Thermal decomposition of polystyrene,polyoxyethylene glycol and their mixtures by thermogravimetric techniques

The thermal decompositions of polystyrene, polyoxyethylene glycol and mixtures of the two have been studied by thermogravimetry. The composition of the mixtures both before and after decomposition, as well as changes in the molecular weights and polydispersities of the polystyrene components, were followed by gel permeation chromatography. Ultra-violet spectrophotometry also served to determine the polystyrene contents of the mixtures after decomposition. The presence of polyoxyethylene glycol as a reaction promoter was found to have a pronounced effect on the decomposition of polystyrene, believed to be initiated, in large part, by intermolecular transfer. The depolymerization that follows takes place more rapidly probably because of the presence of a large number of active fragments. The overall activation energy, calculated by the method of Flynn and Wall, supports this hypothesis, being lower in the presence of polyoxyethylene glycol and higher in its absence.