Photochemical degradation of polymers containing urethane groups in the solid phase:influence of S block cations on the degradation

摘要

Modification of the physico-mechanical properties of films made of biologically compatible polymers,with urethane groups,complexed with metallic ions from the s-block (Soft Block),have been investigated according to cation nature and photochemical irradiation time.Strain at the break,remnant elongation,elasticity modulus and resistance at the break were the main physico-mechanical properties measured.Experiments were carried out by irradiation with ultraviolet light,on solid film,under condition of accentuated degradation.Ions of both alkaline metals and alkaline-earth metals in the first step of irradiation improve the physico-mechanical properties.But in the middle of the investigated range they strongly decrease,concomitantly with the appearance of some deep photochemical induced structural modifications in the structure of the investigated polyesterurethane.