Uluntu lusebenzise imathiriyeli yendalo yepolymeric enje ngamaplanga, ufele kunye noboya ukusukela ekuqaleni kwembali, kodwa i-synthetic.iipholimayaba yinto enokwenzeka kuphela emva kokuphuhliswa kobugcisa berabha kwi-1800s.Isixhobo sokuqala sokwenziwa kwepolymer, icelluloid, yaqanjwa nguJohn Wesley Hyatt ngo-1869, ukusuka kwi-cellulose nitrate kunye necamphor.Impumelelo enkulu kwiipholima zokwenziwa kukuveliswa kwe-Bakelite ngu-Leo Hendrik Baekeland ngo-1907. Umsebenzi ka-Hermann Staudinger ngeminyaka yoo-1920 wawubonisa ngokucacileyo ubume be-macromolecular yamatyathanga amade aphinda-phinda iiyunithi.1 Igama elithi 'polymer' lisuka kwisiGrike, kwaye lithetha 'ezininzi. iinxalenye'.Ukukhula ngokukhawuleza kweshishini lepolymer kwaqala kungekudala ngaphambi kweMfazwe yeSibini yeHlabathi, ngophuhliso lweepolima ze-acrylic, i-polystyrene, inayiloni, i-polyurethanes kunye nokuqaliswa okulandelayo kwe-polyethylene, i-polyethylene terephthalate, i-polypropylene kunye nezinye iipholima kwi-1940 kunye ne-1950s.Ngelixa kuphela iitoni ezimalunga nesigidi esi-1 zaveliswa ngo-1945, ukuveliswa kweeplastiki ngomthamo kwadlula ezo zentsimbi ngo-1981, kwaye umsantsa ukhula ngokuqhubekayo ukususela ngoko.
I-Thermoplastics idla ngokuqhutyelwa kwimeko etyhidiweyo.Iipholima ezinyibilikisiweyo zinexabiso eliphezulu kakhulu le-viscosity kwaye zibonisa indlela yokuziphatha yokucheba.Njengoko isantya sokucheba sikhula, i-viscosity iyancipha, ngenxa yokulungelelaniswa kunye nokuchithwa kwamatyathanga amade eemolekyuli.I-viscosity nayo iyancipha ngokunyuka kweqondo lokushisa.Ukongeza kwindlela yokuziphatha ye-viscous, iipholima ezityhidiweyo zibonisa ukunwebeka.I-Elasticity ijongene nenani lezinto ezingaqhelekanga ze-rheological.Ukuphumla koxinzelelo olucothayo kunoxanduva lokukhenkceza kuxinzelelo lwenaliti exonxiweyo kunye neemveliso ezikhutshiweyo.Umahluko oqhelekileyo woxinzelelo unoxanduva lokungazinzi ngexesha lokusetyenzwa kunye nokudumba okungaphezulu, okt ukwanda kwesigniŽ cant kwindawo enqamlezileyo xa into etyhidiweyo ikhutshelwa ngaphandle kwefa.
Eyona misebenzi ibalulekileyo yokusetyenzwa kwepolymer yi-extrusion kunye nenaliti yokubumba.I-extrusion yinto enzima kwaye ukubunjwa kwesitofu kufuna umsebenzi onzima.Zombini ezi nkqubo zibandakanya olu landelelwano lwamanyathelo alandelayo: (a) ukufudumeza nokunyibilikisa ipholima, (b) ukumpompa ipholima kwiyunithi yokubunjwa, (c) ukwenza inyibilika ibe kwimilo efunekayo kunye nemilinganiselo kunye (d) nokupholisa kunye nokuqiniswa kwe-polymer. .Ezinye iindlela zokusetyenzwa zibandakanya ukubunjwa kwekhalenda, ukubumba ukuvuthela, i-thermoforming, ukubunjwa koxinzelelo kunye nokubumba okujikelezayo.Kukho ngaphezu kwama-30 000 amabakala eepholima ezicutshungulwa ngezi ndlela.Ukufaneleka kwezinto zenkqubo ethile ngokuqhelekileyo kugqitywa ngesiseko se-melt ow index (i-MFI, ebizwa ngokuba yi- melt ow rate okanye i-MFR).Lo ngumlinganiselo ochaseneyo we-viscosity esekelwe kuvavanyo olungenangqondo olubandakanya ukugqithiswa kwepolymer ngokufa komlinganiselo oqhelekileyo phantsi kwesenzo sobunzima obumiselweyo.8 I-MFI linani leegram zepolymer eziqokelelwe kwi-apparatus yokuvavanya kwi-10. imiz.Amaxabiso e-MFI aphantsi athetha i-viscosity ephezulu kunye nobunzima obuphezulu be-molecular, kunye namaxabiso aphezulu e-MFI abonisa okuchaseneyo.Oku kulandelayo luhlu oluqhelekileyo lwe-MFI kwezinye iinkqubo: i-extrusion 0 .01 - 10, i-injection molding 1 - 100, i-blow molding 0 .01 - 1, i-rotation molding 1.5 - 20.
Ixesha lokuposa: Jan-14-2018