ϵ‐caprolactone grafting on a poly(vinyl alcohol‐<i>co</i>‐vinyl acetate) in the melt without added initiator

Abstract

Abstract Polycaprolactone (PCL) grafting on vinyl alcohol‐ co ‐vinyl acetate) (PVA‐Ac), was investigated in the melt at high temperature (170°C), below the PVA‐Ac melting point, by ring opening polymerization of ϵ‐caprolactone initiated by metal alkoxyde sites present in PVA‐Ac: no additional initiator was used. The obtained average structures were determined by 1 H NMR. As expected, small grafts, with low average polymerization degree (DP), were obtained, between 4 and 12 h of reaction. These DP are due to exchange reactions between hydroxyl groups and PCL growing chains. The PVA‐Ac was shown to be partially substituted by short PCL grafts. The DP linearly increased with the initial Lactone/PVA‐Ac ratio, and the substituted alcohol sites rate were limited to 63%.It was shown that the used reactive system is characterized by a quazi‐living polymerization mechanism. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2007