDEGEE）, triisobutylaluminium（TIBA）,and alkyllithium（RLi）.The homopolymerization of Butadiene （Bd）,Isoprene（Ip）,or Styrene（St） and the copolymerization of Bd and Ip were studied.The effect of Al/Li ratio on the microstructure of the polymer and the kinetic behavior were both carefully investigated.Last,but not least,a series of block copolymers containing HTPB were synthesized and characterized.The main results and conclusions are as follows:The trans-1,4 content of polybutadiene（PB） increased from 50%to 89%along with the increasing of Al/Li ratio;the trans-1,4 content of polyisoprene（PI） increased from 24%to 46%as well as 3,4 content along with the increasing of Al/Li ratio;the microstructure of polystyrene（PS） was invariable and atactic.In addition,the trans-1,4 content of PB was promoted to 92.1%by lowering the polymerization temperature.The morphology of PB transformed from amorphous phase to crystalline phase through the intermediate state of semicrystalline phase with the increasing trans-1,4 content of PB.The kinetic behavior of Bd, Ip,or St was significantly influenced by Al/Li ratio,especially for St,the retarding effect was obvious when Al/Li ratio was bigger than 1.0;when using different RLi,the effect of Al/Li ratio on the kinetic behavior of Bd and Ip was different.For Bd-Ip copolymerization,the value of r_Bd was bigger than that of r_Ip and decreased with the increasing of polymerization temperature or Al/Li ratio,however,the value of r_Ip increased.The value of r_Bdr_Ip increased and approaching to constant,which indicated the random nature of the copolymer. Furthermore,the copolymerization of Bd and Ip tended to be constant copolymerization by lowering the polymerization temperature or raising Al/Li ratio.The anionic polymerization of St using BaDEGEE/TIBA/n-BuLi as initiation system was investigated.The molecular weight distribution of PS obtained by BaDEGEE/PSLi was bimodal distribution.Simultaneous promoted-retarded polymerization was supposed and proved to be responsible for the bimodal distribution:the polymerization was promoted when 0＜Ba/PSLi＜0.17,the polymerization was simultaneous promoted and retarded when 0.17≤Ba/PSLi＜0.33,and the polymerization was retarded when Ba/PSLi≥0.33.Noncrystalline-crystalline stereo diblock PB（LCPB-b-HTPB）,crystalline-noncrystalline -crystalline stereo triblock PB（HTPB-b-LCPB-b-HTPB）,and crystalline-noncrystalline star-shaped stereoblock PB were well designed.Attributed to the lubricant-effect of flexible LCPB,cold crystallization was observed in stereoblock PB.Bd-Ip block copolymers（HTPB-b-PI,C-（PI-b-HTPB）n,C-（HTPB-b-PI）n,and PI-b-HTPB -b-PI） and Bd-St block copolymers（HTPB-b-PS,C-（PS-b-HTPB）n,C-（HTPB-b-PS）n, and PS-b-HTPB-b-PS ） containing crystallizable HTPB were well synthesized,the microstructures and properties of the copolymers were investigated in detail.When the chain length of PI segments was long enough,cold crystallization was observed in Bd-Ip block copolymers,however it was not observed in Bd-St block copolymers.When the chain length of PS segments in Bd-St block copolymers was long enough,micro phase separation took place and two glass transition temperatures were observed and belonged to amorphous PB phase and PS phase,respectively.As a consequence of the above,the requirements of cold crystallization were list as follows:the segments were soft and long enough.Because the PS segments were hard,which resulted in no lubricant effect,cold crystallization was not observed although the chain length of PS segments was long enough.In the same way,the soft PI segments with insufficient chain length could not induce cold crystallization;however,the cold crystallization took place when the length of soft PI segments was long enough.更多还原