取向碳纳米管/聚合物复合材料摩擦学各向异性研究

【作者】 张慧；

【导师】 彭慧胜；

【作者基本信息】 复旦大学 ， 高分子化学与物理， 2013， 硕士

【摘要】 碳纳米管是近年来被研究最多的纳米材料之一。因为优异的力学、光学、电学、磁学、热学等综合性能,碳纳米管在结构材料、储能、生物医药、光电器件等广泛领域显示重要的应用前景。另一方面,聚合物因成本低、加工容易、结构可控等优点而在摩擦学领域被广泛研究应用。聚合物的机械强度和耐磨性往往较低,为了提高其摩擦学性能,经常需要加入其它组分如碳纳米管形成高性能的复合材料,但长期以来面临一个共同而关键的挑战,即碳纳米管在聚合物基体中无规聚集,导致无法充分发挥碳纳米管的优异性能。本学位论文重点制备了具有高度取向结构的碳纳米管／聚合物复合材料,获得高性能的摩擦材料。首先,通过化学气相沉积法合成了碳纳米管阵列；然后,进一步通过干法纺丝和压膜方法得到高度取向的碳纳米管膜；最后,加入聚甲基丙烯酸甲酯溶液旋涂成膜或者苯乙烯单体溶液后进行原位聚合,制备两类典型的取向碳纳米管／聚合物复合材料。复合材料表面的碳纳米管一侧嵌入聚合物基体中,另一侧露在表面。通过摩擦力显微镜和M-2000摩擦磨损测试仪,分别重点研究了上述两类复合材料在微摩擦和宏观摩擦性能的各向异性。主要结论总结如下：(1)对于取向碳纳米管／聚甲基丙烯酸甲酯复合膜,垂直于碳纳米管取向方向的微摩擦系数约为平行方向的两倍；(2)对于取向碳纳米管／聚苯乙烯复合材料,垂直于碳纳米管取向方向的磨损率是平行方向的约三倍；(3)加入碳纳米管显著提高了复合材料的力学强度、耐磨性、导电性和热稳定性。更多还原

【Abstract】 Carbon nanotubes (CNTs) represent one of the most studied nanostructures in recent years. Due to their extraordinary mechanical, optical, electrical, magnetic, and thermal properties, CNTs have been proposed for a broad spectrum of applications in the fields of structural material, energy storage, biology, medicine and photovoltaics. On the other hand, due to their low cost, easy fabrication, and tunable structures, polymers have been widely studied and used for friction materials. Nevertheless, the use of polymers in tribological applications has been limited by low mechanical strength and wear resistance. To further improve the tribological property, a second phase was usually introduced to produce composite materials with incorporated new properties. Among them, CNT has been widely studied as one of ideal candidates. However, there remains a common and critical challenge, i.e., random dispersion and aggregation of CNTs in polymer matrices. The resulting composite materials have not fully taken advantage of the excellent properties of individual CNTs. This thesis focuses on the preparation of high performance CNT/polymer composites in which CNTs are highly aligned in the polymer matrices.Firstly, CNT arrays were synthesized via chemical vapor deposition method; then, highly aligned CNT films were prepared by dry spinning or pressing method; finally, aligned CNT/poly(methyl methacrylate) and CNT/polystyrene composites were produced by spin-coating and in-situ polymerization, respectively. In these composites, the side walls of CNTs were partially exposed on the composite surface while the others were imbedded in the polymer matrices. Friction force microscopy and M-2000friction and wear tester were used to study their tribological properties at microsized and macroscopic scales, respectively.Three main conclusions are summarized as below:(1) For the aligned CNT/PMMA composite film, the friction coefficient in the transverse direction was about2times of that in the longitudinal direction relative to the CNT axis;(2) For the aligned CNT/PS composite material, the wear rate in the transverse direction was nearly3times of that in the longitudinal direction relative to the CNT-aligned direction; (3) The addition of CNTs had greatly increased mechanical strengths, wear rates, electrical conductivities and thermal stabilities of the composite materials.更多还原