A Study to Investigate the Mechanical Properties of Recycled Carbon Fibre/Glass Fibre-Reinforced Epoxy Composites Using a Novel Thermal Recycling Process

Abstract

Manufacturing-based carbon fibre-reinforced polymer (CFRP) and glass fibre-reinforced polymer (GFRP) wastes (pre-consumer waste) were recycled to recover valuable carbon fibres (CFs) and glass fibres (GFs), utilising a novel thermal recycling process with a cone calorimeter setup. The ideal conditions to recycle both the fibres occurred at 550 °C in atmospheric pressure. The processing time in the batch reactor to recycle CFs was 20–25 min, and to recycle GFs it was 25–30 min. The recovery rate of the recycled CFs was 95–98 wt%, and for GFs it was 80–82 wt%. Both the recycled fibres possessed a 100–110 mm average length. The resin phase elimination was verified by employing scanning electron microscopy (SEM). Furthermore, the fibres were manually realigned, compression moulded at room temperature, and cured for 24 h by a laminating epoxy resin system. The newly manufactured CFRP and GFRP composites were continuous (uniform length from end to end), unidirectionally oriented (0°), and non-woven. The composites were produced in two fibre volumes: 40 wt% and 60 wt%. The addition of ≈20 wt% recycled CFs increased the tensile strength (TS) by 12%, young modulus (YM) by 34.27% and impact strength (IS) by 7.26%. The addition of ≈20 wt% recycled GFs increased the TS by 75.14%, YM by 12.23% and the IS by 116.16%. The closed-loop recycling approach demonstrated in this study can effectively recycle both CFRP and GFRP manufacturing wastes. Preserving the structural integrity of the recycled fibres could be an advantage, enabling recycling for a specified number of times.

A Review of Recent Developments in Composites Made of Recycled Carbon Fiber Textiles

“…The result was fiber alignment of greater than 80% within ±10 • . In 2020, Gopalraj et al [48] manually realigned fibers recovered from unidirectional composites pyrolyzed in a cone calorimeter and remanufactured epoxy composites using a wet compression process. The resulting mechanical properties were subpar and such an alignment process is not likely conducive to high-volume manufacturing.…”

“…Composites with 41% fiber volume fraction showed good mechanical properties. Gopalraj and Karki [48] at LUT University recycled carbon fibers using a cone calorimeter for remanufacturing into aligned continuous fiber epoxy composites via compression molding. They showed good tensile modulus for the manually aligned recycled fiber composites at 40 wt% and 60 wt% but poor tensile strength due to char formation on the fiber surface and a loss in fiber strength.…”

A Finite Element Study to Investigate the Mechanical Behaviour of Unidirectional Recycled Carbon Fibre/Glass Fibre–Reinforced Epoxy Composites

“…The materials used in this research work were taken from the author's previous study [31]. It comprises of rCF/EP, rGF/EP and EP composite without fibres.…”

“…For damage, a continuum ductile damage model is used to predict their damage behaviours in uniaxial tensile and impact modes. The experimental TT results from the previous study [31] are processed as primary input data for all of the numerical test models. Finally, the numerical results from the TT and IT are validated and discussed for their respective experimental results.…”

Chemical–Electrochemical Process Concept for Lead Recovery from Waste Cathode Ray Tube Glass

“…Conventional CRT glass recycling is carried out in a closed-loop, where waste glass, after an appropriate removal of metal and luminophore contaminants, is utilized during manufacturing of new CRTs [ 15 , 16 ]. However, the above-mentioned recycling method is insufficient, as technology develops and modern liquid crystal display (LCD), plasma or light-emitting diode (LED) screens are introduced, the demand for CRT glass decreases [ 17 ].…”