Copolyesteramides—I. Anionic copolymers of ω-laurolactam with ϵ-caprolactone

Abstract

Anionic copolymerisation of ω-laurolactam with ε-caprolactone yields copolyesteramides with NH(CH 2) 11CO and O(CH 2) 5CO unit contents similar to those in the feeds. Over the major part of the composition range, only the amide component crystallises, showing the γ-nylon 12 form. A transition of crystalline type to that of poly(ε-caprolactone) occurs at low ( ca. 20 mol%) amide-group content and with marked depression of the degree of crystallinity of the polyester component. I.R. spectroscopy indicates the co-existence of amide-ester with amide-amide hydrogen-bonding in the copolymers, and the monotonic form of the T m vs composition curve is explained in terms of this dual bonding. It is suggested that such interactions between the sub-species may be a general feature underlying the properties of linear aliphatic copolyesteramides.