Patterns of Fungal Attack in Wood-Plastic Composites Following Exposure in a Soil Block Test
Keywords:Wood-plastic composite, high-density polyethylene (HDPE), white rot fungus, brown rot fungus, fungal hyphae, voids
AbstractThe ability of white and brown rot fungi to colonize wood-plastic composites was investigated by measuring weight loss and anatomical changes. Three composite materials were evaluated. The material containing a 70/30 wood-high density polyethylene (HDPE) mixture was most susceptible to fungal attack, while two different 50/50 wood-HDPE composites experienced little or no attack. Scanning electron microscopic (SEM) examination of samples not exposed to fungus revealed the presence of voids between the wood and HDPE in all three materials. Similar examination of decayed samples of the composite with a higher wood content revealed that the fungi had thoroughly colonized the particles, particularly near the point of initial fungal exposure. Fungal hyphae were also prevalent in the voids deeper in the composite. The two composites containing higher HDPE levels had little evidence of fungal attack, despite the presence of voids.
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