多壁奈米碳管合成與含氧官能基化之研究

Study on Synthesis and Oxygenated Functionalization of Multi-walled Carbon Nanotubes

陳興龍(Hsing-Lung Chen)

指導教授 ： 江右君

元智大學/工程學院/機械工程學系/碩士(2007年)

摘要

迅速發展的奈米科技是近幾年開發的新領域，結合高分子材料所形成的奈米複合材料是奈米材料發展應用的一個重要方向。然而如何控制及利用奈米碳管表面與高分子鏈間的交互作用，得到適當的分散性以施展奈米碳管的特性，仍是目前極具挑戰性的問題。因此，本研究的目的是將所合成的奈米碳管進行氧化反應，使奈米碳管表面產生含氧官能基。以增強奈米碳管與高分子基材間的界面相容性，提升奈米複合材料的性能。
本研究藉由化學氣相沉積法合成多壁奈米碳管，先利用NHO3 /HCl作純化；接下來利用濃H2SO4/濃H2O2或濃H2SO4/濃HNO3等兩種混酸溶液進行氧化處理，使奈米碳管的表面產生含氧官能基團。探討多壁奈米碳管表面含氧官能基的種類、含量和分佈，同時也進一步評估改質後的碳管與高分子間的界面反應。奈米碳管的特性係利用FESEM、TEM/HRTEM、EDS、EA、TGA、XRD、Raman spectroscopy、XPS、FTIR和氮氣等溫吸脫附曲線等技術予以分析得知。
研究發現所合成的奈米碳管為細長捲曲的型態，層數對比清晰且具有中空結構；純化和氧化程序均可有效去除殘留的Fe觸媒。經過氧化處理後，O元素有顯著增加的趨勢。雖然抗氧化能力可隨著氧化處理而提升，但樣本均質性卻明顯降低。奈米碳管經過純化和氧化後，晶面間距有些微改變，可能是表面官能基所造成之影響。奈米碳管經過H2SO4/H2O2氧化後，主要產生C-OH和C=O官能基，而H2SO4/HNO3氧化主要形成C-OH、C=O和C-OOH等官能基；這些含氧官能基主要分佈在管壁和管端。由N2等溫吸脫附曲線發現，奈米碳管可視為多孔性的材料，比表面積和總孔體積經過純化和氧化後有增加的現象。研究結果顯示，氧化後奈米碳管與環氧樹脂或PDADMAC的反應，與碳管表面的含氧官能基有關。

關鍵字

多壁奈米碳管 ； 氧化 ； 含氧官能基 ； 高分子聚合物 ； 特性分析

並列摘要

In recent years the nanotechnology has been developed as an innovative field, and the nano-composites have become an important application of nano-materials. However, how to control and utilize the interactions between carbon nanotubes (CNTs) and polymers in order to obtain a good dispersion and develop the excellent properties of CNTs is still a great challenge. Therefore, the objective of this study is to synthesize CNTs, and then modify the CNTs by introducing the surface oxides onto the surface of CNTs. Thus the interface of CNTs and polymers can be enhanced and the performance of nano-composites can be improved.
The chemical vapor deposition method was used to prepare the multi-walled carbon nanotubes (MWNTs). The as-grown MWNTs were purified by NHO3/HCl solution. And then the H2SO4/H2O2 or H2SO4/HNO3 solution was used to modify the MWNTs so that surface oxides could be generated on the surface of MWNTs. The species, amounts, and locations of surface oxides were discussed and the interface reactions between MWNTs and polymers were evaluated. The characterizations of MWNTs were probed using several techniques such as FESEM, TEM/HRTEM, EDS, EA, TGA, XRD, Raman spectroscopy, XPS, FTIR, and N2 adsorption/desorption isotherms.
Results show that the as-grown MWNTs are long and entangled with a good crystallization and a tubular structure. Purification and acid oxidations can effectively remove the Fe catalysts. After oxidation, the O content has significantly increased. Although the ability of resistant to oxidation can be enhanced with oxidation treatment, the homogeneity of the samples is evidently deteriorated. The purification and oxidation process cause the inter-planner spacing changed a little, which could be ascribed to the interactions with surface oxides. The H2SO4/H2O2 oxidation of MWNTs generates C-OH and C=O groups primarily, while the H2SO4/HNO3 oxidation introduce C-OH, C=O, and C-OOH groups. These surface oxides are mainly located on the surface walls and at the tips of MWNTs. The data from N2 adsorption/desorption isotherms indicate that MWNTs can be regarded as a porous material, and specific surface area and total pore volume increase after purification and oxidation. The results also imply that the reactions of MWNTs oxidized with epoxy or PDADMAC are related to the surface oxides.

並列關鍵字

Multi-walled carbon nanotubes ； Oxidation ； Surface oxides ； Polymer ； Characterization

參考文獻

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