Thermal degradation behaviors and reaction mechanism of carbon fibre-epoxy composite from hydrogen tank by TG-FTIR

•The crude material from 70 MPa hydrogen tank were analyzed by TG-FTIR.•The pyrolysis of carbon fibre-epoxy composite mainly occurs at 550–750 K.•A exponential correlation of activation energy was proposed.•C = O group > alcohols > phenol > ε - caprolactam > CO2 > H2O in evolved gases. Thermal degradation behaviors and reaction mechanism of Carbon fibre-epoxy composite, obtained from Chinese widely applied hydrogen storage tank, were studied by thermogravimetry combined with Fourier transform infrared spectrometry at varying heating rates. The pyrolysis of carbon fibre-epoxy composite mainly occurs at 550–750 K. The average value of final residue is 72.42%. The calculated activation energies increase exponentially from 206.27 KJ/mol to 412.98 KJ/mol with the average value of 276.6 KJ/mol. The fourth reaction order model is responsible for the pyrolysis of carbon fibre-epoxy composite. The absorption spectra of the evolved gases provided the information that the main evolved products are H2O, CO2, CO (acid anhydride, ketone or aldehyde), ε- caprolactam, alcohols and phenol. Moreover, CO group > alcohols > phenol > ε- caprolactam > CO2 > H2O. Epoxy is the main pyrolysis crude material in carbon fibre-epoxy composite.