巯基-内酰胺引发活性自由基接枝聚合制备凹凸棒土/聚苯乙烯杂化粒子的研究

Preparation of Attapulgite/Polystyrene Hybrid Particles via Living Radical Graft Polymerization Initiated by Thiol-Lactam System

通过γ-巯丙基三甲氧基硅烷(MTS)与凹凸棒土(ATP)表面上的羟基发生脱醇反应,制得表面巯基化的改性粒子ATP-MTS;基于"引发剂转移终止剂"(iniferter)原理,构建巯基-己内酰胺(thiol-caprolactam)双组份引发剂转移终止体系引发苯乙烯活性自由基接枝聚合,制得表面接枝聚苯乙烯的杂化粒子ATP-g-PS.通过红外光谱(FTIR)、X射线光电子能谱(XPS)、热失重分析(TGA)、高分辨率透射电镜(TEM)等方法对杂化粒子ATP-g-PS的结构、组成、形貌进行了表征.结果表明,巯基-己内酰胺双组份引发剂转移终止体系可有效实现苯乙烯的活性接枝聚合,聚苯乙烯成功接枝到改性粒子ATP-MTS表面;模拟实验表明聚合体系呈现活性聚合的特征,单体转化率和PS的分子量均随反应时间的增加而增大,TGA结果表明制得的杂化粒子表面PS接枝率为33.3%.

The surface of attapulgite （ATP） was treated with the y-mercaptopropyltrimethoxysilane coupling agent （MTS） to give thiol functionalized ATP （ATP-MTS） ,and then a thiol-caprolactam initiation system was constructed with the thiol groups on the surface of ATP-MTS and caprolactam （CL） in the sultion, surfaceinitiated living radical graft polymerization of styrene based on ＂ iniferter＂ was realized to afford polystyrene grafted ATP hybrid particles （ATP-g-PS）. The structure,composition and morphology of hybrid particles were characterized by Fourier transform infrared spectroscopy （ FTIR）, X-ray photoelectron spectroscopy （ XPS）, thermo gravimetric fanalyze （TGA） and transmission electron microscopy （TEM） methods. The polymerization kinetics of solution polymerization with different amounts of caprolactam was discussed in detail by model experiments. The results showed that MTS was bonded onto the surface of attapulgite successfully. Thiolcaprolactam initiation system can effectively initiated styrene to be graft-polymerized from the surface of ATPMTS,and a high grafting degree of 33.3% was obtained according to TGA analysis. The diameter of ATP-g-PS hybrid particles was increased to about 60 nm. The kinetic results revealed the controllability of polymerization, and the conversion and molecular weight of PS increased with increasing polymerization time. Under the condition that the ratio value of [ CL]/[ SH ] was 20/1, the Mn and PDI of PS obtained from slution plymerization were 1.1 × 10^4 and 1.33 respectively when the conversion of monomer was 38.9%.