Investigation On Polylactide/Multi-Walled Carbon Nanotubes/Hydroxyapatite Composites

A new class of materials based on organic and inorganic, such as polylactide(PLA) /hydroxyapatite(HA), has obtained more attention recently. The greatest advantage of the hybrid composites is that they offer the possibility of tailing its properties by playing with the volume fraction of the discontinuous, dimension of the particles and its orientation. However, the conventional hybrid composites can not meet the need of natural bone. The ideal bone tissue engineering materials should provide a connection between nanoscale ang microcale to meet the require of different cells. Rencently the application of carbon nanotubes(CNTs) and its composites in biomaterials has received considerable attentions. CNTs possesses several unique properties, such as high surface energy and outstanding mechanical properties, which suggests the materials may be ofvalue in the development of novel devices for bone tissue engineering scaffold.Multi-walled carbon nanotubes (MWNTs) were firstly treated by anodic oxidation, which resulted in various functional groups such as C—O, CO and O — C=O on the surface of oxidized MWNTs. Then the MWNTs/Hydroxyapatite (HA) nano-composites (MWNTs content: 3wt%) were in situ synthesized by wet method with the help of ultrasonic. Because of the strong interaction between the functional groups on the surface of MWNTs and Ca2+ in HA, the obtained HA nano-particles were deposited onto the surface of oxidized MWNTs. The prepared nano-composites have the same component and crystallinity.PLA/MWNTs/HA composite membranes were prepared by solution casting method. The effect of MWNTs/HA nanoparticle content on mechanical and dynamic was tested using tensile tests and dynamic mechanical analysis(DMTA). As the MWNTs/HA nano-composites content increased, the tensile strength of composite membranes decreased because of the agglomeration of MWNTs/HA nano-particles, tensile modulus and storage modulus first increased then decreased, and the glass transition temperature increased due to polymer chain adsorption and immobilization onto the MWNTs/HA nano-particles.The PLA/MWNTs/HA hybrid nanofibers were electrospun under the voltage of 18Kv and the capillary to target distance of 4cm using...