Evaluating the load-bearing performances of flax- carbon hybrid composites enhanced with graphene-oxide

Abstract

Environmental sustainability is a key issue that is propelling the current composite industries in terms of manufacturing, recycling, marketing, and policy making. While the use of carbon or glass fibres are introducing huge benefits to the industry regarding manufacturing lightweight structural components with superior performances compared to metal alloys, and the market volume is rapidly increasing, environmental damages and carbon footprints and damages to environment are also increasing at the same time. To mitigate these environmental issues, natural fibres are getting popular to be used in structural composites as well as in other areas, due to their biodegradable nature, low cost, and the fact that the overall manufacturing process for jute or flax fibres is carbon negative. Another way of mitigating the environmental hazard is to increase recycling, and to increase the use of recycled materials, such as composites manufactured from carbon mats reobtained from carbon composites. However, a significant technological advancement for commercial recycling method for synthetic and natural fibres composites is still required. At the same time, the alignment of the natural fibres in their preforms is still a challenge, which is necessary to ensure the optimum translation efficiency of the fibres to their corresponding composites. In this project, nonwoven carbon fibre mat from recycled carbon and highly aligned flax tape were used to manufacture hybrid composites using epoxy resin. Furthermore, epoxy resin was enhanced with graphene oxide powder via solution compounding method to improve the fibre-matrix bondage. It was found that the inclusion of the low-cost recycled carbon fibre mat with randomly oriented short carbon fibre improved the tensile and flexural properties of the composites by 22% and 81%, compared to the composites made from only flax tapes; the increment can be attributed to the fact that the flax tapes were replaced with carbon mats even when the carbon fibres were randomly oriented in carbon fibre mat. Therefore, the potential for using recycled carbon fibre mat can be substantiated. For graphene inclusion at 0.4 wt% of epoxy, a decline of 11% and 18% were observed for both the tensile and flexural properties; agglomeration or restacking of GO sheets due van der Waals force within the matrix can be a plausible explanation to this degradation.

Date of Award	1 Aug 2023
Original language	English
Awarding Institution	The University of Manchester
Supervisor	Hugh Gong (Supervisor) & Constantinos Soutis (Supervisor)