Comparative Study of Solid Wood and Medium‐Density Fiberboard Fibers as Reinforcements in Polypropylene‐Based Wood‐Plastic Composites

Abstract

The demand for high‐performance polymer composites has driven the use of lignocellulosic fillers as functional reinforcements. This study investigates the influence of solid wood flour (SWF) and medium‐density fiberboard‐derived flour (MDFF) on the morphological, mechanical, thermal, and hygroscopic properties of polypropylene‐based wood–plastic composites (WPCs). Composites were produced without compatibilizers, with filler contents from 10 to 40 wt%. SWF exhibited larger and more uniform particles, whereas MDFF consisted of finer particles prone to agglomeration. Both fillers reduced tensile strength and ductility but increased stiffness compared to neat polypropylene (PP). Flexural strength improved by up to 22% for SWF and 18% for MDFF at optimal loadings. The superior performance of SWF‐based composites is attributed to its morphology and higher aspect ratio, which enhance stress transfer. MDFF showed higher water absorption due to its greater surface area. Fillers also acted as nucleating agents, increasing melting temperatures. Life cycle assessment indicated reduced global warming potential for all composites, reaching 1.81 and 2.22 kg CO 2 eq/kg for SWF and MDFF at 40 wt%, respectively, compared to 2.75 kg CO 2 eq/kg for PP. These results demonstrate the potential of both fillers to balance mechanical performance and environmental impact.