The thermal degradation of poly(vinyl alcohol)

This paper is concerned with the thermal degradation of poly(vinyl alcohol) , both in the solid and molten state. Initially, thermal degradation in the solid state was considered to be due to the elimination of hydroxyl side g roups, but this process should have produced appreciable amounts of isolate d and conjugated polyenes in the degradation residue and small amounts of c arbonyl group were detected. Side group elimination was followed by a reduc tion in the melting point and the degree of crystallinity. In the molten st ate, thermal degradation led to the production of volatile saturated and un saturated aldehydes and ketones, as well as water. It was considered that t he greater flexibility of the polymer chains in the melt facilitated fragme ntation of the chain and elimination of chain segments. (C) 2001 Elsevier S cience Ltd. All rights reserved.