Impact of Atmosphere on Recovered Carbon Fibers From Poly Ether Ether Ketone (PEEK) Based Composites During Thermoconversion

Author(s)

Fontaine, P. ^{[1, 2, 3]} ; Weiss-Hortala, E. ^[2] ; Botaro, V. ^[3] ; Paiva, J. M. F. ^[3] ; Soudais, Y. ^[2]

Affiliation

^[1] ADEME Agence Transit Ecol, F-49000 Angers - France

^[2] RAPSODEE Ctr CNRS, UMR 5302 Mines Albi, F-81013 Albi 9 - France

^[3] Fed Univ Sao Carlos UFSCar, Campus Sorocaba, Sao Carlos - Brazil

• Document type: Journal article
• Source: WASTE AND BIOMASS VALORIZATION; v. 12, n. 12, SI, p. 6389-6402, DEC 2021.
• Web of Science Citations: 0

Abstract

Carbon Fibers Reinforced Polymer composites (CFRP) are high added value materials used in many manufactured products. Especially in aeronautics, thermosetting resins tend to be replaced by heat-resistant thermoplastic polymers. The aim of the work is to evaluate suitable operating conditions of thermoconversion for the recovery of carbon fibers from Poly Ether Ether Ketone (PEEK)/carbon fibers composites. Micro and pilot scale tests have been performed in nitrogen, wet nitrogen, air, and wet air. Thermogravimetric analysis of PEEK/carbon fiber composites showed a moderate decomposition onset temperature of the composite at 515 degrees C and 510 degrees C in dry nitrogen and dry air respectively. The oxidative atmosphere did not significantly impact this temperature since the first mass loss was not atmosphere dependent. However, after the first PEEK degradation reaction, the nature of the atmosphere appeared as a great issue. Total mass loss was significantly improved with temperature (full oxidation of polymer and carbon fibers up to 800 degrees C) and with reaction time using air. Indeed, at pilot scale, the matrix was fully degraded in air atmosphere at 550 degrees C for 1 h while only 42% and 46% was reached in nitrogen and steam/nitrogen respectively. Comparison of thermogravimetric data between wet and dry atmospheres revealed that steam plays a thermal retardant role leading to some differences on the matrix degradation and on the surface morphology of the carbon fiber at pilot scale. Air treatments at pilot scale induced a reduction of fiber diameters (< - 3.7%) but the tensile strengths of recovered carbon fibers were preserved with an average retention of mechanical properties of 81%-85%. It has been concluded that recycling of PEEK/carbon composite required an oxidant to split up carbon fibers from the PEEK matrix. Graphic (AU)

• FAPESP's process: 16/19896-2 - Study of dynamic thermal-mechanical behavior of polymeric hydrogels films for application as future biocompatible materials
• Grantee: Vagner Roberto Botaro
• Support Opportunities: Regular Research Grants