光聚合制备PVC大分子引发剂及两亲接枝共聚物  

Photo-induced Synthesis of PVC Macroinitiators and Preparation of Amphiphilic Graft Copolymers

作　　者：郑晓曼[1] 杜兰英[2] 马育红[1] 刘莲英[1] 杨万泰[1] 

机构地区：[1]北京化工大学材料科学与工程学院化工资源有效利用国家重点实验室,北京100029 [2]沧州医学高等专科学校,河北061000

出　　处：《高分子学报》2014年第2期248-254,共7页Acta Polymerica Sinica

基　　金：国家自然科学基金(基金号20974008;51273012;21074006);化工资源有效利用国家重点实验室开放课题(项目号0-6463;CRE-2012-C-205)资助项目

摘　　要：利用UV光照自引发、双异丙基硫杂蒽酮(BIITX)和异丙基硫杂蒽酮(ITX)引发氯乙烯(VC)聚合得到含缺陷结构或/和ITX残基的PVC.考察了不同引发方式时单体浓度、光强、反应时间和温度对单体转化率、产物分子量及其分布的影响,UV-Vis、1H-NMR和FTIR分析表明所得PVC含缺陷氯或/和ITX残基.以此PVC为大分子引发剂(缺陷结构和ITX残基为引发点),50℃下有效引发了甲基丙烯酸二甲氨基乙酯(DMAEMA)聚合,获得了PVC-g-PDMAEMA共聚物.相比起始PVC,接枝共聚物分子量稍有提高,PDI下降.1H-NMR和FTIR分析证实了接枝共聚物的形成,接枝共聚物在水(pH=3)中组装形成了稳定核-壳结构胶束,显示其具有两亲性.To increase number of labile sites on PVC and thus facilitate grafting from PVC by aids of free radical polymerization （FRP） under mild conditions, self-initiated, or bi-isopropyl thioxanthone （BIITX） and isopropyhhioxanthone （ITX） initiated FRP of vinyl chloride （VC） in THF at 0 ℃or 20 ℃ was carried out under UV irradiation. Influences of monomer concentration, incident light intensity, reaction time and temperature on monomer conversion, polymer molecular weight and its distribution were investigated. Radical ITX＂ produced by dissociation of BIITX or by H abstraction of ITX from monomer could combine with a macroradical. This allowed ITX residues to be incorporated onto PVC via weak C--C bonds which could be cleaved easily to regenerate radicals under UV light or heat stimuli, and thus yielded new labile sites on PVC for initiation. UV-Vis,H-NMR and FTIR spectra analyses demonstrated the presence of labile chlorines and ITX residues on the resultant PVC, and indicated that PVC resulted from self-initiated or ITX initiated FRP contained great labile sites. Using the PVC as a macroinitiator, grafting polymerization of N, N- dimethylaminoethyl methacrylate （DMAEMA） in THF at 50 ℃was started, and PVC-based graft copolymer （PVC-g-PDMAEMA） was synthesized. Compared with the initial PVC used, the graft copolymer achieved an increased molecular weight and narrowed molecular weight distribution. H-NMR and FTIR analyses further confirmed the formation of PVC-based graft copolymer, and revealed that more labile chlorines or ITX residues on PVC favored initiation of graft polymerization. SEM and TEM observations showed that the graft copolymers containing more than 15 tool% （analyzed by 1H-NMR） of PDMAEMA segments could assemble into stable core-shell micelles in water （pH 3 ）. The grafted hydrophilic PDMAEMA stretched towards aqueous media, forming the shell, while hydrophobie PVC portion coiled up to the core. This phenomenon suggested an amphiphilieity of the graft eopolymers. In

关 键 词：光聚合 PVC 大分子引发剂 接枝共聚物 两亲性 

分 类 号：TQ316.312[化学工程—高聚物工业]