AbstractN‐alkylmaleimides from theN‐methyl to theN‐octadecyl derivative were polymerized in the solid state by γ‐radiation. Polymerization during irradiation generally showed sigmoidal conversion curves with high rates and complete conversion 10°C below the melting point. Post‐irradiation rates were lower and showed the typical approach to a “limiting” conversion. The polymerization rates increased with temperature and radiation dose and with the length of the alkyl chain.N‐methylmaleimide had a high rate of in‐source polymerization which was attributed to the volati