原位微拉曼测试技术在碳纳米管纤维和薄膜材料力学性能研究中的应用

利用宏观应力联合原位微拉曼测试技术对双壁碳纳米管(Carbon Nanotube,CNT)纤维和薄膜材料的力学性能进行了实验分析,探讨了拉伸加载期间纤维和薄膜内CNT的载荷响应及其与宏观力学性能的关联,揭示了两种材料力学性能差异性的微观机理。实验分析表明,CNT纤维和薄膜的拉伸变形呈现弹性、强化和损伤断裂三个阶段,但其内的CNT只发生弹性变形,没有塑性形变,且没有明显的损伤或键的断裂,纤维和薄膜呈现阶段性拉伸变形的原因可归结为滑移。纤维的弹性模量显著高于薄膜,是薄膜的4.7倍,原因是弹性阶段纤维中CNT的轴向伸长对宏观应变的贡献较大。纤维和薄膜的拉伸强度相差较小,原因是强化阶段薄膜内不断有大量CNT进入承载队伍,这也使得薄膜具有比纤维更高的韧性。

On the Application of In-situ Micro-Raman Spectroscopy in Study of Material Mechanical Properties of Carbon Nanotube Fiber and Film

Experimental analysis of material mechanical properties of double-walled carbon nanotube (CNT) fibre and film was conducted by means of in-situ micro-Raman spectroscopy combined with macroscale stress testing. CNT load response and its relation with macroscale mechanical properties during tensile loading of fiber and film were explored. Microscopic mechanism which causes mechanical property differences between fiber and film was revealed. Experimental analysis demonstrates that although the macroscale mechanical response of both CNT fiber and film may be divided into 3 stages as elastic stage, strengthening stage and damage-fracture stage, but there is only elastic deformation inside CNT without plastic deformation and obvious damage or bond breaking. The staged mechanical response of fiber and film can be attributed to slippage. Young's modulus of fiber is significantly higher than that of film, former is 4.7 times higher than latter. This can be attributed to the greater contribution of CNT axial extensions in fiber to macroscale strain. There is little difference in tensile strength of fiber and film, due to continuous involving of a large amount of CNT film in load bearing during strengthening stage.