RADICAL CATION TRANSFORMATION POLYMERIZATION AND ITS APPLICATION TO THE PREPARATION OF BLOCK-COPOLYMERS/

ESR study on the primary radicals obtained by decomposition of ate-com pounds showed that primary radicals with electron donating substituent s were transformed to the corresponding cations in the presence of ele ctron acceptors such as ph(2)I(+)PF(6)(-). Accordingly, propagating ra dicals are transformed to the corresponding cations in the polymerizat ion of p-methoxy-styrene (MOS), n-butyl vinyl ether (EVE), and N-vinyl carbazole (VCZ) with azoinitiators such as AIBN in the presence of ele ctron accepters such as Ph2I+PF6-. In the case of BVE, the polymer for mation was caused by cationic species produced by the transformation o f the initiating radical. The polymerizations of MOS and VCZ were ascr ibed to the transformation of the growing radical to the corresponding cation during the propagation step which was classified as the radica l/cation transformation polymerization. Block copolymers of MOS/cycloh exene oxide (CHO) and VCZ/CHO were effectively prepared by the radical /cation transformation polymerization of the appropriate monomers in t he presence of AIBN, electron acceptor and CHO. The formation of block copolymers was characterized by turbidimetry, thin-layer chromatograp hy; and solubility tests.