AbstractThermal and microwave‐induced free‐radical non‐aqueous dispersion polymerization of methyl methacrylate (MMA) in the presence of poly(styrene)‐block‐poly(ethene‐alt‐propene) dispersing agent were compared. For controlled polymerization in the microwave field, a new microwave polymerization reactor was built to afford uniform heating and to control temperature via microwave power variation. At identical MMA concentration and polymerization temperature of 70°C no special effect of the microwave field on conversions, molecular weights and particle sizes of PMMA was detected with respect to conventional thermal free radical dispersion