Title

Copolymerization of Epsilon Caprolactone and Delta-Valerolactone

Document Type

Article

Publication Date

3-1-1991

Department

Polymers and High Performance Materials

Abstract

Hydroxy-terminated poly(epsilon-caprolactone-co-delta-valerolactone) (PCV) copolymers were synthesized by the diol initiated bulk copolymerization of epsilon-caprolactone (C) and delta-valerolactone (V). The two homopolymers were semicrystalline, with almost identical melting temperatures; copolymerization significantly lowered the melting point (T(m)) compared to either homopolymer. Copolymer melting points were found to decrease with decreasing molecular weight and to be dependent on composition, i.e., the incorporation of a comonomer into either homopolymer resulted in a decrease in T(m), with the maximum decrease occurring at a copolymer composition of about 60 mole-% epsilon-caprolactone. The molar composition of the copolyesters was determined from C-13 NMR spectra. At conversion > 50 % the copolymer composition was found to be richer in epsilon-caprolactone than predicted from the integrated form of the first-order Markov copolymer equation, suggesting that the depolymerization of delta-valerolactone becomes important at high conversions and the addition of epsilon-caprolactone is greatly favored regardless of the ultimate unit.

Publication Title

Makromolekulare Chemie/Macromolecular Symposia

Volume

42-3

First Page

185

Last Page

193