A modified diffusional model of Me methacrylate polymn. at 130-170 Deg was described qual. Based on the polymn. and the reactor model, the stability behavior of a pilot recycle reactor was predicted. In pilot expts. under stable reactor conditions, polymer product with mean mol. wt. ? 250,000 was obtained. The polydispersity index was .apprx. 2 which indicated that concn. and temp. gradients in the reactor could be neglected. [on SciFinder (R)]