Six corn. Co, Al, Cr, Zn and Fe-contg. spinet pigments were purified by n-BuOH extn. and treated under acidic or basic conditions, dried at 60 degrees C and mixed in a mortar with 8.3, 14.3 and 20% by mass of poly(vinyl chloride) plastisol then vented for 24 h, poured on a flat surface and dried at 140 degrees C for 1 h to gels. The membranes were irradiated with UV radiation. The elemental compn. of membranes, color, degree of crystallinity, softening point, tensile strength and relative elongation before and after UV irradn. were detd. UV radiation resulted in deterioration of membrane properties and degradation processes of both pigments and polymer.