Eight corn. CdS, ZnS and CdSe-contg. Cd pigments were purified by AcOBu extn. and treated with H2SO4 or NaOH. They were dried at 60 degrees C and mixed in a mortar with 8.3, 14.3 and 20% by mass of PVC plastisol then vented for 24 h, poured on a flat surface and dried at 140 degrees C for 1 h to a gel. The membranes were irradiated with UV. The changes in membrane color, degree of crystallinity, softening point, tensile strength and relative elongation before and after UV irradn. were detd. The UV irradn. resulted in a deterioration of membrane properties and degrdn. of both pigments and polymer.