Kouzou Kanayama

Production of long rods by sequential extrusion of wood powders

Abstract Wood-based materials are environment-friendly resources as they eventually decompose into carbon dioxide and water after disposal. However, there are a number of productivity and workability related problems: it takes many years for a tree to grow to a useable size, and wood materials are more difficult to process than metal and plastic materials. To overcome these problems, sequential extrusion of cryptomeria powders mixed with Japanese cypress was performed in an attempt to make long wooden rods. In sequential extrusion, the powder replenishment and short-stroke extrusion steps are alternated until the desired rods are obtained. In this process, a strong extrusion seams were required between the new powder batch and the extruded portion of the rod. A steel container with a device for controlling replenishment temperature was used to increase the bonding strength of extruded rods. The results showed that there exist an optimal replenishment pressure and temperature, and that, under these optimal conditions, long rods with the strength of natural wood can be obtained. Finally, it is found that the presence of back-pressure is key in producing sound, high-strength rods.

Effect of various organic solvents on rheological properties of wood

Plastics depend strongly on underground resources such as petroleum. To produce novel wood materials as a substitute for plastics, the fine structure of wood impregnated with various organic solvents—ethylene glycol(EG), tri‐ethylene glycol, dimethyl folmamyde(DMF), dimethyl sulfoxide(DMSO)—was examined. The dynamic Young’s modulus and tanδ—frequency curves of every sample indicated that the relaxation process due to the glass transition of lignin in wood exists. To obtain basic data about the processes, the apparent activation energies (ΔE) were examined. The values of ΔE of the sample impregnated with water and EG were higher than that with DMSO and DMF. These results may not only be due to the hydrogen bonding per volume, but also the confined effect in wood. In fact, the CP/MAS spectra of EG—Wood sample indicates the existence of slow movement EG at higher temperatures of the melting point.