Microwave syntheses of poly(epsilon-caprolactam-co-epsilon-caprolactone)

Microwave irradiation was applied to synthesize poly(epsilon-caprolactam-co -epsilon-caprolactone) directly from the anionic catalyzed ring opening of two cyclic monomers, epsilon-caprolactam and epsilon-caprolactone using a v ariable frequency microwave furnace, programmed to a set temperature and co ntrolled by a pulsed power on-off system. Dielectric properties of epsilon- caprolactam, epsilon-caprolactone, and their mixture were measured in the m icrowave range from 0.4 to 3 GHz, showing that, both epsilon-caprolactam an d epsilon-caprolactone exhibited effective absorption of microwave energy t o induce a fast chemical reaction. The microwave induced anionic copolymeri zation of epsilon-caprolactam and epsilon-caprolactone generated copoly(ami de-ester)s in yields as high as 70%. Conventional thermal and microwave cop olymerization studies were also conducted for comparison with the microwave results. These studies demonstrated that an effective and efficient microw ave method to copolymerize epsilon-caprolactam with epsilon-caprolactone in higher yield, higher amide content, and higher T-g's, relative to the ther mal process, has been developed. (C) 2000 John Wiley & Sons, Inc.