碳纳米管/环氧树脂复合材料的制备及性能研究
作者：王世凯
院校:北京化工大学
关键字:碳纳米管;环氧树脂;纳米复合材料;力学性能;摩擦性能;导电性能
学位：硕士
专业:应用化学
摘要:
碳纳米管是由具有六边形结构的石墨片层卷曲而成接近理想的圆柱形晶须。 碳纳米管具有优异的力学性能、热稳定性与导电性能，与聚合物复合可开发出许 多新型复合材料。目前碳纳米管大量制备技术的发展为其在复合材料领域的应用 提供了可能。 本文以环氧树脂（E－51）为基体，CNTs 为增强剂，制备了 CNTs/环氧树 脂纳米复合材料。研究不同超声功率及表面处理方法对制备碳纳米管/环氧树脂 纳米复合材料的力学性能、摩擦性能及电学性能的影响，并 CNTs 在环氧树脂中 的分散性进行了研究。 力学性能的研究结果表明，使用低功率超声仪制备的未表面处理 CNTs/环氧 树脂复合材料，其拉伸强度、拉伸弹性模量较纯树脂都有不同程度的降低。CNTs 经表面处理后制备的复合材料拉伸弹性模量较纯树脂提高 78MPa，但拉伸强度、 拉伸应变随 CNTs 添加量的增加逐渐降低。使用高功率超声仪制备的未表面处理 CNTs/环氧树脂复合材料，其拉伸应变随 CNTs 添加量的增加逐渐增加，当 CNTs 的添加量为 1％时，拉伸应变较纯树脂提高 20％。随 CNTs 表面氧化程度的加深， 所制备的复合材料的拉伸弹性模量逐渐增加，当 CNTs 经浓硝酸处理 16hr 后， 制备的复合材料的拉伸弹性模量较纯树脂提高约 342MPa。使用单壁 CNTs 制备 的复合材料的拉伸强度、拉伸弹性模量、拉伸应变较纯环氧树脂有所下降。 碳纳米管/环氧树脂纳米复合材料摩擦性能研究结果表明，CNTs 的加入能够 极大改善环氧树脂的摩擦磨损性能。当 CNTs 的含量为 4wt％，复合材料的摩擦 系数和磨损质量损失分别达到 0.22 和 2.22×10-5mg(N·m)-1，较纯树脂降低 63％ 和 80％。使用 600 W 超声仪较 100 W 超声仪制备的复合材料的摩擦磨损性能优 良。环氧树脂同 45＃钢对磨时主要发生粘着磨损和疲劳剥落，而复合材料的粘着 I 磨损和疲劳剥落显著减轻；纯环氧树脂的磨损表面粗糙，而当 CNTs 的含量为 4 ％时，复合材料的磨损表面非常光滑。 在环氧树脂中加入 CNTs 能够使基体树脂的电阻率极大地降低，使环氧树脂 由绝缘体变为导体（电阻率
Abstract:
Carbon nanotubes (CNTs) possess unique structure and significant advantages, such as excellent mechanical properties, high thermal stability and electrical conductivity. CNTs are considered as the ultimate type for the novel composites with polymer. Rapid advance in bulk synthesis of carbon nanotubes (CNTs), coupled with their remarkable mechanical properties, are positive signs for application in a host of composites materials. In this paper, carbon nanotubes/epoxy nanocomposites were prepared by ultrasonication with carbon nanotubes as reinforcements and epoxy as matrx. We deal with CNTs with nitric acid, prepare CNTs/epoxy nanocomposites by different power ultrasonication, and study on the electric, mechanical and tribological performance of the nanocomposites. We also investigate the dispersity of CNTs in epoxy. Pristine CNTs/epoxy nanocomposites were produced by low energy ultrasonication, and the mechanical properties were studied. The results show that the tensile strength, the tensile modulus and the tensile strain decrease to some extent. CNTs treated with nitric acid were used to produce CNTs/epoxy nanocomposites, which tensile modulus increase about 78MPa, but the tensile strength and the tensile strain decrease sharply with the loading increase of the treated CNTs. On the other hand, the tensile strain of the nanocomposites produced by high energy ultrasonication with pristine CNTs and epoxy increase with the enhancement of the pristine CNTs. When the loading of the pristine CNTs is 1 wt%, the tensile strain of the nanocomposites enhances about 20%. The tensile modulus of the nanocomposites III increases with the increase in oxidation time of the CNTs. When the CNTs were oxidized 16 hr, the tensile modulus of the nanocomposites prepared by it increase about 342MPa. When using the SWNTs as reinforcement, the tensile strength, tensile modulus and tensile strain of the nanocomposites decreases entirely. The influences of CNTs loading on the friction and wear behavior of the resulting nanocomposites sliding against AISII 045 steel were investigated on an Optimal-SRV tribotester at ambient condition. It has been shown that, with the increase of CNTs addition from 1 wt % to 4 wt%, both the friction coefficient and the wear rate of the nanocomposites decreased from 0.60 and 1.11×10-4mg/(N·m) for pure epoxy to 0.22 and 2.22×10-5mg/(N·m) for nanocomposite loading 4 wt% CNTs, respectively. The composites with the same 1 wt% CNTs content prepared by high power machine exhibited lower friction coefficient than that of the composites prepared by low power dispersion because of the uniform dispersion of CNTs in epoxy. The wear surface of the epoxy is coarse, while the surface of the nanocomposites with 4 wt% CNTs content is smooth. The conductivity of the nanocomposites increases sharply, when CNTs was added to the epoxy. Epoxy can be made conductivity or semi-conductivity with the content of CNTs in nanocomposites.