【摘要】 以过硫酸钾(K2S2O8)/硫代硫酸钠(Na2S2O3)氧化还原体系为引发剂,以三乙醇胺(TEA)为添加剂,在氧气存在条件下,进行了N-异丙基丙烯酰胺(NIPAM)的水相可逆加成-断裂-链转移自由基聚合(RAFT聚合).实验结果表明,聚合物分子量随转化率线性增长,分子量分布窄(Mw/Mn≤1.10),ln([M]0/[M])对时间成线性关系,符合一级动力学特征.扩链聚合反应表明,聚合物的分子量随之会继续线性增大.在25~35℃范围内,聚合速率随温度的升高而增加.研究结果表明,聚合反应呈现活性特征,而且在室温和有氧条件下能以较快的反应速度进行.更多还原

【Abstract】 RAFT polymerization of N-isopropylacrylamide(NIPAM) in aqueous solution at room-temperature in the presence of oxygen was conducted by using K2S2O8/Na2S2O3 redox initiator and triethanolamine(TEA) as the additive.The polymers obtained were characterized by GPC.The molecular weight of the polymer linearly increases with the conversion and molecular weight distribution is narrow(Mw/Mn≤1.0).The linear time dependence of ln([M]0/[M]) indicates a first order polymerization.Moreover,the chain extension polymerization demonstrated that the molecular weight of the macro-chain transfer agents linearly increases with monomer conversion.All the facts indicate that the polymerization exhibits living characteristics.Moreover,the polymerization rate increases with temperature in the range of 25~35 ℃.And the polymerization can be performed at a relatively high rate at room-temperature and in the presence of oxygen.更多还原