混合溶剂法合成高分子量聚丙烯腈

以偶氮二异丁腈为引发剂 ,采用丙烯腈 (AN)与衣康酸 (IA)为共聚单体在混合介质二甲基亚砜 水 (DMSO H2 O)中自由基沉淀共聚合 ,合成了粘均分子量为 10～ 80× 10 4 的聚合物 .重点研究了聚合反应条件 ,如混合介质DMSO H2 O质量配比、IA单体含量等对聚合反应的转化率和粘均分子量的影响 .还分别采用SEM和落球粘度等手段研究了聚合物的形态结构与溶液性能 .研究结果表明 :降低喂料AN IA配比中IA的含量 ,均有利于提高聚合反应的转化率 .AN与IA共聚反应的转化率随着反应介质中DMSO含量的降低而增加 ,聚合物的粘均分子量也增大 ,同时所得聚合物的颗粒特性发生变化 ,由松软的块状到不规则的细粒状转化 .溶液的粘度随着分子量的增加而增加 ,随着温度的升高而降低 .

Synthesis of higher molecular weight PAN polymers in DMSO/H2O

High molecular weight polyacrylonitrile(PAN) was obtained by the free radical suspension copolymerization of itaconic acid(IA) and acrylonitrile(AN), which was carried out in DMSO/H 2O using azodiisobutyronitrile(AIBN) as initiator. The effects of polymerization parameters, such as IA monomer concentration, DMSO/H 2O ratio, the conversion of polymerization and viscosity average molecular weight were specially described. The copolymerization reaction rate and the viscosity average molecular weight of copolymer decrease with the result of high chain transfer constant of DMSO. For copolymerization of AN and IA, with the inclusion of suitable solvent DMSO, the solution degree of AN in DMSO/H 2O is higher than that in water. As a result, the resulting copolymer pellets becomes from soft bulk to solid grain. The morphology structure PAN copolymers was also studied by the use of SEM. For the same solid content in the PAN solution, high molecular weight polymers have the higher viscosity which will decrease as temperature increases.