Yuav ua li cas txheeb xyuas PE zaj duab xis thiab PVC zaj duab xis nyob rau hauv ib tug xws li los yog niaj hnub txoj kev?
Qhov koj tab tom nrhiav yog Beilstein xeem.Nws txiav txim siab muaj PVC los ntawm kev kuaj pom muaj cov tshuaj chlorine.Koj xav tau lub teeb hluav taws xob propane (los yog Bunsen burner) thiab tooj liab hlau.tooj liab hlau los ntawm nws tus kheej kub hnyiab tab sis thaum ua ke nrog cov khoom uas muaj chlorine (PVC) nws hlawv ntsuab.Tshav kub ntawm cov hlau tooj liab hla lub nplaim hluav taws (siv cov pliers los tiv thaiv koj tus kheej thiab siv cov xaim ntev) kom tshem tawm cov khoom seem uas tsis xav tau.Nias lub xov hlau kub tawm tsam koj cov qauv yas kom qee qhov nws melts mus rau cov hlau ces hloov cov yas npog hlau mus rau cov nplaim taws thiab saib kom pom ntsuab ntsuab.Yog tias nws kub hnyiab ntsuab, koj muaj PVC.
Thaum kawg, PE hlawv nrog tsis hnov tsw zoo li hlawv cov quav ciab thaum PVC muaj cov tshuaj tsw qab heev thiab tua nws tus kheej tam sim ntawd thaum tua hluav taws.
"Puas yog polyethylene tib yam li PVC?"Tsis muaj.
Polyethylene tsis muaj chlorine hauv cov molecule, PVC ua.PVC muaj chlorine-hloov polyvinyl, polyethylene tsis.PVC yog inherently nruj dua li polyethylene.CPVC txawm ntau npaum li ntawd.PVC leaches compounds rau hauv dej thaum lub sij hawm uas muaj tshuaj lom, polyethylene tsis.PVC ruptures nyob rau hauv overpressure (yog li tsis haum rau compressed cua daim ntaub ntawv), polyethylene tsis.
Ob leeg yog thermoformed plastics.
Puas yog PVC yog polyethylene?
PVC, los yog polyvinyl chloride, yog hloov polyethylene.Qhov no txhais tau hais tias txhua lwm cov pa roj carbon monoxide ntawm cov saw muaj ib qho chlorine txuas ntxiv rau hydrogen, tsis yog ob lub hydrogens ib txwm pom ntawm polyethylene.
Dab tsi yog polyethylene yas ua los ntawm?
Ethylene
Polyethylene (PE), lub teeb, ntau yam hluavtaws cob ua los ntawm polymerization ntawm ethylene.Polyethylene yog ib tug tswv cuab ntawm tsev neeg tseem ceeb ntawm polyolefin resins.
Dab tsi yog cross linked polyethylene?
Polyethylene yog ib txoj hlua ntev hydrocarbon uas yog tsim los ntawm kev sib txuas ntawm ethylene molecules hauv cov tshuaj tiv thaiv hu ua polymerization.Muaj ntau txoj hauv kev los ua cov tshuaj tiv thaiv polymerization no.
Yog tias siv Ti-raws li inorganic catalyst (Ziegler polymerization) yog siv, cov kev mob tshwm sim yog me me thiab cov polymer uas tau tshwm sim nyob rau hauv daim ntawv ntawm cov saturated hydrocarbon chains ntev heev nrog me ntsis unsaturation (un-saturated -CH = CH2 pawg) xws li ib feem. ntawm cov saw los yog raws li ib pawg dangling.Cov khoom no yog hu ua High Density Polyethylene (HDPE).Txawm tias thaum co-monomers xws li 1-butene suav nrog, theem ntawm unsaturation nyob rau hauv lub resulting polymer (LLDPE) yog tsawg.
Yog tias siv Chromium Oxide raws li inorganic catalyst, ib zaug ntxiv ntev linear hydrocarbon chains raug tsim, tab sis qee theem ntawm unsaturation yog pom.Ib zaug ntxiv qhov no yog HDPE, tab sis nrog cov saw ntev ntev.
Yog hais tias radical pib polymerization yog ua, muaj lub caij nyoog rau ob sab ntev-chains nyob rau hauv lub polymer, nrog rau ob peb lub ntsiab lus ntawm unsaturated -CH = CH2 pawg raws li ib feem ntawm cov saw.Cov resin no hu ua LDPE.Ob peb co-monomers xws li vinyl acetate, 1-butene thiab dienes tuaj yeem muab tso ua ke los hloov kho thiab ua haujlwm ntawm cov saw hlau hydrocarbon, thiab tseem suav nrog kev tsis txaus ntseeg ntxiv hauv pawg dangling.
LDPE, vim nws qib siab ntawm cov ntsiab lus tsis txaus ntseeg, yog qhov tseem ceeb rau kev sib txuas.Qhov no yog ib qho txheej txheem uas tshwm sim tom qab thawj zaug linear polymer tau npaj.Thaum LDPE sib xyaw nrog tshwj xeeb cov dawb radical pib ntawm qhov kub siab, nws txuas ntau cov saw hlau los ntawm "kev sib txuas" ntawm.cov unsaturated sab chains.Qhov no ua rau cov qauv tertiary (3-dimensional qauv) uas yog "khoom" ntau dua.
Crosslinking cov tshuaj tiv thaiv yog siv los "teeb" ib qho duab tshwj xeeb, xws li cov khoom los yog ua npuas dej, pib nrog pliable, yooj yim tuav polymer.Cov txheej txheem zoo sib xws ntawm kev sib txuas yog siv nyob rau hauv "vulcanization" ntawm cov roj hmab, qhov twg cov kab hluav taws xob ua los ntawm isoprene polymerization tau ua rau hauv cov qauv 3-dimensional uas siv sulfur (S8) ua tus neeg sawv cev los khi ua ke ntau cov saw hlau.Cov qib ntawm kev sib txuas sib txuas tuaj yeem tswj tau kom qiv cov hom phiaj tshwj xeeb rau cov khoom ntawm cov txiaj ntsig polymer.
Post lub sij hawm: Oct-11-2022