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

Radical terpolymerizations of maleic anhydride (MA), irans-stilbene (Stb) and N-phenylmaleimide (PhMI) were carried out in methyl ethyl ketone (MEK) at 60-80 degrees C in the presence of 2,2'-azoisobutyronitrile (AIBN) as initiator. The terpolymerization was evaluated by using either the free monomer or complex participation models. The relative reactivity of MA toward poly(Stb) radical was found to be about 10,6 times lower than that of PhMI. The initial rate of copolymerization, the participation of the charge transfer complex (CTC) monomers and free monomers was quantitatively estimated. It was established that, even with a considerable change in the ratio of electron-acceptor monomers (MA and PhMI) in the initial reaction mixture, terpolymers possessed always 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 and PhMI...Stb complexes, respectively, were obtained. The result of kinetic studies of terpolymerization was interpreted as involving mainly alternating copolymerization of two complexomers with predominant participation in chain growth. Thermogravimetric analyses indicated the high thermal stabilities of terpolymers obtained.