Kini Fluoropolymer?

Fluoropolymer nigbagbogbo jẹ polymer olefinic eyiti o ni apakan tabi awọn monomers olefinic fluorinated ni kikun gẹgẹbi vinylidene fluoride (CH2¼CF2) ati tetrafluoroethylene (TFE) (CF2¼CF2).Awọn polima wọnyi ni a ti bo ni awọn alaye nla ni nọmba awọn itọkasi.Awọn polima fluorinated pataki diẹ sii pẹlu fun-fluoroethers, fluoroacrylates, ati awọn fluorosilicones eyiti a lo ni iwọn kekere ti o kere pupọ ju olefinic fluoropolymers.

Awọn fluoropolymers ti iṣowo pẹlu homopolymers ati copolymers.Homopolymers ni 99% tabi diẹ sii nipasẹ iwuwo monomer kan ati 1% tabi kere si nipasẹ iwuwo monomer miiran ni ibamu si apejọ nipasẹ Ẹgbẹ Amẹrika fun Awọn Ohun elo Idanwo (ASTM).Copolymers ni diẹ ẹ sii ju 1% tabi diẹ ẹ sii nipasẹ iwuwo ti ọkan tabi diẹ ẹ sii comonomers.Awọn fluoropolymers iṣowo pataki da lori awọn monomers mẹta:

TFE, vinylidene fluoride (VF2), ati si iwọn diẹ chlorotrifluoroethylene (CTFE).Awọn apẹẹrẹ ti comonomers pẹlu perfluoromethyl vinyl ether (PMVE), perfluoroethyl vinyl ether (PEVE), perfluoropropyl vinyl ether (PPVE), hexafluoropropylene (HFP), CTFE, perfluorobutyl ethylene (PFBE), ati awọn monomers nla bi 2,2-bistri-fluoromethyl -4,5-difluoro-1,3-dioxole.

Ofin atanpako ti o dara lati ranti ni pe jijẹ akoonu fluorine ti moleku polima kan mu ki kemikali rẹ pọ si ati resistance olomi, resistance ina, ati iduroṣinṣin fọto;se awọn oniwe-itanna-ini bi kekere dielectric ibakan;lowers olùsọdipúpọ ti edekoyede;ji yo ojuami;mu iduroṣinṣin gbona rẹ pọ;ati ki o weakens awọn oniwe-darí-ini.Solubility ti awọn polima ni awọn olomi nigbagbogbo n dinku nipasẹ jijẹ akoonu fluorine ti moleku naa.

Fluoropolymer Classification

Awari serendipitous ti PTFE ni 1938 nipasẹ Roy Plunkett ti Ile-iṣẹ DuPont bẹrẹ akoko ti fluoropolymers.PTFE ti ri ẹgbẹẹgbẹrun awọn ohun elo nitori awọn ohun-ini alailẹgbẹ rẹ.Awọn oriṣiriṣi fluoroplastics ti ni idagbasoke lati igba awari PTFE.Nọmba awọn ile-iṣẹ ṣe agbejade awọn pilasitik wọnyi ni ayika agbaye.Fluoropolymers ti pin si awọn kilasi meji ti perfluorinated ati awọn polima fluorinated apa kan.Awọn fluoropolymers perfluorinated jẹ homopolymers ati copolymers ti TFE.Diẹ ninu awọn comonomers le ni iye kekere ti awọn eroja miiran ju C tabi F.

Polima Development History

PTFE ko le ṣe iṣelọpọ nipasẹ awọn ilana imuṣiṣẹ yo nitori iki giga rẹ.Awọn fluoropolymers ti o ni ilọsiwaju ti ni idagbasoke nipasẹ copolymerization ti TFE.FEP, copolymer ti TFE ati HFP, ni iwọn otutu lilo ti o pọju ti o pọju ju PTFE (200 C vs. 260 C) nitori ibajẹ ti awọn ohun-ini ẹrọ.PFA, a copolymer ti TFE pẹlu PPVE tabi PEVE, nfun gbona iduroṣinṣin, yo-isese ati ki o pọju lemọlemọfún lilo otutu 260 C. Mejeeji FEP ati PFA ti wa ni kà perfluoropolymers.

Copolymers ti ethylene pẹlu tetrafluoroethylene (ETFE) ati chlorotrifluoroethylene (ECTFE) ni agbara agbara ju awọn perfluoropolymers, ti o wa pẹlu awọn iṣowo ti idinku ninu resistance kemikali wọn ati iwọn otutu lilo lilọsiwaju ati ilosoke ninu iyeida ti edekoyede.

Amorphous copolymers ti TFE jẹ tiotuka ni awọn nkanmimu halogenated pataki ati pe o le lo si awọn ibi-ilẹ bi ojutu polima lati ṣe awọn aṣọ tinrin.Awọn ti o gbẹ ti a bo jẹ bi sooro si fere bi ọpọlọpọ awọn kemikali bi PTFE.