Isintu sisebenzise izinto zemvelo ze-polymeric njengokhuni, isikhumba noboya kusukela ekuqaleni komlando, kodwa okokwenziwa.ama-polymerskwenzeka kuphela ngemva kokuthuthukiswa kobuchwepheshe benjoloba ngawo-1800.I-Ž yokuqala yokwenziwa kwe-polymer material, i-celluloid, yasungulwa nguJohn Wesley Hyatt ngo-1869, isuka ku-cellulose nitrate kanye ne-camphor.Impumelelo enkulu kuma-polymer okwenziwa kwakuwukusungulwa kwe-Bakelite ngu-Leo Hendrik Baekeland ngo-1907. Umsebenzi ka-Hermann Staudinger ngawo-1920 wabonisa ngokusobala imvelo yama-macromolecular yamaketango amade amayunithi aphindaphindayo.1 Igama elithi 'polymer' livela kwelesiGrikhi, futhi lisho 'okuningi. izingxenye'.Ukukhula okusheshayo kwemboni ye-polymer kwaqala ngaphambi nje kweMpi Yezwe Yesibili, ngokuthuthukiswa kwama-polymers e-acrylic, i-polystyrene, inayiloni, i-polyurethanes kanye nokwethulwa okulandelayo kwe-polyethylene, i-polyethylene terephthalate, i-polypropylene namanye ama-polymers ngawo-1940 kanye nawo-1950.Nakuba kuphela amathani ayizigidi ezingu-1 akhiqizwa ngo-1945, ukukhiqizwa kwamapulasitiki ngevolumu kudlula okwensimbi ngo-1981, futhi igebe belilokhu likhula ngokuqhubekayo kusukela ngaleso sikhathi.
I-Thermoplastics ivame ukucutshungulwa esimweni esincibilikisiwe.Ama-polymer ancibilikisiwe anamanani aphezulu kakhulu e-viscosity futhi abonisa ukuziphatha kokugunda kwe-shear.Njengoba izinga lokugunda likhuphuka, i-viscosity iyancipha, ngenxa yokuqondanisa nokuhlukana kwamaketanga amade wamangqamuzana.I-viscosity nayo iyancipha ngokukhuphuka kwezinga lokushisa.Ngaphezu kokuziphatha kwe-viscous, ama-polymer ancibilikile abonisa ukunwebeka.I-Elasticity inesibopho sezinto eziningi ezingavamile ze-rheological.1 ,5 - 7 Lokhu kufaka phakathi ukuphumula kokucindezeleka kanye nokuhluka kokucindezeleka okujwayelekile.Ukuphumula kancane kwengcindezi kubophezele ekucindezelekeni okufriziwe emikhiqizweni ekhiqizwe ngomjovo kanye ne-extruded.Umehluko ojwayelekile wengcindezi ubangela ukuntengantenga okuthile ngesikhathi sokucutshungulwa kanye nokuvuvuka kwe-extrudate, okungukuthi ukwanda kwe-signiŽ cant endaweni ephambanayo lapho into encibilikisiwe ikhishwa endaweni yokufa.
Imisebenzi ebaluleke kakhulu yokucubungula i-polymer i-extrusion kanye nokubunjwa komjovo.I-Extrusion inamandla kakhulu futhi ukubumba umjovo kuwumsebenzi omningi.Zombili lezi zinqubo zihlanganisa ukulandelana kwezinyathelo ezilandelayo: (a) ukushisisa nokuncibilikisa i-polymer, (b) ukupompa i-polymer kuyunithi yokubunjwa, (c) ukwenza incibiliki ibe yisimo nobukhulu obudingekayo kanye (d) nokupholisa kanye nokuqina .Ezinye izindlela zokucubungula zifaka i-calendering, i-blow molding, i-thermoforming, i-compression molding kanye nokubumba okujikelezayo.Kunamabanga angaphezu kuka-30 000 ama-polymer acutshungulwa yilezi zindlela.Ukufaneleka kwempahla yenqubo ethile kuvame ukunqunywa ngesisekelo senkomba ye- melt ow (MFI, ebizwa nangokuthi i- melt ow rate noma i-MFR).Lesi isilinganiso esiphambene se-viscosity esisekelwe ekuhlolweni okungenangqondo okuhilela ukukhishwa kwe-polymer ngokusebenzisa i-die of dimensions ejwayelekile ngaphansi kwesenzo sesisindo esinqunyiwe.8 I-MFI inombolo yamagremu e-polymer eqoqwe emshinini wokuhlola ngo-10 imiz.Amanani aphansi e-MFI asho i-viscosity ephezulu nesisindo samangqamuzana aphezulu, futhi amanani aphezulu e-MFI abonisa okuphambene.Okulandelayo ububanzi be-MFI obuvamile kwezinye izinqubo: i-extrusion 0 .01 - 10, ukubumba komjovo 1 - 100, ukubunjwa kwe-blow 0 .01 - 1, ukubumba okujikelezayo 1.5 - 20.
.
Isikhathi sokuthumela: Jan-14-2018