I-Tetrafluoroethylene yaqala ukulungiswa ngo-1933. I-synthesis yorhwebo yangoku isekelwe kwi-fluorspar, i-sulfuric acid kunye ne-chloroform.
Inkqubo yeMveliso eyiSiseko yePTFE Polymer:
Uveliso lwe-PTFE Polymer/Resin luqhutywa ngokwamanqanaba amabini.Okokuqala, i-TFE Monomer iveliswa ngokubanzi nge-Calcium Fluoride (Fluorospar), i-Sulfuric Acid & Chloroform & kamva i-polymerisation ye-TFE iqhutyelwa kwiimeko ezilawulwa ngononophelo ukwenza i-PTFE.Ngenxa yobukho beebhondi zeCF ezizinzileyo nezomeleleyo, imolekyuli ye-PTFE inokungasebenzi kakuhle kweekhemikhali, ukumelana nobushushu obuphezulu kunye neempawu ezimangalisayo zokugquma umbane;ukongeza kwiipropati ezigqwesileyo zokukhuhlana.
Ukucocwa kwe-TFE:
Imonoma ecocekileyo iyafuneka kwipolymerisation.Ukuba ukungcola kukho kuya kuchaphazela imveliso yokugqibela.Irhasi iqale ikhuhlwe ukuze isuse nayiphi na i-hydrochloric acid kwaye emva koko idistilwe ukwahlula obunye ubumdaka.
Ukwenziwa kwePolymerization ye-TFE:
I-Tetrafluoroethylene esulungekileyo engathintelwanga inokupholisa ngobundlobongela, nakumaqondo obushushu angaphantsi kobushushu begumbi.I-reactor efakwe kwi-silver-plated, ikota-ezaliswe isisombululo esine-0.2 ye-ammonium persulphate, i-1.5 ye-borax kunye neengxenye ze-100 zamanzi, kunye ne-pH ye-9.2.I-reactor yayivaliwe;bakhutshiwe kwaye 30 iinxalenye monomer zavunyelwa ukuba zingene. I-reactor yaphazamiseka iyure enye kwi-80 ° C kwaye emva kokupholisa wanika i-86% isivuno se-polymer.PTFE yenziwa urhwebo ngeenkqubo ezimbini eziphambili, enye ekhokelela kwinto ebizwa ngokuba 'yigranular'. i-polymer kunye neyesibini ekhokelela ekusasazweni kwepolymer yobungakanani besuntswana elicolekileyo kakhulu kunye nobunzima obuphantsi bemolekyuli.Enye indlela yokuvelisa le yokugqibela ibandakanya ukusetyenziswa kwe-0.1 °% yesisombululo se-aqueous disuccinic acid peroxide.Iimpendulo zenziwa kwiqondo lobushushu ukuya kuma-90°C.
Ezinye iindlela :
Ukubola kwe-TFE phantsi kweempembelelo ze-arc yombane.I-Polymerisation eyenziwa ngendlela ye-emulsion ngokusebenzisa iziqalisi zeperoxide umz. H2O2 (i-Hydrogen peroxide) kunye ne-ferrous sulphate.Kwezinye iimeko ioksijini isetyenziswa njengomqalisi.
Ubume kunye neePropati ze-PTFE:
Ubume bemichiza ye-PTFE yipolymer emgca ye-C– F2 – C– F2 ngaphandle kwesebe & neempawu ezibalaseleyo ze-PTFE zinxulunyaniswa neCarbon eyomeleleyo & ezinzileyo – ibhondi yeFluorine.
