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Abstract
The role of moisture in the biological decay of wood-plastic composites was investigated. Southern pine wood fiber and ponderosa pine wood flour were chemically modified using either acetic anhydride (AA), butylene oxide (BO), or propylene oxide (PO). A 50:50 mixture of high density polyethylene and either chemically modified fiber or flour, or untreated fiber or flour was compounded (blended) and then compression molded. After preconditioning specimens either by a 2-week water soaking or a 5-day boil/dry cycling, a modified soil block test with the brown rot fungus Gloeophyllum trabeum was performed. Weight loss, moisture content, and mechanical properties were measured after 12 weeks of fungal exposure. The equilibrium moisture content at 30%, 65%, and 90% relative humidity and 27 °C was determined. Results show a correlation between moisture and decay. Weight loss from decay increased with increasing specimen moisture content (MC). Ranking of the specimens from the lowest weight loss and MC to the highest are as follows: AA
Keywords
Composites,
polyethylene,
chemical modification,
acetic anhydride,
butylene oxide,
propylene oxide,
equilibrium moisture content,
decay,
mechanical properties,
biodegradation,
wood plastic composites,
wood-decaying fungi,
moisture content,
wood flour,
wood fibers,
ponderosa pine,
southern pine,
Gloeophyllum trabeum
Citation
Ibach, Rebecca E.; Clemons, Craig M. 2002. Biological resistance of polyethylene composites made with chemically modified fiber or flour. Proceedings of the 6th Pacific Rim Bio-Based Composites Symposium & Workshop on the Chemical Modification of Cellulosics, Portland, Oregon, USA, 2002: pages 574-584.
