Dab tsi yog qhov txawv ntawm Polyurethane thiabpolyurethane roj hmab?
Polyurethane thiab polyurethane roj hmab yog qhov tseem ceeb tib yam khoom. Vim nws zoo elasticity, polyurethane feem ntau hu ua polyurethane roj hmab los yog elastomer.
Polyurethane yog tsim los ntawm polyesters (los yog polyethers) thiab diisocyanate compounds. Nws pom zoo ua kom tsis zoo, ua raws li cov elasticity zoo, siab hardness, thiab tsis kam rau cov roj thiab cov kuab tshuaj. Txawm li cas los xij, nws cov thermal aging kuj tsis zoo. Polyurethane roj hmab pom dav siv nyob rau hauv kev lag luam xws li tsheb, khau, thiab mechanical engineering.
Txawm hais tias polyurethane yuav tsum tau muab cais ua yas lossis roj hmab yog nyob ntawm cov ntsiab lus tshwj xeeb.
Hauv cov cheeb tsam xws li Taiwan thiab Hong Kong, cov yas feem ntau hu ua "plasticizers," yog li tsis muaj qhov tseem ceeb hauv kev sib txawv ntawm cov yas thiab roj hmab. Txoj kev sib txawv ntawm cov yas thiab cov roj hmab feem ntau yog raws li cov khoom siv iav hloov kub (Tg), txawm tias nws nyob saum toj lossis hauv qab chav tsev kub. Feem ntau, cov polymers nrog lub iav hloov pauv kub hauv qab chav tsev kub yog hu ua plastics (piv txwv li, polyethylene nrog Tg ntawm -78 degrees Celsius), thaum cov Tg siab dua chav tsev kub yog hu ua roj hmab.
Polyurethane yog ib qho tshwj xeeb polymer tsim los ntawm cov ntu tawv thiab mos. Cov ntu nyuaj muaj qhov kub hloov pauv iav qis, zoo li cov yas, thaum lub qhov muag muag lub iav hloov qhov kub thiab txias yog qhov siab dua li chav tsev kub, zoo li roj hmab. Thaum lub sij hawm kev sib txuas ntawm polyurethane, tswj cov tshuaj tiv thaiv polymerization tso cai rau kev kho qhov sib piv ntawm cov ntu tawv thiab mos, yog li tso cai rau polyurethane los nthuav tawm cov khoom ntawm ob qho tib si yas thiab roj hmab.
Hauv cov ntsiab lus, seb "cov khau roj hmab" suav nrog "cov khau yas" nyob ntawm cov ntsiab lus tshwj xeeb. Feem ntau, cov khau roj hmab hais txog cov khau tsis muaj dej hnav hauv cov dej nag lossis cov khau tub rog, thaum khau yas muaj xws li cov khoom xws li flip-flops.