Repetitive flow forming of wood impregnated with thermoplastic binder

A processing technique for applying plastic deformation to a solid wood has been developed. In the present study, the effects of repetitive flow forming on the fluidity of solid wood materials impregnated with thermoplastic binder and on the mechanical properties of the products were investigated. The results showed that the increase in the number of extrusions decreased the load of the starting point of the extrusion especially in the lower polymer content of the wood materials. The bending strengths of the products were decreased with the repetitive extrusion using the lower polymer content (less than approximately 50 %) of the materials. On the other hand, the strength with higher polymer content (more than approximately 50 %) increased with the repetitive extrusion. The wood particles were found to become smaller in size with the repetitive extrusion. The tangles of the wood particles were also observed in higher polymer content of the materials. It was speculated that these configuration changes during reprocessing strongly affect both the fluidity during the extrusion and the mechanical properties of the products.