Plasticizing Cell Walls as a Strategy to Produce Wood-plastic Composites with High Wood Content by Extrusion Processes

A challenge in producing wood-plastic composites (WPCs) with a high wood content using extrusion processes is the poor processability, which gives rise to inadequate properties of the resulting WPC. Plasticizing the stiff wood cell walls can be a strategic response to this challenge. Two thoughts are addressed herein on improving the plasticity of wood particle cell walls: use of ionic liquids or use of low molecular weight organic thermal conductors. An ionic liquid can dissolve the cell wall surface and therefore reduce the stiffness of cell wall during an extrusion process. Organic thermal conductors can be incorporated into the cell wall (bulking) to improve the thermal conductivity, thereby sufficiently softening the lignin, a native plasticizer embedded in the cell walls. The potential issues that may arise as a result of these approaches are also presented and discussed.