Study on process of ultrasound-assisted inverse emulsion copolymerization of cationic polyacrylamide

Cationic polyacrylamide P(DMDAAC-AM) was synthesized by inverse emulsion polymerization with acrylamide(AM) and diallyl dimethyl ammonium chloride(DMDAAC) as co-monomers enhanced by ultrasonic emulsification.The results show that fine droplets can be feasibly produced in the emulsion when treated with ultrasound,leading to a higher stability.The optimal reaction conditions were as follows:initiator K2S2O8 1.6 ‰,emulsifier 8%,hydrophile-lipophile balance number(HLB) 7,mass fraction of monomer 35 %,mass ratio of oil to water 1.1 ∶1.0,ultrasonic time 4 min,cationic degree 15%,reaction temperature 60 ℃,and reaction time 4 h.The copolymer with molecular weight of 3.53×106 was obtained and its composition,P(DMDAAC-AM),was confirmed by a combination of FTIR and SDTA-TGA analysis.It was found that the copolymer prepared with the assistance of ultrasonic irradiation had a good thermal stability as indicated by the high decomposition temperature of 382.83 ℃.