木棉基碳纤维的制备及其吸波性能-中国材料进展

文章信息/Info

Author(s):: Guo wei; Li Yu ling; Li Guang; 1. College of Materials Science and Engineering, Donghua University, Shanghai 201620, China 2. College of Textile Science and Engineering，Donghua University, Shanghai 201620, China

Keywords:: carbonized kapok fibers; microwave absorbent; composites; reflection loss; microwave absorbing mechanism

摘要:: 以具有中空结构的天然木棉纤维为碳前驱体，采用直接碳化法制得木棉基碳纤维，并将其作为吸波剂制备吸波复合材料。通过对比具有中空结构的木棉基碳纤维和实心结构棉花基碳纤维作为吸波剂时复合材料的吸波性能，证明了含有中空结构的碳纤维能增强对电磁波的衰减；以在不同碳化温度下制得的木棉基碳纤维为吸波剂，以不同添加量与石蜡复合制得复合材料，发现用碳化温度为1000 ℃制备的木棉基碳纤维作为吸波剂，质量分数为7%、吸波复合材料厚度2 mm时，复合材料表现出优良的吸波性能：最低反射损耗达-32.7 dB，有效频带宽度达5.1 GHz。木棉基碳纤维不但依靠其中实体碳通过介电损耗吸收电磁波，而且其中空结构引发了大量界面极化和干涉相消，实现多种机制共同衰减电磁波。木棉基碳纤维是一种有潜力的吸波剂，有望在拓宽吸波频带、吸波材料轻量化方面发挥作用。

Abstract:: Natural kapok fibers with hollow structures were employed as carbon precursors, and carbonized kapok fibers (CKF) were prepared through a direct carbonization method. These CKF were subsequently utilized as absorbents to fabricate absorbent composites, simultaneously comparing the absorbent performance of composites containing hollow-structured CKF and solidstructured cotton-based carbon fibers as absorbents. It was demonstrated that carbon fibers with hollow morphology enhance electromagnetic wave attenuation. Furthermore, the absorbent properties of composites filled with CKF carbonized at different temperatures under different mass fractions were investigated. When the CKF carbonized at 1000 ℃ was used, and with a 7wt% absorbent addition, composite plates with a thickness of 2 mm exhibited excellent absorbent performance, achieving a minimum reflection loss of -32.7 dB and an effective bandwidth of 5.1 GHz. CKFs not only rely on their solid carbon content for electromagnetic wave absorption through dielectric loss, but also benefit from the abundant interface polarization and interference cancellation induced by their hollow structure, enabling multiple mechanisms for electromagnetic wave attenuation. CKFs show significant potential as absorbents and are poised to play a role in expanding the absorption bandwidth and reducing the weight of absorbent materials.