Microwave‐assisted ring‐opening polymerization of ϵ‐caprolactone

Ring‐opening polymerization of ϵ‐caprolactone was carried out smoothly and effectively with constant microwave powers of 170, 340, 510, and 680 W, respectively, with a microwave oven at a frequency of 2.45 GHz. The temperature of the polymerization ranged from 80 to 210 °C. Poly(ϵ‐caprolactone) (PCL) with a weight‐average molar mass (Mw) of 124,000 g/mol and yield of 90% was obtained at 680 W for 30 min using 0.1% (mol/mol) stannous octanoate as a catalyst. When the polymerization was catalyzed by 1% (w/w) zinc powder, the Mw of PCL was 92,300 g/mol after the reaction mixture was irradiated at 680 W for 270 min.