EFFECT OF PVC ON LOW-POLAR ISOBUTYLENE POLYMERIZATION IN THE PRESENCEOF BCL3 .2. VINYL CHLORIDE 2-CHLOROPROPENE COPOLYMER AS AN INITIATOR/

The low-polar polymerization of isobutylene (IB) in the presence of BC l3 was carried out in CH2Cl2 ([IB] = 7 mol/l) at -78, -20 and +20 degr ees C in the presence of vinyl chloride/2-chloropropene (VC/2CP) copol ymer, representing PVC resin enriched in structures with chlorine atom s bonded to the tertiary carbons. The polymerization products consist of mixtures of polyisobutylenes (PIE) and grafted VC/2CP-g-PIB copolym er. Attention was focused on evaluation of the extent of the grafting reaction. VC/2CP-g-PIB was analyzed by GPC, H-1-NMR and C-13-NMR spect roscopies and elemental analysis. The results obtained indicate that t he rate of polymerization of IB decreases with increasing temperature but that the grafting efficiency increases. The experiments demonstrat ed that the VC/2CP copolymer induces strong grafting, compared with PV C, and that it might therefore be assumed that the C-Cl bonds with chl orine atoms bound to tertiary carbons directly initiate the polymeriza tion of IB. The effect of the C-Cl bonds is discussed in terms of thei r catalytic and initiation activities.