含弱键结构苯乙烯衍生物、聚合物的设计合成及其在橡胶中的应用

发布时间：2018-08-29 10:52

【摘要】：具有弱键结构的化合物受热易分解产生自由基,可作为自由基聚合的引发剂或炭材料的改性剂。将弱键结构引入苯乙烯单体或聚合物对复杂精细结构聚合物合成方法学以及高分子材料改性具有重要意义。相比于链端和主链中弱键聚合物,侧基为弱键结构的聚合物具有官能化程度高、结构控制准确、后续反应不会影响主链结构等特点。本文在综合分析及研究多种模型化合物热解行为的基础上,设计合成了三种含有碳-碳或碳-氮弱键结构的苯乙烯衍生物,以其为构筑单元设计合成了多种侧基含弱键结构的聚合物及其他复杂精细结构高分子。基于碳材料表面对自由基的捕捉机理将所制备的侧基弱键官能化溶聚丁苯橡胶应用于对炭黑(CB)和石墨烯(GNS)等碳基填料的原位接枝改性,制备了两种具有高分散、强界面作用的碳基填料/橡胶复合材料。主要研究工作及取得的成果如下:(1)含弱键结构苯乙烯衍生物的设计合成。基于弱键化合物1,1,2-三苯乙烷(TPE)结构以及化学键键能的分析,设计并合成了另外两种与TPE结构相似的化合物1,1,1,2-四苯乙烷(TEPE)和N,N-二苯基苄基胺(DPBA)。研究了 TEPE和DPBA热解机理。结果表明,TEPE/DPBA在85℃以上的时候可以裂解产生苄基自由基和二苯甲基/二苯胺基自由基,并引发MMA自由基聚合。在此基础上,以对氯甲基苯乙烯为母体,设计合成了侧基分别为TPE、DPBA、TEPE的新型苯乙烯衍生物:4-(1,1-二苯乙基)苯乙烯(DPES)、4-(N, N-二苯胺基甲基)苯乙烯(DPAMS)和4-(1,1,1-三苯乙基)苯乙烯(TPES)。(2)含弱键结构苯乙烯衍生物的聚合物的设计合成。分别通过DPES、TPES、DPAMS的负离子聚合,制备了侧基为弱键结构的聚合物,并研究了上述苯乙烯衍生物最佳的负离子聚合反应条件。研究结果表明,DPES在环己烷与四氢呋喃混合溶剂(V环己烷/V四氢呋喃=20)、n-BuLi聚合体系中的负离子聚合反应为活性聚合,反应所得PDPES分子量和结构精确可控;TPES在有机溶剂中溶解性差,无法通过负离子聚合得到分子量可控分子量分布窄的PTPES; DPAMS在四氢呋喃、-78℃、sec-BuLi聚合体系中的负离子聚合反应可控性强,所得PDPAMS分子量可控,分子量分布较窄。上述侧基弱键聚合物与烯烃单体一同加热到90℃以上,弱键聚合物热解产生聚合物自由基引发烯烃单体聚合,从而得到不同结构的接枝聚合物。根据上述机理提出了一种基于阴离子-自由基机理转换制备接枝聚合物的方法,并成功合成了PMMA-g-PDPES 和 hypergrafted PDPAMS。这种合成PMMA-g-PDPES的聚合体系,反应条件温和,适用单体种类广泛,可用于制备更多种类的极性-非极性接枝聚合物。这种方法制备的hypergrafted PDPAMS,侧链为超支化结构,并且改变主链PDPAMS的分子量可对hypergrafted PDPAMS的分子量进行调控。(3)弱键官能化丁苯共聚物在碳基填料增强橡胶中的应用。利用含碳-碳弱键苯乙烯衍生物(DPES/TPES)、苯乙烯和丁二烯的负离子共聚合方法合成了不同DPES含量的官能化丁苯橡胶(SBDR)和不同TPES含量的官能化丁苯橡胶(SBTR)。SBDR链中DPES的含量和SBTR链中TPES的含量可由单体的投料比和n-BuLi的用量进行调控。另外,弱键官能化溶聚丁苯橡胶负离子聚合条件接近负离子工业化产品生产条件,具有很好的工业适用性。通过SBDR与炭黑(CB)的接枝反应证明了 SBDR与CB之间的共价键结合。研究了DPES引入SBDR链中对于CB填充SBDR硫化胶性能的影响,结果表明随着DPES在SBDR链中含量的升高,CB在SBDR基体中的分散性变好,CB/SBDR硫化胶的力学性能提高,0℃的tanδ升高,60℃的tanδ降低,表明材料具有高强度、高抗湿滑、低滚动阻力的性能,可用于绿色环保轮胎。硫化曲线以及XPS测试结果说明,SBTR与石墨烯(GNS)热处理后生成含SP3碳原子的共价键。研究了 TPES引入SBTR链中对GNS填充SBTR硫化胶性能的影响,结果表明随TPES在SBTR中含量的升高,GNS与SBTR基体之间的界面结合增强,GNS在SBTR基体中的分散性改善,GNS/SBTR硫化胶的力学性能提高。本论文设计合成的弱键官能化溶聚丁苯橡胶不含杂原子,实现了 CB和GNS增强橡胶体系的原位接枝改性。
[Abstract]:Compounds with weak bond structure can be easily decomposed to produce free radicals by heating and can be used as initiator of free radical polymerization or modifier of carbon materials.The introduction of weak bond structure into styrene monomer or polymer is of great significance to synthesis methodology of complex fine structure polymers and modification of polymer materials. Polymers with weakly bonded side groups have the characteristics of high functionalization, accurate structure control and no influence on the structure of the main chain. Based on the comprehensive analysis and study of the pyrolysis behavior of various model compounds, three styrene derivatives with weakly bonded carbon-carbon or carbon-nitrogen structure were designed and synthesized. Polymers with weakly bonded side groups and other complex fine structures were synthesized by unit design. Based on the free radical trapping mechanism on the surface of carbon materials, the prepared weakly bonded side group functionalized SBR was applied to in-situ grafting modification of carbon-based fillers such as carbon black (CB) and graphene (GNS). The main research work and achievements are as follows: (1) Design and synthesis of styrene derivatives with weak bond structure. Based on the analysis of the structure of weak bond compound 1,1,2-triphenylethane (TPE) and the bond energy of chemical bond, two other compounds 1,1,1,1,1 similar to TPE were designed and synthesized. 