EFFECT OF PCV ON LOW-POLAR ISOBUTYLENE POLYMERIZATION IN THE PRESENCEOF BCL3

The isobutylene polymerizations in the presence of BCl3 were carried o ut in dichloromethane ([M] = 7 mol/l) at -20-degrees-C in the presence and absence of PVC. The products of polymerizations in the absence of PVC are oligoisobutylenes with a narrow molecular weight distribution (MBAR(w)/MBAR(n) almost-equal-to 1.3, MBAR(n) almost-equal-to 2700); their structure was analyzed by H-1-NMR spectroscopy. In addition to t he signals assigned to known unsaturated terminal structures [delta 4. 62 and 4.82 -CH2C(CH3)=CH2, 5.12 -CH=C(CH3)2], a new intense signal wa s found at delta 5.09 ppm and and assigned to the structure -CH=C(CH3) CH2CH3. A mixture of isobutylene homopolymers (MBAR(n) almost-equal-to 2700, 15000) and PVC grafted with isobutylene (approx. 9.5% wt. isobu tylene grafted) is formed in the presence of PVC.