Macromers by carbocationic polymerization. IV. Synthesis and characterization of polyisobutenyl methacrylate macromer and its homopolymerization and copolymerization with methyl methacrylate

Abstract This article describes the synthesis and characterization of a new macromer, polyisobutenyl methacrylate (PIB‐MA), its free‐radical homopolymerization and copolymerization with methyl methacrylate (MMA) to afford the graft copolymer poly(methyl methacrylate‐ g ‐isobutylene) (PMMA‐ g ‐PIB), the characterization of these polymers, and some physical‐mechanical (stress‐strain) measurements of the graft copolymer. The key intermediate toward the synthesis of the target macromer was the preparation of polyisobutenyl chloride PIB‐Cl t by the minifer technique. As shown by 1 H‐NMR spectroscopy, and independently by IR spectroscopy coupled with M̄ n determination, the PIB‐MA macromer carries one terminal methacrylate function per polyisobutylene chain. The free‐radical homopolymerization of PIB‐MA to very high‐molecular‐weight product was achieved in bulk at 60°C. The free‐radical copolymerization of PIB‐MA with MMA also occurs readily and is a convenient route to PMMA‐ g ‐PIB. The reactivity of PIB‐MA is almost identical to that of MMA; however, in highly viscous systems its rate of diffusion to the reaction site is reduced.