Wood Particles of Various Sizes from Primary Wood Processing as Filler in Rigid Polyurethane Foams

The use of wood particle in the process of producing composite materials is an interesting issue that fits into current research trends. Application of wood particles as a filler in the production of polyurethane foams raises many interesting issues. The additive of wood particles can affect the structure and, consequently, the mechanical and physical properties. The research used a 10% addition of pine wood particles, differing in particles size: F1: 0.05 - <0.125 mm; F2: 0.125 - <0.315 mm; F3: 0.315–1.25 mm; F4: >1.25–2.0 mm. It was observed that with the increase in particles size, the density of the produced composites increased. A similar trend was observed in thermal conductivity. In the case of mechanical properties, it was shown that the F2 (0.125 - <0.315 mm), F3 (0.315–1.25 mm) and F4 (>1.25–2.0 mm) fractions slightly reduced the mechanical properties. In each case, a decrease in brittleness was observed, which could be attributed to changes in cellular structure. Despite the fact, that some decrease was observed, the obtained results are satisfactory.