ABSTRACT

Carbon fibre-reinforced carbon aerogel composites (C/CAs) were prepared by using polyacrylonitrile (PAN) and phenolic (PH) carbon precursor fibres as reinforcements, respectively, then impregnated with resorcinol-formaldehyde sol, aging, solvent exchanging, CO₂ supercritical drying and carbonization at 1000°C. The physical properties, structural morphology and mechanical and thermal insulation behaviour of the two kinds of composites were further compared. Pore structure analysis shows that the PH-based C/CAs have a larger specific surface area (438.92 m²·g⁻¹) and richer mesoporous volume than the PAN-based C/CAs. Mechanical behaviour of the C/CAs has been changed, but the stronger enhancement effects belong to PAN-based C/CAs (compressive strength in xy and z-directions are 1.63±0.10 MPa and 1.22±0.19 MPa, bending strength is 3.62±0.50 MPa). However, the PH-based C/CA composites have relatively low thermal conductivities, ranging from 0.027 to 0.164 W·m⁻¹·K⁻¹ between 25 and 1800°C.

摘要

以聚丙烯腈(PAN)和酚醛(PH)碳前驱体纤维分别为增强体，经间苯二酚-甲醛溶胶浸渍、老化、溶剂交换、CO 2 超临界干燥制备碳纤维增强碳气凝胶复合材料(C/ _CAs )并在 1000°C 下碳化。进一步比较了两种复合材料的物理性能、结构形貌以及力学和隔热性能。孔结构分析表明，PH 基 C/CA比 PAN 基 C/CA具有更大的比表面积（438.92 m ² ·g ^{-1 ）和更丰富的介孔体积。}C/CAs 的力学行为已经改变，但更强的增强效果属于基于 PAN 的 C/CAs（抗压强度xy和z方向分别为1.63±0.10 MPa和1.22±0.19 MPa，弯曲强度为3.62±0.50 MPa)。然而，PH 基 C/CA 复合材料具有相对较低的热导率，在 25 至 1800°C 之间的范围为 0.027 至 0.164 W·m ^-1 ·K ^-1。