Process for producing carbon fibres from biosourced precursors and the carbon fibres obtained
A process for producing a highly carbonaceous fibre or set of fibres including combining a structured precursor comprising a hydrocellulose fibre or a set of fibres, and an unstructured precursor, including lignin or a lignin derivative in the form of a solution having a viscosity less than 15,000 mPa·s −1 at the temperature at which the combination step takes place, in order to obtain a hydrocellulose fibre or set of fibres coated with the lignin or lignin derivative, wherein the process further includes a step of thermal and dimensional stabilization of the hydrocellulose fibre or set of fibres covered with the lignin in order to obtain a hydrocellulose fibre or set of fibres covered with a deposit of lignin or lignin derivative, and a carbonization step of the hydrocellulose fibre or set of fibres coated with a lignin deposit in order to obtain a highly carbonaceous fibre or set of fibres.
1. A hydrocellulose fibre or set of fibres coated with a lignin deposit or a lignin derivative, wherein the coated hydrocellulose or set of fibres are formed from a combination of a structured precursor comprising a hydrocellulose fibre or set of fibres, and an unstructured precursor comprising a lignin deposit or a lignin derivative at a temperature between −10° C. to 80° C.,
wherein the unstructured precursor is in the form of a solution having a viscosity of less than 15,000 mPa·s −1 [[at a temperature between −10° C. to 80° C.]]; and
wherein the combination is further reacted in a thermal and dimensional stabilization to form the coated hydrocellulose fibre or set of fibres,
wherein the coated hydrocellulose fibre or set of fibres possess a weight ratio of fibre to lignin deposit or lignin derivative between 1/2 and 100/1.
2. The coated hydrocellulose fibre or set of fibres according to claim 1 , wherein the lignin deposit or lignin derivative further comprises between 0.50% and 50% by weight of flame retardant compound.
3. A highly carbonaceous fibre or set of fibres obtained by a process comprising:
reacting the coated hydrocellulose fibre or set of fibres of claim 1 in a carbonization step, wherein the highly carbonaceous fibre or set of fibres possess a density between 0.20 g/cm 3 and 1.95 g/cm 3 .
4. The highly carbonaceous fibre or set of fibres according to claim 3 , wherein highly carbonaceous fibre or set of fibres possess a density between 1.45 g/cm 3 and 1.60 g/cm 3 .
5. A part made of thermoplastic or thermosetting composite materials, wherein the part comprises the highly carbonaceous fibre or set of fibres according to claim 3 .
6. The coated hydrocellulose fibre or set of fibres according to claim 1 , wherein the lignin deposit or lignin derivative comprises between 2% and 30% by weight of flame retardant compound.
7. The coated hydrocellulose fibre or set of fibres according to claim 1 , wherein the structured precursor comprises a twisted multi-filament, non-twisted multi-filament, a set of non-woven fibres, or a set of woven fibres.
8. The coated hydrocellulose fibre or set of fibres according to claim 1 , wherein the unstructured precursor comprises between 1 and 50% by weight of lignin or lignin derivative.
9. The coated hydrocellulose fibre or set of fibres according to claim 1 , wherein the unstructured precursor is an aqueous solution, an organic solution, or a mixture of both.
10. The coated hydrocellulose fibre or set of fibres according to claim 1 , wherein the structured precursor comprises at least one hydrocellulose fibre with a diameter between 0.5 μm and 300 μm.
11. The coated hydrocellulose fibre or set of fibres according to claim 1 , wherein the structured precursor and/or the unstructured precursor comprises carbon nanotubes, wherein the carbon nanotubes are present at a concentration of between 0.0001% and 10% by weight.
12. The coated hydrocellulose fibre or set of fibres according to claim 1 , wherein the combination of the structured and un-structured precursors further comprises an impregnation.
13. The coated hydrocellulose fibre or set of fibres according to claim 1 , wherein the thermal and dimensional stabilization step is repeated one or more times.
14. The highly carbonaceous fibre or set of fibres according to claim 3 , wherein before the carbonization step, a sizing step of contacting the coated hydrocellulose fibre or set of fibres with an aqueous solution comprising at least one flame retardant compound occurs; and wherein a post-sizing drying step occurs after the sizing step.
15. The highly carbonaceous fibre or set of fibres according to claim 14 , wherein the sizing step and post-sizing drying step are repeated one or more times.
16. The highly carbonaceous fibre or set of fibres according to claim 3 , wherein a graphitization step occurs after the carbonization step.
17. The highly carbonaceous fibre or set of fibres according to claim 3 , wherein after the carbonization step, a sizing step comprising contacting the highly carbonaceous fibre or set of fibres with a solution comprising at least one organic component occurs, wherein the solution comprises at least one silane or silane derivative and/or at least one siloxane or siloxane derivative.