PENDANT VINYL GROUP REACTIVITY DURING THE FREE-RADICAL COPOLYMERIZATION OF METHYL-METHACRYLATE AND ETHYLENE-GLYCOL DIMETHACRYLATE

Methyl methacrylate - ethylene glycol dimethacrylate (MMA-EGDM) copolymerization has been investigated in toluene at a monomer concentration of 22 w/v %. The kinetic models developed recently along with the experimental conversion curve and gel point data provided the calculation of the average reactivity of pendant vinyl groups. It was found that the pendant vinyl reactivity for intermolecular links is much less than the monomeric vinyl reactivity and it decreases further as the EGDM concentration increases. At 5 - 15 mol % EGDM, the average pendant reactivity is 1 - 2 orders of magnitude lower than the monomeric vinyl reactivity. The reduced pendant reactivity is mainly responsible for the shift of the gel point towards higher conversions.