Polyurethane elastomers, polyurethaneurea elastomers, thiab polyurea elastomers sib txawv hauv lawv cov muaj pes tsawg leeg thiab cov khoom.
Polyurethane elastomersyog tsim los ntawm reacting oligomeric diols los yog triols, diisocyanates, thiab me me molecular hnyav polyols. Cov khoom siv raw no tsis muaj cov tshuaj amine-raws li. Lub elastomer tuaj yeem npaj tau los ntawm ib kauj ruam lossis ib txoj hauv kev prepolymer.
Polyurethaneurea elastomers yog tau los ntawm thawj reacting oligomeric diols los yog triols nrog diisocyanates los ua ib tug prepolymer, uas yog ces solidified los ntawm ntxiv cov tshuaj tiv thaiv nrog ib tug aromatic diamine chain extender. Qhov tshwm sim elastomer muaj ob pawg urethane thiab urea. Thaum hais lus nruj me ntsis, nws poob rau hauv qeb ntawm polyurethanerea, nws feem ntau cais raws li polyurethane.
Polyurea elastomers, ntawm qhov tod tes, feem ntau yog tsim los ntawm kev ncaj qha cov amino-terminated polyethers (xws li polyether diamines lossis polyether triamines) nrog diisocyanates thiab aromatic diamines. Vim yog cov tshuaj tiv thaiv sai ntawm cov amino thiab isocyanate pawg, cov txheej txheem tshuaj tsuag molding yog siv rau lawv cov kev npaj.
Nws yog ib nqi sau cia hais tias yog ib tug sib tov ntawm amino-terminated polyether thiab aromatic diamine reacts nrog ib tug isocyanate-terminated polyurethane prepolymer thaum lub sij hawm txau molding, cov khoom uas tshwm sim tsis yog ib tug ntshiab polyurea elastomer, tab sis ib tug polyurethaneurea elastomer, raws li muaj carbamate pawg nyob rau hauv nws. molecular saw.
Polyurea elastomers, nrog rau lawv cov ntsiab lus ntau dua urea pawg, pom ntau dua polarity thiab muaj peev xwm tsim tau ntau dua hydrogen bonds. Yog li ntawd, lawv feem ntau muaj ntau dua modulus thiab lub zog piv rau polyurethane elastomers.