EFFECTS OF HYDRODYNAMIC TREATMENT OF WOOD PARTICLES ON MECHANICAL PROPERTIES OF WOOD- POLYMER COMPOSITES

This study is aimed to investigate the mechanical properties of wood-polymer composites (WPC) made on the basis of polylactic acid (PLA) with the addition of mechanically activated wood particles (WPs) from larch wood (Larix sibirica) in a mass ratio of 70/30%. WPs were obtained by hydrodynamic treatment that lasted for 5-45 min. Size estimation and distribution of WPs were carried out using the sieve method, and an analytical sieving machine. It was found that the size of WPs decreased with increasing hydrodynamic treatment time. WPs with sizes ranging from 100 to 300 mu m constituted the majority of the wood pulp. After testing, the SEM method was used to examine the WP surface and WPC samples. The mixing of WPs and PLA was carried out using the melt mixing method. WPC for the study of mechanical properties was obtained by flat pressing in a mold. Tensile tests were conducted in accordance with GOST 11262-2017, bending tests in accordance with GOST 4648-2014. It is shown that the duration of hydrodynamic treatment of WPs for 25 min provides the highest strength parameters of PLA-based WPC. This can be explained by the uniform dispersion of fibrillated WPs in the polymer matrix and the formation of their adhesive bond by mechanical engagement.