Hidenori Yamanashi

EMI application of highly conductive plastic composite using vapor-grown carbon fibers (VGCF)

Carbon fiber plastic composite is prepared using vapor-grown carbon fibers (VGCF) as filler with thermo-plastic resin. Basic electrical properties and the stability of electrical conductivity of VGCFs composite in comparison with those using conventional carbon filler such as PAN- based carbon fibers (PAN) and electroconductive carbon black (CB) are studied. The VGCFs have lower resistivity than those of PAN and CB filler based composites at room temperature. The composite where the VGCF added with CB as mixing filler to matrix resin shows lower resistivity than those using VGCF or CB filler individually. This mixed filler composite has a high EMI shielding effect in the near-electric field. The value of EMI shielding effects is 70 dB at 2 mm sample thickness. On the stability of electrical conductivity, VGCFs and mixed filler composites have better performances than PAN-based ones under tensile stresses, bending stresses, temperature change and exposure test in air at a constant temperature (room temperature and 60 degree(s)C). The VGCF based composites are applicable as a useful electroconductive composite.

Whiskerizing on Carbon Fibers by Heating with a Carbon Dioxide Laser

Using a continuous wave CO2 laser, whiskerizing on the surface of carbon fibers was achieved by the catalytic pyrolysis of allene (C3H4). As a catalyst, iron particles generated by laser-induced thermal decomposition of pentacarbonyliron (Fe(CO)5) or ferrocene ((C5H5)2Fe) were used. The whiskers grown on the surface of the carbon fibers were found to have disordered carbon structures, as determined by Raman spectroscopic measurement.