有关反相乳液聚合法制备聚丙烯酸增稠剂的几个问题

SOME PROBLEMS IN THE PREPARATION OF POLYACRYLIC ACID THICKENER BY INVERSE EMULSION POLYMERIZATION

以两性共聚物为稳定剂、亚甲基双丙烯酰胺为交联剂 ,引发丙烯酸铵进行反相乳液聚合 ,以制备高性能的涂料印花增稠剂。研究了不同的稳定剂、引发剂、共聚单体及链转移剂对聚合的影响。指出甲基丙烯酸十二酯与丙烯酸的共聚物能作为稳定剂 ;过氧化苯甲酰 -二甲基苯胺及叔丁基过氧化氢 -焦亚硫酸钠两种氧化还原引发剂均能在 35℃引发聚合 ,得到 1.5 %白浆粘度分别达 9.2× 10 4m Pa.s及 8.7× 10 4m Pa.s的产物。丙烯酸铵与 15

Thickener was prepared by inverse emulsion polymerization of ammonium acrylate using an amphiphilic copolymer as steric stabilizer, Span 80 as emulsifier and methylene bisacrylamide as crosslinker. The effects of amphiphilic copolymer with different structures, different types initiators, acrylamide as comonomer and diffferent chain transfer agents on the polymerization and the properties of thickener were studied. The results showed that copolymer of dodecyl methacrylate and methacrylic acid can be used as a good steric stabilizer. Two redox initiators, namely, benzoyl peroxide dimethylaniline and tertiary butyl hydrogen peroxide sodium pyrosulfite can initiate the inverse emulsion polymerization at 35 ℃ smoothly and the products obtained after dispersed in water to 1.5% concentration showed a viscosity of 9.3 ×10 4 and 8.7 ×10 4 mPa·s, respectively. When ammonium acrylate acrylate was copolymerization with < 15% acrylamide, the product obtained exhibited a lower viscosity, but higher anti electrolyte ability. Formic acid can play a role of chain transfer agent.