Volatiles release from photodegrading, pigmented PVC: kinetic changes

Volatile species produced during the ultraviolet irradiation of a rigid, poly(vinyl chloride) construction panel have been established as a function of irradiation time. Residual organic and chloroorganic compounds were detected in the polymer surface after irradiation. Similar species are also directly released during irradiation. In both cases, these were identified and quantified by gas chromatography, with mass spectrometry detection. Rates of volatilisation of organic and chloroorganic compounds were measured directly during accelerated exposure conditions and dropped sharply with irradiation time. This drop may be attributable to the cross-linking of the irradiated surface which becomes chlorine deficient and rich in titanium dioxide pigment (rutile). In contrast, samples exposed to sunlight did not undergo surface cross-linking but did thermally desorb volatiles similar to laboratory exposed samples.