| 초록 |
Semicrystalline ternary poly(α-methylstyrene-b-isobutylene-b-pivalolactone) linear triblock copolymers (poly(αMeSt-b-IB-b-PVL)) have been synthesized via the combination of living cationic sequential block copolymerization and site-transformation from living cationic to anionic ring-opening polymerization (AROP). First, poly(αMeSt-b-IB) copolymer was synthesized by living cationic polymerization using chain end modification of living PαMeSt ends with a small amount of p-chloro-α-methylstyrene before the addition of IB and TiCl4. After complete conversion of IB, capping with 1,1-diphenylethylene followed by in-situ quenching with 1-methoxy-1-trimethylsiloxy-propene resulted in poly(αMeSt-b-IB) copolymer having ω-methoxycarbonyl group. Poly(αMeSt-b-IB) ω-carboxylate macroinitiator, prepared by subsequent hydrolysis of ω-methoxycarbonyl group, initiated AROP of PVL in conjunction with 18-crown-6 in THF at 60 °C. Characterization by 1H NMR spectroscopy and DSC confirmed that poly(αMeSt-b-IB-b-PVL) copolymers were obtained with low glass transition (Tg = -66 °C) rubbery PIB, amorphous glassy PαMeSt, and high melting (Tm = 232 ~ 235 °C) PPVL with 72 ~ 92% of crystallinity. |
