Peb nquag hnov txog antioxidants thaum peb los rau hauv kev sib cuag nrog cov yas lossis lwm cov ntaub ntawv polymer. Tej zaum kuv tseem nkag siab tias lub hom phiaj ntawm kev ntxiv cov tshuaj tua kab mob antioxidants yog kom tawm tsam oxidation thiab kev laus, tab sis feem ntau ntawm kuv cov phooj ywg yuav tsis nkag siab txog cov tshuab. Niaj hnub no, cia peb kawm ua ke txog qhov ua rau, kev siv tshuab, thiab cov kev daws teeb meem ntawm polymer khoom siv laus.
Yog li, ua ntej ntawm txhua yam, peb yuav tsum nkag siab txog dab tsi oxidation yog?
Kev piav qhia kev paub:Oxidation, nyob rau hauv ib tug nqaim kev txiav txim siab, yog hais txog cov tshuaj tiv thaiv ntawm oxygen thiab lwm yam khoom siv, thiab kuj yog ib qho txheej txheem tshuaj lom neeg. Dav hlau tham, oxidation yog hais txog cov txheej txheem ntawm cov tshuaj poob hluav taws xob (nce tus lej oxidation).
Cias muab:Qhov tshwm sim xws li yellowing, laus, ua kom nruj, xeb, dej nag, thiab cua, thiab cua yaig yuav yog cov kwv yees li ntawm oxidation.
Cov piv txwv zoo tshaj plaws yog qhov tshwm sim ntawm cov kua hlais me me tig daj tom qab raug cua rau ib lub sijhawm.
Qhov tseeb, tsis tsuas yog txiv apples yuav oxidize, tab sis peb cov tawv nqaij tseem yuav oxidize. Cov khoom yas thiab cov molecular ntau polymers kuj tseem yuav oxidize thiab hnub nyoog!
Kev laus yog ib qho txheej txheem thoob ntiaj teb nyob hauv qhov xwm, thiab feem ntau ib puag ncig peb yog cov txheej txheem ntawm lub neej los ntawm kev yug los, thiab kev laus, uas yog feem ntau cov kev laus laus.
Lub xeb ntawm cov ntaub ntawv hlau kuj tseem yog ib hom kev laus, los ntawm cov khoom ci ntsa iab kom xeb, kom txog thaum lawv poob nqi.
Ib yam li ntawd, hauv kev ua thiab siv cov khoom siv polymer, vim yog cov khoom siv hluav taws xob, thiab cov tshuaj lom neeg, ua kom muaj kuab lom, thiab tshuaj lom neeg, thiab xiam lub zog. Cov kev hloov pauv no thiab kev tshwm sim hu ua kev laus.
1, Dab tsi yog qhov tsis zoo ntawm cov pob zeb molecular polymer?
1. Txo kev ua haujlwm zoo
2. Fading
3. Txo cov pob tshab
4. Yellowing thiab laus
5. Cracking
6. Cov ntxhiab tsw (Cawv, Aldehydes, Ketones)
2, yam dab tsi ua rau cov kev laus polymer?
1. Tus qauv ntawm polymers: cov qauv nrog cov pob zeb tsis ruaj khov thiab benzene rings tuaj yeem yooj yim ua rau polymer decomposition thiab yellowing
2. Residual impurities nyob rau hauv polymer synthesis: peroxides, hlau ions ua rau polymer teeb meem, daj
3. Oxygen (Huab cua): Muaj cov pa oxygen thiab ozone ua rau lub decomposition ntawm polymers
4. Zog: Mechanical kev ntxhov siab, kub, ultraviolet hluav taws xob
5. Cua vied: Nox, Sox.
6. Dej thiab av noo: Tej zaum yuav rho tawm, kev sib cais, thiab nag lossis daus. Cov muaj sia: kev ua tsis raws kev tshwm sim los ntawm kev siv roj ntsha
3, tracing lub hauv paus ua rau thiab delving rau hauv lub tshuab ntawm polymer laus:
Vim li cas nws hnub nyoog? (Kev laus mechanism)
Raws li kev nqis tes ua ntawm tshav kub lossis lub teeb, polymer molecules yuav tsim cov xeev zoo siab. Thaum lub zog yog qhov siab txaus, cov molecular chains yuav tawg thiab sau dawb radicals. Dawb radicals tuaj yeem tsim cov saw sab hauv lub polymer hauv cov polymer, txuas ntxiv ua rau muaj kev cuam tshuam, thiab tseem yuav ua rau txuas kev sib txuas.
Culprit tseem ceeb: dawb radical R ·
Yog tias muaj oxygen lossis ozone nyob ib puag ncig, nws tseem tuaj yeem ntxias cov tshuaj oxidation, tswj hydrogen peroxide (rooh) thiab txuas ntxiv decomposing rau hauv cov pab pawg carbonyyl.
Yog tias muaj cov ntawv tseem tshuav hlau ions hauv cov polymer, lossis yog tias tus tooj liab, hlau, khi, nws yuav ua haujlwm nrawm, nws yuav ua haujlwm nrawm nrawm ntawm cov polymer.
Yog li, txhawm rau txhawm rau txhawm rau tiv thaiv cov polymer laus, nws yog ib qho tseem ceeb kom ntxiv cov tshuaj tiv thaiv kab mob antioxidants rau cais lub teeb thiab kub!
