ABSTRACT

This work developed a novel approach for carbon nanotube (CNT) direct deposition on carbon fiber (CF) tow surface by chemical vapor deposition (CVD), without degrading CF mechanical properties. This approach combines conditions for growth at low-temperature (650°C), small growth induction period for a fast growth and fast surface modification to enable the growth. The lower growth temperature comes from using the well-known equimolar C₂H₂/CO₂ gas mixture. The floating catalyst from a liquid precursor (with high ferrocene concentration dissolved in hexane) reduced the growth induction period. Gentle surface modification, either by a mild oxidation of CF fiber with silicon containing sizing, or by desized CF exposition to a hexamethyldissiloxane (HMDSO) environment, create silicon oxide clusters. The X-ray Photoelectron Spectroscopy (XPS) analysis show that such clusters need to be in a higher oxidation state – Si(-O)₂, Si(-O)₃ and Si(-O)₄ – to anchor catalyst and enable CNT growth. The first oxidation state – Si(-O)₁ – is not enough. A resin droplet wetting test developed shows that even though the success in CNT growth, the entire processes decrease CF wetting, exposing the need for a resizing procedure. CF mechanical properties were characterized by single-filament and CF tow tensile strength tests.

摘要

这项工作开发了一种通过化学气相沉积 (CVD) 在碳纤维 (CF) 丝束表面直接沉积碳纳米管 (CNT) 的新方法，而不会降低 CF 的机械性能。这种方法结合了低温（650°C）生长条件、快速生长的小生长诱导期和快速表面改性以实现生长。较低的生长温度来自使用众所周知的等摩尔 C ₂ H ₂ /CO ₂气体混合物。来自液态前体（溶解在己烷中的二茂铁浓度高）的漂浮催化剂缩短了生长诱导期。温和的表面改性，无论是通过含硅胶料对 CF 纤维的温和氧化，还是通过将 CF 脱浆暴露于六甲基二硅氧烷 (HMDSO) 环境中，都会产生氧化硅簇。的X射线光电子能谱（XPS）分析表明，这种集群需要在较高氧化态-硅（= O）₂，硅（-O）₃和Si（-O）₄ -到锚催化剂和使CNT生长。第一个氧化态——Si(-O) ₁- 是不足够的。开发的树脂液滴润湿测试表明，即使 CNT 生长成功，整个过程也会降低 CF 润湿，从而需要调整尺寸程序。CF 机械性能通过单丝和 CF 丝束拉伸强度测试表征。