Spherical PVC paticles and Short fiber-like PE particles were used as the polymeric matrix and spherical Ni particles and platelike Cu particles were added to these matrix to make the composite specimens. The size ratios of the polymeric particles to the metallic particles were set as 1,5, and 20 and the compacting pressures were 100-1, 500kg/㎠. Varying the shape of particles, compacting pressures, temperature, and the electrical specific resistivities of these specimens were measured. A drastic fall in the electrical resistivity at a critical volume percent of metallic particles, Vc was observed and remarkable changing of Vc with the particle size ratio was also observed. When the sperical metallic particles were used, the resistivity showed a sudden increase near the glass transition temperature of the polymeric matrix where the concentration of metallic particles was lower than Vc. However, in the case of higher content of metallic particles then Vc, there was no marked change in electrical resistivity. The specific resistivties of the composites were not effected by temperature and compacting pressure the plate like Cu particles were employed.

구형의 PVC 입자와 짧은 섬유형의 PE 입자를 고분자 모상으로 하고, 구형의 Ni 입자와 판상의 Cu 입자를 여기에 첨가하되 고분자입자/금속입자의 크기비(Rp/Rm)가1,5,20되게하고, 성형 압력을 100∼1,500kg/㎠으로 해서 복합재료의 시편을 만들었다. 이들 시편의 전기 비저항을 입자의 모양, 성형 압력 및 온도를 변화 시키면서 측정하였다. 비저항은 금속 입자의 임계부피분율, Vc에서 급격한 감소를 보이고 있으며, Vc는 입자 크기비(Rp/Rm)에 따라 크게 변하였다. 구형 금속입자를 사용 했을때는 금속입자의 농도가 Vc보다 높은경우 고분자 모상의 Tg 부근에서 저항이 별안간 증가함을 볼 수있었으나, 금속입자의 농도가 Vc보다 낮은경우 저항의 급격한 변화는 없었다. 또 판상의 금속입자를 사용했을 때는 복합재의 비저항은 온도나 성형압력의 영향을 받지 않았다.

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