Igama lemveliso:i-polyurethane

Ulwakhiwo lwemolekyuli yemveliso:

Iinkcazelo ngeMichiza:

I-polyurethanes yaveliswa okokuqala kwaye yaphandwa nguDkt. Otto Bayer ngo-1937. I-polyurethane yipolymer apho iyunithi ephindaphindiweyo iqulethe i-urethane moiety.IiUrethanes ziphuma kwi-carbamic acids ekhoyo kuphela ngohlobo lwee-esters zazo[15].Inzuzo enkulu ye-PU kukuba ikhonkco aliqulunqwanga kuphela iiathom zekhabhoni kodwa kune-heteroatoms, i-oksijini, i-carbon kunye ne-nitrogen[4].Kwizicelo zamashishini, i-polyhydroxyl ikhompawundi ingasetyenziswa.Ngokufanayo, iikhompawundi zenitrogen ezisebenza ngemininzi zinokusetyenziswa kumakhonkco e-amide.Ngokutshintsha kunye nokutshintsha i-polyhydroxyl kunye ne-polyfunctional nitrogen compounds, ii-PU ezahlukeneyo zingenziwa [15].I-polyester okanye i-polyether resins equkethe amaqela e-hydroxyl isetyenziselwa ukuvelisa i-polyesteror polyether-PU, ngokulandelelana [6].Iiyantlukwano kwinani lokutshintshwa kunye nesithuba phakathi nangaphakathi kwamakhonkco esebe livelisa i-PUs ukusuka kumgca ukuya kwi-branched kunye ne-9 exekekileyo ukuya eqinile.Umgca wePUs usetyenziselwa ukwenziwa kweentsinga kunye nokubumba[6].Ii-PU eziguquguqukayo zisetyenziselwa ukuveliswa kwee-agent ezibophelelayo kunye neengubo[5].Iiplastiki ezinogwebu ezithambileyo neziqinileyo, ezenza uninzi lweePU eziveliswayo, zinokufumaneka ngeendlela ezahlukeneyo kwishishini[7].Ukusebenzisa i-prepolymers ye-molecular mass ephantsi, ii-copolymers zebhloko ezahlukeneyo zinokuveliswa.Iqela le-terminal hydroxyl livumela iibhloko ezitshintshanayo, ezibizwa ngokuba ngamacandelo, ukuba zifakwe kwikhonkco le-PU.Ukwahlukahlukana kula macandelo kubangela amanqanaba ahlukeneyo okuqina kunye nokuqina.Iibhloko ezibonelela ngesigaba sekristale esomeleleyo kwaye equlathe i-extender chain zibhekiswa kuzo njengamacandelo anzima[7].Abo bavelisa isigaba serabha ye-amorphous kunye ne-polyester / i-polyether ibizwa ngokuba ngamacandelo athambileyo.Ngokwentengiso, ezi polima zebhloko zaziwa njenge-Segmented Pus

Isicelo:

I-polyurethane ene-Flexible ubukhulu becala i-linear structure kunye ne-thermoplasticity, enozinzo olungcono, ukuxhathisa iikhemikhali, ukuqina kunye neempawu zemishini kune-PVC ye-foam, kunye nokuguquguquka okuncinci.Ine-insulation efanelekileyo ye-thermal, i-sound insulation, ukuxhathisa ukothuka kunye neempawu ezichasayo.Ke ngoko, isetyenziselwa ukupakisha, ukugquma isandi kunye nezixhobo zokucoca.Iplastiki ye-polyurethane eqinile ilula, i-insulation yesandi, ukugquma kwe-thermal ephezulu, ukumelana neekhemikhali, iimpawu zombane ezilungileyo, ukusetyenzwa lula, kunye nokufunxa kwamanzi aphantsi.Isetyenziswa ikakhulu njengezinto zokwakha, iimoto, ishishini lokubhabha, ukugquma ubushushu kunye nokugqunyelelwa kwe-thermal.Ukusebenza kwe-polyurethane elastomer phakathi kweplastiki kunye nerabha, ukuxhathisa kweoli, ukuxhathisa ukunxiba, ukumelana nobushushu obuphantsi, ukumelana nokuguga, ukuqina okuphezulu, ukuqina.Isetyenziswa kakhulu kwishishini leembadada kunye neshishini lezonyango.I-polyurethane inokwenziwa ibe yi-adhesives, i-coatings, i-synthetic yesikhumba, njl.