Pyrolysis–gas-chromatographic study of a series of polyester thermosets

Abstract

Thirteen different unsaturated polyester prepolymers have been synthesised in an attempt to establish a relationship between the structures of the commonly used polyesters and the pyrolysis products of their cross-linked polymers. All the polyesters contained maleic anhydride units as the unsaturated sites and all were cured using styrene as the cross-linking monomer. The variation in structure involved either the glycol component or the aromatic acid. The cross-linked polyesters were pyrolysed at 600°C and the products separated and identified using gas chromatography and gas chromatography–mass spectrometry. Many products were identified as arising from either the styrene cross-links or the polyester chains. The presence of cinnamate esters confirmed that degradation occurred across both distinct parts of the polymer network. The identity of some other products, particularly the phthalate esters, suggested that more than one degradation mechanism was occurring.