Factors affecting accelerated testing of polymer photostability

The effect of components of the atmosphere on photostabilized polymers and development of degradation phenomena is outlined. The processes are characteristic of heterogeneity in distribution of products of polymer degradation and stabilizer transformation or consumption. Concentration gradients of the products indicate preferential surface and near-surface changes having U-shaped characteristics and affected by the polymer material or sample thickness due to limited penetration of oxygen. Increased intensity of radiation in artificial sources induces material changes different from those resulting from natural weathering, complicating correlation between the two processes and lifetime prediction. Surface and near-surface analyses of tested samples provide a realistic insight into heterogeneity characteristic of photodegradation.