Process for the production of dispersions of thermally oxidised carbon-based materials

Patent metadata

Field	Value
Publication number	US-2019161353-A1
Application number	US-201616320891-A
Country	US
Kind code	A1
Filing date	Jul 27, 2016
Priority date	Jul 27, 2016
Publication date	May 30, 2019
Grant date	—

Abstract

Methods of preparing dispersions of carbon-based materials are disclosed herein. In some embodiments, a method comprises exposing the carbon-based material to an atmosphere comprising between about 0.5% v/v and about 5.0% v/v of oxygen for a selected time at an oxidation temperature to obtain a thermally oxidized material; and dispersing the thermally oxidized material in a liquid medium.

First claim

1 . A method of preparing a dispersion of a carbon-based material, comprising:
exposing the carbon-based material to an atmosphere comprising between about 0.5% v/v and about 5.0% v/v of oxygen for a selected time at an oxidation temperature to obtain a thermally oxidized material; and
dispersing the thermally oxidized material in a liquid medium.

2 . The method of claim 1 , wherein the selected time is between about 10 minutes and about 2 hours.

3 . The method of claim 1 , wherein the oxidizing temperature is between about 350° C. and about 425° C.

4 . The method of claim 1 , wherein the carbon-based material is a multi-layered graphene or graphene-like material.

5 . The method of claim 1 , wherein the carbon-based material is selected from the group consisting of multi-walled carbon nanotubes, graphene, and graphene nanoplatelets.

6 . The method of claim 1 , wherein the atmosphere includes an oxidizing gas selected from the group consisting of air, oxygen (O 2 ), nitrogen (N 2 ), carbon monoxide (CO), nitrogen monoxide (NO), sulfur monoxide (SO), sulfur dioxide (SO 2 ), and combinations thereof.

7 . The method of claim 1 , wherein the atmosphere includes at least one second gas.

8 . The method of claim 7 , wherein the second gas is selected from the group consisting of nitrogen (N 2 ), argon (Ar), helium (He), carbon dioxide (CO 2 ), and combinations thereof.

9 . The method of claim 8 , wherein the atmosphere includes between about 80% v/v and about 99.5% v/v of the second gas.

10 . The method of claim 8 , wherein the atmosphere includes about 8% v/v nitrogen (N 2 ), and about 90% v/v % v/v of argon (Ar)

11 . The method of claim 1 , further comprising:
determining the oxidizing temperature prior to the exposing.

12 . The method of claim 11 , wherein the determining comprises:
exposing a test sample of the carbon-based material having a known initial weight to the atmosphere;
heating the test sample at a heating rate from an initial temperature below the temperature at which the carbon-based material oxidizes to a final temperature above the temperature at which the carbon-based material oxidizes; and
weighing the test sample during the heating at a plurality of temperatures between the initial temperature and the final temperature, wherein a temperature increment between each weighing is about 10° C. or less;
determining as a threshold temperature the first temperature at which the weight of the test sample is less than the initial weight;
selecting as the oxidizing temperature a temperature that is between about 50° C. and about 100° C. below the threshold temperature.

13 . The method of claim 12 , wherein the temperature increment between each weighing is between about 1° C. and about 5° C.

14 . The method of claim 12 , wherein the weight of the test sample at the threshold temperature is less than about 1 wt % less than the initial weight of the test sample.

15 . The method of claim 12 , wherein the oxidation temperature is between about 350° C. and about 425° C.

16 . The method of claim 12 , wherein the heating rate is between about 1° C./min. and about 10° C./min.

17 . The method of claim 1 , wherein the dispersing includes:
sonicating the thermally oxidized material in the liquid medium.

18 . The method of claim 1 , wherein the liquid medium is water.

19 . The method of claim 1 , wherein a concentration of the thermally oxidized material in the liquid medium is between about 0.01 wt % and about 0.5 wt % of the total weight of the liquid medium.

20 . A method of preparing a dispersion of a carbon-based material, comprising:
determining a threshold temperature at which a specific carbon-based material begins to oxidize in a given atmosphere; exposing the carbon-based material to the given atmosphere at an oxidation temperature less than the threshold temperature for a time sufficient to at least partially oxidize the carbon-based material; and dispersing the at least partially oxidized carbon-based material in an aqueous medium.

Assignees

• Schlumberger Technology Corp
• Torino Politecnico

Inventors

• Musso Simone
• Pavese Matteo
• Lavagna Luca

Classifications

• C01B32/194 Primary

  After-treatment · CPC title

• C01P2004/24

  Nanoplates, i.e. plate-like particles with a thickness from 1-100 nanometer · CPC title

• C01P2002/82

  by IR- or Raman-data · CPC title

• C01P2006/22

  Rheological behaviour as dispersion, e.g. viscosity, sedimentation stability · CPC title

• C01P2004/03

  obtained by SEM · CPC title