Melamine-formaldehyde aerogels
AssigneeThe United States of America as represented by the Department of Energy
InventorRichard Walter Pekala
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Abstract
Organic aerogels that are transparent and essentially colorless are prepa from the aqueous, sol-gel polymerization of melamine with formaldehyde. The melamine-formaldehyde (MF) aerogels have low densities, high surface areas, continuous porsity, ultrafine cell/pore sizes, and optical clarity.
Claims8
A composition of matter comprising a low density, melamine=formaldehyde (MF) aerogel which s transparent and essentially colorless, wherein the cell/pore sizes of the aerogel are less than or equal to 500 angstroms (A) and the density of the aerogel is from about 0.1 to 0.8 g/cc.
A melamine-formaldehyde aerogel having cell/pore sizes of less than or equal to 500 angstroms (A) and a density of from about 0.1 to about 0.8 g/cc produced by a method comprising the steps of:
- a) mixing formaldehyde and melamine in a predetermined ratio wherein there is an excess of formaldehyde in water in the pressure of a base catalyst;
- b) heating the mixture to a predetermined temperature for a sufficiently long period of time to form a clear solution;
- c) allowing the solution to cool to a predetermined temperature and then adding a sufficient amount of an acid to make the solution acidic;
- d) allowing the acidic melamine-formaldehyde solution to cure for a sufficient time at a predetermined temperature to
- e) placing the gel in a basic solution to neutralize the acid within the pores of the gel;
- f) replacing the aqueous solution within the pores of the gel with a suitable organic solvent;
- and
- g) critical point drying the gel.
Dependencies are inferred from the claim text.