Amaqondo obushushu angaphezulu kwe-77°C awalungelanga amacandelo eelastomers ezininzi kunye neeplastiki, kanti i-PTFE imelana nobushushu obuphezulu njenge-260°C.Nangaphantsi kwe-77°C, ukuba iiasidi ezidlekayo kwisinyithi kunye nezinyibilikisi eziphilayo zidityanisiwe, iilitha kunye namalungu e-PTFE ahlala ekhethwa ngenxa yokuba ii-elastomers kunye nezinye iiplastiki zihlala zingenakumelana nokudumba kwe-solvent kunye nokuthamba.
Ngokungangeni kweMichiza, sithetha loo ntoPTFEIintlaka ze-fluorocarbon zinokudibana ngokuqhubekayo nenye into kwaye akukho mpendulo yekhemikhali ebonwayo eyenzekayo.Ngokubanzi, i-PTFE fluorocarbon resins are chemically inert.Nangona kunjalo, le nkcazo, njengazo zonke izinto eziqhelekileyo, kufuneka ifaneleke ukuba ichaneke ngokugqibeleleyo.Isiqinisekiso asiyi kukhokelela ekudidekeni, nangona kunjalo, ukuba umntu ugcina engqondweni iinyaniso ezisisiseko malunga nokuziphatha kwe-PTFE resins.
Isishwankathelo senkcazo esiqhelekileyo sedatha yovavanyo eyahlukeneyo sinokulahlekisa, kuba sinokudibana ngokusisiseko kwiindidi ezahlukeneyo zokuziphatha "kweKhemikhali".Ukuba inkcazo kufuneka icace, kufuneka yahlule phakathi kweekhemikhali ezichanekileyo kunye nezenzo zomzimba ezifana nokufunxa.Inkcazo kufuneka ivumele umsebenzisi ukuba athathele ingqalelo ubudlelwane beempawu ezibonakalayo kunye neekhemikhali ezinokuchaphazela isicelo esithile.
Ngokomzekelo, i-PTFE resins ayiyi kuchaphazeleka ngokuntywiliselwa kwi-aqua regia.Nangona kunjalo, ukuba iqondo lobushushu kunye noxinzelelo lwesiphumo sale reagent liphezulu, ukufunxwa kwamalungu e-reagent kwi-resin kuya kwanda.Ukuguquguquka okulandelayo, okufana nokulahleka koxinzelelo ngequbuliso, kunokuba yingozi emzimbeni ngenxa yokwandiswa komphunga ofakwe kwi-resin.Ngokucacileyo ke, xa sithetha ngeepropathi zeekhemikhali ze-PTFE kufuneka sahlule phakathi kweekhemikhali ezichanekileyo, njengoko sibonakalisile ngokwemiqathango "yokuhambelana kweMichiza" kunye nezenzo zomzimba, ezifana "nokufunxa" kudityaniswe noxinzelelo lomatshini kunye nobushushu.
Ngaphakathi kokusetyenziswa okuqhelekileyo kwamaqondo obushushu, iireyini ze-PTFE zihlaselwa yimichiza embalwa kunokuba kudweliswe iikhemikhali ezihambelana nazo.Ezi reactants ziphakathi kwezona oxidizer ezinobundlobongela kunye neearhente zokunciphisa ezaziwayo.I-sodium ye-Elemental ekunxibelelaneni ngokusondeleyo kunye ne-fluorocarbons isusa i-fluorine kwi-molecule ye-polymer.Le mpendulo isetyenziswa ngokubanzi kwizisombululo ze-anhydrous ukuchola imiphezulu ye-PTFE ukuze iireyini zibe nokuncamathelisa okudityanisiweyo.Ezinye iintsimbi zealkali (i-potassium, i-lithium, njl.) zisabela ngendlela efanayo.
Imixube esondeleleneyo yomgubo wesinyithi owahlulwe ngokucokisekileyo (umzekelo, i-aluminiyam okanye i-magnesium) enomgubo we-fluorocarbon resins inokusabela ngobundlobongela xa ilayitiwe, kodwa amaqondo obushushu okutshisa angaphezulu kakhulu kobushushu benkonzo obucetyiswayo obuphezulu be-PTFE resins.Ii-oxidizers ezinamandla kakhulu, i-fluorine (F2) kunye neekhompawundi ezinxulumene nazo (umzekelo, i-chlorine trifluoride, i-CIF3), inokuphathwa yi-PTFE kuphela ngononophelo olukhulu kunye nokuqatshelwa kweengozi ezinokubakho.I-Fluorine ifakwe kwii-resin, kwaye ngoqhagamshelwano olusondeleyo olunjalo umxube uba novakalelo kumthombo wokutshisa njengempembelelo.
Kwezinye iimeko okanye kufutshane nomda wenkonzo ocetyisiweyo wobushushu obuyi-260°C kwi-TFE & PFA, kunye ne-204°C ye-FEP, iikhemikhali ezimbalwa ezikugxininiso oluphezulu ziye zaxelwa ukuba zisebenza ngokubhekiselele kwi-PTFE.Ukuhlaselwa okufana ne-sodium etch kuye kwaveliswa kwiqondo lokushisa eliphezulu nge-80% ye-NaOH okanye i-KOH, i-hydrides yensimbi efana ne-boranes (umzekelo, i-B2H6), i-aluminium chloride, i-ammonia (NH3), kunye ne-amines ethile (R-NH2) kunye nemines ( R = NH).Kwakhona, uhlaselo olucothayo lwe-oxidative luye lwabonwa yi-70% ye-nitric acid phantsi koxinzelelo kwi-250 ° C.Uvavanyo olukhethekileyo luyafuneka xa iimeko ezinjalo zokunciphisa okanye i-oxidizing zisondela.
Yiyo loo nto, ngaphandle kokukhetha njengoko kuphawuliwe, iireyini ze-PTFE zibonisa uluhlu olubanzi kakhulu lweekhemikhali kunye nokusebenza kwe-thermal.Kodwa umthengi okanye umcacisi wamacandelo e-PTFE naye kufuneka ayazi kwaye aqonde imida yayo ngokumalunga nemo engqongileyo yekhemikhali eqhelekileyo.Ngokungafaniyo nokunciphisa isinyithi, ezi ngokuqhelekileyo aziyiyo ikhemikhali yokuthenga ngokwasemzimbeni.Iimpembelelo zeqondo lokushisa, uxinzelelo, kunye nokufunxa kweekhemikhali kwi-PTFE, kunye nokusebenzisana kwazo, yintoni ekuhambeni kwexesha ngokuqhelekileyo ukunciphisa iimeko apho i-PTFE iya kwenza ngokwanelisayo.Ekubeni oku kwahlukile phantse kuzo naziphi na ezinye izinto zokwakha, kufuna uqwalaselo olucokisekileyo lweengcaciso ezingakumbi ezilandelayo.
Ixesha lokuposa: Oct-04-2019