节点文献
碳纳米管功能化及其对聚酰亚胺力学性能的影响
Functionalized CNTs and Its Effects on Mechanical Properties of Polyimide Films
【作者】 田丰；
【导师】 张明艳；
【作者基本信息】 哈尔滨理工大学 ， 高分子化学与物理， 2010， 硕士
【摘要】 碳纳米管自从1991年被Iijima发现以来,其优异的电、力、热学性能引起了世界范围内学术界和工业界研究人员的关注,同时碳纳米管还具有很大的长径比,可以利用来制备低渗滤阈值的聚合物基复合材料。碳纳米管本身具有很高的比表面积和表面活化能,极易团聚,这会导致碳纳米管不能在聚合物基体中均匀分散,从而对所得复合材料的性能造成不良影响。因此,如何对碳纳米管进行有效的功能化,并使其在聚合物基体中均匀分散,成为近年来的研究热点。本文采用混酸对多壁碳纳米管进行了酸化处理,通过原位聚合法制备了聚酰胺酸/多壁碳纳米管杂化胶液,经热亚胺化制得了聚酰亚胺/多壁碳纳米管杂化薄膜。采用电子扫描显微镜对碳纳米管及杂化薄膜的表面形貌和断面形貌进行表征,并测试了杂化薄膜热失重性能及力学性能。测试结果表明,酸化处理后的碳纳米管能均匀分散在乙醇中,且放置一周后仍不产生沉淀,保持良好的分散状态;将功能化碳纳米管掺入到聚酰亚胺聚合体系,掺杂量在1wt%以下时,碳纳米管能均匀分散在聚酰胺酸胶液中,不发生团聚;功能化碳纳米管的加入,使杂化薄膜的热分解速度随着掺杂量的增加而降低,略微提高了杂化薄膜的耐热性;碳纳米管含量变化对杂化薄膜力学性能的影响规律并不明显,在碳纳米管含量为0.36wt%时,杂化薄膜拉伸强度达到110.05MPa,此时断裂伸长率为31%,比纯膜低15%。
【Abstract】 Since discovered by Iijima in 1991, CNTs had attracted great interests throughout the academic and industrial world due to its extraordinary electrical, mechanical and thermal properties, which makes them possible to possess percolation threshold at low loading in polymer matrix nanocomposites. But CNTs tend to form into aggregates for their high specific area and extremely high surface energy, which lead to heterogeneous dispersion in the polymer matrix and negative effects on the properties of the resulting composites. Therefore, great attentions were focused on the effective functionalize method on CNTs.In this paper, Multi-wall carbon nanotubes (MWNTs) were acid modified by refluxing with the mixture of H2SO4 and HNO3 under ultrasound, then were attended into the synthesis of PI/MWNTs hybrid films via in situ polymerization process. The dispersion situation of MWNTs in the nanofilms was characterized using scanning electronic microscopy (SEM); mechanical and thermal properties of nanoflims were tested, with the results indicating that the acid modified able to facilitate the homogeneous dispersion of MWNTs in the ethanol solvent, remain in fine monodispersity condition after one week; functionalized MWNTs can be dispersed homogeneously in the PI matrix with MWNTs content under 1wt%, the the addition of functionalized MWNTs increase the heat resistance of PI/MWNTs appreciably, slow down its thermal decomposition with the increased MWNTs content; as the MWNTs increased, the mechanical property has not an significantly discipline, tensile strength of nanofilms content reaches 110.05MPa at the MWNTs content of 0.36wt%, while its elongation is 31%, 15% lower than the pure PI films.