THE INFLUENCE OF TOTAL MONOMERS CONCENTRATION AND POLYMERIZATION SOLVENT ON THE REACTIVITY OF OMEGA-(P-VINYLBENZYL ETHER) MACROMONOMERS OF POLY(2,6-DIMETHYL-1,4-PHENYLENE OXIDE)

The influence of the total monomers concentration and of the copolymerization solvent on the reactivity ratio, r1, of methyl methacrylate (MMA) (M1) ω‐(p‐vinylbenzyl ether) macromonomer of poly(2,6‐dimethyl‐1,4‐phenylene oxide) (PPO–VBE) (M2) monomer pair was investigated. For two different molecular weights of PPO‐VBE macromonomers: Mn = 15,200 and Mn = 5,100, the determined reactivity ratio, r1, decreases with the increase in macromonomer concentration. Therefore the reactivity of the macromonomer, 1/r1, follows the opposite trend. The influence of monomers concentration on r1 is higher for higher molecular weight macromonomers. The nature of polymerization solvent also affects the value of reactivity ratio, r1. Micelle formation was demonstrated by 1H‐NMR spectroscopy performed on the resulting graft copolymers in different solvent mixtures. An attempt to explain the observed concentration and solvent effects based on the partition of comonomer concentrations between the bulk of solvent and around the growing chain is presented. Based on this explanation, the determined r1 represents a product of the partition coefficient, k, and the true reactivity ratio, r10. Copyright © 1990 John Wiley & Sons, Inc.