双硫酯为链转移剂的活性自由基水相聚合  

LIVING FREE-RADICAL POLYMERIZATION IN WATER USING DITHIOESTER AS CHAIN TRANSFER AGENT

作　　者：陈昊鸿[1] 庄荣传[1] 林建[1] 叶剑良[1] 戴李宗[1] 邹友思[1] 

机构地区：[1]厦门大学材料科学系和固体表面物理化学国家重点实验室,福建厦门361005

出　　处：《高分子材料科学与工程》2002年第3期53-56,共4页Polymer Materials Science & Engineering

基　　金：固体表面物理化学国家重点实验室资助课题

摘　　要：在通常的自由基乳液聚合体系中加入双硫酯链转移剂 Ph C(S) SCH(CH3 ) Ph,研究了 3种酯类单体的活性自由基水相聚合。发现在引发剂与链转移剂的摩尔比为 1∶ 3.3～ 1∶ 4时 ,可得到多分散性系数小 (<1.3) ,实测分子量与理论分子量相近的聚甲基丙烯酸丁酯 (PBMA)、聚丙烯酸丁酯 (PBA)等聚合物 ;聚合物的分子量随时间和转化率的增加而增加 ,具有活性聚合特征 ;醋酸乙烯酯的聚合未得到理想产物。以偶氮二异丁腈 (AIBN)为引发剂时 ,合适乳化剂为 OP- 8(占单体量 10 % ) ;以 (NH4) 2 S2 O8引发时 ,合适乳化剂是十二烷基磺酸钠 (占单体量 2 .4 % )与聚乙烯醇 (PVA,占单体量 1% )的混合乳化体系。油溶性引发剂 AIBN具有较好的控制聚合效果。Butyl methacryle(BMA), butyl acrylate(BA) and vinyl acetate(VAc) were polymerized by controlled/living radical polymerization in water using reversible addition fragmentation chain transfer(RAFT process). 1 phenylethyl dithiobenzoate (PhC(S)SCH(CH 3)Ph) was selected as dithioester chain transfer agent, 2,2′ azobis(2 cyanopropane)(AIBN) and ammonium peroxysulfate(APS) were used as initiator respectively. The best ratio of chain transfer agent to initiator for controlling polymer molecular weight and molecular weight distribution was 3.3 ～ 4.0 . The living character of the RAFT process in water was also indicated by the narrow polydispersity product( 1.1 ～ 1.3 ), a linear molecular weight conversion profile, the predictability of the molecular weight from the ratio of monomer consumed to chain transfer agent. By contrast, AIBN was more effective than APS for living radical polymerization in water using reversible addition fragmentation chain transfer, VAc did not polymerize well in this system. The effects of the ratio of chain transfer agent to initiator, surfactants and the amount used on the polymer molecular weight and molecular weight distribution were discussed.

关 键 词：双硫酯 链转移剂 活性自由基 水相聚合 

分 类 号：TQ316.322[化学工程—高聚物工业] O631.5[理学—高分子化学]