Mechanism of thermal degradation of poly(vinyl acetate)

Abstract

The thermal degradation of poly(vinyl acetate) was investigated under dynamic atmosphere of helium up to 400 ~ with a thermobalance. The volatile products were analyzed by a gas chromatograph.Acetic acid proved to be the main component of the volatile products (90 to 95 ~). Kinetic measurements of numerous samples obtained showed that the rates and orders of the degradation were different for all the samples and depended on their internal structures (the polydispersity). This is contrary to data published by A. Servotte et al. [1] and agreed with N. Grassie [2,3].This dependence of the degradation on the internal structures of the samples is latter verified by a probabilistic approach.In recent years, the degradation of a number of poly (vinyl) compounds has been studied. On the thermal degradation of poly (vinyl acetate), important works have been published by N. Grassie [2. 3] and A. Servotte et al. [1].Existing techniques for studying the thermal degradation of polymeric materials are either very time consuming or very qualitative especially when the degradation reaction is complex.A method that gives rapid, yet quantitative results for the parameters of thetmal degradation of polymeric material is by thermobalance which combines DTA, TG and DTG. Moreover, the heating atmosphere can be controlled and changed quite easily.There is no shortage of publications presenting DTA curves for a wide range of polymeric materials. This might possibly give the impression that the DTA curve, for a plastic is unique and characteristic i.e. is a "finger-print" which can serve for identification when compared with curves for known materials.In fact, this is not so, the DTA curve itself, is not necessarily reproducible since the thermal degradation of polymeric material depends -beside many factorson the internal structure of the sample used.In this paper, poly (vinyl acetate) is degraded up to 400 ~ in a thermobalance, under the inert dynamic atmosphere of helium. The heating temperature is programmed linearly at 10~The results, obtained by the analytical scheme concurrently developed for deter-

Characterization of Low Molecular Weight Polyvinyl Acetate

“…Therefore the rapid weight loss between 287 and 375°c orresponds to the complete deacetylation of the oligomer. These results confirm the data reported by Bataille and Van (1975). Since the residue is highly colored and hence presumably conjugated, the decomposition reaction can be visualized according to the mechanism proposed by Grassie (1952Grassie ( ,1953.…”

Thermal degradation of poly(vinyl butyral) in alumina, mullite and silica composites

“…The residual carbon in excess of 50 to 100 ppm would decrease the density and also affect many substrate properties like flexural strength, breakdown voltage [1] and dielectric constant [2]. In order to optimize the binder removal processes, some attention has been paid to studies such as polymer degradation mechanism [3][4][5], interactions of ceramics and binders [6][7][8], and effect of processing variables [9]. However information on kinetics of thermal degradation is limited.…”

Using Paint to Investigate Fires: An ATR‐IR Study of the Degradation of Paint Samples Upon Heating

“…Mass losses between 300°C and 450°C and 550°C and 650°C come from decomposition of the binder. Polyvinyl acetate is reported to decompose thermally in two steps . The first leads to loss of acetic acid and the second results from decomposition of the resulting carbon chain.…”