Copolymerization of methacryloyl‐terminated PMMA macromonomers with methyl methacrylate

Methacryloyl‐terminated macromonomers (MM) of polymethylmethacrylate (PMMA) of two different molecular weights were prepared by group transfer polymerization (GTP). They were copolymerized with methyl methacrylate (MMA) by radical polymerization using toluene as the solvent. The relative reactivity of the MM, 1/r1, decreases with increasing initial MM concentration. This is interpreted as a consequence of the increasing viscosity of the reaction medium leading to an increasing diffusion control of the MM addition. At a constant weight ratio of MMA to MM the reactivity of the longer macromonomer is higher than of the shorter one. Increasing the molar ratio [MMA]/[MM], i.e. increasing the average distance between two grafts in the resulting comb polymer, increases the reactivity of the MM. These results are interpreted on the basis of a model describing the segment density in the vicinity of the radical chain end of the comb polymer.