碳纤维表面构筑碳纳米管网笼结构用于增强碳纤维/热塑性树脂界面

Carbon fibers (CFs) are of inert surfaces and small roughness, which is unfavorable for infiltration of high viscous thermoplastic resin, leading to the limited improvement of interfacial properties of carbon fiber reinforced thermoplastic composites (CFRTPs). The recent studies show that a porous cage-networking structure of carbon nanotubes (CNTs) is capable of increasing the wettability and adhesion of a thermoplastic resin. We found that an uniform CNT cage-networking structure can be formed in alcohol by electrophoretic deposition; however, the short CNTs used in our study can only form small mesh holes, which is not good for the resin infiltration. This project is focused on studying the dispersion of CNTs with lengths of 1-5μm in alcohol by use of solvent solubility parameter matching, electrostatic repulsion and steric repulsion of a polymer, and on controlling the dispersion / agglomeration dynamics of CNTs by varying the ultrasonic frequency, thereby depositing the CNTs uniformly onto the CF surfaces; we will discuss the dispersion mechanism of CNTs, and reveal the formation mechanism of a CNT cage-networking structure; on this basis, effects of the CNT cage-networking structure on interfacial properties of a CFRTP will also be revealed. The innovation of this project is to develop an environmental-friendly and potentially scallable new CNT/CF composite fibers with controlled cage-networking sizes of the CNTs, aiming to establish theoretical foundation for solving the problems in CRFTP applications.

碳纤维表面惰性且粗糙度小，不利于高粘度熔融热塑性树脂的浸润，制约了碳纤维增强热塑性树脂复合材料（CFRTP）性能的提升。最新研究进展表明：在碳纤维表面形成碳纳米管相互搭接的多孔网笼结构，可改善热塑性树脂的浸润性。我们发现碳纳米管在醇溶剂中电泳沉积可形成均匀的网笼结构；然而，由于所用碳纳米管过短，仅能形成小网孔，不利于热塑性树脂的浸润。本项目以长度1-5μm的较长的碳纳米管为研究对象，通过溶度参数匹配、电排斥和高分子立体排斥等将其分散在醇溶剂中，并通过超声波和电场控制碳纳米管的分散/凝聚动力学，使碳纳米管均匀沉积到碳纤维表面；主要探讨碳纳米管的分散机制，揭示碳纳米管网笼结构的形成机理；在此基础上探讨碳纳米管网笼结构对CFRTP界面性能的影响机制。本项目的创新点是发展一种可调控表面网笼尺寸的、环境友好且可工业化的新型碳纳米管/碳纤维复合纤维，为解决CRFTP的应用问题奠定基础。

碳纤维表面惰性且粗糙度小，不利于高粘度熔融热塑性树脂的浸润，制约了碳纤维增强热塑性树脂复合材料（CFRTP）性能的提升。通过在碳纤维表面形成碳纳米管相互搭接的多孔网笼结构，可改善热塑性树脂的浸润性，但碳纳米管应有适宜的长度。本项目的主要研究内容是：长碳纳米管解束及分散；碳纳米管在碳纤维表面构筑网笼结构；碳纳米管网笼结构对碳纤维力学性能及复合材料界面性能的影响机制。按照项目原定计划，本项目研究了：⑴ 原材料碳纳米管的预处理，开发出碳纳米管氧化、可控切断及纯化一体化技术，并阐明了碳纳米管的结构调控模型机理；该技术在国际上属于首创；⑵ 研究了碳纳米管的解束与分散稳定性。通过碳纳米管的选择性氧化解束，实现了碳纳米管的长时间水分散稳定性，为碳纳米管的进一步应用奠定了基础；⑶ 研究了碳纳米管在碳纤维表面网络结构的构筑，实现了均匀、多孔、厚度可控碳纳米管薄膜理论和技术的突破；⑷ 通过粘结剂和激光烧蚀技术的运用，实现了碳纳米管网络结构的稳固化；⑸ 研究了碳纳米管/碳纤维复合纤维的力学性能，发现力学性能得到良好的保持；在此基础上，研究了CNT/CF复合纤维与基体树脂聚碳酸酯间界面性能，实现了界面浸润性和粘结性能的显著提升；揭示了界面浸润和界面增强的内在机理，为下一代高性能碳纤维复合材料的研制提供了思路。