Abstract: Structure and properties of polycarbonate before and after weathering in WanNing，HaiNan province were investigated. Mechanical testing showed that, after weathering, the tensile strength of PC slowly reduced, and stiffness increased remarkably. During weathering, craze or crack appearing on the exposed surface resulted in decreasing light transmittance and generating carbon-carbon coupling double bond resulted in increasing yellowness; ATR-FTIR of exposed and back surface showed that, the possible degradation mechanism of exposed surface were Fries-rearrangement and photo-oxidation, but only Fries-rearrangement for back surface.

Key words: polycarbonate, weathering, photo-oxidation degradation, Fries- rearrangement reaction