Yoichi KOJIMA and Hikaru KOBORI
The mission of our laboratory is to develop the new wood-based materials and their processing technology. Recently our laboratory focuses on the field of new biomass-based material such as wood plastic composite (WPC) and lingo cellulose nanofiber.
Keywords: Wood biomass, wood based materials, Cellulose nanofiber (CNF), Wood plastic composite
Current research trend
 Production procedure of wood based panels
Particle board (PB), also known as chip board is made from wood particle and adhesive by hot pressed together. Today PB is one of the most popular wood based panels that has been widely used as furniture and floor substrate. To uncover the heat and mass transfer during hot pressing is of importance to optimize the pressing procedure. We produce PB in a laboratory scale with various mat conditions to monitor the vapor pressure and temperature behavior during hot pressing. Furthermore recycled wood particle is used as a raw material of PB to enhance the usage of recycled material.
 Development of wood based panel reinforced by cellulose nanofiber (CNF)
CNF is the fibrous cellulose material and basic structure of plant life. CNF has several excellent mechanical properties whereas its lightweight. This plant-derived green material is highly expected to be used in a various field. We expected that the strong cohesion force of CNF will act as adhesive in a binder-less wood based panel. The aim of this study is to improve the mechanical properties of wood based panel by adding the CNF.
 Wood plastic composite (WPC)
WPC has been widely used in the exterior application such as deck and bench, and it is generating a lot of attention in the world. In our laboratory, addition of CNF and other additive are investigated in order to improve the mechanical properties of WPC.
 Evaluation of durability performance for wood based panel
Various types of wood based panel such as plywood, OSB, particleboard etc., are used as furniture and constructions. It is very important for wood industry and customer to know the durability performance of wood based panels. This research tries to define the duration when the panel keeps the desired mechanical properties and estimate the mechanical properties after aging. In our laboratory, various kind of wood based panels are subjected to outdoor-exposure test and several accelerated aging treatment to evaluate the degradation behavior during aging.
 Characterization of thermal treated wood
Some tropical wood species has their own attractive color and properties suitable for furniture and musical instruments. However they are limited to cut from the viewpoint of the tropical ecosystem protection. Thermal treated wood is expected to alternate tropical wood species with unused and domestic wood species. Thermal treatment adds darker appearance on the surface of wood, and improves the dimensional stability. In this study change in vibrational characteristics are investigated. Furthermore, chemical change during thermal treatment is evaluated by near infrared spectroscopy (NIRS).
 Light propagation simulation for the evaluation of internal properties of composite material
Near infrared light has low energy and high transmittivity. Therefore NIR light is applied for the functional brain imaging and transmittance imaging for food safety and security. NIR transmittance imaging has a potential to evaluate the inside of composite material. However NIR light highly scatter in the organic substances, therefore it is difficult to obtain the clear transmittance image. Our laboratory are trying to develop the diffusion light tomography with aid of light propagation simulation.