COMPLEX-RADICAL ALTERNATING TERPOLYMERIZATION OF MALEIC-ANHYDRIDE, TRANS-STILBENE AND N-PHENYLMALEIMIDE

Radical terpolymerizations of maleic anhydride (MA), irans-stilbene (S tb) and N-phenylmaleimide (PhMI) were carried out in methyl ethyl keto ne (MEK) at 60-80 degrees C in the presence of 2,2'-azoisobutyronitril e (AIBN) as initiator. The terpolymerization was evaluated by using ei ther the free monomer or complex participation models. The relative re activity of MA toward poly(Stb) radical was found to be about 10,6 tim es lower than that of PhMI. The initial rate of copolymerization, the participation of the charge transfer complex (CTC) monomers and free m onomers was quantitatively estimated. It was established that, even wi th a considerable change in the ratio of electron-acceptor monomers (M A and PhMI) in the initial reaction mixture, terpolymers possessed alw ays a composition ratio close to 1:2:1. Constants for copolymerization of MA...Stb (M(1)) and PhMI...Stb (M(3)) were determined by using the Kelen-Tudos equation, and r(1) . K-1/K-3 = 0,03 and r(2) . K-3/K-1 = 0,08, where K-1 and K-3 are complex-formation constants of MA...Stb an d PhMI...Stb complexes, respectively, were obtained. The result of kin etic studies of terpolymerization was interpreted as involving mainly alternating copolymerization of two complexomers with predominant part icipation in chain growth. Thermogravimetric analyses indicated the hi gh thermal stabilities of terpolymers obtained.