Inverse Vulcanisation of canola oil as a route to recyclable chopped carbon fibre composites

As a result of crude oil desulfurisation, elemental sulfur is a significant by-product of the petrochemical industry with millions of tonnes produced annually, and a significant portion remains unused. The use of this feedstock for the generation of new materials has seen increased growth, though such materials that utilise inverse vulcanisation have limited practicality in everyday applications due to their poor mechanical properties. Another underutilised waste product is that of carbon fibre composites. The increased need for high performance materials has resulted in a significantly amplified demand for carbon fibre reinforced composites. In line with this demand, an increase in scrap, waste, and fibre offcuts is also increasing in proportion. Within this paper the combination of these two resources was explored: recycled chopped carbon fibre was incorporated into a polymer derived from elemental sulfur and waste canola oil. The aim was to generate composites with improved physical properties, enabling their widespread use in high volume material applications. The introduction of 20 wt% carbon fibre was found to significantly improve tensile strength and modulus in iterative generations of recycling with tensile strength reaching a maximum of 909.1 kPa (+137.4%) and tensile modulus to 94.3 MPa (+160.1%) as compared to the initial introduction of carbon fibre. We demonstrate that fibre and polymer components were able to be repeatedly separated from each other, mechanically or chemically, recombined and processed into new composites.