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Abstract
Wood-plastic composites (WPCs) have been gaining market share in the residential construction industry as lumber for decking, roof tiles, and siding. The durability of these materials in exterior environments is just beginning to be understood. Current research suggests that controlling moisture absorption by the composite is key to improving durability. Methods to improve moisture resistance of WPCs have met with limited success. Co-extrusion involves the simultaneous extrusion of two dissimilar materials as a single profile. In this study, co-extrusion was used to improve the moisture resistance, and in this manner, the durability of WPCs. We manufactured a material with a WPC base coated with a clear plastic cap layer of either high-density polyethylene or polypropylene. The co-extruded composites and corresponding WPCs without a plastic coating were tested for moisture absorption and weathering performance. The cap layer co-extruded over a WPC provided improved moisture resistance compared with the control WPC. Co-extrusion of WPCs with a clear plastic cap layer did not provide protection against changes in mechanical performance. However, composites capped with high-density polyethylene exhibited some resistance to color change.
Keywords
Color fading,
plastics,
extrusion,
polypropylene,
polyethylene,
weathering,
composite materials,
deterioration,
mechanical properties,
moisture,
wood-plastic composites,
discoloration,
co-extrusion,
wood-plastic materials,
durability
Citation
Stark, Nicole M.; Matuana, Laurent M. 2007. Coating WPC''s using co-extrusion to improve durability. Proceedings : Coating Wood and Wood Composites : Designing for Durability, July 23-25, 2007, Seattle, WA. [S.l. : s.n.], 2007: Pages 1-12
