Investigations on thermal and hydrolytic degradation of poly(ethylene terephthalate)

The thermal properties of poly(ethylene terephthalate) (PET) are sensitively affected by polycondensation catalysts and temperature. The kinetics of thermal degradation were investigated by determining the rates of formation of carboxyl groups on isothermal heating. Carboxyl groups in PET were not only a result of thermal exposure but they were also an influence on hydrolytic stability. The hydrolytic cleavage of polyester chains, i.e., the formation of carboxyl groups, was found to be an autocatalytic reaction.