Photodegradation of bisphenol A polycarbonate with different types of stabilizers

When unstabilized bisphenol A polycarbonate is exposed to outdoor weathering conditions, it degrades due to irradiation, humidity and other parameters. To overcome this undesired degradation process BPA-PC can be stabilized. In this study the influence of different types of stabilizers (i.e. UV-absorbers and hindered amine stabilizers) on the photodegradation of BPA-PC were compared. It is shown that the best way to stabilize BPA-PC is to keep the harmful UV light out. Almost all stabilizers caused a decreased degradation rate. The UVAs showed the best results, although radical scavengers cause a decrease in degradation too. By applying a layer of UVA-stabilized BPA-PC on top of unstabilized BPA-PC led to a decreased degradation rate of the unstabilized BPA-PC, which can quantitatively be explained by a reduction of the irradiation intensity.