Fabrication Of Carbon Nanomaterial And Its Application In Calcium Phosphate Cement

Calcium phosphate cement (CPC) is a bioactive cement and degradable implanting material, which has fast setting time, excellent mold-ability and biological properties. However, its poor mechanical property limits its application in bone repair and medical treatment. Carbon materials are commonly used as reinforcements in composites, as the same with one dimensional carbon nanotubes (CNTs) and two dimensional graphene. However, the aggregation of CNTs has weakened its reinforcement and made it more toxic. So it is important to improve its performance to make it less deleterious to human bodies. Furthermore, it is inevitable to synthetize biomedical materials with better biocompatibility to promote wound healing, tissue repair and so on.In this thesis, fabrication of carbon nanotubes (CNTs)-based carbon nanotubes network (CNTN), reduced graphene oxide-carbon nanotubes (RGO-CNTs) composites and improvement of the properties of CPC was studied.Firstly, CNTN was prepared via chemical crosslinking process. When ethylene diamine (EDA) was used as the crosslinking agent. CNTN was synthesized with different CNTs/weight to volume ratio (2:1,5:1and10:1). Results showed with decrease of CNTs/EDA weight to volume ratio, crosslinking process was more complete if the experimental period was sufficient, and CNTN appeared apparently. Then CNTN was synthesized with CHIT decorated CNTs. The CNTN prepared with CHIT of different molecular weight (Mw<10000, Mw=10000-50000and Mw=50000-100000) with/without glutaraldehyde (GA) was studied. Results showed with the increase of Mw of CHIT, the layer attached on the outside of CNTs composed of CHIT was thicker, came with larger diameter of CNTs. and pore size of CNTN got smaller. The addition of GA had loosened these CNTN particles, and promoted the degree of crosslinking. After that, CNTN contained with CHIT was chosen to prepare CPC via physical blending method, and CPC reinforced with CNTs was as the control group. Results showed that additive used in this experiment didn’t have any impact on the components of phases in CPC. Compared to CNT/CPC, the addition of CNTN had shortened the setting time of CPC, improved the hydrophilic and mechanical property. With the increase of molecular weight of CHIT, the content of hydroxyapatite (HA) in CPC and the mechanical property of CPC increased, and hydrophilic property and the porosity of CPC decreased.Then, RGO-CNTs composites were prepared via CVD method and self-assembly process. When CVD was used to prepare RGO-CNTs, the temperature (140℃,160℃,180℃and200℃) of hydrothermal treatment was controlled to prepare catalyst precursors with different microstructure which contained Fe element. Then these precursors were treated with CVD to get RGO-CNTs. Results showed that the change of hydrothermal temperature had impacts on the micro-morphologies of precursors, which resulted in different components of the post-CVD products. Especially, post-CVD products of precursors prepared at160℃and180℃contained an amount of helical CNTs. At the same time, RGO-CNTs composites were prepared under different GO/CNTs weight ratio (3:7,5:5,7:3and9:1) and with different contents (40.0wt%,80.0wt%,120.0wt%and160.0wt%) of carboxymethyl chitosan (C-CHIT) via self-assembly process. Results showed that the weight ratio of the raw material had impacts on the micro-morphology of RGO-CNTs composites.