A new mixing technique in the production of wood plastic composites from recycled materials

This work introduces a new mixing technique for producing wood-plastic composites. The main constituents of the wood-plastic composites are recycled low-density polyethylene and residual dust from routing medium-density fiberboard. The new mixing technique depends on separating the fibers and the polymer during the melting stage of the polymer to avoid the degradation of the fibers due to heat. Physical tests including a water absorption test and a thickness swelling test were applied on specimens produced with the single screw extruder and a new mixing technique, with different fiber-polymer weight ratios (50–50%, 55–45%, 60–40%, 65–35%, and 70–30%). It was found that at a (70–30%) mixing ratio, a reduction in water absorption of about 70% and 67% for densities of 1100 and 1250 kg/m³, respectively was reached. While at a (50–50%) mixing ratio, a reduction of about 24% and 14% for densities of 1100 and 1250 kg/m³, respectively  was accomplished. In general, the resistance to water absorption and thickness swelling was observed to be improved for the new mixing technique for all mixing ratios compared to the single-screw extruder.