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)).