2009 年 34 巻 4 号 p. 651-654
We have carried out the project for the useful utilization of the remaining rice hull as an industrial carbon material. The rice hull carbon (RHC) powder is manufactured by carbonizing in a nitrogen gas atmosphere at high temperature, then crushing and sieving. The rice hull has a natural porous structure. The diameter of the unit cell is about 10μm. The porous structure retained even after the carbonizing and crushing. The composite material comprised of the RHC and Ethylene Propy -lene Diene Methylene linkage rubbers is manufactured by molding and vulcanizing. In this study, the characteristic of electromagnetic wave absorption (reflectivity) was measured in frequency band between 50MHz and 8GHz for the composite material. The composite material possessed a high characteristic of electromagnetic wave absorption for 2GHz-8GHz. The characteristics were further affected by the test piece thickness and theRHC powder content.