Fabrication Of Electroconductive CNTs/BMI Composites And Study On Their Mechanical Properties

In the present thesis, CNTs/BMI composites with excellent electric properties are successfully prepared. The electric conductivities of the prepared CNTs/BMI composites are improved up to nine and three orders of magnitude compared to pure resins and CNTs/BMI composites prepared by traditional mechanical mixing the same content of CNTs and resins, respectively. Such a huge improvement in electric conductivity is due to the micro structure of three-dimensional (3D) networks composed of CNTs in the prepared CNTs/BMI composites. The successful utilization of ice-templating (IT) method in CNTs assembling helps to prepare this CNTs/BMI composite with CNTs3D network structure inside. In this thesis, the effects of different freezing modes in IT method to the micro structure of CNTs assemblies are investigated, and the self-standing CNTs assemblies with3D porous structures are successfully fabricated. Then, Use this CNTs assembly as a preform, followed by infiltrating resins into it to prepare CNTs/BMI composites. And this is a new scheme for CNTs-based composite preparation proposed by us in this thesis, which is different from the traditional preparation methods. It is indicated that, besides excellent electric properties, the mechanical properties such as fracture toughness of the CNTs/BMI composites prepared according to this new scheme could be preserved well. The lamellar structure composed of CNTs in the prepared CNTs/BMI composites helps to enhance fracture energy, and thus improve fracture toughness of the composite. However, it is hard for resins to infiltrate totally into the micro pores in the CNTs preform, and as a result, many defects would be produced in the prepared CNTs/BMI composites, so that the fracture toughness decrease little compared to that of pure resins.