链转移剂单体合成支化聚苯乙烯及其表征

以α-甲基丙烯酸和3-巯基己醇为原料,采用直接酯化法合成了链转移剂单体α-甲基丙烯酸-3-巯基己酯(MMH)。以偶氮二异丁腈(AIBN)为引发剂,在MMH存在下进行苯乙烯的常规自由基聚合反应。通过高效液相色谱、气相色谱、三检测凝胶渗透色谱(TD-GPC)和核磁共振氢谱(1H-NMR)对链转移剂单体、聚合反应过程和聚合物进行了表征分析。结果表明,链转移剂单体MMH的纯度可以达95%以上,以MMH为支化单体,可以通过常规自由基聚合反应合成支化聚苯乙烯,得到的支化聚苯乙烯不但具有相对较高的分子量和相对较窄的分子量分布(-Mw.MALLS=370300,-Mw/-Mn=6.9),而且具有较高的支化程度因而表现出较低的特性黏度(g′=0.427)。

Synthesis and Characterization of Branched Polystyrene with Chain Transfer Monomer

3-mercapto-hexyl methacrylate(MMH),a chain transfer monomer,was synthesized from α-methyl acrylic acid and 3-mercapto-hexanol.The polymerization of styrene was carried out using MMH as the branching agent.Gas chromatography(GC), high-performance liquid chromatography(HPLC),proton nuclear magnetic resonance(1H-NMR) and triple-detection gel-permeation chromatography(TD-GPC) were used to characterize and analyze the chain transfer monomer,the polymerization and the resulting branched polymer.It shows that MMH has moderate storage stability.The polymerization processes are almost the same with and without MMH.As expected,branched polystyrene with high degree of branching is prepared, and the branched polystyrene has high molecular weight,and also relatively narrow molecular weight distribution,compared to polymers prepared via living/controlled radical polymerization.