Effects of soaking and freezing on composites made from wood‐based fillers and biodegradable plastics

Abstract Biodegradable plastic composites were subjected to prolonged soaking and freezing treatments to assess the effects on the mechanical performance. Radiata pine flour and thermomechanical pulp fibers were used as fillers at various addition levels in three different commercial polymer matrices. Two were bioderived, one oil‐derived, each with different hydrophobicities. Depending on the nature of the biodegradable polymer matrix, the rates and extents of water uptake were found to be either enhanced or reduced by the wood‐derived fillers. Although the higher aspect ratio of the pulp fibers improved mechanical performance, relative to the wood flour, water uptake was also significantly enhanced in some cases. POLYM. COMPOS. 27:323–328, 2006. © 2006 Society of Plastics Engineers