CATIONIC COPOLYMERIZATION OF 1,3-PENTADIENE WITH ISOPRENE

The cationic copolymerization of 1,3-pentadiene (PD) with isoprene (IF ) initiated by AlCl3 was carried out in toluene. The microstructure of the copolymer chain was characterized by IR and H-1 NMR. IP is incorp orated in the copolymer chain mainly in cyclic segments. The PD-IP cop olymer has a much higher cyclic content than the PD homopolymer, which shows that the cyclization reaction during PD polymerization is enhan ced by the addition of IP. In addition, the reactivity ratios for IP(M (1)) and PD(M(2)) determined by the Kelen-Tudos method from low-conver sion data are r(1) - 1.22 and r(2) = 1.09.