Kodi Fluoropolymer ndi chiyani?

Fluoropolymer nthawi zambiri ndi olefinic polima yomwe imakhala ndi ma monomers olefinic pang'ono kapena athunthu monga vinylidene fluoride (CH2¼CF2) ndi tetrafluoroethylene (TFE) (CF2¼CF2).Ma polima awa afotokozedwa mwatsatanetsatane muzofotokozera zingapo.Ma polima apadera opangidwa ndi fluorinated amaphatikizapo per-fluoroethers, fluoroacrylates, ndi fluorosilicones omwe amagwiritsidwa ntchito mochepa kwambiri kuposa olefinic fluoropolymers.

Ma fluoropolymers amalonda amaphatikiza ma homopolymers ndi copolymers.Ma homopolymers ali ndi 99% kapena kupitilira apo ndi kulemera kwa monoma imodzi ndi 1% kapena kuchepera pa kulemera kwa monomer ina malinga ndi msonkhano wa American Society for Testing Materials (ASTM).Ma copolymers ali ndi zoposa 1% kapena kupitilira apo potengera kulemera kwa comomers imodzi kapena zingapo.Ma fluoropolymers akuluakulu azamalonda amatengera ma monomers atatu:

TFE, vinylidine fluoride (VF2), ndi pang'ono chlorotrifluoroethylene (CTFE).Zitsanzo za ma comomers ndi monga perfluoromethyl vinyl ether (PMVE), perfluoroethyl vinyl ether (PEVE), perfluoropropyl vinyl ether (PPVE), hexafluoropropylene (HFP), CTFE, perfluorobutyl ethylene (PFBE), ndi monomers kunja monga 2,2romethyl- -4,5-difluoro-1,3-dioxole.

Lamulo labwino la chala chachikulu kukumbukira ndikuti kuchulukitsa kwa fluorine mu molekyulu ya polima kumawonjezera kukana kwake kwamankhwala ndi zosungunulira, kukana lawi, ndi photostability;imawongolera mphamvu zake zamagetsi monga kutsika kwa dielectric;amachepetsa coefficient ya kukangana;imakweza malo osungunuka;kumawonjezera kukhazikika kwake kwamafuta;ndi kufooketsa mphamvu zake zamakina.Kusungunuka kwa ma polima mu zosungunulira nthawi zambiri kumachepetsa powonjezera kuchuluka kwa fluorine mu molekyulu.

Gulu la Fluoropolymer

The serendipitous discovery of PTFE in 1938 by Roy Plunkett of DuPont Company started era of fluoropolymers.PTFE wapeza masauzande ofunsira chifukwa cha katundu wake wapadera.Ma fluoroplastic osiyanasiyana apangidwa kuyambira pomwe PTFE idapezeka.Makampani angapo amapanga mapulasitiki amenewa padziko lonse lapansi.Fluoropolymers amagawidwa m'magulu awiri a ma polima a perfluorinated ndi pang'ono fluorinated.Perfluorinated fluoropolymers ndi homopolymers ndi copolymers a TFE.Zina mwazophatikizazo zitha kukhala ndi zinthu zochepa kupatula C kapena F.

Mbiri Yachitukuko cha Polymer

PTFE sichingapangidwe ndi njira zosungunulira chifukwa cha kukhuthala kwake kwakukulu.Ma fluoropolymers osungunuka apangidwa ndi copolymerization ya TFE.FEP, copolymer ya TFE ndi HFP, imakhala ndi kutentha kwapamwamba kosalekeza kosalekeza kuposa PTFE (200 C vs. 260 C) chifukwa cha kuwonongeka kwa makina.PFA, copolymer ya TFE yokhala ndi PPVE kapena PEVE, imapereka kukhazikika kwamafuta, kusungunuka kwachangu komanso kugwiritsa ntchito mosalekeza kosalekeza kutentha kwa 260 C. Onse FEP ndi PFA amaonedwa kuti ndi perfluoropolymers.

Ma copolymers a ethylene okhala ndi tetrafluoroethylene (ETFE) ndi chlorotrifluoroethylene (ECTFE) ndi amphamvu mwamakina kuposa ma perfluoropolymers, omwe amatsagana ndi kuchepetsedwa kwa kukana kwawo kwamankhwala ndi kutentha kosalekeza komanso kuwonjezereka kwa coefficient of friction.

Amorphous copolymers a TFE amasungunuka mu zosungunulira zapadera za halogenated ndipo amatha kugwiritsidwa ntchito ngati njira ya polima kuti apange zokutira zopyapyala.Chophimba chouma chimakhala chosagwirizana ndi mankhwala ambiri monga PTFE.