Rigid PVC-wood flour compositelumber containing either Maple or Pine woodflour (50%) was exposed to fungi for 2 and 4weeks respectively as per ASTM Standard G-21 96 (ASTM 2002, Standard practice fordetermining resistance of synthetic polymericmaterials to fungi). Both types of Rigid PVCwoodflour composite lumber were colonizedand discolored by fungi. Bottom faces ofcomposites that were in constant contact withmoisture exhibited greater susceptibility tofungal discoloration. Further, Rigid PVCwoodflour composite lumber containingMaple wood flour demonstrated higher fungaldiscoloration than those containing Pine woodflour. Environmental scanning electronmicroscopy studies indicated that surfacebreaks in PVC matrix may cause wood flourfiller to be exposed to the environment.Consequently, the wood filler becomes asource of water sorption and subsequentfungal colonization and discoloration.
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