A Review of Recycling Methods for Fibre Reinforced Polymer Composites

Abstract

This paper presents a review of waste disposal methods for fibre reinforced polymer (FRP) materials. The methods range from waste minimisation, repurposing, reusing, recycling, incineration, and co-processing in a cement plant to dumping in a landfill. Their strength, limitations, and key points of attention are discussed. Both glass and carbon fibre reinforced polymer (GFRP and CFRP) waste management strategies are critically reviewed. The energy demand and cost of FRP waste disposal routes are also discussed. Landfill and co-incineration are the most common and cheapest techniques to discard FRP scrap. Three main recycling pathways, including mechanical, thermal, and chemical recycling, are reviewed. Chemical recycling is the most energy-intensive and costly route. Mechanical recycling is only suitable for GFRP waste, and it has actually been used at an industrial scale by GFRP manufacturers. Chemical and thermal recycling routes are more appropriate for reclaiming carbon fibres from CFRP, where the value of reclaimed fibres is more than the cost of the recycling process. Discarding FRP waste in a sustainable manner presents a major challenge in a circular economy. With strict legislation on landfill and other environmental limits, recycling, reusing, and repurposing FRP composites will be at the forefront of sustainable waste-management strategies in the future.

Recycling of Epoxy/Fiberglass Composite Using Supercritical Ethanol with (2,3,5-Triphenyltetrazolium)2[CuCl4] Complex

“…Thus, the introduction of a catalyst helps to efficiently reduce both the process temperature by 30 °C and the duration of solvolysis, increasing its energy efficiency. One of the key limitations of implementing the solvolysis method for large-scale use is the high cost of production and the highest energy intensity compared to other methods [ 51 ]. The use of the methodology presented in this study contributes to the promotion of this method.…”

Mechanical Recycling of Carbon Fiber-Reinforced Polymer in a Circular Economy

“…To perform this mechanical approach, equipment such as multiple shafts is commonly used, as can be seen in Figure 6. The shredding products are large and identical pieces of around 50-100 mm (about 3.94 in) in size, controlled by the distance between blades, the sieve size, and their rotation speeds [45][46][47]. These products can then be ground into both micro-and nano-size powders.…”

“…These products can then be ground into both micro-and nano-size powders. blades, the sieve size, and their rotation speeds [45][46][47]. These products can then be ground into both micro-and nano-size powders.…”

“…Kiss et al [58] and Friedrich et al [103] revealed that recycled CFRPCs can be used for future opportunities in automotive applications. In addition, Colucci et al [46] concluded that the recycled CF-reinforced polyamide matrix could be effectively used for structural and/or semi-structural automotive purposes, promising decent final performances and benefits from the environmental point of view. Souppez et al [110] provided an innovative quantitative valuation of recycled CF for automotive industrial parts, which might contribute to future developments in sustainable CFRPCs in the automotive industry.…”

Strategies towards Fully Recyclable Commercial Epoxy Resins: Diels–Alder Structures in Sustainable Composites

“…This specific research focuses specifically on environmental impact reduction through the adaptation of possible recycling methods, minimizing the negative environmental impact, and efficiently treating the materials after their end of life [ 16 ]. There are three main approaches [ 17 ] that break down the chemical structure of the thermoset [ 18 ]: (a) thermal, the pyrolysis [ 19 ] which is the only technology available on a commercial scale [ 20 ]. Its research is currently focussed on the process optimization for higher quality carbon fibers, the viability of the obtention of glass fibers, and the increase in quantity and quality of pyrolytic oils; (b) biological; enzymes are used to break down the thermoset structure into monomers or oligomers [ 21 ]; (c) chemical; use of solvents and chemicals as a strategy to reduce the polymer length, solvolysis [ 22 , 23 ], or a second chemical approach, modification of the thermoset structure to incorporate dynamic bonds [ 24 ].…”