沉淀聚合法合成聚丙烯酸的研究

聚丙烯酸用作锌锰电池凝胶剂可改善CMC胶凝剂易水解的弊病,使电池性能得到根本性提高。丙烯酸的聚合活性大,是一个强放热反应,特别是纯聚丙烯酸,难以用普通方法得到。以偶氮二异丁腈为引发剂、正己烷为溶剂,用沉淀聚合法制备聚丙烯酸。研究了引发剂用量、相对分子质量调节剂用量、单体浓度等因素对聚合物黏均相对分子质量的影响,合成出黏均相对分子质量在9000~270000之间的聚丙烯酸,且单体转化率在96%以上。扫描电镜显示产物为细腻蓬松的粉末。沉淀聚合法可直接得到粉末状产品,后处理简单,溶剂可回收利用,是一种高效、低成本的聚合方法。

The Synthesis of Polyacrylic Acid by Precipitation Polymerization

As a gelling agent for Zn/MnO2 battery,polyacrylic acid can improve the performance of the battery to avoid hydrolyzation which is a disadvantage of the CMC gelling agent.The polymerization of acrylic acid is too active to get pure polyacrylic acid with common method.Polyacrylic acid is synthesized by precipitation polymerization in hexane with using azodiisobutyronitrile as an initiator.The influences of the initiator and molecular weight regulator amount,monomer concentration on the viscosity average molecular weight of polymer are discussed.The polyacrylic acid with a viscosity average molecular weight from 9000 to 270000 can be synthesized while the monomer conversion is above 96%.It is found that the production is fine fluffy powder observed by SEM.Precipitation polymerization is an effective,low cost method which can gain powdery production directly with a simple post treatment and the solvent can be recycled.