seek hi-temp porous polymer membrane

Ceramic fiber or fiberglass.....

Gregg

No polymer-based fabric will go as high as Gore-Tex, which is essentially not-quite-Teflon. 550F happens to be the sintering temperature of Teflon. Polyimides might get somewhere close (still lower). What is the application? Glass fiber will go much higher - it is available woven and non-woven. Usually used for insulation, I've used it up to 500-600C.

The special thing about Gore-Tex is both it being fluorinated (low wetting) combined with the porosity. Tiny capillary spaces + low surface energy = very difficult to get a drop of water through. However the high porosity also makes it 'breathable' because gases can pass surface tensionlessly through the pores. If these properties are what you are looking for, you won't find anything higher temp, sorry.

Correction - sintering temp of Teflon is 380C not 280C. Gore-tex is much lower because the fluoropolymer is only one of the components.

You might check out some of the inoganic polymers to see if they have what you need. I think Dow had something a while back. By using boron, silicon, phosphorous, etc, there are some polymers that have been made which might have the temperature range you need. Carbon fiber might also do something for you, though I doubt that you can get the great properties of Gore Tex.

What properties are you looking for? flexibilty, insulation, breathabilty, high temperature?

Michael

I think this is precisely how the discussion should have started. Materials science is mostly about combinations of material properties.

The original poster does not explain why limit the search only to polymers.