Abstract
Electromagnetic wave absorption characteristics, electrical resistivity and micro pore structure (specific surface area and micro pore size distribution) of the powder-method woodceramics, which were prepared by carbonizing the compacted mixtures of wood powder and 10-30 mass% of phenolic resin powder, were examined in comparison with those of the conventional MDF-method woodceramics, which were prepared by carbonizing the medium density fiber (MDF) boards impregnated with phenolic resin solution. The powder-method woodceramics carbonized at 650°C showed remarkable electromagnetic absorption characteristics as same as MDF-method woodceramics, namely the absorption values of 10%, 20% and 30% phenolic resin specimens were 35 dB at 11 GHz, 40 dB at 9 GHz and 50 dB at 2 GHz, respectively. These remarkable absorptions were mainly due to the suitably high electrical resistivities (101-103 Ωcm) of these woodceramics. The specific surface area of these woodceramics became to the maximum in the case of the carbonization at 700°C, namely 380 m2 · g-1 in the 30% phenolic resin powder specimen, 300 m2 · g-1 in the MDF specimen and 230 m2 · g-1 in the 10% phenolic resin powder specimen, respectively.
