Polyimide nanoweb with amidized surface and method for preparing
View Patent ↗The present invention is directed to the preparation and use of aromatic polyimide nanowebs with amide-modified surfaces. Uses include as a filtration medium, and as a separator in batteries, particularly lithium-ion batteries. The invention is also directed to a filtration apparatus comprising the aromatic polyimide nanoweb with amide-modified surface. The invention is further directed to a multi-layer article comprising the aromatic polyimide nanoweb with amide-modified surface, and to an electrochemical cell comprising the multi-layer article.
1. An article comprising a nanoweb comprising nanofibers of aromatic polyimide, said nanoweb having a free surface area at least a portion of which is chemically modified by reaction with a primary amine to form a secondary amide comprising a functional group comprising a hydrocarbyl radical.
2. The article of claim 1 wherein said functional group further comprises a functional group comprising oxygen, sulfur or nitrogen.
3. The article of claim 2 wherein said functional group is an amine.
4. The article of claim 1 wherein said nanofibers are characterized by a number average diameter in the range of 50 to 500 nanometers.
5. The article of claim 4 wherein said nanofibers are characterized by a number average diameter in the range of 100 to 400 nanometers.
6. The article of claim 1 wherein said hydrocarbyl radical is a saturated hydrocarbyl radical.
7. The article of claim 6 wherein said saturated hydrocarbyl radical is an alkyl radical.
8. The article of claim 7 wherein said alkyl radical is a n-alkyl radical.
9. The article of claim 8 wherein said n-alkyl radical has 15 to 20 carbon atoms.
10. The article of claim 1 wherein said aromatic polyimide is a fully aromatic polyimide.