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 imichiza, 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, ukumelana nokunxiba, ukumelana nobushushu obuphantsi, ukumelana nokuguga, ubunzima obuphezulu, ukuqina. Isetyenziswa kakhulu kwishishini leembadada kunye neshishini lezonyango. I-polyurethane inokwenziwa ibe yi-adhesives, i-coatings, isikhumba sokwenziwa, njl.