Preparation of High Density Products from Various Biomass Resources Using Their Injectabilities

Abstract

To investigate the injectability of wood at a temperature range between 160 to 180 °C, the effects of the initial moisture content (IMC) of wood, temperature-holding time and nozzle diameter of the mold on the relationships between pressure versus stroke during injection molding were discussed. To know the mechanical and physical properties of obtained products, the bulk density, Vickers hardness and a size-stability against boiling water were measurements. Furthermore the possibility in applying this method to the other biomass resources was investigated. The results showed that the nozzle diameter drastically affects to the pressure required for injection molding, and the smaller diameter resulted in the higher pressure. By increasing IMC up to 40% the pressure tended to decrease, however successful injection runs couldn't achieve using less than 20% of IMC. It was found that the temperature-holding time set as a steaming time was an effective parameter to reduce the pressure even using the small nozzle diameter. The average density and the Vickers hardness of the products reached about 1.3 g/cm3 and almost 19HV respectively. Whereas the products didn't show size-stability, a product being compressed by a counter presser in a mold after the injection whose bulk density was 1.35 g/cm3 got an improved size-stability. Finally it was demonstrated that various spices of plant as well as the other biomass including food residues could be shaped and densified by this injection molding, and their molded product densities reached 1.3-1.45g/cm3, which were equivalent to almost true densities of biomass resources.