Unimolecular combination of an atom transfer radical polymerization initiator and a lactone monomer as a route to new graft copolymers
Unimolecular combination of an atom transfer radical polymerization initiator and a lactone monomer as a route to new graft copolymers
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DOI：
10.1021/ma982005a
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发表时间：
1999-08-10
期刊：
影响因子：
5.5
通讯作者：
Hedrick, JL
中科院分区：
文献类型：
--
作者：
Mecerreyes, D;Atthoff, B;Hedrick, JL
描述了一种新的环状酯，γ-（2-溴-2-甲基丙酰基）-ε-己内酯（3）的合成、聚合和共聚，所述环状酯含有侧基活化的烷基溴官能团。这种新化合物既可作为“活性”开环聚合（ROP）的单体，也可作为可控原子转移自由基聚合（ATRP）的引发剂。通过连续或同时活性聚合方法，研究了三种不同的聚己内酯-接枝-聚甲基丙烯酸甲酯共聚物的合成路线。第一种方法涉及具有3的各种组成的ε-己内酯的ROP，随后通过ATRP从活化的烷基溴位点沿聚酯主链沿着聚合甲基丙烯酸甲酯。或者，α-内酯官能化甲基丙烯酸甲酯大分子单体通过由3引发的甲基丙烯酸甲酯的ATRP制备。大分子单体与ε-己内酯通过ROP共聚形成目标接枝共聚物。最后，接枝共聚物可以在一个简单的一步方法中制备的ε-己内酯，3，和甲基丙烯酸甲酯与适当的引发剂的ROP和ATRP的催化剂一起的并行聚合。新的单体能够实现新的接枝共聚物，其具有脂族聚酯主链和可控分子量和窄多分散性（类似于1.3）的聚（甲基丙烯酸甲酯）接枝物。
The synthesis, polymerization, and copolymerization of a new cyclic ester, gamma-(2-bromo-2-methyl propionyl)-epsilon-caprolactone (3), containing a pendent-activated alkyl bromide functional group is described. This new compound serves as both a monomer for "living'' ring-opening polymerization (ROP) as well as an initiator for the controlled atom transfer radical polymerization (ATRP). Three distinctive routes to poly(epsilon-caprolactone)-graft-poly(methyl methacrylate) copolymers were surveyed by either sequential or concurrent living polymerization procedures. The first approach involves the ROP of epsilon-caprolactone with various compositions of 3, followed by the polymerization of methyl methacrylate via ATRP from the activated alkyl bromide sites along the polyester backbone. Alternatively, alpha-lactone functional methyl methacrylate macromonomers were prepared by ATRP of methyl methacrylate initiated from 3. The macromonomers were copolymerized with epsilon-caprolaetone via ROP to form the target graft copolymers. Finally, the graft copolymers could be prepared in a simple one-step approach by the concurrent polymerization of epsilon-caprolactone, 3, and methyl methacrylate together with the appropriate initiator for the ROP and the catalyst for the ATRP. The new monomer enabled new graft copolymers having an aliphatic polyester backbone with poly(methyl methacrylate) grafts of controlled molecular weight and narrow polydispersities (similar to 1.3).