Resistance of Flat-Pressed Wood-Plastic Composites to Fungal Decay: Effects of Wood Flour Content, Density, and Manufacturing Technology


  • J. T. Benthien
  • H. Thoemen
  • S. Maikowski
  • M. T. Lenz


Wood-plastic composites, WPC panel, flat-pressing technology, fungal decay, mass loss, wood-degrading basidiomycetes, density, wood flour content


Use of wood-based materials in exterior application is inherently at risk of degradation caused by fungal decay. This risk also holds for wood-plastic composites (WPCs), whether they are extruded into rod-shaped elements or flat-pressed to large-dimensioned panels. In this study, to show the potential of WPC panels in exterior applications, fungal decay was studied by investigating mass loss in an agar-block test using Gloeophyllum trabeum (Gt), Coniophora puteana (Cp), and Pleurotus ostreatus (Po) as test fungi. Characterization of WPC panel durability was performed in comparison with solid wood samples by calculating the decay susceptibility index (DSI). Moreover, durability of WPC panels from laboratory (single-daylight press) and industrial (continuous double-belt press) manufacturing were compared with commercial extruded WPC decking planks. Experiments showed that the wood particles in flat-pressed panels were well protected against fungal decay by the polymeric matrix. The fungal-induced mass loss depended on panel density and wood flour content. Using DSI as an evaluation tool, WPC panels were found to be more durable than wood samples used as reference materials (DSI < 100).


Benthien JT, Thoemen H (2012) Effects of raw materials and process parameters on the physical and mechanical properties of flat pressed WPC panels. Compos Part A-Appl S 43(4):570-576.nClemons CM, Ibach RE (2004) Effects of processing method and moisture history on laboratory fungal resistance of wood-HDPE composites. Forest Prod J 54(4):50-57.nDominik M (2006) Continuous process for manufacturing natural-fibre-filled plastic boards. Kunststoffe International 2:88-91.nGeimer RL, Clemons CM, Wood JE (1993) Density range of compression-molded polypropylene-wood composites. Wood Fiber Sci 25(2):163-169.nHuckfeldt T, Schmidt O (2006) Holzfäule- und bauholzpilze, diagnose und sanierung. Rudolf Müller Verlag, Köln, Germany. 377 pp.nKhavkine M, Kazayawoko M, Law S, Balatinecz JJ (2000) Durability of wood flour-thermoplastic composites under extreme environmental conditions and fungal exposure. Int J Polym Mater 46:255-269.nMankowski M, Morrell JJ (2000) Patterns of fungal attack in wood-plastic composites following exposure in a solid block test. Wood Fiber Sci 32(3):340-345.nMorris PI, Cooper P (1998) Recycled plastic/wood composite lumber attacked by fungi. Forest Prod J 48(1):86-88.nSchirp A, Ibach RE, Pendleton DE, Wolcott MP (2008) Biological degradation of wood-plastic composites (WPC) and strategies for improving the resistance of WPC against biological decay. Pages 480-507 in Tor P. Schultz, Holger Militz, Michael H. Freeman, Barry Goodell, Darrel D. Nicholas, eds. Development of commercial wood preservatives. ACS Symposium Series, Vol. 982, American Chemical Society, Washington, DC.nSellers T, Miller GD, Katabian M (2000) Recycled thermoplastics reinforced with renewable lignocellulosic materials. Forest Prod J 50(5):24-28.nVerhey S, Laks P (2002) Wood particle size affects the decay resistance of woodfiber/thermoplastic composites. Forest Prod J 52(11/12):78-81.nVerhey S, Laks P, Richter D (2001) Laboratory decay resistance of woodfiber/thermoplastic composites. Forest Prod J 51(9):44-49.n






Research Contributions