HIGH STRENGTH AEROGEL MATERIAL AND METHOD
An aerogel with a polyimide matrix and associated methods are disclosed. In one example, the aerogel includes linear polyimide molecules with high molecular weight.
1 - 26 . (canceled)
27 . An aerogel composition comprising:
a polyimide matrix comprised of linear polyimide molecules, the polyimide matrix having a nanoporous structure,
wherein the polyimide matrix includes amorphous regions and crystalline regions,
wherein the linear polyimide molecules include a polymer chain length of N, where 30≤N≤650, and wherein the polymer chain length is defined by rheology using intrinsic viscosity, and
wherein the aerogel composition having a density normalized compressive modulus greater than 13 J/g, and wherein the density normalized compressive modulus is a compressive modulus of the aerogel composition normalized with respect to bulk density of the aerogel composition.
28 . The aerogel composition of claim 27 , wherein the polyimide matrix is prepared by dissolving a diamine in a solvent first followed by dissolving a dianhydride in the solvent.
29 . The aerogel composition of claim 27 , wherein the linear polyimide molecules include a polymer chain length of N, where 50≤N≤400.
30 . The aerogel composition of claim 27 , wherein the aerogel composition includes a density normalized compressive modulus greater than 100 J/g.
31 . The aerogel composition of claim 27 , wherein the aerogel composition has a bulk density between 0.05 and 0.80 g/cm 3 .
32 . The aerogel composition of claim 27 , wherein the polyimide matrix includes a percent of crystallinity greater than zero.
33 . The aerogel composition of claim 27 , wherein the polyimide matrix includes a percent of crystallinity greater than 5%.
34 . The aerogel composition of claim 27 , wherein the polyimide matrix includes a percent of crystallinity between 5% and 60%.
35 . An aerogel composition comprising:
a polyimide matrix comprised of linear polyimide molecules, the polyimide matrix having a nanoporous structure;
the linear polyimide molecules being a reaction product of monomer dianhydride to monomer diamine at a stoichiometric ratio of 0.8 to 1.0, wherein the linear polyimide molecules include a molecular weight greater than 10,000 g/mol, and wherein the molecular weight is measured by rheology at 25° C. and at 1 rad/s; and
the aerogel composition having a compressive yield stress greater than 1.5 MPa for a bulk density between 0.05 and 0.35 g/cm 3 .
36 . The aerogel composition of claim 35 , wherein the linear polyimide molecules include a molecular weight greater than 15,000 g/mol and less than 200,000 g/mol.
37 . The aerogel composition of claim 35 , wherein the aerogel composition includes a bulk density between 0.05 and 0.20 g/cm 3 .
38 . The aerogel composition of claim 35 , wherein the aerogel composition has a compressive yield stress greater than 1.5 MPa for a bulk density between 0.05 and 0.20 g/cm 3 .
39 . The aerogel composition of claim 35 , wherein the aerogel composition has a flexural stress greater than 0.4 MPa for a molecular weight greater than 10,000 g/mol.
40 . The aerogel composition of claim 35 , wherein the polyimide matrix includes a percent of crystallinity greater than zero.
41 . The aerogel composition of claim 35 , wherein the polyimide matrix includes a percent of crystallinity greater than 5%.
42 . The aerogel composition of claim 35 , wherein the polyimide matrix includes a percent of crystallinity between 5% and 10%.
43 . An aerogel composition comprising:
a polyimide matrix comprised of linear polyimide molecules, the polyimide matrix having a nanoporous structure,
wherein the polyimide matrix is prepared by dissolving a diamine in a solvent first followed by adding a dianhydride,
wherein the diamine is solubilized by pyridine for a solution with a percent solid solution greater than 0.05 g/cm 3 ,
wherein the linear polyimide molecules include a molecular weight greater than 10,000 g/mol, and
wherein the aerogel composition has a flexural stress greater than 0.4 MPa.
44 . The aerogel composition of claim 43 , wherein the aerogel composition has a bulk density between 0.05 and 0.80 g/cm 3 .
45 . The aerogel composition of claim 43 , wherein the polyimide matrix includes a percent of crystallinity greater than zero.
46 . A method of forming an aerogel composition, comprising:
polymerizing dianhydride and diamine to form a linear molecule polyimide matrix with a molecular weight greater than 10,000 g/mol, wherein a stoichiometry of the dianhydride and diamine is 0.8 to 1.0;
gelling the linear molecule polyimide matrix without crosslinking to form a wet gel; and
removing a solvent from the wet gel to form a polyimide aerogel.
47 . The method of claim 46 , wherein polymerizing dianhydride and diamine includes polymerizing PMDA and PDA.
48 . The method of claim 46 , wherein polymerizing dianhydride and diamine includes polymerizing a dianhydride chosen from BTDA, BPADA, BPDA, ODPA, DSDA, and 6FDA.
49 . The method of claim 46 , wherein polymerizing dianhydride and diamine includes polymerizing a diamine chosen from meta-PDA, ODA, BAPP, BDAF, DABP, DDM, DDS.
50 . The method of claim 46 , further including solubilizing the diamine in an amount of pyridine prior to polymerizing for a solution with a percent solid solution greater than 0.05 g/cm 3 .
51 . The method of claim 46 , further including annealing the wet gel at 68° C. before removing the solvent from the wet gel.
52 . The method of claim 51 , further including heat treating the polyimide aerogel at 300° C. for approximately 4 hours.
53 . The method of claim 46 , further including carbonizing the polyimide aerogel.