油酸咪唑啉在原子转移自由基聚合中的应用

APPLICATION OF OLEIC ACID IMIDAZOLINE IN ATOM TRANSFER RADICAL POLYMERIZATION

以二乙烯三胺和油酸反应合成了油酸咪唑啉(OLC)新配体,以叔丁基过氧化氢和2-溴代丙酸乙酯分别为引发剂,氯化铁、氯化镍、氯化铜分别作催化剂,实现了苯乙烯的反向原子转移自由基聚合和甲基丙烯酸甲酯的电子活化再生原子转移自由基聚合。聚合反应均为"活性"/可控,符合一级反应动力学。OLC在电子活化再生原子转移自由基聚合中具有配体和还原剂双重功能,CuCl_2/OLC体系的苯乙烯反向原子转移自由基聚合得到的聚合物相对分子质量分布较小(1.29),而CuCl_2/OLC体系的甲基丙烯酸甲酯电子活化再生原子转移自由基聚合得到的聚合物相对分子质量分布更小(1.24)。

Reverse atom transfer radical polymerization （RATRP） of styrene （St） and electron transfer for atom transfer radical polymerization（AGET ATRP） of methyl methacrylate （MMA） were studied using oleic acid imidazoline （OLC） as ligand, the relation of the monomer conversion measured by the weight method and the molecular weight （M.） and the molecular weight distribution measured by Gel Permeation Chromatography（GPC） were discussed, respectively. The polymeric kinetics and kinetic parameters of RATRP of St and AGET ATRP of MMA were also investigated. The results showed that the RATRP of St could be successfully carried out using OLC as ligand, hydrogen peroxide tertbutyl as initiator and FeCl3, CuCl2 or NiCl2 as catalysts; the polymerization exhibited first order kinetics and the activity could be well-controlled. For the system of TBHP/CuCl2/OLC, the rate was fast, the molecular weight distribution was as narrow as 1.29 and the initiation efficiency was high （f= 0.89）. The AGET ATRP of MMA was also carried out in the presence of ethyl 2-bromopropanoate as initiator and OLC as ligand that served not only as ligand but also as reducing agents and also showed first order kinetics. Well-controlled poly（methyl methacrylate） （PMMA） with low molecular weight distribution （1.24） was prepared in the presence of Cu（ Ⅱ ）CIz/OLC. The comparison of the kinetic parameters indicated Apparent Rate Constant （kapp） and Concentration of Propagating Radicals of AGET ATRP of MMA were 4.33× 10^-4 s^-1 and 4. 351 × 10^-7 mol/L, respectively, higher than those of RATRP of St.