| Popis: |
The thermo-oxidative degradations (TOD) of polyaroylene-bis-benzimidazoles, synthesized from naphthalene-1,4,5,8- or perylene-3,4,9,10-tetracarboxylic acids and diaminobenzidine or tetraaminodiphenyl ether, of their copolymers, and of some low mol.wt. models, were studied. The TOD was found to be complicated and to be initiated by various reactive centres, thus creating differences in the actual reaction progress. Vacuum heat treatment at 300–400°C enhanced the resistance of the materials to TOD. Insertion of perylene blocks produced an extremal dependence of resistance to TOD on the ratio of perylene to napthalene chain units. |
