I-Polytetrafluoroethylene iyi-fluoropolymer yokwenziwa ye-tetrafluoroethylene enezinhlelo eziningi zokusebenza.Igama lomkhiqizo elaziwa kakhulu lamafomula asuselwa ku-PTFE yi-polymer by Chemours.Iphoyinti elincibilikayo: 620.3°F (326.8°C);Ifomula: (C2F4)n;Ukuminyana: 2.2 g/cm³;I-IUPAC ID: poly(1,1,2,2-tetrafluoroethylene).
I-PTFE ikhiqizwa ngendlela ye-free-radical polymerization kumidiya enamanzi ngokuhlanganisa i-polymerization ye-TFE kwinqubo yenqwaba.Umqalisi we-polymerization ngokuvamile i-peroxide encibilikayo emanzini njenge-ammonium persulfate noma i-disuccinic peroxide.I-redox catalyst isetshenziselwa ukushisa okuphansi kwe-polymerization.I-PTFE ikhiqizwa yi-suspension (noma i-slurry) i-polymerization ngaphandle kwe-surfactant ukuze kutholwe izinhlaka ze-granular noma nge-perfluorinated surfactant (emulsion polymerization) njenge-ammonium perfluorooctanoate ukuze kukhiqizwe impushana ecolekileyo kanye nemikhiqizo yokuhlakazwa.Izinga lokushisa le-polymerization nokucindezela kuvame ukusuka ku-0 kuye ku-100 C kanye no-0.7 kuya ku-3.5 MPa.
I-PTFE eyi-Granular ikhiqizwa nge-polymerizing TFE iyodwa noma ngokusebenzisa amanani okulandelela ama-comonomers.Isiqalisi se-peroxide, i-surfactant encane noma engekho, nezinye izithasiselo zingase zibe khona endaweni ye-aqueous polymerization enyakaziswa ngamandla futhi ngezinye izikhathi ivinjwe ingxube ye-alkali.Iningi le-polymer lakhiwa esigabeni segesi ngesimo sezinhlayiya ezinezintambo nezingajwayelekile.Izinhlayiya zihanjiswa ngobukhulu obuhlukahlukene, kuye ngokuthi izakhiwo zempushana ezidingekayo ngenqubo yokukhiqiza.Isibonelo, ingxenye engaphezulu eshelelayo idinga usayizi wezinhlayiyana ezincane kuyilapho ukugeleza okuhle kuthuthukiswa usayizi wezinhlayiyana ezinkulu.
I-Fine powder PTFE ikhiqizwa yi-polymerization ye-TFE endaweni enamanzi phambi komqalisi kanye ne-surfactant.I-polymerization ayilandeli indlela evamile ye-emulsion kodwa ezinye zezimiso, ezisebenzayo.Ukuzinza kokuhlakazeka ngesikhathi se-polymerization, ukugwema ukuhlangana ngaphambi kwesikhathi, kulinganisa nesidingo sokuphula i-emulsion ukuze kubuyiselwe i-PTFE.Ukuyaluza kwesilinganiso esiphansi se-shear kugcinwa ngesikhathi se-polymerization kusetshenziswa amaleveli e-surfactant angaphansi kwezinga elibalulekile le-micelle.Izinga le-polymerization kanye nokuma kwezinhlayiyana nosayizi kuthinteka ekugxilweni kwe-surfactant.Iningi lezinhlayiya likhiqizwa engxenyeni yokuqala ye-polymerization futhi liyakhula njengoba umjikelezo uqhubeka.Isisindo samangqamuzana nokwakheka ngaphakathi kwezinhlayiyana zingalawulwa kusetshenziswa izithako nezimo ze-polymerization.
Inqubo efanayo ye-polymerization yenza ama-aqueous dispersions we-PTFE njengempushane ecolekile.Ukuhlakazwa kugxilile futhi kuzinziswe kusetshenziswa izinhlobonhlobo ze-ionic ne-nonionic surfactants.Izindlela zokugxilisa ezimbalwa ziye zabikwa ezihlanganisa i-electrodecantation, ukuhwamuka, kanye nokuhlushwa kwe-thermal.Izithasiselo zamakhemikhali ezizozifanisa nenqubo yokwenziwa noma ingxenye yezidingo zesakhiwo zingashintsha ukuhlakazwa kokugcina kwe-PTFE.
Ama-compounds agcwalisiwe akhiqizwa kuzo zontathu izinhlobo ze-PTFE kusetshenziswa izigcwalisi ezifana ne-glass fibre, graphite, metal powder, carbon fibre, nokunye.
Isikhathi sokuthumela: Sep-24-2018