Recycling of carbon/epoxy composites

Abstract

ABSTRACT:The recycling of carbon fibers from carbon/ epoxy composites was attempted with a solvent method in nitric acid solutions. Gel permeation chromatography and gas chromatography/mass spectrometry showed that the epoxy resin could entirely decompose into low-molecularweight compounds, and the main components of the dissoluble decomposed compounds were 2,4-dinitrophenol and 2-nitro-4-carboxylphenol. Electron probe microscopy showed no damage to the recycled carbon fibers. The singlefiber tension strength loss of the recycled carbon fibers was 1.1% under the following conditions: a decomposition temperature of 90°C, a nitric acid solution concentration of 8M, and a ratio of the sample weight to the nitric acid solution volume of 6 g:100 mL. Through orthogonal experimentation, the recycling conditions for the carbon/epoxy composites were examined. The best combination was a decomposition temperature of 90°C, a nitric acid solution concentration of 8M, and a ratio of the sample weight to the nitric acid solution volume of 4g:100 mL. This method could liquefy raw materials for rocket engine shells reinforced with carbon fibers.

Recycling of carbon fibers from carbon fiber reinforced polymer using electrochemical method

“…According to the statistics, the world-wide demand for carbon fibers reached approximately 35,000 tons in 2008 and this number is expected to double in 2014, indicating a growth rate of over 12% per year [5]. The increasing requirement of carbon fiber has raised an environmental and economic awareness among researchers for the need to recycle the CFRP waste material in a suitable way [10].…”

Recycled carbon fiber filled polyethylene composites

“…The recovery of CF from the composite material has been attempted using a range of processes, including chemical, mechanical, thermal, and even its use as a fuel after incineration has been investigated. Liu et al 1 reported a thermochemical method for recycling of CF filled epoxy composites from rocket engine shells. Optimum recovery of CF was obtained, with no damage to the fibers, using an 8M nitric acid solution and a decomposition temperature of 908C for a 4% nitric acid solution.…”

Recycling of carbon fibre reinforced polymeric waste for the production of activated carbon fibres

“…Williams et al [10] used a pyrolysis process to recover glass fibres and volatile materials from different composites. Liu et al [11] used nitric acid to recover carbon fibres from epoxy resin/carbon fibre composite at 90 • C. Meng et al [12] used supercritical water to recycle carbon fibre composites.…”