摘要
将乙基黄原酸丙酸乙酯作为链转移剂,进行甲基丙烯酸甲酯(MMA)的可逆加成断链转移自由基聚合(RAFT),并将得到的产物作为大分子链转移剂,加入第二单体苯乙烯(St)进行扩链反应,制备了PMMA-b-PS嵌段共聚物。通过红外光谱、核磁共振、凝胶渗透色谱、热重分析和差示扫描量热等测试手段对制备的PMMA-b-PS嵌段共聚物进行分析表征。研究表明,第二单体St与大分子链转移剂发生了共聚,形成了嵌段共聚物;制备所得PMMA-b-PS嵌段共聚物的数均相对分子质量明显增加,相对分子质量分布变宽,初始热分解温度明显提高,玻璃化转变温度介于PMMA与PS的玻璃化转变温度之间。
Ethyl xanthate ethyl propionate was used as chain transfer agent for reversible addition – fragmentation chain transfer( RAFT) polymerization of methyl methacrylate( MMA). The PMMA-CTA was employed for the preparation of PMMA-b-PS block copolymer by adding the second monomer styrene( St). The PMMA and PMMA-b-PS block copolymer was characterized by FT-IR,1 H-NMR,GPC,TG and DSC. The results indicate that the PMMA macromolecular chain transfer is copolymerized with the second monomer St and the expected block copolymer is formed. The PMMA-b-PS block copolymer possesses a higher molecular weight and a wider molecular weight distribution. The initial decomposition temperature of the PMMA-b-PS block copolymer is significantly increased,while the glass transition temperature is between that of PMMA and PS.
引文
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