Mechanistic study of the light-induced copolymerization of maleimide/vinylether systems

Full Paper: Real-time infrared spectroscopy was used to monitor the high-sp eed copolymerization of N-substituted alkyl maleimide (MI) and vinyl ether (VE) mixtures upon UV exposure, with or without photoinitiator. The monomer feed composition was shown to play a decisive role in the polymerization k inetics of each monomer. When VE is in excess, the two monomers disappear a t similar rates to yield in alternating copolymer. When MI is in excess, th e copolymerization and the MI homopolymerization occur simultaneously to yi eld a copolymer with isolated VE units. The reaction scheme proposed to acc ount for the kinetic data is based on the homopolymerization of a donor-acc eptor complex, with VE. radicals acting as the main propagating species. Th e kinetic chain length was evaluated from quantum yield measurements perfor med under controlled initiation conditions and found to be on the order of 10(3). The propagation rate constant of the VE/MI copolymerization was calc ulated to be twice that of the MI homopolymerization.