TERMINAL AND PENULTIMATE MODELS OF COPOLYMERIZATION IN THE STYRENE-ACRYLONITRILE SYSTEM IN BULK ACCORDING TO UNIFAC

UNIFAC-group contribution method for determination of local monomer co ncentrations and the simplex method for determination of reactivity ra tios were used to describe the terminal and penultimate models of copo lymerization in the styrene-acrylonitrile monomer system in bulk at 33 3.15 K. Results show that the procedure is applicable for prediction o f the kinetic behaviour of the comonomer pair. Local monomer concentra tions, true reactivity ratios, distribution coefficients K and the new ly introduced parameter A, measuring deviation of the local concentrat ion from the global concentration, were calculated. According to the r esults, the absolute value of the distribution coefficient K depends o n the type of reactivity ratio but not on the monomer ratio in the fee d. (C) 1998 Elsevier Science Ltd. All rights reserved.