Electrolysis: processes – compositions used therein – and methods – Electrolytic synthesis – Preparing organic compound
Reexamination Certificate
1999-09-03
2001-04-17
Wong, Edna (Department: 1741)
Electrolysis: processes, compositions used therein, and methods
Electrolytic synthesis
Preparing organic compound
C205S415000, C205S416000, C205S417000
Reexamination Certificate
active
06217740
ABSTRACT:
The present invention relates to a process for electrochemically producing a carbonaceous material with a surface modified by organic groups, in particular functionalized organic groups.
It also relates to a novel carbonaceous material with a surface modified by organic groups, in particular functionalized organic groups, and to various applications of this carbonaceous material.
The surface modification of carbon fibres constitutes a well known solution to improving the mechanical properties of composite materials. Some composite materials are formed of a matrix of organic resin reinforced by carbon fibres. It is known that the mechanical properties of these materials depend, at least partially, on the shear stress. The shear stress increases as the laminar cohesive strength increases, that is to say as the fibre/matrix adhesion increases. The surface modification of the carbon fibres makes it possible to create groups at the surface which improve the affinity (or the adhesion) of the fibres for the matrix.
In the majority of these processes, the fibre/matrix adhesion is improved by treating the surface of the carbon fibres chemically or electrochemically.
The usual methods for modifying the surface of carbonaceous materials involve powerful oxidation processes resulting in the formation of carboxyl, quinone, ketone or hydroxyl groups which can subsequently be coupled to substrates, in particular organic matrices.
Other processes via the electrochemical route make it possible to attach amino compounds to the fibre.
Document FR-A-2,477,593 discloses a process which consists in electrochemically treating the fibres in a solution of an ammonium sulphate or bisulphate, which results in the formation, on the surface of the fibres, of groups such as —NH
2
and ═NH and in the improvement, for this reason, in the fibre/matrix adhesion.
Documents FR-A-2,564,489 and FR-A-2,607,528 disclose electrochemical processes in which nitrogenous groups are grafted to the carbon fibres, for example by oxidation of an aqueous solution of an amino compound.
Document JP-A-59 82467 discloses the electrochemical treatment of carbon fibres by cathodic reduction of amino compounds in aqueous medium.
The process disclosed in Patent EP-B-569,503 makes it possible to attach an aromatic group to the surface of a carbonaceous material by electrochemical reduction of a diazonium salt of formula ArN
2
X by bringing the carbonaceous material into contact with a solution of diazonium salt in an aprotic solvent and by negatively polarizing the carbonaceous material with respect to an anode also in contact with the solution of diazonium salt. This results in the attachment of the aromatic groups via a carbon (of the carbonaceous material)-aromatic carbon (of the Ar radical) bond.
In addition to the applications of these modified carbonaceous materials in the production of fibres/matrix composite materials, the said modified carbonaceous materials can be used to graft complexing compounds, biological molecules or other organic groups.
It is nevertheless desirable to provide other processes for the surface treatment of carbonaceous materials which will allow access to novel modified carbonaceous materials, the properties of which may vary or even be improved with respect to the properties of the already existing materials, with a greater diversity of grafted molecules.
The object of the present invention is to provide a solution to these problems.
REFERENCES:
patent: 4097344 (1978-06-01), Drury
patent: 4844781 (1989-07-01), Sanchez et al.
patent: 0374680 (1990-06-01), None
Andrieux Claude
Gonzalez Felipe
Pinson Jean
Saveant Jean-Michel
Centre National de la Recherche Scientifique
Finnegan Henderson Farabow Garrett & Dunner L.L.P.
Wong Edna
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