Thermohydrolytic ageing of polynadimide IP960
This study deals with the thermal ageing of a polynadimide matrix IP 960, developed for composite aircraft applications in the 250 −300°C temperature range. In a first chapter, it is tried to give a suitable representation of the network structure on the basis of literature data, analytical results and rubbery modulus measurements. Ageing in air at 300 −360°C is then studied. The role of diffusion control of degradation kinetics is shown from comparison of samples of various volume/surface ratios. The crucial role of sorbed water is put in evidence. Ageing in vacuum at 360°C allows to reveal the existence of at least three kinetics steps. The corresponding degradation mechanisms are discussed. Chemical (NMR, FTIR, UV) as physical (weight loss, water sorption or mechanical testing) are used to quantify the sample degradation.