NaHSO_3-(NH_4)_2S_2O_8引发体系制备低相对分子质量聚丙烯酸钠

Preparation of sodium polyacrylate with lower molecular weight assisted by NaHSO_3-(NH_4)_2S_2O_8

以丙烯酸和氢氧化钠为原料,NaHSO3-（NH4）2 S2 O8为氧化还原引发剂体系,NaHSO3为链转移剂合成低相对分子质量聚丙烯酸钠.研究了单体、引发剂及链转移剂的用量、反应温度和反应时间等对产物相对分子质量的影响.结果表明,反应温度为60℃、w（单体）=25％、w（引发剂）=0.6％、w（链转移剂）=2.0％、反应时间2h,可制得聚丙烯酸钠的粘均相对分子质量在2 000～3 000,单体转化率在98％以上.

Sodium polyacrylate was prepared using acrylic acid and sodium hydroxide as raw materials . Low molecular weight of sodium polyacrylate was synthesized with NaHSO3-（NH4）2S2O8 as initiator and NaHSO3 as chain transfer agent.The influences of factors,such as the concentrations of monomer,initiator and chain transfer agent,the temperature and time of polymerization,on the molecular weight of polymer were discussed.The results showed that lower molecular weight of sodium polyacrylate （about 2 000～3 000）can be obtained at 60 ℃ for 2.0 h,with the monomer concentration of 25％,the initiator concentration of 0.6 ％,the chain transfer agent concentration of 2.0 ％.The conversion of the monomer is above 98％.