Structure–property relationship of recycled carbon fibres revealed by pyrolysis recycling process

Abstract

The structure-property relationship for recycled carbon fibres is investigated by characterisation of the structure changes induced by the pyrolysis recycling process. Two important factors influencing the properties of recycled carbon fibres are identified for various recycling processes: oxidative effect and thermal effect. The oxidative effect results in surface defects, and the surface defects causes a reduction in tensile strength and lateral crystallite size. The thermal effect of the recycling process results in an expansion in the distance between graphite layers and a decrease in surface oxygen concentration, which would lead to a drop in interfacial shear strength with epoxy resins. The tensile strength of recycled carbon fibres has a strong correlation with the intensity ratio of the D and G bands of the Raman spectra (ID/IG). With an increase in ID/IG, the tensile strength of recycled carbon fibre decreases linearly.

Conductive hybrid polymer composites based on recycled carbon fibres and carbon nanofillers

“…The O/C ratio of the investigated fibres equalled 11.01%, whereas the O/C ratio of virgin fibres was 20%. This value is comparable to the results obtained by Jiang and Pickerling, where the O/C ratio for fibres after recycling was about 15% and before it 25% [20]. The results indicate that applied recycling process decreases the concentrations of oxygen in comparison with virgin carbon fibres.…”

“…The testing range was up to 5 nm deep into the carbon fibres and the percentages of carbon (C1s), oxygen (O1s), nitrogen (N1s), sulphur (S2p) and silicone (Si2p) were also taken into account [20][21][22][23]. The results are presented in the high-resolution XPS spectra ( Fig.…”

“…On the other hand, Raman studies conducted by Jiang and Pickering show the increase in both the overall carbon percentage and the disorder of the structure during the CF recycling. Such a phenomenon should lead to the decrease in fibres conductivity [20]. The aim of this study was to assess the suitability of milled PAN-derived recycled carbon fibres used as a primary filler in CPC and to investigate the effect of nanoadditives-multiwalled carbon nanotubes (MWCNT), graphene nanoplatelets (GN) and graphitized carbon black (GCB)-on electrical, mechanical and thermal properties of the composites.…”

Impact of Solvolysis Process on Both Depolymerization Kinetics of Nylon 6 and Recycling Carbon Fibers from Waste Composite

“…It has been shown that the use of alkali catalysts could decrease the tensile strength. Guozhan and Pickering [19] have shown that the effect of recycling process on recovered carbon fibers properties can be attributed to two factors: oxidative effect and thermal effect. In solvolysis process, only the thermal effect can be considered, while, in pyrolysis process followed by the char oxidation, both are involved.…”

Effect of fiber surface treatment on the incorporation of carbon nanotubes and on the micromechanical properties of a single-carbon fiber-epoxy matrix composite

“…It is evident that the different fiber surface treatments result in a change of the fiber free surface energy as reflected by the change in contact angle. Jiang and Pickering [35] reported that the use of the Yamaki and Katayama criteria to study the structure-property relationships for recycled carbon fibers is able to detect changes of the contact angle resulting from the pyrolysis of the carbon fibers. From both, the contact angle and the concept of work of adhesion they estimated the surface free energy of the fibers.…”