Ukuthelekiswa kwe-LLDPE kunye ne-LDPE.

I-linear low density polyethylene, ngolwakhiwo olwahlukileyo kwi-polyethylene yoxinaniso oluphantsi ngokubanzi, kuba akukho masebe omxokelelwane omde. Uluhlu lwe-LLDPE luxhomekeke kwiimveliso ezahlukeneyo kunye neenkqubo zokusetyenzwa kwe-LLDPE kunye ne-LDPE. I-LLDPE idla ngokusekwa yi-copolymerization ye-ethylene kunye ne-alpha olefins ephezulu efana ne-butene, i-hexene okanye i-octene kwiqondo lokushisa eliphantsi kunye noxinzelelo. I-polymer ye-LLDPE eveliswa yinkqubo ye-copolymerization inokusabalalisa ubunzima be-molecular kune-LDPE jikelele, kwaye kwangaxeshanye inesakhiwo somgca esenza ukuba ibe neempawu ezahlukeneyo ze-rheological.

ukunyibilika iipropati zokuhamba

Iimpawu zokunyibilika kwe-LLDPE zilungelelaniswe kwiimfuno zenkqubo entsha, ngakumbi inkqubo yefilimu ye-extrusion, enokuvelisa iimveliso eziphezulu ze-LLDPE. I-LLDPE isetyenziswa kuzo zonke iimarike zemveli zepolyethylene. Ukolulwa okongeziweyo, ukungena, impembelelo kunye neempawu zokuxhathisa ukukrazula kwenza i-LLDPE ilungele iifilimu. Ukumelana kwayo okugqwesileyo kokuqhekeka koxinzelelo lokusingqongileyo, ukumelana nefuthe eliphantsi lobushushu kunye nokumelana ne-warpage kwenza i-LLDPE ibe nomtsalane kumbhobho, i-extrusion yamaphepha kunye nazo zonke izicelo zokubumba. Usetyenziso lwamva nje lwe-LLDPE lufana nesigcina-kufuma seendawo zokulahla inkunkuma kunye nezaleko zamachibi enkunkuma.

Imveliso kunye neempawu

Imveliso ye-LLDPE iqala ngeenguqu zesinyithi ze-catalysts, ngakumbi i-Ziegler okanye uhlobo lwe-Phillips. Iinkqubo ezintsha ezisekwe kwi-cycloolefin metal derivative catalysts yenye inketho kwimveliso ye-LLDPE. I-polymerization reaction real ingenziwa kwisisombululo kunye ne-gas phase reactors. Ngokuqhelekileyo, i-octene i-copolymerized nge-ethylene kunye ne-butene kwi-reactor yesigaba sesisombululo. I-Hexene kunye ne-ethylene zenziwe nge-polymerized kwi-reactor yesigaba segesi. Intlaka ye-LLDPE eveliswa kwisigaba segesi sereactor ikwimo yesuntswana kwaye inokuthengiswa njengomgubo okanye iphinde igalelwe iipellets. Isizukulwana esitsha se-LLDPE ephezulu esekwe kwi-hexene kunye ne-octene siphuhliswe yi-Mobile, i-Union Carbide. Iinkampani ezinjengeNovacor kunye neDow Plastics ziqalisiwe. Ezi zixhobo zinomlinganiselo omkhulu wokuqina kwaye zinamandla amatsha kwizicelo zokususa ingxowa ngokuzenzekelayo. Uxinzelelo oluphantsi kakhulu lwe-PE resin (ubuninzi obungaphantsi kwe-0.910g/cc.) luye lwavela kwiminyaka yakutshanje. I-VLDPES inokuguquguquka kunye nokuthamba i-LLDPE engenako ukuyifumana. Iimpawu ze-resin zibonakaliswa ngokubanzi kwisalathisi sokunyibilika kunye nobuninzi. Isalathiso sokunyibilika sibonisa i-avareji yobunzima bemolekyuli ye-resin kwaye ilawulwa ngokuyintloko ngubushushu bokusabela. I-avareji yobunzima bemolekyuli izimeleyo kwi-molecular weight distribution (MWD). Ukhetho lwe-Catalyst luchaphazela i-MWD. Uxinaniso luchongwa ngokugxininiswa kwe-comonomer kwikhonkco le-polyethylene. I-comonomer concentration ilawula inani lamasebe amakhonkco amafutshane (ubude obuxhomekeke kuhlobo lwe-comonomer) kwaye ngaloo ndlela ilawula ukuxinana kwe-resin. Okukhona iphezulu icomonomer concentration, kokukhona isezantsi ingxinano yeresin. Ngokwesakhiwo, i-LLDPE yahlukile kwi-LDPE kwinani kunye nodidi lwamasebe, i-LDPE yoxinzelelo oluphezulu inamasebe amade, ngelixa i-LDPE emgca inamasebe amafutshane kuphela.

ukuqhubekeka

Zombini i-LDPE kunye ne-LLDPE zine-rheology egqwesileyo okanye ukuhamba okunyibilikayo. I-LLDPE inovakalelo oluncinci lokucheba ngenxa yokusabalalisa ubunzima bemolekyuli kunye namasebe amakhonkco amafutshane. Ngexesha lokucheba (umz. i-extrusion), i-LLDPE igcina i-viscosity enkulu kwaye ke ngoko kunzima kakhulu ukusetyenzwa kune-LDPE enesalathiso sokunyibilika okufanayo. Kwi-extrusion, uvakalelo olusezantsi lokucheba lwe-LLDPE luvumela ukukhululeka koxinzelelo olukhawulezileyo lwamakhonkco eemolekyuli ze-polymer, kwaye ke ngoko kuncitshiswa kobuthathaka bepropathi yomzimba kutshintsho kumlinganiselo wokuvuthela. Kulwandiso lwenyibilika, i-LLDPE iyahluka phantsi kweentlobo ezahlukeneyo Ngokuqhelekileyo zine-viscosity esezantsi ngesantya. Oko kukuthi, ayizukuba nzima xa isoluliwe njenge-LDPE. Ukwandisa ngesantya sokuguqulwa kwe-polyethylene. I-LDPE ibonisa ukunyuka okumangalisayo kwe-viscosity, okubangelwa ukuxhamla kwamaketanga e-molecular. Lo mcimbi awujongwa kwi-LLDPE ngenxa yokuba ukunqongophala kwamasebe omxokelelwane omde kwi-LLDPE kugcina i-polymer ikhululekile ekubopheni. Le propati ibaluleke kakhulu kwizicelo zefilimu ezincinci. Kuba iifilimu ze-LLDPE zinokwenza ngokulula iifilimu ezincinci ngelixa zigcina amandla aphezulu kunye nokuqina. Iimpawu ze-rheological ze-LLDPE zinokushwankathelwa njenge "rigid in shear" kwaye "ithambile ekwandisweni".