YPolyethylene vs Polypropylene
Polymers yog cov molecules loj, uas muaj tib lub qauv tsim rov ua dua. Cov units rov ua dua yog hu ua monomers. Cov monomers no yog sib koom ua ke nrog covalent bonds los tsim ib lub polymer. Lawv muaj qhov hnyav molecular thiab muaj ntau dua 10,000 atoms. Nyob rau hauv cov txheej txheem synthesis, uas yog hu ua polymerization, ntev polymer chains tau txais. Muaj ob lub ntsiab ntawm cov polymers nyob ntawm lawv cov txheej txheem synthesis. Yog hais tias cov monomers muaj ob daim ntawv cog lus ntawm carbons los ntawm kev sib txuas ntxiv, polymers tuaj yeem ua ke. Cov polymers no hu ua ntxiv polymers. Hauv qee qhov kev cuam tshuam polymerization, thaum ob lub monomers koom nrog, ib qho me me zoo li dej raug tshem tawm. Xws li cov polymers yog condensation polymers. Polymers muaj qhov sib txawv ntawm lub cev thiab tshuaj lom neeg ntau dua li lawv cov monomers. Ntxiv mus, raws li tus naj npawb ntawm rov qab units hauv cov polymer, cov khoom sib txawv. Muaj ntau cov polymers tam sim no nyob rau hauv ib puag ncig ntuj, thiab lawv ua lub luag haujlwm tseem ceeb heev. Synthetic polymers kuj tau siv dav rau ntau lub hom phiaj. Polyethylene, polypropylene, PVC, nylon, thiab Bakelite yog ib co ntawm cov hluavtaws polymers. Thaum tsim cov khoom siv hluavtaws, cov txheej txheem yuav tsum tau tswj xyuas kom tau txais cov khoom xav tau ib txwm. Polyethylene thiab polypropylene tau dhau los ua qhov teeb meem tsis sib haum xeeb nyob rau niaj hnub no, vim lawv tsis muaj peev xwm degradation. Lawv ua ib feem ntau ntawm peb cov khib nyiab; yog li ntawd, lawv pheej nce zuj zus tuaj ntawm lub ntiaj teb. Qhov teeb meem no tau ntes cov neeg tshawb nrhiav, thiab cov khoom siv rov ua dua tshiab tau raug tsim los.
YPolyethylene
Nov yog cov yas siv ntau tshaj plaws hauv ntiaj teb niaj hnub no. Polyethylene yog ib qho polymer ua los ntawm ethylene. Ethylene muaj ob lub pa roj carbon atom sib txuas rau ib leeg nrog ob daim ntawv cog lus. Ob lub hydrogen atom yog sib txuas rau txhua cov pa roj carbon. Thaum polymerizing, ob daim ntawv cog lus yog tawg, thiab tshiab sigma daim ntawv cog lus ntawm ob carbons ntawm ob ethylene molecules tshwm sim. Hauv lwm lo lus, polyethylene yog tsim los ntawm kev sib ntxiv ntawm cov monomer ethylene. Nws chav tsev rov ua dua yog –CH2– CH2-. Yog li, qhov no muaj cov qauv yooj yim heev nrog cov saw ntev carbon atoms. Nyob ntawm txoj kev uas nws yog polymerized, cov khoom ntawm cov synthesized polyethylene hloov. Qee lub sij hawm lawv tuaj yeem ua cov saw ncaj, lossis qee zaum lawv tuaj yeem ua tau ceg. Branched polyethylene yog ib qho yooj yim ua thiab ntau pheej yig dua. Txawm li cas los xij, nws lub zog yog qis dua cov hlua ncaj nraim polyethylene. Polyethylene yog siv los ua lub raj mis, hnab, khoom ua si, thiab lwm yam.
YPolypropylene
Polypropylene kuj yog cov yas polymer. Nws cov monomer yog propylene, uas muaj peb cov pa roj carbon monoxide thiab ib daim ntawv cog lus ntawm ob ntawm cov pa roj carbon atom. Polypropylene yog tsim los ntawm propylene roj nyob rau hauv lub xub ntiag ntawm ib tug catalyst xws li titanium chloride. Nws yog ib qho yooj yim los tsim thiab tuaj yeem tsim nrog siab purity. Polypropylene yog qhov hnyav. Lawv muaj kev tiv thaiv siab rau kev tawg, acids, organic solvents thiab electrolytes. Lawv kuj muaj cov ntsiab lus siab melting thiab zoo dielectric zog thiab tsis muaj tshuaj lom. Polypropylene muaj tus nqi qis dua. Lawv siv rau cov kav dej, ntim khoom, khoom siv hauv tsev, ntim khoom, thiab cov khoom siv tsheb.
Qhov txawv ntawm Polyethylene thiab Polypropylene yog dab tsi?
• Monomer ntawm polyethylene yog ethylene thiab monomer ntawm polypropylene yog propylene.
• Polyethylene muaj qhov qis dua melting piv rau cov ntsiab lus melting ntau dua ntawm polypropylene.
• Polypropylene tsis ruaj khov li polyethylene.
• Polypropylene yog qhov tawv thiab tiv taus cov tshuaj thiab cov kuab tshuaj organic piv rau polyethylene.
• Polypropylene yog ntshiab, tsis ncab thiab feem ntau nruj dua polyethylene.
