Ukuqhathaniswa kwe-LLDPE ne-LDPE.

I-linear low density polyethylene, ngokwesakhiwo ehlukile kune-polyethylene evamile ephansi, ngoba awekho amagatsha amaketango amade. Ukulandelana kwe-LLDPE kuncike ezinqubweni ezihlukene zokukhiqiza nokucubungula ze-LLDPE ne-LDPE. I-LLDPE ivame ukwakhiwa yi-copolymerization ye-ethylene kanye ne-alpha olefin ephakeme njenge-butene, i-hexene noma i-octene ekushiseni okuphansi nokucindezela. I-polymer ye-LLDPE ekhiqizwa inqubo ye-copolymerization inokusabalalisa kwesisindo samangqamuzana emincane kune-LDPE evamile, futhi ngesikhathi esifanayo inokwakheka komugqa okwenza ibe nezakhiwo ezahlukene ze-rheological.

ncibilikisa izakhiwo zokugeleza

Izici zokuncibilika kokuncibilika kwe-LLDPE zijwayelana nezidingo zenqubo entsha, ikakhulukazi inqubo ye-extrusion yefilimu, engakhiqiza imikhiqizo yekhwalithi ephezulu ye-LLDPE. I-LLDPE isetshenziswa kuzo zonke izimakethe zendabuko ze-polyethylene. Ukunwebeka okuthuthukisiwe, ukungena, umthelela kanye nezakhiwo zokumelana nezinyembezi zenza i-LLDPE ifanele amafilimu. Ukumelana kwayo okuhle kakhulu nokuqhekeka kokucindezeleka kwemvelo, ukumelana nomthelela wokushisa okuphansi kanye nokumelana ne-warpage kwenza i-LLDPE ikhange ipayipi, i-extrusion yeshidi kanye nazo zonke izinhlelo zokusebenza zokubumba. Ukusetshenziswa kwakamuva kwe-LLDPE kufana nemboza yezindawo zokulahla imfucumfucu kanye nezindonga zamachibi emfucuza.

Ukukhiqiza kanye Nezici

Ukukhiqizwa kwe-LLDPE kuqala ngama-transition metal catalysts, ikakhulukazi ohlobo lwe-Ziegler noma i-Phillips. Izinqubo ezintsha ezisuselwe ku-cycloolefin metal derivative catalysts zingenye inketho yokukhiqizwa kwe-LLDPE. Ukusabela kwe-polymerization kwangempela kungenziwa kusixazululo kanye ne-gas phase reactors.Ngokujwayelekile, i-octene i-copolymerized nge-ethylene ne-butene ku-reactor yesigaba sesisombululo. I-Hexene ne-ethylene zenziwe nge-polymerized ku-reactor yesigaba segesi. I-resin ye-LLDPE ekhiqizwa kwi-reactor yesigaba segesi isesimweni sezinhlayiya futhi ingathengiswa njengempushana noma iphinde igaywe ibe ngamapellets. Isizukulwane esisha se-super LLDPE esekwe ku-hexene ne-octene sakhiwe yi-Mobile, Union Carbide. Izinkampani ezifana neNovacor neDow Plastics zethulwe. Lezi zinto ezisetshenziswayo zinomkhawulo omkhulu wokuqina futhi zinamandla amasha wezinhlelo zokusebenza zokususa izikhwama ezizenzakalelayo. Ukuminyana okuphansi kakhulu kwe-PE resin (ukuminyana ngaphansi kuka-0.910g/cc.) nakho kuvele eminyakeni yamuva. I-VLDPES inokuvumelana nezimo nokuthamba i-LLDPE engakwazi ukukufeza. Izakhiwo zama-resin ngokuvamile zibonakala kunkomba yokuncibilika kanye nokuminyana. Inkomba yokuncibilika ibonisa isilinganiso sesisindo samangqamuzana e-resin futhi ilawulwa ngokuyinhloko izinga lokushisa lokusabela. Isilinganiso sesisindo samangqamuzana sizimele ekusabalaliseni isisindo se-molecular weight (MWD). Ukukhethwa kwe-Catalyst kuthinta i-MWD. Ukuminyana kunqunywa ukugcwala kwe-comonomer ochungechungeni lwe-polyethylene. I-comonomer concentration ilawula inani lamagatsha eketango elifushane (ubude bawo buncike ohlotsheni lwe-comonomer) futhi ngaleyo ndlela ilawula ukuminyana kwe-resin. Ukuphakama kwe-comonomer concentration, kuyancipha ukuminyana kwe-resin. Ngokwesakhiwo, i-LLDPE yehlukile ku-LDPE ngenombolo kanye nohlobo lwamagatsha, i-LDPE enomfutho ophezulu inamagatsha amade, kuyilapho i-LDPE ewumugqa inamagatsha amafushane kuphela.

ukucubungula

Kokubili i-LDPE ne-LLDPE zine-rheology enhle kakhulu noma ukugeleza okuncibilikayo. I-LLDPE inokuzwela okuncane kwe-shear ngenxa yokusabalalisa kwayo isisindo samangqamuzana amancane namagatsha amaketango amafushane. Ngesikhathi sokugunda (isb. i-extrusion), i-LLDPE igcina i-viscosity enkulu ngakho-ke kunzima kakhulu ukuyicubungula kune-LDPE enenkomba efanayo yokuncibilika. Ku-extrusion, ukuzwela okuphansi kwe-shear kwe-LLDPE kuvumela ukukhululeka kwengcindezi ngokushesha kwamaketanga e-polymer yamangqamuzana, futhi ngaleyo ndlela kube nokuzwela okuncishisiwe kwezakhiwo zomzimba ekushintsheni kwesilinganiso sokuqhuma. Ekwandisweni kwe-ncibilika, i-LLDPE iyahlukahluka ngaphansi kwezinhlobo ezihlukahlukene Ngokuvamile ibe ne-viscosity ephansi ngesivinini. Okusho ukuthi, ngeke iqine uma yeluliwe njenge-LDPE. Khulisa ngezinga lokuguquguquka kwe-polyethylene. I-LDPE ikhombisa ukwanda okumangazayo kwe-viscosity, okubangelwa ukuboshwa kwamaketanga wamangqamuzana. Lesi simo asibonwa ku-LLDPE ngoba ukuntuleka kwamagatsha amaketango amade ku-LLDPE kugcina i-polymer ingabosheki. Lesi sakhiwo sibaluleke kakhulu ekusetshenzisweni kwefilimu emincane. Ngoba amafilimu e-LLDPE angenza kalula amafilimu amancanyana ngenkathi egcina amandla aphezulu kanye nokuqina. Izakhiwo ze-rheological ze-LLDPE zingafingqwa ngokuthi "i-rigid in shear" kanye "nothambile esandisweni".