水溶性偶氮引发剂引发丙烯酸钠的反相乳液聚合反应

采用水溶性偶氮引发剂V50和NaHSO3组成的复合引发剂,通过反相乳液聚合制备了相对分子质量高的聚丙烯酸钠。研究了引发剂种类及用量、乳化剂的HLB值及其用量、反应温度等因素对聚丙烯酸钠相对分子质量的影响规律。并采用正交优化方法对聚丙烯酸钠的聚合反应工艺进行优化研究。结果表明:复合引发剂V50/NaHS03效果优于APS/NaHSO3。最佳聚合工艺条件为复合乳化剂的用量为9%(占油相的质量百分数)、其HLB值为5.7、单体中和度为90%、引发剂用量为2.0%(占单体的质量百分数)、反应温度为40°C。在最佳反应条件下,得到的聚合物相对分子质量可达到2.1×107,溶解时间23 min(0.3 g/100 g H2O,45°C)。

Studies on the Inverse Emulsion Polymerization of Sodium Acrylate via Water-soluble Azo Initiators

High molecular weight sodium polyacrylate was synthesized by inverse emulsion polymerization via water-soluble azo initiation system V50/NaHSO_3.Effects of various factors such as the kinds and the amount of initiator,HLB and the dosage of emulsifier and reaction temperature on molecular weight of sodium polyacrylate were studied.The polymerization process conditions of preparing sodium polyacrylate were also studied by the orthogonal experimental method.The molecular weight of resulted polymer PDA initiated with complex initiator system of V50/NaHSO_3 was higher than that initiated withAPS/NaHSO_3.The optimal process conditions were: the dosage of Op10/Span 60 9%(oil system),its HLB (5.7),neutralization level 90%,the dosage of initiator 2.0%(monomer weight) and reaction temperature 40(°C). The molecular weight of the product at the optimal experimental conditions reached 2.1×10~7 and its soluble time was 23 min(0.3 g/100 g H_2O,45(°C)).