含亲水羟基丙烯酸酯单体的乳液聚合动力学

Kinetics of acrylate emulsion polymerization containing hydrophilic hydroxyl acrylate monomer

研究了反应温度、乳化剂用量、引发剂用量和羟基单体用量对含亲水羟基丙烯酸酯单体乳液聚合动力学的影响.结果表明:反应温度和引发剂用量对含有亲水单体的丙烯酸酯乳液聚合影响较大,较理想的反应温度在75℃以上,聚合反应的表观活化能为62.3 kJ/mol;乳化剂或引发剂用量增加,乳液聚合速率加快,单体转化率提高,聚合速率Rp对乳化剂浓度[S]的关系为Rp∝0.436[S],对引发剂浓度[I]的关系为Rp∝1.57[I];含有亲水单体时,乳液聚合有一定的引发诱导期,其用量对初期单体转化率影响不大,而最终转化率随用量的增加而提高,聚合速率与亲水单体浓度[OH]的关系为Rp∝-0.13[OH].

Kinetics of acrylate emulsion polymerization containing higher level of hydrophilic hydroxyl monomer was carried out.The effects of reaction temperature,the level of emulsifier,initiator,and hydrophilic hydroxyl methacrylate（HEMA） on the monomer conversion and polymerization rate were investigated.The results showed that the temperature and the level of initiator had great influence on the emulsion polymerization system,the ideal polymerization temperature was 75 ℃,and apparent active energy was 62.3 kJ/mol.As the concentration of emulsifier [S] or initiator [I] increased,the polymerization rate（Rp） increased,the relationship was Rp∝0.436×[S] and Rp∝1.57×[I].There existed inducing period when acrylate emulsion polymerization was carried out in the presence of hydrophilic monomer.The concentration of HEMA（[OH]） had a little of influence on initial monomer conversion,but final monomer conversion increased with the increase of HEMA level.The relationship of polymerization rate and [OH] was Rp∝-0.13×[OH].