Volatiles released during the weathering of PVC

Volatile organic compounds and organochlorine species liberated by UV exposure of poly(vinyl chloride) (PVC) siding samples have been identified and preliminary quantification made. These volatiles included those remaining in a PVC sample after weathering or laboratory UV exposure and which could be released by thermal desorption. In addition, by using a flow‐through cell and granular carbon adsorbents, volatile species directly desorbed during laboratory UV exposure were measured. Total directly desorbed organochlorine compounds were about 1/20 of the weight of hydrogen chloride as measured by conductometric analysis, Quite similar products were observed from old (∼1984) and current (1995) commercial siding formulations. Observed volatile compounds are proposed to come from the TiO 2 ‐controlled photo‐oxidation of both PVC and its additives such as impact modifiers.