TL;DR; PFA == nFEP, PFA > FEP. Buy PFA from McMaster Carr for ~1/2 the price of PFA(nFEP) from ePax. Or stick with FEP its pretty good and cheap.

For a while Ive been trying to find any info on what the epax nFEP film was. It was clearly not FEP because well...(non)FEP. I have access to an FTIR machine and so got a sample of PFA from mcmaster carr and a sample of the epax nfep film from amazon. Below is a spectral absorbance curve of PFA overlaid on nFEP. Looks pretty much the same to me. The background has been averaged for both. They looked basically the same to me so to ensure I did not mix up my samples (as I had to remove them to take background) and scan the same one twice I scanned the nFEP a second time after deliberately switching it.

https://imgur.com/gallery/txv6AG1

Below are the mechanical properties of PFA and FEP

https://www.fluorotherm.com/technical-information/materials-overview/pfa-properties/

https://www.fluorotherm.com/technical-information/materials-overview/fep-properties/

Whats the difference between FEP and PFA. Almost nothing, and if you dig else where they basically have the same level of non stick, except PFA has a higher tensile strength and elongation at break. PFA has a tensile strength of 21-31 MPa compared to 14.5-28 MPa for FEP. The elongation at break of PFA is 260-300% compared to 240-300% So basically the force that it takes to break PFA is higher AND it is stiffer compared to FEP. This likely leads to each layer being more easily removed when lifted because the PFA fights back more, and a longer life for PFA films because of slightly higher crack resistance. how much longer...well I only have numbers not empirical data.

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A warning about mcmaster. They dont immediately quote you shipping/taxes and that shows up once you receive the item. Could end up with sticker shock. My price typically is around 10 USD (assuming nothing huge)

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Heres numbers where I got that ePax film: 290 mm X 210 mm >>> 11.6 in X 8.2 in = 95 sq in. PFA from MMC: 12" X 24" = 288 sq in

price epax from amazon (assuming free shipping from amazon): 25 usd price from MMC: 32 10 (that was my shipping) = 42

usd/sqin epax : 25/95 = .263 MMC 42/288 = .145

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So some additonal info after the fact. I still havent found a supplier yet (honestly havent looked too hard) But the material is trademarked under NEOFLON (much as PTFE is trademarked under TEFLON). That may help. PFA is superior in almost every way compared to FEP. Another area I am currently exploring to try to understand more is the gas permeability of the materials. Long story short PFA should let less O2 through than FEP. It is likely an extremely small amount at our operating temperatures and pressures, but we are working in layers on the order of 10s of microns so it could make a difference. I just dont have enough info to make a backed statement at the moment.

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I have personally purchased and use .005" thickness without issue. That is what I recommened getting