Esokuqala yingoba indawo yayo yokuncibilika icishe ibe ngu-327 degrees Celsius, ephakeme kakhulu kunaleyo ye-PE (~130) ne-PVDF (~177) enezakhiwo ezifanayo. Isici esiyinhloko esinquma indawo yokuncibilika amandla phakathi kweketango nama-molecule eketango. , nakuba i-fluorine ine-electronegativity ephezulu, kodwa kusukela esakhiweni samakhemikhali se-PTFE, izikhathi ze-dipole zikhanseliwe, ngakho-ke iyinto engeyona i-polar futhi ayikhiqizi amandla okuqondisa asobala, okusho ukuthi amandla okuhlakazeka angumphumela oyinhloko , kunengqondo ukusho ukuthi indawo yokuncibilika ye-PTFE akufanele ibe phezulu kakhulu kune-PE, kodwa ukuminyana kwe-electron ephezulu ye-fluorine kwenza lawa ma-athomu e-fluorine ahlelwe eduze abe nomphumela wokuphikisa kanye nomphumela wokuvinjelwa kwe-steric, ukuze i-molecular chain conformation. yethula ukwakheka kwe-spirochete, kunephethini eyisicaba eyisicaba evame kuma-polymer agcwele, esiza ukupakishwa okuphumelelayo kwamaketanga wamangqamuzana ukuze akhe amakristalu, futhi ukuncipha kwebanga lokuhlukanisa phakathi kwamaketanga apakishwe kuphindaphindeka amandla e-intermolecular futhi ngaleyo ndlela kwandisa iphuzu lokuncibilika. .
Okwesibili ukuzinza kwe-PTFE ekushiseni okuphezulu. Kuma-polymers, esinye sezizathu eziyinhloko zokuwohloka kokusebenza kanye nobuthi ukubola kwezibopho zibe ama-molecule amancane. Njengoba amabhondi e-CF ezinzile kakhulu, amabhondi e-CC esigabeni esikhulu seketango Uma sikhuluma, ijwayele ukuphuka, kodwa ngenxa yokuba khona kwe-CF, ikhiqiza umphumela we-hyperconjugation ku-CC yayo eseduze (i-anti-bonding orbital of I-CF kanye nokusebenzisana kwe-orbital okubophayo kwe-CC), okuthuthukisa futhi ukumelana kweketango eliyinhloko kumazinga okushisa/ukukhanya okuphezulu. Ngesikhathi esifanayo, umphumela we-hyperconjugation uletha amandla aphansi we-ortho position (i-gauche) kune-anti position (anti), echaza nokuthi kungani nakuba kukhona ukuxoshwa kwe-electrostatic phakathi kwama-fluorines, basathinteka amandla angaba khona. Izinzuzo zama-athomu e-fluorine zi-offset ukuze ama-athomu e-fluorine ahlelwe eduze kakhulu ku-PTFE.
Lawo ma-athomu e-fluorine ahlelwe ngokuseduze anesakhiwo se-octahedral esiphelele, ngakho akuwona abanikeli bama-electron abahle noma abamukeli be-electron. Basonga iketango eliyinhloko elintekenteke phakathi nendawo, njengokwenza ifilimu evikelayo. Imelana nokuhlaselwa kwamakhemikhali, inika i-PTFE ukumelana namakhemikhali okuhle kakhulu. Omunye umphumela wohlelo oluqinile amandla angaphezulu aphansi, ukuze i-PTFE ingakhangi kakhulu kuma-molecule angaphandle, yingakho inganamatheli.
Isikhathi sokuthumela: Aug-29-2022