Degradation mechanism on the surface of epoxy composites

In order to analysis the degradation process of epoxy/glass fiber for outdoor condition, FRP laminate was exposed to thermal and plasma discharge. Especially, this study is focused on the inter-relation between chemical changes and electrical properties. In XFS spectrum to analyze surface chemical structures, the increased hydrophobicity in thermal treatment was originated from the continuous decrease of side-chains caused by secessions of oxygen groups and the increase of unsaturated double bond in carbon chains. The spot of hydrophilicity in plasma treatment showed the increase of relative oxygen conents with respect to the carbon contents. Especially, increased oxygen was identified as carboxyl radicals binding with oxygen C, molecules in the air. In surface potential decay to measure the electrostatic behaviors, corona charge injected to the spot of hydrophilic surface decreased faster than that of hydrophobic surface.