Abstract In the following study, the electrical and mechanical properties of granular-fibrous carbon-carbon composites with short recycled carbon fibres have been investigated. The examined composites contained from 0 to 12 wt% of three types of recycled carbon fibres that differ in length. The conducted study has proven that it is not the type of applied fibre, but rather the resultant porosity of composites that exerts the predominant influence on the electrical resistivity and mechanical properties of the tested materials. The curve fitting revealed mathematical formulas correlating the studied properties with the apparent density of the composite samples. Owing to the addition of the shortest carbon fibres, the mechanical and electrical properties were significantly improved (50.14% and 24.06% increase in modulus of elasticity and flexural strength respectively for the sample with 12 wt% of the shortest fibres). A 21.39% decline in the resistivity ( ϱ = 161.26 µ Ω ⋅ m ) of the composite containing 4% of shortest fibres was noted in comparison with the reference sample. Unlike powdered fibres, the addition of longer fibres caused an increase in porosity and deterioration of microstructure, which resulted in a significant decline in the key properties of the investigated composites.

中文翻译：

---

再生碳纤维颗粒-纤维状碳-碳复合材料的电学和机械性能

摘要 在接下来的研究中，研究了具有短再生碳纤维的颗粒-纤维状碳-碳复合材料的电气和机械性能。检查的复合材料包含 0 到 12 wt% 的三种不同长度的回收碳纤维。所进行的研究已经证明，对测试材料的电阻率和机械性能产生主要影响的不是应用纤维的类型，而是复合材料的孔隙率。曲线拟合揭示了将所研究的特性与复合样品的表观密度相关联的数学公式。由于添加了最短的碳纤维，机械和电气性能得到显着改善（50.14% 和 24. 对于具有 12 wt% 最短纤维的样品，弹性模量和弯曲强度分别增加 06%）。与参考样品相比，含有 4% 最短纤维的复合材料的电阻率 ( ϱ = 161.26 µ Ω ⋅ m ) 下降了 21.39%。与粉末纤维不同，添加较长的纤维会导致孔隙率增加和微观结构恶化，从而导致所研究复合材料的关键性能显着下降。