應用改質石墨烯補強高分子纖維積層複合材料機械性質與疲勞行為之研究

Investigation on the Application of Modified Graphene to Improve Epoxy/Fiber Laminates Composites on Mechanical Properties and Fatigue Behaviour

劉家秀(Liu, Chia Hsiu)

指導教授 ： 葉銘泉

國立清華大學/工學院/動力機械工程學系/碩士(2015年)

摘要

本研究主要利用自由基接枝法改質石墨烯，藉由拉曼光譜、高解 析 電 子 能 譜 儀 、 霍 式 紅 外 線 光 譜 儀 確 認 馬 來 酸 酐 (Maleic anhydride,MA)分子共價接枝於石墨烯表面。實驗過程中探討不同濃 度奈米碳材添加量對於高分子基材中的分散性，並分析未改質與改質 石墨烯的添加對於纖維與基材介面補強效果。
TGA 結果顯示表面改質劑殘留重量約 11.02%，研究結果更指出 改質石墨烯較未改質石墨烯有較佳的機械性質與分散性。0.25wt.%改 質石墨烯的添加提升效果最好，相較純環氧樹脂拉伸強度與彎曲強度， 分別提升 15.43%與 11.99%。藉由掃描式電子顯微鏡觀察破壞斷面可 發現，添加改質石墨烯明顯改善團聚效應。
添加石墨烯對於纖維積層板層間有補強效果，彎曲強度於未改質 石墨烯提升 2.37%，於改質石墨烯提升 16.19%；層間剪切強度未改 質與改質石墨烯分別提升 34.19%與 36.99%；動態扭轉疲勞測試，添 加改質石墨烯對於疲勞壽命均提升 2 倍以上。石墨烯可以增強纖維和 樹脂的介面黏著性，更藉由改質，增加石墨烯分散性且可以有效延遲 脫層及抑制裂紋延伸，進而提升整體層間機械強度。

關鍵字

自由基接枝、石墨烯、環氧樹脂、複合材料、機械性質、扭轉疲勞

並列摘要

This study adopted free-radical grafting method to modify graphene. And utilize Raman spectroscopy, X-ray photoelectron spectroscopy(XPS) and Fourier transforms infrared spectra(FTIR) to confirm that maleic anhydride molecules are covalently grafted on the surface of graphene. Influence of concentration of carbon nano material on dispersion in polymer composite and influence of modified graphene and unmodified graphene on enhancing interfacial strength of composite would be analyzed in the process of research.
According to the the result of TGA analysis that content of maleic anhydride was about 11.02%. Experimental results indicate that the mechanical properties and dispersion of modified graphene are better than those of unmodified graphene composite. The 0.25wt.% modified graphene is said to be the best ratio for enhancing the mechanical properties, improving the tensile strength by 15.43% and the flexural strength by 11.99% compared to epoxy. Scanning electron microscopy was used to observe the failure surface. It can be found that adding modified graphene significantly improves the phenomenon of aggregation.
Adding graphene, it is useful to enhance interfacial interaction between matrix and fiber. Experimental results show that both unmodified and modified graphene have positive influence, improving the flexural strength by 2.37% and 16.19%, and the interlaminar shear strength by 34.19% and 36.99%, respectively. In the torsion fatigue test, fatigue life of CFRP with modified graphene can drastically improve two times longer than neat CFRP. Graphene can improve adhesion between fiber and matrix. Moreover, modification can improve graphene dispersion and effectively slow the crack growth rate. Therefore, the mechanical properties of composite material could be enhanced.

並列關鍵字

free-radical grafting, graphene, epoxy, composites, mechanical property, torsion fatigue

參考文獻

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