The synthesis of poly(isoprene-graft-styrene) copolymers with multiple, regularly spaced branch points is reported. The synthetic strategy employs classical anionic polymerization techniques and utilizes a modular approach in which polystyryllithium and alpha,omega-poly(1,4-)isoprenyldilithium are sequentially incorporated into chlorosilane linking centers. Previous syntheses employing this basic strategy have yielded graft copolymers with trifunctional (combs) and tetrafunctional (centipedes) branch points. Here we further develop and extend this methodology to include a novel regular multigraft material with hexafunctional branch points (barbwires); these materials possess polystyrene side chains of uniform length attached in clusters of four at regularly spaced points along a narrow molecular weight distribution polyisoprene main chain. In the synthesis of barbwires, PSLi is added first to 1,6-bis(trichlorosilyl)hexane, in an incremental fashion, until 4 equiv has been incorporated into the linking silane; LiPILi is next added in a slight stoichiometric excess, resulting in a condensation between macromolecular dinucleophiles and dielectrophiles. Homogeneous multigraft samples of all three architectures were synthesized, with a polydispersity index of about 1.2, through fractionation of the raw condensation products.
作者
我是这篇论文的作者
点击您的名字以认领此论文并将其添加到您的个人资料中。
推荐
暂无数据