Eyokuqala kukuba indawo yayo yokunyibilika imalunga ne-327 degrees Celsius, ephezulu kakhulu kune-PE (~ 130) kunye ne-PVDF (~ 177) enezakhiwo ezifanayo. Into ephambili emisela indawo yokunyibilika ngamandla phakathi kwekhonkco kunye ne-molecule ye-chain. , nangona i-fluorine ine-electronegativity ephezulu, kodwa ukusuka kwisakhiwo sekhemikhali ye-PTFE, i-dipole moments iyacinywa enye kwenye, ngoko yinto engeyiyo i-polar kwaye ayivelisi amandla okuqhelanisa okucacileyo, oku kuthetha ukuba amandla okusasazwa yimpembelelo ephambili , kunengqiqo ukutsho ukuba indawo yokunyibilika ye-PTFE akufanele ibe phezulu kakhulu kune-PE, kodwa i-electron ephezulu yoxinaniso lwe-fluorine yenza ezi athom ze-fluorine zicwangciswe ngokusondeleyo zibe nefuthe eliphikisanayo kunye ne-steric hindrance effect, ukwenzela ukuba i-molecular chain conformation. ibonisa isakhiwo se-spirochete, kunokuba ipateni ye-zigzag ecaba eqhelekileyo kwiipolymers ezigcweleyo, eziququzelela ukupakishwa ngokufanelekileyo kwamatyathanga eemolekyuli ukwenza iikristale, kunye nokuncipha komgama wokwahlula phakathi kwamatyathanga apakishweyo kwandisa amandla e-intermolecular kwaye ngaloo ndlela kwandisa indawo yokunyibilika. .
Okwesibini kukuzinza kwe-PTFE kwiqondo lokushisa eliphezulu. Kwiipolymers, esinye sezizathu eziphambili zokuthotywa kokusebenza kunye netyhefu kukuchithwa kweebhondi kwiimolekyuli ezincinci. Ekubeni iibhondi ze-CF zizinzile kakhulu, iibhondi zeCC kwisigaba sekhonkco eliphambili Xa sithetha, sithande ukuphuka, kodwa ngenxa yobukho be-CF, ivelisa umphumo we-hyperconjugation kwi-CC yayo ekufutshane (i-orbital anti-bonding of I-CF kunye ne-bonding orbital interaction ye-CC), ekwaphucula ukuxhathisa kwekhonkco eliphambili kubushushu obuphezulu / ukukhanya. Kwangaxeshanye, i-hyperconjugation effect izisa amandla asezantsi e-ortho position (gauche) kune-anti position (anti), ekwachaza ukuba kutheni nangona kukho i-electrostatic repulsion phakathi kwefluorines, basachatshazelwa ngamandla anokubakho. Uncedo lweeathom zefluorine zilungelelaniswe ukuze iiathom zefluorine zilungelelaniswe ngokusondeleyo kakhulu kwi-PTFE.
Ezo athom zefluorine zicwangciswe ngokusondeleyo zinesakhiwo esipheleleyo se-octahedral, ngoko ke azibaniki kakuhle i-electron okanye abamkeli be-electron. Basonga ngokuqinileyo ikhonkco eliphambili elithe tye phakathi, njengokwenza ifilimu ekhuselayo. Ukumelana nokuhlaselwa kweekhemikhali, ukunika i-PTFE ukuxhathisa imichiza ebalaseleyo. Esinye isiphumo solungiselelo oluqinileyo ngamandla aphantsi komhlaba, ukuze i-PTFE ingabinamtsalane kakhulu kwiimolekyuli zangaphandle, yiyo loo nto ingancangathi.
Ixesha lokuposa: Aug-29-2022