Thermoformability study of wood flour–HDPE composites with variations in wood content under vacuum forming

Wood–plastic composites (WPCs) have emerged as sought-after substitutes for plastic. However, their use is restricted primarily to linear profiles owing to the lack of techniques for their three-dimensional (3D) forming. Thermoforming is a potential method for the 3D formation of WPCs. Accordingly, the aim of this study was to evaluate the thermoforming behaviour of extruded wood flour–high-density polyethylene composites with two different wood flour compositions (34 % and 54 %) under vacuum forming. This study examined the thermal behaviour of each structure during the forming process and the shape conformability, shape consistency, and surface quality of the formed samples. The findings suggest that increasing the quantity of plastic in composites can improve the obtained shape dimensions. Nevertheless, this improvement is accompanied by an increased level of inconsistency in the acquired profiles due to the distinct stretching rates of plastic and wood. Furthermore, the results reinforced the reliability of thermal analysis as a credible means of evaluating quality.