An Efficient Method of Recycling of CFRP Waste Using Peracetic Acid

Abstract

We report a one-step oxidative method for the recycling of carbon fiber-reinforced polymer (CFRP) composite waste and the recovery of carbon fiber and the epoxy resin by treatment with peracetic acid (PAA) formed in situ from a mixture of acetic acid and hydrogen peroxide. The surfaces of the recovered carbon fibers were clean, and the tensile strength was comparable to that of the virgin fibers. A higher resin decomposition ratio of 97% could be achieved for the epoxy matrix under mild reaction conditions in comparison to other chemical recycling processes. ATR-FTIR, MALDI/TOF-MS, GPC, GC-MS, 1H NMR, and Pyro-GC/MS analyses showed the formation of low molecular weight oxidation products of amine-cured epoxy resin along with high molecular weight compounds of high viscosity. A possible reaction mechanism for the degradation of the epoxy matrix is proposed. All the solvents used were recovered in pure and reusable form with more than 90% recovery efficiency. The recovered epoxy was reused along with an adhesive grade epoxy (2 wt %) with no significant loss of tensile strength. Almost complete recovery of the recycled products as well as the solvent along with no gaseous emissions and mild reaction conditions make this process more environmentally friendly.

A Sustainable Approach to the Low-Cost Recycling of Waste Glass Fibres Composites towards Circular Economy

“…Two different control experiments using solutions of pure H 2 O 2 and pure TA (5 M) were also performed. Afterwards, the remaining WCP, which mainly consisted of recycled GFs, was washed with acetone in an ultrasonic cleaner for 5 min, followed by drying at 60 • C. The decomposition yield (D y ) was calculated according to the following Equation (1) [38]:…”

“…This implies that only the reaction of TA and H 2 O 2 under microwave irradiation provides an oxidation medium suitable for epoxy matrix decomposition. It can be discussed that the reaction of H 2 O 2 and TA can produce various reactive species (e.g., organic peroxides) which can decompose epoxy resin possibly through C-N bonds cleavage [23,33,37,38]. Moreover, to investigate the role of microwave irradiation, an H 2 O 2 /TA solution without WCP was also treated under microwave irradiation, which can only raise the temperature up to~70 • C within 1.5 min irradiation.…”

“…They achieved recycled CFs with a strength >95% of the original strength and a degradation ratio of >90%. Peracetic acid, a mixture of H 2 O 2 and acid acetic, was introduced by Das et al [38] to degrade a highly cross-linked amine-epoxy resin system, leaving behind CF with 94% retention of its original strength. However, the potential of these methods for recycling of GFRPs and their effects on the final properties of GFs have not been investigated yet.…”

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

“…The single fibre tensile test only showed a 2% tensile strength loss compared to the vCF after a 10 °C process temperature increase. In a recent study, Das et al [91] showed a 97% resin decomposition ratio from a single-stage oxidation process using an aqueous mixture (AM) of peracetic acids. The rCF retained 94% of its original strength.…”

Remanufacturing of Woven Carbon Fibre Fabric Production Waste into High Performance Aligned Discontinuous Fibre Composites

“…Chemical reclamation methods use reactive, solution-based processes to break down the matrix material (e.g., acid digestion, solvolysis, and supercritical fluid solvolysis). Acid digestion uses a variety of highly corrosive reactant systems (e.g., nitric acid [8,9], sulphuric acid [10], acetic acid [11,12], and some alkalis [13]), to degrade the thermoplastic matrix at low temperatures (<150 • C). Solvolysis methods use less hazardous solvents and catalysts, but suitable reactivity is achieved by operating at higher temperatures (200-300 • C) to afford a suitable reactivity for a specific polymer [14].…”