Method to produce colorless, high porosity, transparent polymer aerogels
A dried polymer aerogel has a Brunauer-Emmett Teller (BET) surface area over 100 m2/g, porosity of greater than 10%, visible transparency greater than 20%, color rendering index of over 20%, and average pore size of less than 100 nm.
1. A dried polymer aerogel having a Brunauer-Emmett Teller (BET) surface area over 100 m 2 /g, porosity of greater than 10%, visible transparency greater than 20% per 3 mm thickness, color rendering index of over 20%, and average pore size of less than 100 nm, the aerogel including at least a portion of a stable free radical molecule in the polymer, the portion of the stable free radical molecule including nitroxide.
2. The dried polymer aerogel as claimed in claim 1 , wherein the aerogel has pore sizes of less than 10 nm.
3. The dried polymer aerogel as claimed in claim 1 , wherein the aerogel has less than 5% of pore volume occupied by pores larger than 100 nm.
4. The dried polymer aerogel as claimed in claim 1 , wherein the aerogel is formed using more than 5 wt % of monomers having two or more polymerizable groups, wherein the aerogel is crosslinked.
5. The dried polymer aerogel as claimed in claim 1 , wherein the aerogel has porosity of at least 30%.
6. The dried polymer aerogel as claimed in claim 1 , wherein the aerogel has porosity of at least 59%.
7. The dried polymer aerogel as claimed in claim 1 , wherein the aerogel has a BET surface area of at least 659 m 2 /g.
8. The dried polymer aerogel as claimed in claim 1 , wherein the aerogel has a pore size distribution with full width at half maximum below 400 nm.
9. The dried polymer aerogel as claimed in claim 1 , wherein the nitroxide comprises one selected from the group consisting of: a nitroxide species derived from the decomposition of an alkoxyamine, 4-hydroxy-TEMPO, TEMPO, TIPNO, chlorobenzyl-TIPNO, SG1, and an alkoxyamine based on SG1 nitroxide joined to a methacrylic acid radical.
10. The dried polymer aerogel as claimed in claim 1 , wherein the portion of the stable free radical molecule comprises 0.0016-16.67% by weight of the polymer aerogel.
11. The dried polymer aerogel as claimed in claim 1 , the aerogel further comprising at least a portion of a initiating radical molecule bonded into the polymer aerogel.
12. The dried polymer aerogel as claimed in claim 11 , wherein the portion of the initiating radical comprises one selected from the group consisting of: an initiating radical derived from a conventional thermal initiator; an initiating radical derived from a photoinitiator; and an initiating radical derived from decomposition of an alkoxyamine species.
13. The dried polymer aerogel as claimed in claim 11 , wherein the portion of the initiating radical comprises 0.0016-16.67% by weight of the polymer aerogel.
14. The dried polymer aerogel as claimed in claim 1 , the aerogel further comprising at least a portion of a time-controlled decomposing initiator bonded into the polymer aerogel.
15. The dried polymer aerogel as claimed in claim 14 , wherein the portion of the time-controlled decomposing initiator comprises one of either a thermally-decomposing radical initiator or a mixture of thermally-decomposing initiators with half-life greater than 1 hour at the temperature of polymerization, and in a solvent of polymerization.
16. The dried polymer aerogel as claimed in claim 14 , wherein the portion of the time-controlled decomposing initiator is one or more of the group consisting of: dicumyl peroxide, di-tert-butylperoxide, 2,2-bis(tert-butylperoxy) butane, 1,1-bis(tert-butylperoxy) cyclohexane, 2,5-bis(tert-butylperoxy)-2,5-dimethylhexane, 2,5-bis(tert-butylperoxy) 2,5-dimethyl-3-hexyne, tert-butylhydroperoxide, cumene hydroperoxide, or 2,4-pentanedione peroxide.
17. The dried polymer aerogel as claimed in claim 14 , wherein the portion of the time-controlled decomposing initiator comprises 0.0016-16.67% by weight of the polymer aerogel.