Abstract
The thermal deterioration of PPG-TDI-PG polyurethanes was studied under N2 and air atmosphere at different temperatures ranging from 80-120°C. The method for the determination of allophanate crosslink sites in polyurethanes by the amine degradation technique was applied to the determination of the scissions of crosslink sites during the thermal deterioration of PPG-TDI-PG.
These polyurethanes decomposed by the scissions of allophanate crosslink sites under N2 atmosphere at 120°C, while those decomposed by the scissions of both allophanate crosslink sites and main chains under air atmosphere.
The apparent activation energy of the scissions of the allophanate crosslink sites in the polyurethanes under N2 atmosphere was 75-113kJ/mol and under air atmosphere 46-67kJ/mol.
