Igama Lomkhiqizo:i-polyurethane

Isakhiwo samangqamuzana omkhiqizo:

Izakhiwo Zekhemikhali:

I-polyurethanes yaqala ukukhiqizwa futhi yaphenywa nguDkt. Otto Bayer ngo-1937. I-polyurethane iyi-polymer lapho iyunithi ephindaphindayo iqukethe i-urethane moiety. Ama-urethane aphuma kuma-carbamic acid akhona kuphela ngendlela yama-esters awo[15]. Inzuzo enkulu ye-PU ukuthi uchungechunge alukhiwanga kuphela ama-athomu ekhabhoni kodwa kunalokho ama-heteroatom, umoya-mpilo, ikhabhoni ne-nitrogen[4]. Ngezicelo zezimboni, inhlanganisela ye-polyhydroxyl ingasetshenziswa. Ngokufanayo, izinhlanganisela ze-nitrogen ezisebenza nge-poly-functional zingasetshenziswa ekuxhumaneni kwe-amide. Ngokushintsha nokushintshanisa i-polyhydroxyl ne-polyfunctional nitrogen compounds, ama-PU ahlukene angahlanganiswa[15]. Ama-polyester noma ama-polyether resins aqukethe amaqembu e-hydroxyl asetshenziselwa ukukhiqiza i-polyesteror polyether-PU, ngokulandelana[6]. Ukwehluka kwenani lokushintshwa kanye nesikhala phakathi nangaphakathi kwamaketango egatsha kukhiqiza ama-PU asuka kolayini ukuya kwengamagatsha futhi angu-9 avumelanayo kuya kokuqinile. I-Linear PUs isetshenziselwa ukwenza imicu nokubumba[6]. Ama-PU aguquguqukayo asetshenziswa ekukhiqizeni ama-ejenti abophayo kanye nama-coatings[5]. Amapulasitiki anegwebu aguquguqukayo futhi aqinile, akha iningi lama-PU akhiqizwayo, angatholakala ngezindlela ezahlukahlukene embonini[7]. Kusetshenziswa ama-prepolymers aphansi we-molecular mass, kungakhiqizwa ama-block copolymers ahlukahlukene. Iqembu letheminali le-hydroxyl livumela amabhlogo ashintshanayo, abizwa ngokuthi amasegimenti, ukuthi afakwe ochungechungeni lwe-PU. Ukwehluka kulawa masegimenti kuholela kumazinga ahlukahlukene wamandla aqinile nokunwebeka. Amabhulokhi ahlinzeka ngesigaba sekristalu esiqinile futhi aqukethe i-chain extender abizwa ngokuthi amasegimenti aqinile[7]. Lezo ezikhiqiza isigaba se-amorphous rubbery futhi equkethe i-polyester/polyether ibizwa ngokuthi amasegimenti athambile. Ngokwezentengiselwano, lawa ma-polymer block aziwa ngokuthi i-Segmented Pus

Isicelo:

I-polyurethane eguquguqukayo ngokuyinhloko iyisakhiwo esiqondile esine-thermoplasticity, esinokuzinza okungcono, ukumelana namakhemikhali, ukuqina kanye nezakhiwo zemishini kunegwebu le-PVC, elinokuhlukahluka okuncane kokucindezelwa. Inokufakwa kahle kwe-thermal, ukufakwa komsindo, ukumelana nokushaqeka kanye nezakhiwo ezilwa nobuthi. Ngakho-ke, isetshenziswa njengokupakisha, ukwahlukanisa umsindo nezinto zokuhlunga. Ipulasitiki ye-polyurethane eqinile ilula, i-insulation yomsindo, i-thermal insulation ephezulu, ukumelana namakhemikhali, izakhiwo ezinhle zikagesi, ukucubungula kalula, nokumunca amanzi aphansi. Isetshenziswa kakhulu njengezinto zokwakha zokwakha, izimoto, imboni yezokundiza, ukufakwa kokushisa nokushisa okushisayo. Ukusebenza kwe-polyurethane elastomer phakathi kwepulasitiki nerabha, ukumelana nowoyela, ukumelana nokugqoka, ukumelana nokushisa okuphansi, ukumelana nokuguga, ubulukhuni obuphezulu, ukunwebeka. Isetshenziswa kakhulu embonini yezicathulo kanye nemboni yezokwelapha. I-polyurethane nayo ingenziwa ibe yizinto zokunamathisela, okokunamathela, isikhumba sokwenziwa, njll.