以共價與非共價方法改質奈米碳管與市售石墨烯應用於聚醯亞胺奈米複合材料

Comparing Covalent and Noncovalent Methods to Modify Carbon Nanotubes and Commercial Graphene for Applications in Polyimide Nanocomposites

柯宏翰(Hung-Han Ko)

指導教授 ： 程耀毅

國立臺北科技大學/工程學院/有機高分子研究所/博士(2014年)

摘要

聚醯亞胺是一種高性能的材料，因為聚醯亞胺的分子鏈中有很強的分子間作用力及本身也有良好的機械性質和優異熱性質。因此其可以應用於電子、光電、航太中。但是聚醯亞胺本身有絕緣特性，因此會在表面累積靜電荷。在應用於光電材料上會使材料累積過多的電荷而影響元件，降低元件品質。近年來，奈米碳管 (Carbon nanotubes，CNTs) 因為獨特的原子結構和高寬比所形成的特殊電學性質及機械性質，常被使用來強化高分子聚合物基材。但是由於高分子材料與奈米碳管之間的相容性較差，因為奈米碳管本身有強的凡德瓦爾力使得它們聚集成束在聚合物基材中。
本論文研究主要分為三個部分，第一部分中，奈米碳管經過高溫氧化後，經由超音波震盪混酸改質(硫酸：硝酸=3：1)在表面接上極性官能基。隨後，利用矽烷偶合劑將酸化後的奈米碳管進行改質而達到提升其熱性質。我們研究藉由不同矽烷化時間對於其矽烷化程度的影響。在第二個部分中，我們研究非共價改質後奈米碳管的分散性。奈米碳管經由高溫純化及硝酸溶液改質後，在sodium dodecylbenzenesulfonate (SDBS) 進行超音波震盪。在製備界面活性劑改質奈米碳管中，探討過濾及離心兩種方法的效果，並發現經過離心方法處理的碳管在聚醯亞胺中有較好的分散性。在本論文的第三部分中，以市售的石墨烯微片進行混酸及硝酸改質。在酸化處理後，使矽烷基能接上石墨烯微片的表面，在本實驗中，石墨烯微片利用與奈米碳管同樣的改質方法可以有效提升其熱性質與導電性質。

關鍵字

聚醯亞胺複合材料 ； 奈米碳管 ； 偶合劑 ； 界面活性劑 ； 石墨烯

並列摘要

Polyimide (PI) is the one of the highest performance materials because of the strong intermolecular force of its molecular chains and its superior mechanical properties, and excellent thermal stability. Therefore, PI can be applied in electronics, optoelectronics, and aerospace applications. However, PI exhibits insulating properties; thus, electrostatic charges may accumulate on the surface. When applied to optoelectronic materials, polyimide can cause excessive chages to accumulate in the material, thereby reducing its quality. In recent years, carbon nanotubes (CNTs) has attracted great research interest as reinforcement fibers in polymer–matrix composites because of their unique atomic structure, high aspect ratio, particular electrical property, and mechanical property. However, organic polymer materials have poor compatibility with CNTs because CNTs exert a strong van der Waals force that causes them to aggregate into bundles in the polymer matrix.
This study is divided into three parts. In the first part, MWNTs were purified by oxidation and then modified with mixed acid (sulfuric acid: nitric acid = 3:1) by ultra-sonication to attach carboxylic groups onto CNTs surfaces. Subsequently, silane coupling agent was used to modify the acid-CNTs, thereby enhancing the thermal property of CNTs. We investigated the effects of differing silanization time on the process of silanization. The second part describes the dispersibility of non-conalently modified MWNTs. The CNTs were oxidized and modified with nitric acid of sonicated in the solution of sodium dodecylbenzenesulfonate (SDBS). For the preparation of surfactant modified MWNTs, we investigated the effects of filtration and centrifugation. We found that the MWNTs prepared by centrifugation exhibited better dispersion in the PI matrix.
In the third part of this thesis, the commercial graphene nanoplatelets were modified using mix acid (sulfuric acid: nitric acid = 3:1) or HNO3. After acid treatment, the silane groups can be attached onto the carboxylic groups of GNPs by silanization. In this experiment, as with CNTs, the thermal property and electrical conductivity of graphene nanoplatelets can be effectively enhanced by using this modification method.

並列關鍵字

Polyimide composites ； Carbon nanotubes ； Coupling agents ； Surfactant ； Graphene

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