Inqubo Yokukhiqiza ye-PTFE

I-Tetrafluoroethylene yalungiswa okokuqala ngo-1933. I-synthesis yamanje yezohwebo isekelwe ku-fluorspar, i-sulfuric acid ne-chloroform.

Inqubo Yokukhiqiza Eyisisekelo ye-PTFE Polymer:

Ukwenziwa kwe-PTFE Polymer/Resin kwenziwa ngezigaba ezimbili.Okokuqala, i-TFE Monomer ngokuvamile ikhiqizwa ngokuhlanganiswa kwe-Calcium Fluoride (Fluorospar), i-Sulfuric Acid & Chloroform & kamuva i-polymerisation ye-TFE yenziwa ngaphansi kwezimo ezilawulwa ngokucophelela ukuze kwakhiwe i-PTFE.Ngenxa yokuba khona kwamabhondi e-CF azinzile futhi aqinile, i-molecule ye-PTFE inokungena kwamakhemikhali okuvelele, ukumelana nokushisa okuphezulu nezici eziphawulekayo zokufakwa kukagesi;ngaphezu kwezakhiwo ezinhle kakhulu zokungqubuzana.

Ukuhlanzwa kwe-TFE:

I-monomer ehlanzekile iyadingeka ukuze kwenziwe i-polymerization.Uma ukungcola kukhona kuzophazamisa umkhiqizo wokugcina.Igesi iqale ikhuhle ukuze kukhishwe noma iyiphi i-hydrochloric acid bese igaywa ukuze ihlukanise okunye ukungcola.

I-Polymerization ye-TFE:

I-Tetrafluoroethylene emsulwa engavinjelwe ingakhula ibe yi-polymerise ngodlame, ngisho emazingeni okushisa angaphansi kwalawo egumbi lokushisa.Ireactor egcwele isiliva, egcwele ikota ngesixazululo esihlanganisa izingxenye ezingu-0.2 ze-ammonium persulphate, izingxenye ezingu-1.5 zeborax nezingxenye ezingu-100 zamanzi, kanye ne-pH engu-9.2.I-reactor ivaliwe;kwakhishwa futhi izingxenye ezingu-30 ze-monomer zavunyelwa. I-reactor yanyakaza ihora elilodwa ku-80°C futhi ngemva kokupholisa yanikeza isivuno esingu-86% se-polymer.PTFE yenziwa ukuthengisa ngezinqubo ezimbili ezinkulu, eyodwa eholela kulokho okubizwa ngokuthi 'i-granular' i-polymer futhi eyesibili iholela ekuhlakazweni kwe-polymer enosayizi wezinhlayiyana ocoleke kakhulu kanye nesisindo samangqamuzana esiphansi.Enye indlela yokukhiqiza yakamuva ihilela ukusetshenziswa kwesisombululo se-aqueous disuccinic acid peroxide engu-0.1°%.Ukusabela kwenziwa ekushiseni okufika ku-90°C.

Enye Izindlela:

Ukubola kwe-TFE ngaphansi kwethonya le-arc kagesi.I-Polymerisation eyenziwa ngendlela ye-emulsion isebenzisa ama-peroxide initiatores isb i-H2O2 (i-Hydrogen peroxide) kanye ne-ferrous sulphate.Kwezinye izimo, i-oxygen isetshenziswa njengesiqalo.

Isakhiwo kanye Nezakhiwo ze-PTFE:

Isakhiwo samakhemikhali se-PTFE siyi-polymer eqondile ye-C– F2 – C– F2 ngaphandle kwanoma yiliphi igatsha futhi izici ezivelele ze-PTFE zihlotshaniswa ne-Carbon eqinile nezinzile – ibhondi ye-Fluorine.

