【摘要】 用稀土催化剂ＲＥ（Ｐ２０４）３（ｉＢｕ）３ＡｌＢｒＣＨ２ＣＨ２Ｂｒ（ＲＥ＝Ｎｄ，Ｐｒ，Ｙ等）合成嵌段共聚物Ｐ（ＩＰｂＭＭＡ）．系统考察了共聚合反应特征，以ＤＳＣ，１ＨＮＭＲ，１３ＣＮＭＲ技术研究了该嵌段共聚物的微结构．发现以二溴乙烷为添加剂的稀土催化体系是制备Ｐ（ＩＰｂＭＭＡ）的良好催化剂，共聚物含２个玻璃化转变温度，分别为－７５６℃和１２９℃，嵌段共聚物的结构规整，（ＩＰ）ｍ段以ｃｉｓ１，４结构为主，其含量为９７％左右，３，４结构为３％左右，链节间以头尾方式连接．（ＭＭＡ）ｎ段以间同立构为主，其含量达７４％．更多还原

【Abstract】 Poly(isoprene b methyl methacrylate) block copolymer has been synthesized by rare earth coordination catalysts,which are composed of rare earth 2 ethyl hexyl phosphonates RE(P 204 ) 3 ,triisobutyl aluminum Al( i Bu) 3 and 1,2 dibromoethane DBE .It is found that the rare earth coordination catalysts are highly active for the block copolymerization of isoprene and methyl methacrylate.The diblock copolymer prepared has been characterized by DSC, 1H NMR and 13 C NMR.The block copolymer has two glass transition temperatures at -75 6℃ and 129℃ corresponding to the isoprene block phase and the methyl methacrylate block phase,respectively.The microstructure of the diblock copolymer is a highly stereoregular.For the isoprene scgment in the diblock copolymer it mainly exists in the form of cis 1,4 addition.The content of cis 1,4 addition is 97% and of 3,4 addition is 3%.For the methyl methacrylatc segment it is mostly syndiotactic,which is 74% syndiotacticity,4% isotacticity and 22% heterotacticity.The n (ad) probabilities of methyl methacrylate units in the block copolymer are calculated,and it is showed that the methyl methacrylate segment obeys second order Markov statistics model.更多还原