THERMOHYDROLYTIC AGING OF POLYNADIMIDE-IP-960

This study deals with the thermal ageing of a polynadimide matrix IP 9 60, developed for composite aircraft applications in the 250-300 degre es C temperature range. In a first chapter, it is tried to give a suit able representation of the network structure on the basis of literatur e data, analytical results and rubbery modulus measurements. Ageing in air at 300-360 degrees C is then studied. The role of diffusion contr ol of degradation kinetics is shown from comparison of samples of vari ous volume/surface ratios. The crucial role of sorbed water is put in evidence. Ageing in vacuum at 360 degrees C allows to reveal the exist ence of at least three kinetics steps. The corresponding degradation m echanisms are discussed. Chemical (NMR, FTIR, UV) as physical (weight loss, water sorption or mechanical testing) are used to quantify the s ample degradation.