碳纳米管包覆芳纶热压纸的制备与性能研究

Preparation and Performance Study of CNT-Coated Aramid Hot-Pressed Paper

摘要:

芳纶纸因具有高强度、低形变、耐高温、耐化学腐蚀、优良的电气绝缘等特性，自诞生之日起就获得了工业界高度关注，并在各领域得到广泛应用，尤其是在国防军工、航空航天、交通运输等关键领域中展现出巨大优势。随着芳纶纸的应用场景扩展，对其力学、导电、导热、电磁相互作用等功能化需求也日益增多。复合型芳纶纸可通过复配材料调节自身物性，因而成为基础和应用研究的热点。采用静电层自组装技术，在芳纶纤维和浆粕表面保形包覆碳纳米管(CNT)，并以未包覆和CNT包覆的芳纶纤维和浆粕为原料，湿法抄造得到复合芳纶原纸，原纸在270 ℃和10 MPa条件下经热压处理后获得芳纶热压纸。通过调节CNT包覆芳纶纤维和浆粕的占比，可实现对CNT含量的精准调控。结果表明，引入CNT可以有效增强芳纶热压纸的导电能力和力学性能。在电学性能方面，热压纸的直流面电阻率和体电阻率相较于原纸均有明显下降，CNT载量（质量分数）低于2.0%时，面电阻率、体电阻率分别趋近2.5×10⁴ Ω·sq^-1和1.0×10⁵ Ω·m。在力学性能方面，随着CNT改性芳纶浆粕在原料中占比的提升，热压纸的拉伸性能呈现先增强后减弱的趋势，其弹性模量、拉伸强度、抗张强度最大可达1.46 GPa、30.7 MPa和1.78 kN·m^-1，较未改性的纯芳纶热压纸分别提升了13%、12%和16%。CNT包覆芳纶热压纸具有特殊的微观结构、出色的电学和力学性能，有望在工程领域开辟全新应用。

Abstract:

Aramid paper has attracted significant attention and been widely applied in industry since its inception， due to its high strength， low deformation， high-temperature resistance， chemical corrosion resistance， and excellent electrical insulation. It has shown tremendous advantages in some critical areas， such as defense， aerospace， and transportation. As the application scenarios of aramid paper have expanded， there are increasing requirements for some specific properties in mechanical strength， electrical or thermal conductivity， and electromagnetic interactions. Composite aramid paper， which can adjust its physical properties through material compounding， has consequently become a focus of both fundamental and applied research. Carbon nanotubes （CNTs） can be conformally coated on the surfaces of aramid fibers and fibrils， using the electrostatic layer-by-layer self-assembly technique. Composite aramid paper is obtained via a wet papermaking process. Both uncoated and CNT-coated aramid fibers and fibrils can be used as raw materials. The CNT content within the base paper can be precisely adjusted via the proportions of CNT-coated aramid fibers and fibrils in the raw materials. Hot-pressed aramid paper is obtained after hot-pressing at 270 ℃ and 10 MPa. The introduction of CNTs in aramid papers enhances the electrical conductivity and mechanical properties. In terms of electrical properties， the hot-pressed aramid paper shows a significant decrease in both surface and volumetric resistivity as compared to the base paper. When the CNT loading is below 2.0 wt.%， the lowest surface and volumetric resistivity are 1.50×104 Ω·sq-1 and 1.48×105 Ω·m， respectively. In terms of mechanical properties， the tensile strength of hot-pressed aramid papers improves initially， and then decreases， as the proportion of CNT-coated aramid fibril increases in the raw material. The elastic modulus， tensile strength， and breaking strength can reach maximum values of 1.46 GPa， 30.7 MPa， and 1.78 kN·m^-1， respectively， which have increased by 13%， 12%， and 16%， respectively， as compared to the base paper. CNT-coated aramid hot-pressed papers， which have unique microstructures and excellent electrical and mechanical properties， holds great potential for novel applications in industry.