以维生素C为还原剂、AGETATRP为引发体系引发的甲基丙烯酸甲酯活性自由基聚合

"Living" Radical Polymerization of Methyl Methacrylate with AGET ATRP Initiating System Using Vitamine C as Reducer

在甲基咪唑/乙酸盐离子液体中,由维生素C(Vc)/Cu2+/2-溴异丁酸乙酯(EBiB)为引发体系引发的甲基丙烯酸甲酯的聚合反应具有原子转移自由基聚合的特征且反应可控。使用Vc/Cu2+为催化体系避免了Cu+易被氧化的缺点。该催化体系有较高的活性,可使聚合反应以较快的速率进行。所用的离子液体具有较高的粘度,它降低了反应中生成的Cu+在其中的扩散速率,以致聚合反应具有诱导期。增加Vc的浓度能加快聚合反应的速率,Vc过量较多会降低聚合反应的可控度,氧气存在与否对聚合反应无影响。

Atom transfer radical polymerization of methyl methacrylate in [Hmim][CH3COO] ionic liquid was investigated by using Vc/CuBr2/EbiB as an initiating system. Results indicated that the polymerization exhibited active nature and was controllable. Disadvantages in atom transfer radical polymerization （ATRP） using Cuas catalyst which was easily oxidated by oxygen could be avoided by using Vc/ Cu^2- as catalytic system. The higher viscosity of ionic liquid would decrease the diffusion rate of Cu^＋ , formed in the reaction, which caused an induction period for the polymerization. An increase in the concentration of Vc would promote the reaction rate, however, the controllability of polymerization would decrease. The polymerization could be performed in the presence of air.