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:

Plexible polyurethane feem ntau yog cov qauv linear nrog thermoplasticity, uas muaj kev ruaj ntseg zoo dua, tshuaj lom neeg tsis kam, muaj zog thiab cov khoom siv kho tshuab dua li PVC ua npuas ncauj, nrog tsawg compression variability.Nws muaj cov thermal rwb thaiv tsev zoo, suab rwb thaiv tsev, kev poob siab tsis kam thiab cov khoom siv tshuaj lom neeg.Yog li ntawd, nws yog siv los ua ntim, suab rwb thaiv tsev thiab lim cov ntaub ntawv.Rigid polyurethane yas yog lub teeb, suab rwb thaiv tsev, superior thermal rwb thaiv tsev, tshuaj tiv thaiv, hluav taws xob zoo, ua haujlwm yooj yim, thiab nqus dej tsawg.Nws yog tsuas yog siv los ua cov khoom siv rau kev tsim kho, tsheb, kev lag luam aviation, rwb thaiv tsev kub thiab thermal rwb thaiv tsev.Polyurethane elastomer kev ua tau zoo ntawm cov yas thiab roj hmab, roj tsis kam, hnav tsis kam, kub tsis kam, kev laus ua haujlwm, siab hardness, elasticity.Nws yog tsuas yog siv hauv kev lag luam khau thiab kev kho mob kev lag luam.Polyurethane tuaj yeem ua rau cov nplaum, txheej, tawv hluavtaws, thiab lwm yam.