HIGH CONVERSION COPOLYMERIZATION OF FURFURYL METHACRYLATE AND N-VINYL-PYRROLIDONE - A KINETIC APPROACH TO SKEISTS TREATMENT FOR FREE-RADICAL COPOLYMERIZATION IN DIFFERENT REACTION MEDIA

The influence of reaction conditions and temperature on the free radical copolymerization of furfuryl methacrylate with N-vinylpyrrolidone, initiated by 2,2'-azobisisobutyronitrile (AIBN) is studied. The initiation step is promoted by the thermal decomposition at 50-degrees-C of the AIBN molecules in N,N-dimethylformamide (DMF) solution or photochemically at 0 and 40-degrees-C in bulk. The variation of the average composition of copolymer chains with the conversion for two different compositions of the monomer feed, f(F)o = 0.02 and 0.50, is analysed from the classical integrated copolymerization equation. Since the reactivity ratios of this pair are very different, r(F) = 3.92 and r(P) = 0.004, a simplified approximation of the integrated Skeist's equation is proposed. The experimental data obtained under different experimental conditions fit adequately the theoretical predictions, suggesting that the reaction medium (solution or bulk) or initiation technique (thermal or photochemical) do not affect the average composition of the copolymer chains at different conversions. However, the variation of the cumulative composition of copolymer chains with the degree of conversion is very sensitive to the initial composition of monomer feed. In addition, the average rate of copolymerization seems to be also dependent on the feed composition.