Physical and mechanical properties of extruded poly(lactic acid)-based Paulownia elongata biocomposites

Paulownia wood flour (PWF), a byproduct of milling lumber, was tested as bio-filler with polylactic acid (PLA). Paulownia wood (PW) shavings were milled and separated into particle fractions and then blended with PLA with a single screw extruder. Mechanical and thermal properties were tested. Differential scanning calorimetry showed that PLA–PW blends containing smaller particle sizes had lower glass transition and melting temperatures compared to blends containing larger particle sizes. Biocomposites composed of smaller particles exhibited tensile strength values similar to neat PLA but had Young's modulus values that were 25% higher than neat PLA. However, elongation values decreased in all PLA–PW blends compared to neat PLA. Microscopic examination of the biocomposites revealed distinct differences in their morphologies. PLA–PWF blends exhibited color changes based on the size of the wood particles employed.

► Procedures to utilize juvenile Paulownia wood flour obtained from different particles sizes as a bio-filler with polylactic acid to create a wood plastic composite are presented.
► The mechanical, physical and thermal properties of these polylactic acid wood composites were evaluated.
► Paulownia bio-filler blends well with PLA without the use of a coupling agent.