Carbon fibres reinforced composites have the superior stiffness to weight and strength-to-weight ratios, which have been used in a large number of high-performance structural applications such as the automotive, aerospace, military defence and new energy. However, the bulk composite properties of carbon fibres reinforced composites could be affected by the interface between fibres and matrix. The excessive smoothness, chemical inertness, less adsorption and poor wettability characteristics of the carbon fibre leads to weaker bonding with most of the polymeric matrices and result to a week interfacial property. Different surface modification methods have been used to improve the interfacial bonding between carbon fibres and the matrix such as oxidation, plasma and high energy irradiation. Grafting inorganic materials such as carbon nanotubes (CNTs), graphene oxide and carbon nanomaterials on the carbon fibre surface to improve the interfacial properties were getting more and more popular. The outstanding properties of the graphene-related materials, such as large surface area and high mechanical strength, bring them to be distinguished nano-reinforcements for carbon fibre reinforced polymers. In this research, a modified chemical vapour deposition (CVD) method was proposed to in-situ grown 3D graphene-related coatings on the carbon fibre surface, which can not only improve the bonding strength between the coating and the carbon fibre but can also minimise the damage to the mechanical properties of the carbon fibre. Ferrous Sulphate Heptahydrate (FeSOââ 7HâO) and D-Glucose monohydrate (C6H12O6 Â· H2O) were selected as the catalyst and carbon source respectively for the modified CVD method. The optimal heat treatment temperature, processing time and mass ratio between the catalyst and carbon source for synthesising the 3D graphene-related structure were investigated. Raman spectroscopy, scanning electron microscopy (SEM) and transmission electron microscopy (TEM) were applied to characterise the samples after the heat treatment. The optimal conditions for synthesising the 3D graphene-related structure were achieved at temperatures over 950 ÌC, and with at least 1 hour of processing time. The 3D graphene-related structure was in-situ grown on the carbon fibre surface successfully, and the optimal coating was achieved on the carbon surface under the weight ratio of 1:13 between FeSOââ 7HâO and C6H12O6 Â· H2O. The interfacial shear strength (IFSS) of the surface modified carbon fibre has an impressive improvement of 54.9% compared with the desized carbon fibres. The tensile strength of the surface modified carbon fibre has a reduction of 4.6% and 14.1% compared to the heat-treated desized carbon fibres and the desized carbon fibres, respectively. The interlaminar shear strength (ILSS) of the surface modified carbon fibre reinforced composites was 58.7% compared to the desized carbon fibre reinforced composites. In this research, the 3D graphene-related structure was in-situ grown on the carbon fibre surface successfully, which not only have improved the bonding strength between the carbon fibre and the graphene-related coating but also increased the surface area of the carbon fibre, and provided a novel surface modification method for carbon fibres.
|Date of Award||1 Aug 2020|
- The University of Manchester
|Supervisor||Xiaogang Chen (Supervisor) & Jiashen Li (Supervisor)|
- Composites, interface, graphene-related structures, carbon fibre