DEGRADATION PHOTOCHIMIQUE EN PHASE SOLIDE DES POLYMERES AVEC DES GROUPES DE TYPE URETHANNE. INFLUENCE DES CATIONS DU BLOC 'p' SUR LE PROCESSUS DE DEGRADATION

摘要

The modification of physico-mechanical properties of films made of polymers with uretanic groups, complexed with metallic ions from the "p" block, have been investigated taking into consideration the nature of the cation and the photochemical irradiation time. Experiments were carried out by irradiation with ultra-violet light, in solid phase, on film, under conditions of accentuated degradation. The main physico-mechanical properties measured were strain at the break, remanent elongation, elasticity modulus and resistance at the break. The treatment of polymer films with the following ions: A1~(3+), Ga~(3+), In~(3+), Tl~+, Sn~(2+) and Pb~(3+), led to important modifications of the physico-mechanical properties. The biggest modification was obseved for the Tl~+ ion. Mechanisms for the acidic or basic hydrolitic degradation processes were proposed.