Patterns of Fungal Attack in Wood-Plastic Composites Following Exposure in a Soil Block Test

Authors

  • Mark Mankowski
  • Jeffrey J. Morrell

Keywords:

Wood-plastic composite, high-density polyethylene (HDPE), white rot fungus, brown rot fungus, fungal hyphae, voids

Abstract

The 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.

References

Morris, P. I., and P. Cooper. 1998. Recycled plastic/wood composite lumber attacked by fungi. Forest Prod. J. 48(1):86-88.nNaghipour, B. 1996. Effects of extreme environmental conditions and fungus exposure on the properties of wood-plastic composites. M.S. thesis, Faculty of Forestry, University of Toronto, Toronto, Ontario, Canada.nSchmidt, E. L. 1993. Decay testing and moisture changes for a plastic-wood composite. Proc. Am. Wood-Preserv. Assoc. 89:108-109 (Abstract).nSimonsen, W. J. 1997. Efficiency of reinforcing materials in filled polymer composites. Forest Prod. J. 47(1):74-81.nZabel, R. A., and J. J. Morrell. 1992. Wood microbiology—Decay and its prevention. Academic Press, San Diego, CA. 474 pp.n

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Published

2007-06-19

Issue

Number 3 / July 2000

Section

Research Contributions

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