【作者】 陈红燕；

【导师】 王继辉；

【作者基本信息】 武汉理工大学 ， 材料学， 2005， 硕士

【摘要】 本论文以纳米碳纤维的制备与应用为背景,研究了纳米碳纤维的制备方法和工艺优化条件,对所得纳米碳纤维的形貌、微观结构进行了表征,并初步探索了添加纳米碳纤维对聚合物基复合材料的力学性能和电性能影响。 实验中采用气相生长法制备纳米碳纤维,以苯为碳源、氢气为载气、二茂铁为催化剂、含硫化合物噻吩为生长促进剂,在1150℃-1180℃制备直径均匀、纯净的纳米碳纤维。 本实验制得的纳米碳纤维宏观上主要有两种形态:薄膜状和块状。SEM及TEM观察发现,薄膜状产物主要是大量2-50nm左右的纳米碳管组成的纤维束,而块状产物主要由大量直径50-100nm的纯净纳米碳纤维组成。拉曼光谱还发现薄膜状产物中存在有单壁纳米碳管,由此可见,如果适当控制反应条件,利用气相生长法是可以制备出纯净、高质量、直径为5-15nm的多壁纳米碳管甚至单壁纳米碳管的。 实验发现,影响纳米碳纤维生成量和直径的主要因素如下:裂解温度、催化剂挥发量、噻吩体积含量以及氢气流量。其中含硫化合物噻吩的添加量对制备纯净、直径均匀、性能优良的纳米碳纤维起关键性作用。加入少量噻吩添加剂能使纳米碳纤维的生成量成倍增加,并且纳米碳纤维的直径更加细化、均匀。综合考虑纳米碳纤维生成量和直径的关系,得到了最优的工艺参数。 纳米碳纤维用在复合材料中集中于三个方面:作为材料增强体、改善材料导电性和材料的光电性能。本文利用纳米碳纤维的优良力学性能,将其作为环氧树脂的增强体,实验发现纳米碳纤维的加入明显改善了环氧树脂复合材料的力学性能和电性能。通过纳米碳纤维的表面处理可将其较好的分散在树脂基体中。更多还原

【Abstract】 For the purposes of mass production and application of carbon nanofibers (CNFs), the preparation process of CNFs has been investigated. The morphology, microstructure of CNFs have been discussed. The effects of CNFs as fillers into polymer matrix on its mechanical and electrically performance have also been preliminarily studied.Pure CNFs with uniform diameter distribution have been successfully prepared by chemical vapor deposition method, using benzene as carbon source, ferrocene as catalyst precursor, hydrogen as carrier gas, and sulfur-containing compound (thiophene) as growth promoter. The chemical vapor deposition method which allows three-dimensional dispersion of catalyst particles and in which the catalyst introduced can easily be controlled, is thought to be promising as an industrial process for growing CNFs.The products generally have two microscopical forms —filmy and bulk forms. Through SEM and TEM observations, it is found that the former one contain mainly fasciculies of multi-walled and even single-walled carbon nanotubes with diameter of 2-50nm, while the later one are mainly pure nanofibers with diameter of 50-100nm. This result is also been ascertained by Raman spectrometry. It can be proposed that, if the reaction conditions are optimized to prohibit the growth of outer layer pyrocarbon, then the pure and high quality multi-walled carbon nanotubes with diameter of 5-15nm and even single-walled carbon nanotubes can be prepared by the present chemical vapor deposition method.It is experimentally found that four main factors, pyrogenation temperature, volatility of catalyzer, fraction of thiophene and hydrogen flux affect the yield and diameter of CNFs. Sulfur has a dramatic effect on the growth of CNFs, and the addition of small amount of S into the reaction can cause a higher yield of CNFs and obtaining a much more uniform diameter distribution. Preferable process parameters are decided with the endeavor of obtaining high yields of CNFs with controllable diameter.Carbon nanofibers are generally used as reinforcement and electrically conductive filler in polymer composites. Through experiments, it is also found that the mechanical performance and electrical conductivity of epoxy polymer has been dramatically improved by adding additional carbon nanofibers into the polymer. It is also found that surface treatment of carbon nanofibers can lead to better fiber distribution in the matrix.更多还原