Method For Enhancing Adherence of Carbon Fibers With Respect to an Organic Matrix

• US 20080255332A1
• Filed: 09/15/2006
• Published: 10/16/2008
• Est. Priority Date: 09/16/2005
• Status: Active Grant

• Current Assignee: ArianeGroup SAS, Université des Sciences et Technologies de Lille
• Original Assignee: Astrium Sas (Airbus SE)
• Inventors: Defoort, Brigitte, Coqueret, Xavier, Ponsaud, Philippe
• Granted Patent: US 8,328,977 B2
• Time in Patent Office: Days
• US Class Current: 526/273
• CPC Class Codes: C08J 5/06 using pretreated fibrous materials
• CPC Class Codes: D01F 11/14 with organic compounds, e.g. macromolecular compounds
• CPC Class Codes: D01F 11/16 by physicochemical methods
• CPC Class Codes: D06M 14/36 on to carbon fibres
• CPC Class Codes: D06M 2101/40 Fibres of carbon
• CPC Class Codes: D06M 2200/50 Modified hand or grip properties; Softening compositions

Abstract

The invention relates to a process for improving the adhesion of carbon fibres with regard to an organic matrix forming a composite material with these fibres, this composite material being obtained by bringing the fibres into contact with a resin which can be cured by chain polymerization and then polymerizing the resin, which process is characterized in that it comprises the grafting, to the surface of the fibres, before they are brought into contact with the resin, of groups capable of acting as chain transfer agents during the polymerization of said resin.

Fields of application: aeronautical, aerospatial, railway, ship building and automobile industries but also the armaments industry, the industry of sports and leisure articles, and the like.

Claims

1. :

A process for improving the adhesion of carbon fibres with regard to an organic matrix which forms a composite material with these fibres, said composite material being obtained by bringing the fibres into contact with a resin which can be cured by chain polymerization and then polymerizing the resin, which process comprises the grafting to the surface of the fibres, before they are brought into contact with the resin, of groups capable of acting as chain transfer agents during the polymerization of said resin.

2. The process according to claim 1, wherein the groups capable of acting as chain transfer agents are chosen from carbon-based groups comprising an —

I, —

Br, —

Cl, —

F, —

SH, —

OH, —

NH—

, —

NH₂, —

PH—

, —

PH₂ or ═

S functional group.

3. The process according to claim 2, wherein the groups capable of acting as chain transfer agents are carbon-based groups comprising a thiol (—

SH) functional group.

4. The process according to claim 1, wherein the grafting to the surface of the carbon fibres of the groups capable of acting as chain transfer agents is carried out by reacting functional groups present at the surface of these fibres with an organic compound which, by ring opening, becomes covalently bonded to the functional groups of the fibres and simultaneously generates a group capable of acting as chain transfer agent.

5. The process according to claim 4, wherein the functional groups present at the surface of the carbon fibres are carboxyl groups and the organic compound is an episulphide which generates a group comprising a thiol functional group.

6. The process according to claim 5, wherein the episulphide is chosen from propylene sulphide, ethylene sulphide, cyclohexene, epithiodecane, epithiododecane and 7-thiabicyclo-[4.1.0]heptane.

7. The process according to claim 5, wherein the reaction of the carboxyl groups present at the surface of the carbon fibres with the episulphide is carried out under hot conditions and in the presence of a tertiary amine catalyst.

8. The process according to claim 5, wherein the reaction of the carboxyl groups present at the surface of the carbon fibres with the episulphide is followed by one or more operations of washing the fibres and then by one or more operations of drying the fibres.

9. The process according to claim 3, wherein the grafting to the surface of the carbon fibres of the groups capable of acting as chain transfer agents is carried out by reacting functional groups present on the surface of these fibres with an organic compound which comprises a chemical functional group capable of reacting with said functional groups and a group capable of acting as chain transfer agent.

10. The process according to claim 9, wherein the organic compound has, as a group capable of acting as chain transfer agent, a group comprising a thiol functional group.

11. The process according to claim 10, wherein the functional groups present at the surface of the carbon fibres are epoxide functional groups and the organic compound has, as chemical functional group, a carboxyl functional group or a phenol functional group.

12. The process according to claim 11, wherein the reaction of the epoxide groups present at the surface of the carbon fibres with the organic compound having a carboxyl or phenol functional group is carried out under hot conditions, under vacuum, and in the presence of a tertiary amine catalyst.

13. The process according to claim 11, wherein the organic compound is chosen from thiomalic acid, thioglycolic acid, thiolactic acid, 3-mercaptopropionic acid, 11-mercaptoundecanoic acid, 16-mercapto-hexadecanoic acid, 2-mercaptonicotinic acid, 6-mercaptonicotinic acid and 2-mercapto-4-methyl-5-thiazolacetic acid.

14. The process according to claim 1, wherein the resin is chosen from resins which can be polymerized under light or ionizing radiation.

15. The process according to claim 1, wherein the resin is chosen from epoxy acrylate resins, novolac acrylates, polyurethane acrylates, bismaleimide resins and epoxide resins.

16. The process according to claim 15, wherein the resin is an epoxy acrylate resin.

17. A process for the manufacture of a component made of composite material comprising carbon fibres and an organic matrix, which process comprises bringing the fibres into contact with a resin which can be cured by chain polymerization and polymerizing the resin, and wherein it furthermore comprises the implementation of a process according to claim 1 before the fibres are brought into contact with said resin.