2-tetraphenylethane (TEPE) and N,N-diphenylbenzylamine (DPBA). The pyrolysis mechanism of TEPE and DPBA was studied. The results showed that benzyl radical and diphenylmethyl/diphenylamine radical could be produced by the pyrolysis of TEPE/DPBA at above 85 C, and MMA radical polymerization was initiated. On this basis, p-CHLOROMETHYLSTYRENE was used as the parent material to design and synthesize the side. New styrene derivatives with TPE, DPBA and TEPE groups: 4-(1,1-diphenylethyl) styrene (DPES), 4-(N, N-diphenylaminomethyl) styrene (DPAMS) and 4-(1,1,1-triphenylethyl) styrene (TPES). (2) Design and synthesis of styrene derivatives with weak bond structure. Side groups were prepared by anionic polymerization of DPES, TPES and DPAMS, respectively. The results showed that the anionic polymerization of DPES in the mixed solvent of cyclohexane and tetrahydrofuran (V-cyclohexane/V-tetrahydrofuran=20) and n-BuLi system was active polymerization, and the molecular weight and structure of PDPES obtained by the reaction were accurate and feasible. Controlled; TPES is poorly soluble in organic solvents and can not be obtained by anionic polymerization with narrow controllable molecular weight distribution; DPAMS is highly controllable in tetrahydrofuran, - 78 C, sec-BuLi polymerization system, resulting in controllable molecular weight and narrow molecular weight distribution of PDPAMS. The graft copolymers with different structures were synthesized by the free radical polymerization of weakly bonded polymers which were heated above 90 C. Based on the above mechanism, a method of preparing graft copolymers based on anion-free radical mechanism conversion was proposed. PMMA-g-PDPES and hypergrafted PDPAMS were successfully synthesized. Polymerization system of PMMA-g-PDPES was synthesized under mild reaction conditions and suitable for a wide range of monomers. It can be used to prepare more kinds of polar-nonpolar graft polymers. The hypergrafted PDPAMS prepared by this method has hyperbranched side chains, and the molecular weight of the hypergrafted PDPAMS can be controlled by changing the molecular weight of the main chain. Application of bonded functionalized styrene-butadiene copolymers in carbon-based filler reinforced rubber. The functionalized styrene-butadiene rubber (SBDR) with different DPES contents and functionalized styrene-butadiene rubber (SBTR) with different TPES contents were synthesized by anionic copolymerization of carbon-carbon weakly bonded styrene derivatives (DPES/TPES), styrene and butadiene. The content of TPES in BTR chain can be controlled by the ratio of monomers and the amount of n-BuLi. In addition, the weak-bond functionalized SSBR has good industrial applicability because its anionic polymerization conditions are close to the production conditions of anionic industrial products. The covalent bonding between SBDR and CB is proved by the grafting reaction of SBDR and CB. The effect of DPES on the properties of CB-filled SBDR vulcanizates was investigated. The results showed that with the increase of DPES content in SBDR chain, the dispersion of CB in SBDR matrix was improved, the mechanical properties of CB/SBDR vulcanizates were improved, the tan_ _ _ _ _uuuuuuuuuuu The curing curve and XPS test results showed that the covalent bond containing SP3 carbon atom was formed between SBTR and graphene (GNS) after heat treatment. The mechanical properties of GNS/SBTR vulcanizates were improved with the improvement of dispersion in SBR matrix. The weak bond functionalized SBR was designed and synthesized without heteroatoms, and the in-situ grafting modification of CB and GNS reinforced rubber systems was realized.
【学位授予单位】：北京化工大学
【学位级别】：博士
【学位授予年份】：2017
【分类号】：O632.13;TQ330.1

【参考文献】