I-Polytetrafluoroethylene yipolymer ehambelanayo ekhululekile kuyo nayiphi na imali ebalulekileyo ye-branching.Ngexa imolekyuli yepolyethylene ikwimo yeplani yegzag kwindawo yekristale oku akunakwenzeka ngokungqongqo ngale ye-PTFE ngenxa yeeathom zefluorine zikhulu kunezo zehydrogen.Ngenxa yoko, iathom ithatha i-zigzag ejijekileyo kunye neeathom zefluorine zipakisha ngokuqinileyo kwi-spiral ejikeleze i-carbon-carbon skeleton.Ukujikwa ngokupheleleyo kwe-spiral kuya kubandakanya ngaphezulu kwe-26 athom yekhabhoni engaphantsi kwe-19°C kunye ne-30°C ngaphezu kwayo kukho indawo yotshintsho ebandakanya i-1% yokutshintsha kwevolumu kobu bushushu.Ukudityaniswa okudityanisiweyo kweeathom zefluorine kukhokelela kwimolekyuli yokuqina okukhulu kwaye le nto ikhokelela kwindawo ephezulu yokunyibilika kwekristale kunye nokuzinza kwefomu ye-thermal yepolymer.
Umtsalane we-intermolecular phakathi kweemolekyuli ze-PTFE zincinci kakhulu, iparamitha ye-solubility ehlanganisiweyo yi-12.6 (MJ/m3) 1/2Ipolymer ngobuninzi ayinabo ubungqongqo obuphezulu kunye namandla okuqina ahlala edityaniswa neepolima ezinendawo ephezulu yokuthambisa.Ibhondi ye-carbon-fluorine izinzile kakhulu.Ukuqhubela phambili, apho iiathom ezimbini zefluorine zincanyathiselwe kwiathom yekhabhoni enye kukho ukuncipha kumgama webhondi ye-C-F ukusuka ku-1.42 A ukuya ku-1.35 A. Ngenxa yoko amandla ebhondi anokuba phezulu njenge-504 kJ/mole.Ekubeni enye ibhondi ekhoyo kuphela yi-bond ye-C-C ezinzileyo, i-PTFE inozinzo oluphezulu kakhulu lobushushu, nangona ishushu ngaphezu kwendawo yayo yokunyibilika yekristale ye-327 ° C.Ngenxa yobukhazikhazi bayo obuphezulu kunye nokungakwazi ukusebenzisana okuthe ngqo, akukho zinyibilikisi kwindawo yobushushu begumbi.Kumaqondo obushushu asondela kwindawo yokunyibilika ulwelo oluthile lwefluorinated olufana ne-fluorinated parafini luyakunyibilikisa ipholima.
Iipropati ze-PTFE zixhomekeke kuhlobo lwepolymer kunye nendlela yokucubungula.Ipolymer inokwahluka ngobukhulu besuntswana kunye / okanye ubunzima bemolekyuli.Ubungakanani besuntswana buya kuphembelela imeko yokusetyenzwa kunye nobuninzi be-voids kwimveliso egqityiweyo ngelixa ubunzima bemolekyuli buya kuba nefuthe kwikristale kwaye ngenxa yoko iipropathi ezininzi ezibonakalayo.Ubuchule bokucubungula buya kuchaphazela zombini i-crystallinity kunye nomxholo ongenanto.
Ubunzima be-molecular weights of polymers zorhwebo bubonakala buphezulu kakhulu kwaye buyi-400000 ukuya kwi-9000000. I-ICI ibika ukuba izinto zabo zinobunzima be-molecular kuluhlu lwe-500000 ukuya kwi-5000000 kunye nepesenti ye-crystallinity enkulu kune-94 ~ njengoko yenziwe.Iindawo ezenziweyo zinekristale encinci.Iqondo le-crystallinity yemveliso egqityiweyo iya kuxhomekeka kwizinga lokupholisa ukusuka kubushushu bokusebenza.Ukupholisa okucothayo kuya kukhokelela kwikristale ephezulu kunye nokupholisa ngokukhawuleza kunika umphumo ochaseneyo.Izinto ezinobunzima obuphantsi bemolekyuli nazo ziya kuba yikristale ngakumbi.
Kuyaqatshelwa ukuba i-polymer ye-dispersion, enobungakanani besuntswana elicolekileyo kunye nobunzima obuphantsi be-molekyuli, inika iimveliso ezinomgangatho ophucukileyo wokuchasana nokuguquguquka kunye namandla aphezulu acacileyo.Olu phuculo lubonakala luvela ngokwenziwa kwezakhiwo ezifana nefiber kubunzima bepolymer ngexesha lokulungiswa.
Ixesha lokuposa: Jan-04-2019