US4997804A
Expired / Lapsed
US
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Low density, resorcinol-formaldehyde aerogels
Assignee: Lawrence Livermore National Security LLC
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Filing: 1989-09-12
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Granted: 1991-03-05
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Expires: 2009-09-12
Abstract
Abstract The polycondensation of resorcinol with formaldehyde under alkaline conditions results in the formation of surface functionalized polymer "Clusters". The covalent crosslinking of these "clusters" produces gels which when processed under supercritical conditions, produce low density, organic aerogels (density</=100 mg/cc; cell size </=0.1 microns). The aerogels are transparent, dark red in color and consist of interconnected colloidal-like particles with diameters of about 100 &cir& . These aerogels may be further carbonized to form low density carbon foams with cell size of about 0.1 micron. TABLE I- Theo- - [Form- retical Actual -Formu- % alde- [Resor- density Density -lation Solids hyde] cinol] Na2CO3 (g/cc) (g/cc) -A 5.0% 0.29M 0.58M 0.0029M 0.050 0.079 -B 5.0% 0.29M 0.58M 0.0019M 0.050 0.073 -C 5.0% 0.29M 0.58M 0.0015M 0.050 0.070 -D 4.0% 0.24M 0.47M 0.0012M 0.040 0.054 -E 3.5% 0.21M 0.41M 0.0010M 0.035 0.044 -F 2.0% 0.12M 0.24M 0.0006M 0.020 0.030 -
Inventors
- 👤 Richard W. Pekala
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-26 00:51
CPC Classifications
C; C08; C08G; C08G8/00; C08G8/04; C08G8/08; C08G8/20; B; B01; B01J; B01J20/00; B01J20/02; B01J20/20; Y; Y10; Y10S; Y10S521/00; Y10S521/918
Claims Analysis
Total Claims: 13
Claim 1
Independent Claim
48 words
A composition of matter comprising a low density, organic aerogel which is selected from the group of materials consisting of resorcinol-formaldehyde, hydroquinone-resorcinol-formaldehyde, phloroglucinol-resorcinol-formaldehyde, and catechol-resorcinol-formaldehyde with a uniform, pore size of less than about one micron and a density in the range of about 35 to 100 mg/cc.
Claim 2
Dependent Claim
48 words
A composition of matter comprising a low density, organic aerogel which is selected from the group of materials consisting of resorcinol-formaldehyde, hydroquinone-resorcinol-formaldehyde, phloroglucinol-resorcinol-formaldehyde, and catechol-resorcinol-formaldehyde with a uniform, pore size of less than about one micron and a density in the range of about 35 to 100 mg/cc.
Claim 3
Dependent Claim
16 words
The composition of claim 1, wherein the pore size of said aerogel is about 0.1 micron.
Claim 4
Dependent Claim
12 words
The composition of claim 1, wherein said aerogel is a resorcinol-formaldehyde aerogel.
Claim 5
Dependent Claim
22 words
The composition of claim 3, wherein said aerogel is carbonized to form a carbon foam with cell size of about 0.1 micron.
Claim 6
Dependent Claim
12 words
The composition of claim 1, further comprising a metal salt incorporated therein.
Claim 7
Dependent Claim
27 words
The composition of claim 5, wherein said metal salt is selected from the group consisting of thallium acetate, rubidium carbonate, chloroplatinic acid, palladium chloride, and lead acetate.
Claim 8
Dependent Claim
17 words
The composition of claim 1, further comprising the incorporation of a dihydroxy benzoic acid in said aerogel.
Claim 9
Dependent Claim
17 words
As an article of manufacture, an aerogel of claim 3, machined to a predetermined shape and size.
Claim 10
Dependent Claim
18 words
As an article of manufacture, a carbonized aerogel of claim 4, machined to a predetermined shape and size.
Claim 11
Dependent Claim
191 words
A low density, microcellular resorcinol-formaldehyde aerogel having a pore size of less than about one micron and a density in the range of about 35 to 100 mg/cc produced by the process comprising the steps of: (a) mixing resorcinol and formaldehyde in a molar ratio of about 1:2, in the presence of catalytic amounts of sodium carbonate; (b) adjusting the pH of the mixture to a value in the range of about 6.5 to about 7.4.; (c) decanting the mixture into a glass ampoule; (d) sealing the glass ampoule; (e) heating the mixture to about 85° C. in an oven for about seven days to facilitate formation of a gel; (f) removing the ampoule from the oven and cooling it to room temperature; (g) breaking the ampoule and removing the gel from the ampoule; (h) washing the gel in an agitated bath of trifluoracetic acid at 45° C. for three days; (i) transferring the gel from the acid bath to an agitated acetone bath maintained at about 45° C., to remove water; (j) removing the gel from the acetone bath and critical point drying the gel; and (k) characterizing the gel.
Claim 12
Dependent Claim
191 words
A low density, microcellular resorcinol-formaldehyde aerogel having a pore size of less than about one micron and a density in the range of about 35 to 100 mg/cc produced by the process comprising the steps of: (a) mixing resorcinol and formaldehyde in a molar ratio of about 1:2, in the presence of catalytic amounts of sodium carbonate; (b) adjusting the pH of the mixture to a value in the range of about 6.5 to about 7.4.; (c) decanting the mixture into a glass ampoule; (d) sealing the glass ampoule; (e) heating the mixture to about 85° C. in an oven for about seven days to facilitate formation of a gel; (f) removing the ampoule from the oven and cooling it to room temperature; (g) breaking the ampoule and removing the gel from the ampoule; (h) washing the gel in an agitated bath of trifluoracetic acid at 45° C. for three days; (i) transferring the gel from the acid bath to an agitated acetone bath maintained at about 45° C., to remove water; (j) removing the gel from the acetone bath and critical point drying the gel; and (k) characterizing the gel.
Claim 13
Dependent Claim
39 words
A carbon foam produced by heating the aerogel of claim 10 in a nitrogen atmosphere to a temperature in the range of about 600° to about 1200° C. to carbonize said aerogel and form a low density, carbon foam.
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