Preparation and properties of heat-treated esterified wood flour/polylactic acid composites for FDM 3D printing

Polylactic acid (PLA) and wood composites as biodegradable materials have limited applications due to the poor dispersity of wood flour (WF) in PLA matrix and weak adhesion. Thus, this study aims to prepare PLA/WF composite materials by combining high-temperature moist air (220 degrees C), A-187 silane coupling agent, and acetic anhydride with PLA and employing heat treatment (HT) and esterification methods. The effects of different treatment methods on the crystallization, thermal and mechanical properties, and hydrophobicity of the WF/PLA composites are studied. The addition of heat-treated esterified WF decreases the cold crystallization temperature, thermal stability, and water resistance of the composites. Compared with the untreated WF/PLA composite, the heat-treated esterified WF/PLA composite has 40% increase in tensile strength and 13% increase in flexural strength. HT combined with other modification methods significantly reduce the crystallinity of the composites and improve the compatibility between WF and PLA, resulting in excellent performance enhancement of the heat-treated esterified WF composites compared with the untreated composites. Thus, addition of a small amount of HT esterified WF to WF/PLA composites in 3D printing filament extruder enhances its plasticization property and toughness at low cost, suggesting the future wide applications of the material in 3D printing.

Automated summary

This study improves the properties of PLA/wood flour composites through different treatment methods, including crystallization, thermal and mechanical properties, and hydrophobicity. The addition of heat-treated esterified wood flour significantly enhances the strength and water resistance of the composite material.