以二甲基二烯丙基氯化铵为阳离子单体与丙烯酰胺共聚，氧化还原剂-偶氮盐为引发体系，采用水溶液法合成高相对分子质量的阳离子型聚丙烯酰胺（PDA）。研究了温度、氧化剂、还原剂和偶氮盐引发剂用量及阳离子单体/丙烯酰胺质量比对聚合物相对分子质量的影响。结果表明，低温和高温引发反应适宜温度分别为15，50℃，氧化剂-还原剂最佳质量比为7.5∶1，产品相对分子质量随阳离子单体/丙烯酰胺质量比增加而减小，氧化-还原剂、偶氮盐与两种单体质量和的质量比分别为0.155%～0.187%和0.0275%～0.0415%时，合成阳离子单体与两种单体质量和的质量比为26%、30%、35%的PDA，相对分子质量分别可达1445万、1000万和910万。

Cationic polyacrylamide(PDA) with high molecular weight was prepared by copolymerization of dimethyldiallylammonium chloride(DMDAAC) as cationic monomer with acrylamide(AM) in a water solution using oxidizer, reductant and azo salt as initiators. The effects of the temperatures, oxidizer, reductant, azo salt and the proportion in quality of DMDAAC to AM on the molecular weight of PAD were studied. The results show that the proper lowtemperature and hightemperature for the reaction were 15℃ and 50℃ respectively; the optimum proportion in quality of oxidizer to reductant was 7.5 to 1; when the reaction condition and the content of initiators kept constant, the molecular weight of PDA reduced with increasing in the content of DMDAAC in PDA; when the ratios in quality of oxido-reductive initiator and azo salt initiator to total quality of two monomer were respectively 0.155%～0.187% and 0.0275%～0.0415%, molecular weight of PDA in which the contents of DMDAAC were respectively 26%,30%,35%, 40% could reach 14.45×104, 10.0×104, 9.1×104.