PTFE Isakhiwo Property Ubudlelwano

Indlela yokuqonda umthelela we-fluorine ukuhlola umehluko phakathi kwe-linear polyethylene (PE) ne-PTFE okuyi-fluoropolymer yokugcina ngokwezakhiwo nezici.

Kunomehluko obalulekile phakathi kwezakhiwo ze-PE kanye nalezo ze-PTFE:

• * I-PTFE ingenye yama-polymers wamandla aphansi kakhulu
• *I-PTFE i-polymer emelana kakhulu namakhemikhali
• *I-PTFE ingenye yama-polymer azinze kakhulu ngokushisa
• *Iphuzu elincibilikayo kanye namandla athile adonsela phansi e-PTFE angaphezulu kokuphindwe kabili lawo e-polyethylene

Umehluko we-PTFE kanye ne-PE kungenxa yomehluko we-CeF ne-CeH bond.Umehluko wezakhiwo zika-elekthronikhi nosayizi we-F no-H uholela ekuqapheliseni okulandelayo:

• *U-F unamandla kakhulu kuzo zonke izakhi (4 Paulings)
• *F inamapheya ama-electron angabelwe
• *F iguqulelwa kalula ku-Fe
• *Amandla ebhondi e-CeF aphezulu kune-CeH
• *U-F mkhulu kuno-H

I-electronegativity yekhabhoni ku-2.5 Paulings iphakeme kancane kunaleyo ye-hydrogen futhi iphansi kune-electronegativity ye-fluorine.Ngenxa yalokho, i-polarity yebhondi ye-CeF iphambene naleyo yebhondi ye-CeH, futhi ibhondi ye-CeF ihlukaniswa kakhulu.Kubhondi ye-CeF, isiphetho se-fluorine sebhondi sikhokhiswa kabi uma kuqhathaniswa nebhondi ye-CeH lapho ikhabhoni ishajwa khona kabi.

Umehluko ku-polarity yebhondi ye-CeH ne-CeF ithinta ukuzinza okuhlobene kokuvumelana kwamaketango amabili e-polymer.I-Crystallization ye-polyethylene yenzeka ku-planar kanye ne-trans conformation.I-PTFE ingaphoqelelwa ibe yi-conformation enjalo ngengcindezi ephezulu kakhulu.I-PTFE, engaphansi kuka-19 C, icwebezela njenge-helix ene-0.169 nm ngebanga eliphindayo: kuthatha ama-athomu angu-13 C ukuze ukujika okungu-180 kuqedwe.Ngaphezulu kuka-19 C, ibanga eliphindayo liyakhuphuka libe ngu-0.195 nm okusho ukuthi kudingeka ama-athomu ekhabhoni angu-15 ukuze ujike u-180.Ngaphezulu kuka-19 C amaketango ayakwazi ukugudluzwa yi-angular, ekhuphuka ngaphezu kuka-30 C aze afinyelele endaweni yokuncibilika (327 C).

Ukufakwa esikhundleni kuka-F esikhundleni sika-H kubhondi ye-CeH kukhulisa kakhulu amandla ebhondi ukusuka ku-99.5 kcal/imvukuzane kubhondi ye-CeH ukuya ku-116 kcal/imvukuzane kubhondi ye-CeF.Ngenxa yalokho, ukuzinza okushisayo kanye nokumelana namakhemikhali kwe-PTFE kuphakeme kune-PE ngoba kudingeka amandla engeziwe ukuze kunqamuke ibhondi ye-CeF.I-polarity namandla ebhondi ye-CeF kunikeza indlela yokukhipha i-athomu engu-F ukuze kube nzima ukuhlanganisa.Ngokuphambene, i-polyethylene enamagatsha amaningi (>amagatsha angu-8 kuma-athomu ekhabhoni ayi-100) ingahlanganiswa.Indlela yegatsha njengethuluzi lokulungisa ubucwebe ayisebenzi ku-PTFE.Esikhundleni salokho ama-comonomer anamaqembu e-pendent kufanele enziwe i-polymerized nge-TFE.

I-Crystallinity ye-PTFE engakaze incibilike ikububanzi obungu-92e98%, ihambisana nesakhiwo seketango elingamagatsha.I-FEP, i-copolymer ye-TFE ne-HFP, ine-crystallinity e-polymerized engu-40e50%.Ku-FEP, iqembu elilengayo le-CF3 liboshelwe kukhabhoni ephakeme engaqinile ngokushisa okuphansi kunama-athomu ekhabhoni ayisisekelo nawesibili.Amajika okuwohloka abonisa izinga lokushisa lokuqala lokuwohloka lika-300 C ku-FEP (0.02% ukuncipha kwesisindo) kanye no-425 C ku-PTFE (0.03% ukuncipha kwesisindo).