Star-shaped poly(tetrahydrofuran) tetrols were prepared by living cationic ring-opening polymerization of tetrahydrofuran and esterified with bromoacetyl and bromoisobutyryl chloride. The intermediate produced was used as macroinitiator to initiate the atom transfer radical polymerization (ATRP) of styrene and subsequently atom transfer radical polymerization of methyl methacrylate at 80−110 °C with CuBr/2,2‘-bipyridine as catalyst. Kinetic studies and GPC analyses provided the evidences of “living” polymerization: constant concentration of active species, narrow molecular weight distribution, and well control of molecular weight. The NMR spectra and GPC analyses demonstrated the formations of four-armed star polymer and copolymers: S-(PTHF) 4, S-(PTHF-PSt) 4, and S-(PTHF-PSt-PMMA) 4 . For S-(PTHF-PSt) 4, this conclusion was further confirmed by GPC analysis of the PSt obtained from hydrolysis of the copolymer.
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Yijin Xu (2000) studied this question.
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