Experimental Studies Of Carbon Nanotubes/Mineral Composites

Carbon nanotubes (CNTs) are considered as ideal reinforcing materials for composites due to their unique mechanical properties, thermal properties, excellent electrical conductivity. At present, the researches about CNTs composites are focused on organic polymer and metal matrix, very few on the non-metallic mineral ceramic composites materials matrixes, especially the alumina.Unfortunately, the CNTs tend to be aggregated easily. In order to improve the dispersion of CNTs in various media,the modification of CNTs surface were carried out in this paper, also the preparation of alumina. And using the synthesis process prepared CNTs/mineral composites. The works in this paper have important significance and practical application value for development of functional composites. The main results obtained in this paper are shown as follows:The purification of CNTs,modification and functionalization of CNTs were carried out by HNO3, and theirs dispersion were improved by using of surfactants. After refluxing for 4h by HNO3 while the ratio of HNO3/ CNTs is 100ml/1.5g, it can be seen from UV-vis adsorption spectrum and SEM images that the purification of CNTs can be improved obviously. The surface functional groups hydroxyl (-OH), carboxyl (-COOH) groups will be introduced on the surface of CNTs according to the FTIR spectrum. In this way, the pure CNTs can be dispersed in AIBN ethanol solution stability evenly.Nano alumina precursor was prepared by Hydrolysis precipitation, then, it was sintered in the air. The results showed that when the ratio of the excess coefficient of 1.4, PH value of 11, AACH precursor can be achieved, andα-Al2O3 can be obtained in low sintering temperature(lower than the theoretical temperature of 200℃), andα-Al2O3 particle size is at dozens of nanotechnology around.The synthesis process was employed for Preparing CNTs/mineral composites with. The effect of CNTs dispersed in the material on the properties of composites was studied. The SEM was used to study the mechanism of Reinforcement and conductivity. The results showed that an increment of 18.28% of bending strength. The reinforcement mechanism is similar to fiber / whisker bridging mechanisms, at the same time pull-out mechanism is exist; A drop of five orders of magnitude. The conductive mechanism is that CNTs formed a conductive network at alumina grain boundaries.