Water sorption characteristics of two wood-plastic composites

Abstract

Wood-plastic composites are generally presumed to be inherently more resistant to moisture uptake than solid wood, but there is little data on the relative rates of moisture uptake in these materials overtime. Trex® and Strandex® deck sections were immersed in water for up to 215 days, then sections were cut at various distances away from the ends and surfaces. The moisture contents in these zones were then assessed by oven-drying and weighing. Overall moisture increases were relatively slow, particularly for Strandex, but moisture levels in the outer 5 mm of the products were sufficient for fungal attack. This moisture distribution coincides with decay patterns observed in previous laboratory studies and highlights the importance of slow moisture uptake in the performance of these materials.