Effect of molding temperature on fluidity and injection moldability of oven-dry steam-treated bamboo powder

Abstract

The thermal fluidity and injection moldability of oven-dry steam-treated bamboo powder were investigated with control of the temperature. Thermal analysis, such as differential thermal analysis and thermogravimetry, indicated that the steamed powder underwent degradation at lower temperatures, and the weight loss of the steamed powder was larger than that for the untreated powder. Thermal flow tests of the steamed powder at several temperatures revealed the flow rate was high at 180 and 200°C. Injection molding was attempted while controlling the temperature of the injection part and metal mold. It was possible to obtain products with a surface similar to plastic via injection molding and the range of metal mold temperature that resulted in a successfully molded product increased with the injection temperature. The four-point bending strength and Rockwell superficial hardness of the product increased with the mold temperature at each injection temperature. Both characteristics were high when the injection temperature was 180°C, and the highest values obtained were 36MPa and HR15w 78. Observation of the fracture part of the molded product confirmed that the fiber strength of the product molded at an injection temperature of 180°C was maintained, while that molded at an injection temperature of 200°C was not.