Interconnected microcellular material made of industrial lignin and method for preparing same
An interconnected microcellular material, a method for preparing said material using low-value waste from the paper industry, such as industrial lignin, and the use thereof for the production of items such as catalysts, filters or absorbent elements.
1. A method for preparing an interconnected microcellular material, comprising polymerizing a concentrated emulsion, said concentrated emulsion comprising:
an external dispersion phase comprising a mixture of a surfactant and a solution comprising a solvent and at least one polymerizable monomer contained in industrial lignin dissolved in said solvent, said surfactant being in said solvent, and
an internal dispersed phase comprising a solvent that is immiscible with said polymerizable monomer and/or with the solvent of the external dispersion phase.
2. The method according to claim 1 , wherein the volume percent of the internal dispersed phase of the concentrated emulsion is greater than or equal to approximately 55%.
3. The method according to claim 1 , wherein said external dispersion phase is an aqueous phase and wherein said immiscible solvent is an oil having a melting point between approximately 10° C. and approximately 40° C.
4. The method according to claim 1 , wherein the industrial lignin is selected from the group consisting of Kraft lignin, lignosulfonates, organosols lignins and lignins originating from biorefineries.
5. The method according to claim 1 , wherein the solution comprising at least one polymerizable monomer contained in industrial lignin further comprises at least one hemicellulose monomer dissolved in said solvent.
6. The method according to claim 1 , wherein the solution comprising at least one polymerizable monomer contained in industrial lignin is a cooking liquor.
7. The method according to claim 6 , wherein said cooking liquor is a black liquor that comprises from approximately 20% to approximately 80% by mass of dry matter.
8. The method according to claim 1 , wherein said mixture of said external dispersion phase further comprises a cross-linking agent.
9. The method according to claim 1 , wherein the emulsion is polymerized at a temperature below 100° C.
10. The method according to claim 1 , wherein the surfactant is an anionic hydrophilic surfactant or a non-ionic hydrophilic surfactant.
11. The method according to claim 10 , wherein the anionic hydrophilic surfactant is selected by the group consisting of sodium dodecyl sulfate, triethanolamine stearate, sodium lauryl sulfate and triethanolamine lauryl sulfate.
12. The method according to claim 10 , wherein the non-ionic hydrophilic surfactant is selected from the group consisting of alkyl polyethoxylate, ethoxylated alkylphenol, polymer complexes of polyethylene oxide and polypropylene oxide, polyethylene oxide octylphenol, polyethylene oxide nonylphenol, polyethylene oxide and polypropylene oxide block copolymers, sorbitan fatty acid monoester and polyester, glycerol fatty acid monoester and polyester, and mixtures thereof.
13. The method according to claim 1 , further comprising at least one step of washing and drying material formed by said polymerizing of the concentrated emulsion.
14. An interconnected microcellular material formed by the method according to claim 1 .
15. The interconnected microcellular material according to claim 14 , wherein said material has a porosity greater than or equal to approximately 60%.
16. The interconnected microcellular material according to claim 14 , wherein cells of the interconnected microcellular material have a diameter from approximately 2 μm to approximately 50 μm.
17. The interconnected microcellular material according to claim 14 , wherein interconnecting windows of the interconnected microcellular material have a diameter from approximately 50 nm to approximately 1000 nm.
18. A method for preparing an interconnected microcellular material comprising polymerizing a concentrated emulsion comprising at least one polymerizable monomer contained in industrial lignin.
19. The method according to claim 18 , wherein the industrial lignin is selected from the group consisting of Kraft lignin, lignosulfonates, organosols lignins, lignins originating from biorefineries.
20. The method according to claim 18 , wherein the industrial lignin is present in a cooking liquor.
21. An emulsion which is useful for the preparation of an interconnected microcellular material, comprising:
an external dispersion phase comprising a mixture of a surfactant and a solution comprising a solvent and at least one polymerizable monomer contained in industrial lignin dissolved in said solvent, said surfactant being in said solvent, and
an internal dispersed phase comprising a solvent that is immiscible with said polymerizable monomer and/or with the solvent of the external dispersion phase.
22. An article comprising the interconnected microcellular material according to claim 14 .
23. The article according to claim 22 , wherein said article is selected from the group consisting of a filter, a thermal insulation article, an acoustic insulation article, an electrical or mechanical insulation article, a disposable absorbent article, and a support for inks, colorants and catalysts.