Ring-opening polymerization of ?-caprolactam and ?-caprolactone via microwave irradiation

A novel process for synthesizing nylon-6 and poly(ϵ-caprolactone) by microwave irradiation of the respective monomers, ϵ-caprolactam and ϵ-caprolactone, is described. The ring opening of ϵ-caprolactam to produce nylon-6 was performed in a microwave oven by the forward power being controlled to about 90–135 W in the presence of an ω-aminocaproic acid catalyst (10 mol %) and for periods of 1–3 h at temperatures varying from 250 to 280 °C. The ring opening of ϵ-caprolactone to produce poly(ϵ-caprolactone) was performed in a microwave oven by the forward power being controlled to about 70–100 W for a period of 2 h in the presence of stannous octoate with and without 1,4-butanediol over a temperature range of 150–200 °C. The yields, conditions of the reactions, and properties of the products generated relative to the thermal processes are discussed. © 2002 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 40: 2264–2275, 2002