AMINATED WOOD SANDING DUST AS FILLER FOR RECYCLED POLYPROPYLENE-BASED COMPOSITE

The aim of this work was to functionalise birch wood sanding dust, a waste from plywood production, for obtaining recycled polypropylene-based wood-polymer composites (WPCs). The functionalisation of the lignocellulosic waste was carried out through a two-step procedure, namely, by its alkaline pretreatment, followed by amination. The alkaline pretreatment increased the amount of weak acid functional groups, decreased the content of hemicelluloses and enhanced the relative content of cellulose in the lignocellulosic matrix. The amination of the alkaline treated dust was performed with diethylepoxypropylamine. This functionalisation allowed introducing tertiary amino groups in the matrix, the amount of which, in terms of nitrogen content, was 1.6% and 3.4%. The WPC samples were prepared from recycled polypropylene and the aminated dust microparticles -by extrusion and moulding. The complex functionalisation of the birch sanding dust favoured the gain in the mechanical and hydrophobic properties of the WPC samples. Despite the positive effect of the functionalisation on the mechanical properties, the enhanced content of nitrogen in the dust particles deteriorated the hydrophobicity of the WPC samples due to the excess amount of hydrophilic amine groups in the lignocellulosic matrix.