Porous carbon structures and methods for their preparation

• US 4,775,655 A
• Filed: 11/17/1986
• Issued: 10/04/1988
• Est. Priority Date: 11/18/1985
• Status: Expired due to Term

• Current Assignee: Unilever Patent Holdings BV (Unilever PLC)
• Original Assignee: Internationale Octrooi Maatschappij "Octropa" BV
• Inventors: Edwards, Christopher J. C., Sharples, Martin, Hitchen, David A.
• Primary Examiner(s): KONOPKA, PAUL
• Application Number:
  US06/930,926
• Time in Patent Office: 687 Days
• Field of Search: 502/416, 502/418, 502/420, 502/436, 502/437, 502/180, 423/445, 423/449, 264/29.1, 264/29.6, 264/29.7
• US Class Current: 502/416
• CPC Class Codes: C04B 35/52 based on carbon, e.g. graphite
• CPC Class Codes: C04B 35/524 obtained from polymer precursors, e.g. glass-like carbon material
• CPC Class Codes: C04B 38/0022 obtained by a chemical conversion or reaction other than those relating to the setting or hardening of cement-like material or to the formation of a sol or a gel, e.g. by carbonising or pyrolysing preformed cellular materials based on polymers, organo-metallic or organo-silicon precursors
• CPC Class Codes: C04B 38/0067 characterised by the density of the end product
• CPC Class Codes: C04B 38/0074 expressed as porosity percentage

Abstract

This invention relates to the production of a novel, porous, carbon structure. A stabilised porous polymer comprising cavities joined by interconnecting pores is heated in an inert atmosphere to yield a stable, porous, carbon structure having the inherent structure of the original stabilised polymer.

Claims

1. A porous carboniferous structure consisting of concave surfaces and having at least 80% voids and comprising cavities joined by interconnecting pores and having a density of less than 0.5 g/cm³, the carboniferous structure being derived from a porous cross-linked polymer formed by polymerising monomer and cross-linking agent as a continous phase of a high internal phase emulsion having an aqueous discontinuous phase.

2. A porous carboniferous structure as claimed in claim 1 having at least 90% voids and a density of less than 0.25 g/cm³.

3. A process for the manufacture of a porous carbon structure comprising heating a stabilised, cross-linked, porous polymer in an inert atmosphere to a temperature of at least 500°

C., the cross-linked porous polymer being formed by polymerising monomer and cross-linking agent as a continuous phase of a high internal phase emulsion having an aqueous discontinous phase.

4. A process as claimed in claim 3 in which the porous polymer is a sulphonated polystyrene.

5. A process as claimed in claim 4 in which at least 20% of the polymer is cross-linked and 50% of the cross-linked polymer is sulphonated.

6. A process as claimed in claim 3 in which the cross-linked polymer is an alkyl acrylonitrile.

7. A process as claimed in claim 3 in which the cross-linked polymer is a polychlorostyrene.

8. A process as claimed in claim 7 in which the degree of cross-linking is greater than 20%.

9. A process as claimed in claim 3 in which the porous polymer is a flexible polymer and is modified by the incorporation of a resin to coat the interior surfaces of the polymer, prior to heating to carbonise the polymer.