CuX_2络合物催化甲基丙烯酸甲酯的氧化聚合  

CuX_2 COMPLEX-CATALYZED OXIDATIVE POLYMERIZATIONS OF METHYL METHACRYLATE

作　　者：孙燕[1] 孙晋[1] 宋瑾[1] 黄文艳[1] 蒋必彪[1] 翟光群[1] 

机构地区：[1]常州大学材料科学与工程学院大分子与软物质科学研究室,常州213164

出　　处：《高分子学报》2011年第10期1157-1165,共9页Acta Polymerica Sinica

基　　金：江苏省自然科学基金(基金号BK2008142)资助项目

摘　　要：研究了高氧化态过渡金属卤化物络合物催化甲基丙烯酸甲酯(MMA)的氧化聚合.首先在叔胺类聚合物存在条件下以CuBr2/2,2'-联吡啶(bPy)络合物催化MMA在不同溶剂中的氧化聚合,结果在环己酮中得到PMMA均聚物,CuBr2/bPy同叔胺的氧化还原引发可以忽略.随后在环己酮中分别以不同络合物催化MMA的氧化聚合.结果发现,CuCl2、CuBr2或FeCl3与bPy、N,N,N',N″,N″-五甲基二亚乙基三胺或N,N,N',N'-四甲基乙二胺构成的络合物均可催化MMA的氧化聚合,动力学结果显示聚合速度随着催化剂浓度的增加而提高,所得PMMA分子量在聚合初期增加较快,而在聚合后期变化不大.最后,以不同转化率下所得PMMA引发MMA的ATRP扩链结果显示,在低转化率下所得PMMA几乎都含有C—X(X=Cl或Br)末端,而在转化率较高时,大多数PMMA均为不含C—X基团的死链.因此该聚合过程存在两种不同机理:(1)高氧化态过渡金属卤化物络合物与MMA通过单体加成反应形成ATRP引发剂与催化剂,从而以ATRP机理发生链增长反应,并得到具有C—X末端的PMMA分子链;(2)高氧化态过渡金属卤化物络合物引发/催化MMA以普通自由基聚合机理形成不具有引发能力的PMMA死链.Oxidative polymerizations of methyl methacrylate（MMA） catalyzed by complexes of transition metal halides in high oxidation states were investigated.First,CuBr2/2,2′-bipyridine（bPy）-catalyzed oxidative polymerizations of MMA in the presence of poly（2-（N,N-dimethylamino）ethyl methacrylate） were performed in different solvents.When cyclohexanone was used as a solvent,only poly（methyl methacrylate）（PMMA） was obtained,suggesting redox initiation between CuBr2/bPy and tertiary amines in cyclohexanone is negligible.Second,oxidative polymerizations of MMA catalyzed by different complexes were carried out.Complexes of CuCl2,CuBr2or FeCl3with bPy,N,N,N′,N″,N″-pentamethyldiethylenetriamine or N,N,N′,N′-tetramethylethylenediamine can catalyze oxidative polymerizations of MMA,and polymerization rates increased with the increase of the catalyst concentration.Molecular weight of PMMA increases with monomer conversions initially and maintains constant later.Last,atom transfer radical polymerization（ATRP） chain extension using PMMA from the oxidative polymerizations at different conversions was performed.The results show the C—X functionality of PMMA chains at low conversion was also 100%,and it decreased sharply with conversions.Two different mechanisms were conceived to contribute to the oxidative polymerization of MMA：（1） the complexes form ATRP initiators and catalysts with MMA via monomer addition,and then ATRP proceeds to give rise to PMMA chains with C—X terminal groups;（2） the complexes catalyze/initiate conventional free radical polymerizations of MMA.

关 键 词：甲基丙烯酸甲酯 高氧化态过渡金属卤化物 原子转移自由基聚合 单体加成活化剂再生 氧化还原引发 

分 类 号：TQ316.332[化学工程—高聚物工业]