Material resistance of weathered wood-plastic composites against fungal decay

Material performance testing of wood-plastic composites (WPC) requires adequate and time-efficient evaluation of the resistance against fungal colonisation and decay. This study investigates the effects of weathering on WPCs and subsequent material degradation by fungi. Weathering using UV radiation, water spray and repeated frost incidents caused micro- and macro-cracks. Fourier transform infrared spectroscopy (FTIR) demonstrated delignification of wood particles at the weathered WPC surface. Despite of increased surface area, accessibility for fungal hyphae and moisture content, weathering enhanced mass loss due to fungal decay only subtly but not significantly. These potentially enhancing effects for fungal decay are assumed to be outbalanced by delignification due to photo-oxidation and leaching of degradation products resulting in loss of nutrient sources essential for fungal growth.

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► Weathering and fungal decay of wood-plastic composites (WPC) were investigated.
► Weathering caused cracks and delignification at the WPC surface.
► Nevertheless, mass loss due to fungal decay increased only subtly in weathered WPC.
► Delignification and leaching are assumed to deplete nutrients for fungal development.