THERMAL-DEGRADATION OF BISMALEIMIDE AND BISNADIMIDE NETWORKS - PRODUCTS OF THERMAL-DEGRADATION AND TYPE OF CROSS-LINKING POINTS

This study deals with the thermostability and the thermal degradation mechanisms of polyimide model networks (bismaleimide and bisnadimide). that are usually used in aeronautic applications in high temperature environments: 200-250 degrees C. The thermostability of these model ma terials has been studied by thermogravimetry (TGA) both in air and in nitrogen to determine thermal and thermooxidative phenomenon. Thermal degradations have been performed at known temperatures in a glass tube furnace. Products formed during the thermal degradation have been tra pped in a solvent or condensed on the inner side of the glass tube. Th ey have been identified using GC/MS analysis. The results showed a hig h sensitivity to oxygen for these materials and allowed us to propose a network structure and to locate the most thermosensitive points.