I-Polytetrafluoroethylene iyi-polymer eqondile engenalo inani elibalulekile le-branching.Nakuba i-molecule ye-polyethylene isesimweni sokumazombe okuplana endaweni eyikristale lokhu akunakwenzeka neze ngaleyo ye-PTFE ngenxa yokuthi ama-athomu e-fluorine makhudlwana kunalawo e-hydrogen.Njengomphumela i-molecule ithatha i-zigzag esontekile nama-athomu e-fluorine apakisha aqine azungeza uhlaka lwamathambo e-carbon-carbon.Ukuphenduka okuphelele kwe-spiral kuzobandakanya ngaphezu kwama-athomu ekhabhoni angama-26 ngaphansi kuka-19°C kanye no-30°C ngaphezu kwawo kube khona indawo yokuguquka ehilela ukuguqulwa kwevolumu engu-1% kuleli zinga lokushisa.Ukuhlangana okuhlangene kwama-athomu e-fluorine kuholela ku-molecule yokuqina okukhulu futhi yilesi sici esiholela endaweni ephakeme yokuncibilika kwekristale kanye nokuzinza kwefomu elishisayo le-polymer.

Ukukhangana kwama-intermolecular phakathi kwama-molecule e-PTFE kuncane kakhulu, ipharamitha yokunyibilika ekhompuyutha ingu-12.6 (MJ/m3)1/2I-polymer ngobuningi ayinakho ukuqina okuphakeme namandla aqinile avame ukuhlotshaniswa nama-polymers anephuzu eliphezulu lokuthambisa.Ibhondi ye-carbon-fluorine izinzile kakhulu.Ngaphezu kwalokho, lapho ama-athomu amabili e-fluorine enamathiselwe ku-athomu yekhabhoni eyodwa kuba nokuncipha kwebanga lebhondi ye-C–F ukusuka ku-1.42 A ukuya ku-1.35 A. Ngenxa yalokho amandla ebhondi angase abe phezulu aze afike ku-504 kJ/imvukuzane.Njengoba okuwukuphela kwebhondi ekhona kuyibhondi ezinzile ye-C–C, i-PTFE inokusimama kokushisa okuphezulu kakhulu, ngisho noma ishisiswe ngaphezu kwendawo yayo yokuncibilika eyikristale engu-327°C.Ngenxa yokucwebezela kwayo okuphezulu nokungakwazi ukusebenzisana okuthile, azikho izincibilikisi ekamelweni lokushisa.Emazingeni okushisa asondela endaweni yokuncibilika uketshezi oluthile oluyi-fluorinated njengophalafini onefluorinated per-fluorinated per-fluorinated the polymer.

Izakhiwo ze-PTFE zincike ohlotsheni lwe-polymer kanye nendlela yokucubungula.I-polymer ingase yehluke ngosayizi wezinhlayiyana kanye/noma isisindo samangqamuzana.Usayizi wezinhlayiyana uzothonya icala lokucutshungulwa kanye nenani le-voids emkhiqizweni oqediwe kuyilapho isisindo samangqamuzana sizoba nomthelela ekukhanyeni kwekristalu futhi ngenxa yalokho izici eziningi ezibonakalayo.Amasu okucubungula azophinde athinte kokubili ubucwebe nokuqukethwe okuyize.

Isilinganiso sesisindo samangqamuzana esisindo sama-polymers entengiso sibonakala siphezulu kakhulu futhi sisebangeni elingu-400000 kuya ku-9000000. I-ICI ibika ukuthi izinto zabo ezisetshenziswayo zinesisindo samangqamuzana kububanzi obungu-500000 kuya ku-5000000 kanye nephesenti lobukristalu obukhulu kuno-94~ njengoba kukhiqizwa.Izingxenye ezakhiwe zine-crystalline encane.Izinga le-crystallinity lomkhiqizo oqediwe lizoncika kuzinga lokupholisa kusuka emazingeni okushisa okucubungula.Ukupholisa kancane kuzoholela ekucwebezeleni okuphezulu nokupholisa okusheshayo okunikeza umphumela ophambene.Izinto eziphansi zesisindo samangqamuzana nazo zizoba yikristalu eyengeziwe.

Kuyaqashelwa ukuthi i-polymer yokuhlakazeka, enosayizi wezinhlayiyana ezicolekile kanye nesisindo esiphansi samangqamuzana, inikeza imikhiqizo ekwazi ukumelana nokuguquguquka kanye namandla aqine ngokugqamile.Lokhu kuthuthukiswa kubonakala kuvela ngokwakhiwa kwezakhiwo ezinjenge-fiber kusisindo se-polymer ngesikhathi sokucubungula.