Khoom npe:polyurethane

Cov khoom siv molecular:

Chemical Properties:

Polyurethanes yog thawj zaug tsim thiab tshawb xyuas los ntawm Dr. Otto Bayer hauv xyoo 1937. Polyurethane yog ib qho polymer uas nyob hauv chav tsev rov qab muaj cov urethane moiety.Urethanes yog derivatives ntawm carbamic acids uas tsuas muaj nyob rau hauv daim ntawv ntawm lawv esters [15].Qhov txiaj ntsig tseem ceeb ntawm PU yog tias cov saw hlau tsis yog tsim tshwj xeeb ntawm cov pa roj carbon atoms tab sis tsis yog heteroatoms, oxygen, carbon thiab nitrogen [4].Rau cov ntawv thov kev lag luam, polyhydroxyl compound tuaj yeem siv.Ib yam li ntawd, poly-functional nitrogen tebchaw tuaj yeem siv los ntawm kev sib txuas ntawm amide.Los ntawm kev hloov thiab sib txawv ntawm polyhydroxyl thiab polyfunctional nitrogen tebchaw, sib txawv PUs tuaj yeem ua ke [15].Polyester lossis polyether resins uas muaj cov pab pawg hydroxyl yog siv los tsim polyester lossis polyether-PU, raws li [6].Kev hloov pauv ntawm tus lej ntawm kev hloov pauv thiab qhov sib nrug ntawm thiab nyob rau hauv ceg saws tsim PUs xws li linear mus rau branched thiab 9exible to rigid.Linear PUs yog siv rau kev tsim cov fibers thiab molding [6].Saj zawg zog PUs yog siv nyob rau hauv zus tau tej cov binding agents thiab coatings [5].Yooj yim thiab nruj foamed plastics, uas ua rau feem ntau ntawm PUs tsim, tuaj yeem pom nyob rau hauv ntau hom kev lag luam[7].Siv cov khoom siv qis molecular prepolymers, ntau yam thaiv copolymer tuaj yeem tsim tau.Lub davhlau ya nyob twg hydroxyl pab pawg tso cai rau alternating blocks, hu ua ntu, muab tso rau hauv PU saw.Kev hloov pauv hauv cov ntu no ua rau muaj kev sib txawv ntawm lub zog tensile thiab elasticity.Blocks muab rigid crystalline theem thiab muaj cov saw extender yog hu ua nyuaj ntu[7].Cov yielding amorphous rubbery theem thiab muaj cov polyester / polyether yog hu ua mos ntu.Kev lag luam, cov block polymers no hu ua segmented Pus

Daim ntawv thov:

Polyurethanes yog ib qho ntawm cov khoom siv ntau yam hauv ntiaj teb niaj hnub no.Lawv siv ntau yam los ntawm kev ua npuas ncauj yooj yim hauv cov rooj tog zaum hauv cov rooj tog zaum, kom ua npuas ncauj tsis zoo li rwb thaiv tsev hauv cov phab ntsa, ru tsev thiab cov khoom siv rau thermoplastic polyurethane siv hauv cov khoom siv kho mob thiab khau, rau coatings, adhesives, sealants thiab elastomers siv rau hauv pem teb thiab automotive interiors[17,18 ].Polyurethanes tau siv ntau zuj zus nyob rau peb caug xyoo dhau los hauv ntau daim ntawv thov vim lawv txoj kev nplij siab, cov txiaj ntsig zoo, txuag hluav taws xob thiab muaj peev xwm ib puag ncig zoo.Dab tsi yog qee yam ntawm cov khoom uas ua rau polyurethanes xav tau?Polyurethane durability pab txhawb rau lub neej ntev ntawm ntau yam khoom.Kev txuas ntxiv ntawm cov khoom lag luam lub neej thiab kev txuag cov peev txheej yog qhov tseem ceeb ntawm kev txiav txim siab ib puag ncig uas feem ntau nyiam xaiv cov polyurethanes[19-21].Polyurethanes (PUs) sawv cev rau chav kawm tseem ceeb ntawm cov thermoplastic thiab thermoset polymers raws li lawv cov khoom siv hluav taws xob, thermal, thiab tshuaj lom neeg tuaj yeem raug kho los ntawm cov tshuaj tiv thaiv ntawm ntau yam polyols thiab poly-isocyanates.