Polyisobutylene Containing Organic/Inorganic Hybrid Block Copolymers and their Crystalline Behavior

Block copolymer comprising of polyisobutylene (PIB) soft segment and poly(3-(3,5,7,9,11,13,15-heptaisobutyl-pentacyclo[9.5.1.1(3,9).1(5,15).1(7,13)]-octasiloxane-1-yl)propyl methacrylate) (PMAPOSS) hard segment was synthesized by combination of living carbocationic and reversible addition-fragmentation chain transfer (RAFT) polymerizations. Block copolymers were characterized by H-1 and Si-29 NMR spectroscopy, FT-IR study, energy dispersive X-ray spectroscopy (EDX), and gel permeation chromatography (GPC). The EDX, combined with scanning electron microscopy (SEM) was employed for determination of elemental composition. Thermal transition and degradation behaviors were confirmed by differential scanning calorimetry (DSC) and thermo gravimetric analysis (TGA), respectively. Although both the PIB and MAPOSS homopolymers are amorphous in nature, in their block copolymers the PMAPOSS domain showed crystalline behavior, as confirmed from wide-angle X-ray scattering (WAXS) technique, DSC studies and polarized optical microscopy (POM). Interestingly, crystalline melting temperatures (T-m) can be tuned by changing the PIB to PMAPOSS block length ratios. (c) 2015 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2015, 53, 1125-1133