Classification of wood fibre geometry and its behaviour in wood poly(lactic acid) composites

Abstract

This paper presents a comprehensive characterisation of wood flour geometry for polylactic acid (PLA) wood plastic composites (bioWPCs), and hence explores how the wood flour may influence the microstructure and performance of bioWPCs. The results show that current characterisation of wood flour from the literature can be misleading as they mostly rely on sieve analysis. Image analysis was used to critically study the fibres retained at various mesh sizes to investigate and examine the length and width distributions of the fibres prior to and after processing into bioWPCs. There were clear relationships between the reduction in both fibre size and aspect ratio and compounding processes depending on the original fibre geometry. It was also determined that by sieving out only the fibres retained at 500 µm much stronger bioWPCs can be produced than that using a single size fibre, achieving tensile and flexural stress of 15.3 and 13.2 MPa, respectively.