COMPLEX-RADICAL COPOLYMERIZATION OF 2,4,4-TRIMETHYLPENTENE-1 WITH MALEIC-ANHYDRIDE

The mechanism of radical copolymerization of 2,4,4-trimethylpentene-1 (TMP) as donor monomer with maleic anhydride (MA) as acceptor monomer in the presence of benzoyl peroxide is discussed. The constant of char ge transfer complex (K-c) and copolymerization parameters (r(1), r(2), r(1c), r(1c1), r(1c2), Q(1) and e(1)) have been determined; their val ues are as follows: K-c = 0.27 +/- 0.1 L/mol and 0.16 +/- 0.07 L/mol a t 35 degrees C in CH3COCH3-d(6) for TMP-TMA and n-octene-MA (model sys tem) complexes; r(1) = 0.12 +/- 0.005, r(2) = 0.38 +/- 0.02, r(1c) = 0 .0068, r(1c1) = 0.127 and r(1c2) = 0.0072; Q(1) = 0.0012 and e(1) = 0. 49. Some kinetic parameters of the reaction and quantitative contribut ions of TMP-MA complex to reactivity ratios of the monomers have been studied and their contribution to chain growth are estimated as: k(12) /k(21) = 3.51, k(1c)/k(12) = 0 98 and k(2c)/k(21) = 1.03. The copolyme rization is found to proceed predominantly by the ''mixed'' mechanism with equal participation of complex-bound and free monomers in propaga tion. A solvent effect in radical copolymerization of TMP with MA is o bserved. The higher rate of copolymerization in the TMP-MA-dimethylfor mamide system is explained by the effect of the MA-solvent complex inc reasing the acceptor properties of the MA molecule. (C) 1998 Elsevier Science Ltd. All rights reserved.