A review on the recycling of waste carbon fibre/glass fibre-reinforced composites: fibre recovery, properties and life-cycle analysis

Abstract

The growing use of carbon and glass fibres has increased awareness about their waste disposal methods. Tonnes of composite waste containing valuable carbon fibres and glass fibres have been cumulating every year from various applications. These composite wastes must be cost-effectively recycled without causing negative environmental impact. This review article presents an overview of the existing methods to recycle the cumulating composite wastes containing carbon fibre and glass fibre, with emphasis on fibre recovery and understanding their retained properties. Carbon and glass fibres are assessed via focused topics, each related to a specific treatment method: mechanical recycling; thermal recycling, including fluidised bed and pyrolysis; chemical recycling and solvolysis using critical conditions. Additionally, a brief analysis of their environmental and economic aspects are discussed, prioritising the methods based on sustainable values. Finally, research gaps are identified to highlight the factors of circular economy and its significant role in closing the life-cycle loop of these valuable fibres into re-manufactured composites.

Composite Material Recycling Technology – State-of-the-Art and Sustainable Development for the 2020s.

“…These include mechanical, thermal and chemical-based recycling approaches, as the choice of methods depends on the type of material to be recycled and the application in which it is reused [11]. Furthermore, it is difficult to determine a standard recycling method among the various methods [75]. Different recycling processes have been reported and promoted for thermoset composites, as it is depicted in Figure 4.…”

End-of-Life Recycling Options of (Nano)Enhanced CFRP Composite Prototypes Waste—A Life Cycle Perspective

“…Global demand for carbon fibres (CF) is is expected to increase from 72,000 tonnes to 140,000 tonnes; the CFRP global profit is expected to increase from $28.2 billion to $48.7 billion [ 21 ].…”

“…As a result, these endless demands are exacerbating environmental issues such as global warming, climate change, natural resource depletion, waste disposal, loss of biodiversity, deforestation, ocean acidification, ozone layer depletion, acid rain, water pollution, and urban sprawl, which are responsible for environmental damage [ 22 ]. Furthermore, the production of CFs causes environmental hazards besides their high costs, which increased the interest in using more sustainable materials [ 21 ]. Carbon fibre reinforced polymers exhibit great potential among the other lightweight materials, nevertheless, CF manufacturing production generates about 15 times more CO 2 than the conventional steel on a weight basis [ 23 ].…”

“…CFRP has become the preferred choice of material in sectors such as sporting goods and automotive thanks to its lightweight and high-performance properties. However, the rapid development of CFRP will result in increased CFRP wastes disposal in landfills that takes no advantage of the residual value, but adds burden to waste management [ 21 ]. In order to address this problem, various recycling methods, such as mechanical recycling and pyrolysis, have been compared in this study, providing recycling recommendations for decision making in industries.…”

Structure Property Investigation of Glass-Carbon Prepreg Waste-Polymer Hybrid Composites Degradation in Water Condition

“…Numerous studies have explored CF waste management options. A study by Gopalraj and Kärki [9] evaluated existing CF waste-glass fibre (GF) reinforced composites recycling and also fibre recovery methods and determined the properties retained before identifying gaps in the material's lifecycle within a circular economy. Yang et al examined the chemicals used to recycle CF and GF epoxy resin composites; polyethylene glycol (PEG) and sodium hydroxide (NaOH).…”