Peb nyob rau hauv kev sib cuag nrog cov plastics lossis lwm cov polymers, thiab peb nquag hnov txog antioxidants. Nws kuj tseem tuaj yeem nkag siab tias cov tshuaj tiv thaiv kab mob antioxidant siv los tiv thaiv kev tiv thaiv oxidation thiab tiv thaiv kev laus, tab sis tej zaum lawv feem ntau tsis nkag siab txog kev ua haujlwm. Niaj hnub no, peb tab tom yuav kawm txog qhov ua, kev ua thiab kev daws teeb meem ntawm kev laus ntawm cov ntaub ntawv polymer.
Oxidation yog dab tsi?
Oxidation, hauv qhov kev txiav txim siab nqaim, hais txog kev fab tshuaj ntawm oxygen thiab lwm yam khoom siv hauv lub cev. Nws tseem yog txheej txheem txheej txheem tshuaj lom neeg tseem ceeb. Hauv kev paub ntau, oxidation yog hais txog cov txheej txheem ntawmntawv pov thawjlhluav taws xob tsis ua hluav taws xob (nce ntawm oxidation naj npawb).
Cov lus piav qhia nrov: kev daj, laus, ua tawv tawv, embrittlement, muag muag, dullness, xeb thiab lwm yam tshwm sim los ntawm cua, nag, oxygen nyob rau hauv huab cua, dej zog thiab cua yaig tuaj yeem raug cais raws li oxidation.
Qhov ua piv txwv zoo tshaj yog tias cov kua tom qab txiav raug rau hauv huab cua rau lub sijhawm thiab maj mam hloov daj.
Qhov tseeb, tsis tsuas yog txiv apples yuav oxidized, tab sis kuj yog peb daim tawv nqaij. Cov khoom yas thiab cov polymers yuav oxidized thiab laus!
Kev laus yog ib qho txheej txheem thoob plaws ntiaj teb. Cov txheej txheem feem ntau nyob ib puag ncig peb yog txheej txheem ntawm lub neej txij thaum yug los, kev loj hlob thiab laus, uas yog cov txheej txheem kev laus tshaj plaws.
Polymer yog tib yam. Hauv kev tsim thiab siv, vim muaj kev ua tiav ntawm tshav kub, oxygen, dej, lub teeb, microorganism, tshuaj nruab nrab thiab lwm yam ib puag ncig, cov tshuaj lom neeg thiab cov qauv ntawm cov ntaub ntawv polymer yuav muaj kev hloov pauv, thiab cov khoom siv lub cev yuav xa xov xwm tsis zoo, xws li ua tawv tawv, viscosity, embrittlement, tshem tawm, ploj ntawm lub zog thiab lwm yam. Cov kev hloov pauv thiab tshwm sim no hu ua kev laus.
Dab tsi yog qhov tsis zoo ntawm cov laus molecular polymer?
1. Txo cov khoom cua tshuab
2. Kho Siab
3. Txo cov xim pob tshab
4. Daj daj thiab laus
5. Nhov
6. Cov ntxhiab tsw (cawv, aldehydes, ketones) ······
Polymer laus, dab tsi ntxiv hauv cov kev liam?
1. Polymer tus qauv: tus qauv ntawm ob chav sib khi thiab lub nplhaib benzene tsis ruaj khov, uas yog ib qho yooj yim kom ua rau polymer decomposition thiab yellowing
2. Residual impurities nyob rau hauv polymer synthesis: peroxides thiab hlau ions ua rau polymer degradation thiab daj
3. Oxygen (huab cua): muaj cov pa oxygen thiab ozone ua rau lub siab tsis zoo ntawm cov polymers
4. Zog: kev kho tshuab kev ntxhov siab, tshav kub, UV
5. Cov pa phem: NOx, Sox
6. Dej, av noo: yuav ua rau muaj kev mus los los nag thiab los nag; kev ua tsiaj txhu: ua rau muaj noob roj ntsha enzyme
Vim li cas polymers muaj hnub nyoog?
Polymer yuav tsim cov xeev lub xeev zoo li nyob rau hauv kev ua ntawm tshav kub lossis lub teeb. Thaum lub zog qhov hluav taws xob txaus, cov saw hlau yuav tawg ua rau cov dawb radicals, uas tuaj yeem tsim cov saw hlau tiv thaiv nyob rau hauv lub polymer, txuas ntxiv ua rau muaj kev cuam tshuam, thiab tseem yuav ua rau hla kev sib txuas.
Culprit: dawb tshaj dhau R
Yog tias muaj cov pa oxygen lossis ozone nyob rau hauv ib puag ncig, cov tshuaj tiv thaiv oxidation yuav tsim tawm los tsim cov hydroperoxides (ROOH) thiab txuas ntxiv mus rau hauv cov carbonyls.
Yog tias muaj cov seem catalyst hlau ions nyob rau hauv lub polymer, lossis hlau ions xws li tooj liab, hlau, manganese, cobalt, thiab lwm yam yog coj mus rau hauv lub polymer thaum lub sijhawm ua thiab siv, oxidative degradation ntawm lub polymer yuav ua kom nrawm dua.
