PTFE impregnation nɔ jɔs de fɔ fayv glas klos. Dis atikul introduks 7 ɔltɛrnativ sabstret dɛm – aramid, kabɔn fayba, PBI, porous mɛtal, grafayt, asbest (phased out), ɛn sɛramik fil dɛm – wit dɛn prɔses ficha dɛm, advantej dɛm, limiteshɔn dɛm, ɛn ki aplikeshɔn dɛm.

Dis atikul de ɛksplen wetin mek alkali-fri fayv glas klos na di sabstret we dɛn kin lɛk fɔ PTFE ay-tɛmpracha klos. I de kɔba kemikal bɔndin via silane kɔpl ɛjɛn ɛn ki fizik prɔpati dɛn lɛk tɛmal stebiliti, dimɛnshɔnal stebiliti, ɛn kɔrɛshɔn rɛsistɛns – we de mek shɔ se i de wok fɔ lɔng tɛm na harsh ɛnvayrɔmɛnt.