反相乳液聚合制备聚丙烯酸钠

采用反相乳液聚合法合成聚丙烯酸钠 ,研究了反应温度、引发剂用量、乳化剂用量及配比和单体中和度对产物相对分子质量的影响。结果表明 ,最佳的反应温度为 45℃ ,引发剂浓度为 4 0mmol/L ,乳化剂 (占油相 )质量分数为5 % ,单体中和度为 70 %。

Preparation of Poly(Sodium Acrylate) by Inverse Emulsion Polymerization

Poly (sodium acrylate) with high-molecular weight was synthesized with a redox initiator at 30～60 ℃ by inverse emulsion polymerization. The effects of reaction temperature, initiator concentration, molar ratio of oxidant to reductant, emulsifier concentration and weight ratio of compounding emulsifiers as well as acrylic acid neutralization on M w of poly(sodium acrylate) were studied. The results indicate the emulsification and stability of the reaction system are greatly influenced by the weight ratio of compounding emulsifiers and acrylic acid neutralization. The proper reaction temperature is 40～50 ℃. The proper reaction conditions are : initiator concentration , 4×10 -3 mol/L in water phase; molar ratio of oxidant to reductant, 2/1; emulsifier concentration, 5% by weight in total oil phase; hydrophile-lipophile balance(HLB) of compounding emulsifiers, less than 5.65 ; and acrylic acid neutralization, 70%.The M v of the obtained powdery poly (sodium acrylate) ranges from a few million to over ten millions, and the highest M v is up to 30 70 million.