Fluoropolymer feem ntau yog olefinic polymer uas muaj ib feem los yog tag nrho cov fluorinated olefinic monomers xws li vinylidene fluoride (CH2¼CF2) thiab tetrafluoroethylene (TFE) (CF2¼CF2).Cov polymers no tau them rau hauv kev nthuav dav hauv ntau cov ntaub ntawv.Ntau qhov tshwj xeeb fluorinated polymers suav nrog per-fluoroethers, fluoroacrylates, thiab fluorosilicones uas yog siv rau hauv cov ntim me dua li olefinic fluoropolymers.
Kev lag luam fluoropolymer muaj xws li homopolymers thiab copolymer.Homopolymers muaj 99% lossis ntau dua los ntawm qhov hnyav ib monomer thiab 1% lossis tsawg dua los ntawm qhov hnyav ntawm lwm tus monomer raws li kev sib tham los ntawm American Society for Testing Materials (ASTM).Copolymers muaj ntau dua 1% lossis ntau dua los ntawm qhov hnyav ntawm ib lossis ntau dua comonomers.Kev lag luam loj fluoropolymer yog raws li peb lub monomers:
TFE, vinylidene fluoride (VF2), thiab tsawg dua chlorotrifluoroethylene (CTFE).Piv txwv ntawm comonomers muaj xws li perfluoromethyl vinyl ether (PMVE), perfluoroethyl vinyl ether (PEVE), perfluoropropyl vinyl ether (PPVE), hexafluoropropylene (HFP), CTFE, perfluorobutyl ethylene (PFBE), thiab kab txawv monomers xws li 2,2-fluoromethylbis -4,5-difluoro-1,3-dioxole.
Ib txoj cai zoo ntawm tus ntiv tes xoo kom nco ntsoov yog tias ua kom cov fluorine cov ntsiab lus ntawm ib lub polymer molecule tsub kom nws cov tshuaj thiab hnyav tsis kam, nplaim tsis kam, thiab photostability;txhim kho nws cov khoom hluav taws xob xws li qis dielectric tas li;txo coefficient ntawm kev sib txhuam;nce melting point;nce nws thermal stability;thiab tsis muaj zog nws cov khoom siv kho tshuab.Solubility ntawm polymers nyob rau hauv cov kuab tshuaj feem ntau txo los ntawm kev ua kom cov fluorine cov ntsiab lus ntawm lub molecule.
Fluoropolymer Classification
Lub serendipitous discovery ntawm PTFE nyob rau hauv 1938 los ntawm Roy Plunkett ntawm DuPont tuam txhab pib lub era ntawm fluoropolymers.PTFE tau pom ntau txhiab daim ntawv thov vim nws cov khoom tshwj xeeb.Ntau yam fluoroplastics tau tsim txij li thaum nrhiav tau ntawm PTFE.Ntau lub tuam txhab tsim cov yas no thoob ntiaj teb.Fluoropolymers muab faib ua ob chav kawm ntawm perfluorinated thiab ib nrab fluorinated polymers.Perfluorinated fluoropolymer yog homopolymer thiab copolymer ntawm TFE.Qee tus comonomers yuav muaj me me ntawm cov ntsiab lus uas tsis yog C lossis F.
Polymer Development History
PTFE tsis tuaj yeem tsim los ntawm cov txheej txheem yaj ua haujlwm vim nws cov viscosity siab.Melt-processible fluoropolymers tau tsim los ntawm copolymerization ntawm TFE.FEP, lub copolymer ntawm TFE thiab HFP, muaj qhov qis tshaj qhov siv tsis tu ncua kub dua li PTFE (200 C vs. 260 C) vim tias cov khoom siv kho tshuab tsis zoo.PFA, lub copolymer ntawm TFE nrog PPVE los yog PEVE, muaj thermal stability, yaj-processibility thiab siab tshaj plaws kev siv kub ntawm 260 C. FEP thiab PFA yog suav hais tias yog perfluoropolymer.
Copolymers ntawm ethylene nrog tetrafluoroethylene (ETFE) thiab chlorotrifluoroethylene (ECTFE) yog mechanically muaj zog tshaj perfluoropolymers, nrog rau kev lag luam ntawm kev txo qis hauv lawv cov tshuaj tiv thaiv thiab kev siv tsis tu ncua kub thiab nce coefficient ntawm kev sib txhuam.
Amorphous copolymer ntawm TFE yog soluble nyob rau hauv tshwj xeeb halogenated cov kuab tshuaj thiab yuav siv tau rau saum npoo raws li ib tug polymer tov los tsim nyias txheej.Cov txheej txheej qhuav yog tiv taus yuav luag ntau yam tshuaj xws li PTFE.
Post lub sij hawm: Jul-22-2017