Dab tsi yog qhov zoo thiab qhov tsis zoo ntawm PPH thiab PPR kav
PP yeeb nkab cov ntaub ntawv tshwj xeeb tau muab faib ua peb tiam: thawj tiam yog hloov kho los ntawm homopolymer polypropylene, hu ua PP-H, lub cim thib ob yog tsim los ntawm PP thiab PE block copolymerization txheej txheem, hu ua PP-B, thiab tiam thib peb Nws tau hloov kho los ntawm random copolymer polypropylene, hu ua PP-R. Nws lub ntsiab sib txawv yog: kev ua haujlwm zoo thiab ib puag ncig kev ntxhov siab tawg tsis kam ntawm cov khoom peb cov khoom no ua tiav zoo dua qub. PP-B muaj lub zog tsis zoo thiab kev cuam tshuam zoo dua qub, PP-H muaj lub zog zoo dua qub thiab muaj kev cuam tshuam tsis zoo (brittle), thiab PP-R tiv thaiv qhov tsis zoo no.
Lub zog ntawm PP-B thiab PP-H kav dej poob qis dua tom qab ib xyoos, thaum PP-R kav dej tseem tseem muaj zog ntau dua txawm tias tom qab 50 xyoo. Qee hom tshwj xeeb ntawm txawv teb PP-B muaj kev ua tau zoo sib xws rau PP-R thiab kuj yog cov ntaub ntawv zoo kawg nkaus rau cov kav dej. PP-R tau los ntawm copolymerization ntawm propylene monomer thiab ib qho me me ntawm ethylene monomer hauv qab cua sov, siab thiab catalyst. Lub ethylene monomer yog cov tsim thiab ntau cov tau tawg mus rau lub saw ntev ntawm propylene.
Kev koom tes ntawm kev koom ua ke ntawm ethylene txo qhov kub siab thiab qhov chaw tawg ntawm lub polymer, txhim kho qhov cuam tshuam ntawm cov ntaub ntawv, lub sij hawm ntev hydrostatic siab tsis kam, ntev ntev thaum tshav kub-tiv taus oxygen laus, thiab cov yeeb nkab ua thiab molding muaj zog.
PP-R molecular saw qauv thiab ethylene monomer cov ntsiab lus muaj qhov cuam tshuam ncaj qha rau lub sijhawm ntev thermal stability, cov khoom siv cav thiab kev tsim cov khoom ntawm cov khoom siv. Qhov ntau random kev tawg ntawm ethylene monomer nyob rau hauv propylene molecular saw, qhov tseem ceeb dua kev hloov kho ntawm cov khoom polypropylene. PP-H yog polymerized los ntawm ib tus kheej ntawm propylene monomer, thiab cov saw molecular tsis muaj ethylene monomer, yog li qhov tsis tu ncua ntawm cov saw molecular yog ntau heev, yog li crystallinity ntawm cov khoom siv yog qhov siab thiab qhov cuam tshuam tsis zoo. Txhawm rau txhawm rau txhim kho lub brittleness ntawm PP-H, qee cov khoom siv raw kuj tseem siv polyethylene thiab ethylene-propylene roj hmab blending los txhim kho cov tawv ntawm cov khoom, tab sis lawv tsis tuaj yeem cuam tshuam txog lub sijhawm ntev kub ua kom ruaj khov ntawm PP-H. kev ua tau zoo.
