화학공학소재연구정보센터
Polymer Bulletin, Vol.40, No.2-3, 127-134, 1998
New polyisobutylene stars - XI. Synthesis and characterization of allyl-telechelic octa-arm polyisobutylene stars
The synthesis and characterization of a novel star comprising eight allyl-terminated polyisobutylene (PIB) arms radiating from a calix[8]arene core is described. The synthesis was accomplished by a core-first method, by inducing the living polymerization of isobutylene (IB) by a suitably functionalized calix[8]arene initiator (1) conjunction with BCl3-TiCl4 coinitiators, and terminating the growth of the living PIB+ arms by allyltrimethylsilane. The relative concentrations of BCl3, and TiCl4, are critical for the synthesis of well-defined 8-arm stars. Characterization of the products (which included triple detector GPC studies and H-1 NMR spectroscopy) indicated quantitative allylation. A mechanism which summarizes the experimental observations is proposed.