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以苯乙烯为单体、氯丙基七异丁基多面体低聚倍半硅氧烷(chloropropyllsobutyl POSS,POSS-Cl)为封端剂、正丁基锂(n-Bu Li)为引发剂、环己烷为溶剂、四氢呋喃(THF)为结构调节剂,采用阴离子聚合技术,合成了POSS端基官能化聚苯乙烯(PS-POSS).采用核磁共振仪(1~H-NMR、~(13)C-NMR)和凝胶渗透色谱仪(GPC)对PS-POSS的结构和分子量分布进行了表征,证明了POSS与聚苯环乙烯锂(PSLi)发生了封端反应生成PSPOSS;封端后分子量分布略有加宽,特别是相比传统有机封端剂,没有二聚等副产物生成.考察了引发剂种类、结构调节剂用量、POSS用量、PS分子量、封端反应温度和时间等因素对PS-POSS封端效率的影响.结果表明,在THF/n-BuLi摩尔比大于5、POSS/n-BuLi摩尔比等于1.1、反应温度为60℃、反应时间为30 min时,封端效率最高,达到80%以上;而随着PS数均分子量增加,封端效率逐渐降低.
Using styrene as monomer, chloropropyllsobutyl POSS (POSS-Cl) as blocker and n-Bu Li as initiator, POSS functionalized polystyrene (PS-POSS) was synthesized by the anionic polymerization technique using hexane as solvent and tetrahydrofuran as structural modifier.Using nuclear magnetic resonance (~ H-NMR, ~ (13) The structure and molecular weight distribution of PS-POSS were characterized by GPC and GPC. It was proved that POSS reacted with PSLi to form PSPOSS. The molecular weight of PS-POSS Compared with the traditional organic end-capping agents, no dimerization and other by-products were formed.The effects of initiator type, the amount of structure regulator, the amount of POSS, PS molecular weight, the temperature and time of capping reaction PS-POSS.The results showed that the efficiency of end-capping was the highest when the molar ratio of THF / n-BuLi was above 5, the POSS / n-BuLi molar ratio was equal to 1.1, the reaction temperature was 60 ℃ and the reaction time was 30 min , Reaching more than 80%; and as the PS number average molecular weight increases, the end-cap efficiency decreases.