1. Roj hmab aging yog dab tsi?Qhov no qhia dab tsi ntawm qhov chaw?
Nyob rau hauv cov txheej txheem ntawm kev ua, khaws cia thiab siv cov roj hmab thiab nws cov khoom, vim muaj kev ua tiav ntawm cov khoom siv sab hauv thiab sab nraud, lub cev thiab tshuaj lom neeg thiab cov khoom siv roj hmab maj mam deteriorate, thiab thaum kawg poob lawv cov nqi siv.Qhov kev hloov no yog hu ua roj hmab aging.Nyob rau saum npoo, nws yog manifested li tawg, nplaum, hardening, softening, chalking, discoloration, thiab mildew loj hlob.
2. Dab tsi yog yam uas cuam tshuam rau kev laus ntawm cov roj hmab?
Cov yam uas ua rau cov roj hmab aging yog:
(a) Cov pa oxygen thiab cov pa oxygen hauv cov roj hmab tau dhau los ua cov tshuaj tiv thaiv dawb radicals nrog cov roj hmab molecules, thiab cov saw hlau molecular tawg los yog sib txuas ntau dhau, ua rau muaj kev hloov pauv hauv cov khoom siv roj hmab.Oxidation yog ib qho ntawm cov laj thawj tseem ceeb rau kev laus roj hmab.
(b) Cov khoom siv tshuaj lom neeg ntawm ozone thiab ozone ntau dua li cov pa oxygen, thiab nws muaj kev puas tsuaj ntau dua.Nws kuj ua rau cov saw hlau molecular, tab sis cov nyhuv ntawm ozone ntawm cov roj hmab sib txawv nrog seb cov roj hmab puas yog deformed los yog tsis.Thaum siv rau ntawm cov roj hmab deformed (tsuas yog cov roj hmab uas tsis muaj dej txaus), cov kab nrib pleb ntawm qhov kev taw qhia ntawm kev ntxhov siab tshwm sim, uas yog, hu ua "ozone tawg";Thaum siv rau ntawm cov roj hmab deformed, tsuas yog ib qho oxide zaj duab xis yog tsim rau ntawm qhov chaw tsis muaj cracking.
(c) Thaum tshav kub kub: nce qhov kub tuaj yeem ua rau thermal tawg lossis thermal crosslinking ntawm cov roj hmab.Tab sis lub hauv paus nyhuv ntawm tshav kub yog ua kom.Txhim kho cov pa oxygen diffusion thiab qhib cov tshuaj tiv thaiv oxidation, yog li ua kom cov oxidation cov tshuaj tiv thaiv ntawm roj hmab, uas yog ib qho tshwm sim ntawm kev laus - thermal oxygen aging.
(d) Lub teeb: Lub teeb lub teeb luv dua, lub zog ntau dua.Kev puas tsuaj rau cov roj hmab yog cov kab hluav taws xob ultraviolet nrog lub zog siab dua.Ntxiv rau qhov ncaj qha ua rau kev tawg thiab kev sib txuas ntawm cov roj hmab molecular saw, ultraviolet rays tsim cov dawb radicals vim qhov nqus ntawm lub teeb lub zog, uas pib thiab ua kom cov txheej txheem oxidation chain reaction.Ultraviolet lub teeb ua kom sov.Lwm tus yam ntxwv ntawm lub teeb ua haujlwm (sib txawv los ntawm kev ua cua sov) yog tias nws feem ntau tshwm sim ntawm cov roj hmab.Rau cov qauv nrog cov ntsiab lus kua nplaum siab, yuav muaj cov kab nrib pleb ntawm ob sab, uas yog, hu ua "optical txheej txheej tawg".
(e) Mechanical stress: Nyob rau hauv qhov rov ua dua ntawm txhua yam kev nyuaj siab, cov roj hmab molecular saw yuav tawg los tsim cov dawb radicals, uas yuav ua rau oxidation saw cov tshuaj tiv thaiv thiab tsim cov txheej txheem mechanochemical.Mechanical scission ntawm molecular chains thiab mechanical activation ntawm oxidation txheej txheem.Ib tug twg muaj lub sab sauv txhais tes nyob ntawm tej yam kev mob nyob rau hauv uas nws yog muab tso rau.Tsis tas li ntawd, nws yooj yim ua rau ozone tawg nyob rau hauv qhov kev txiav txim ntawm kev ntxhov siab.
(f) Moisture: Cov nyhuv ntawm cov dej noo muaj ob yam: roj hmab tau yooj yim puas thaum raug los nag hauv huab cua ntub lossis raus hauv dej.Qhov no yog vim tias cov dej-soluble tshuaj thiab cov dej ntshiab hauv cov roj hmab tau muab rho tawm thiab yaj los ntawm dej.Ua los ntawm hydrolysis los yog nqus.Tshwj xeeb tshaj yog nyob rau hauv alternating kev txiav txim ntawm dej immersion thiab atmospheric exposure, kev puas tsuaj ntawm roj hmab yuav ceev.Tab sis qee zaum, noo noo tsis ua rau cov roj hmab puas, thiab tseem muaj cov txiaj ntsig ntawm kev ncua kev laus.
(g) Lwm tus: Muaj cov tshuaj lom neeg sib txawv, qhov sib txawv valence hlau ions, hluav taws xob hluav taws xob siab, hluav taws xob thiab biology, thiab lwm yam, uas cuam tshuam rau roj hmab.
3. Dab tsi yog hom roj hmab aging xeem txoj kev?
Yuav muab faib ua ob pawg:
(a) Natural aging test method.Nws tau muab faib ntxiv rau hauv atmospheric aging test, atmospheric accelerated aging test, natural storage aging test, natural medium (xws li hauv av faus, thiab lwm yam) thiab kev kuaj kev laus.
(b) Artificial accelerated aging test method.Rau thermal aging, ozone aging, photoaging, artificial climate aging, photo-ozone aging, biological aging, high-zog hluav taws xob thiab hluav taws xob laus, thiab tshuaj lom neeg kev laus.
4. Dab tsi yog qhov ntsuas kub yuav tsum raug xaiv rau kev ntsuas huab cua kub rau ntau yam roj hmab sib txuas?
Rau cov roj hmab ntuj, qhov ntsuas kub feem ntau yog 50 ~ 100 ℃, rau cov roj hmab hluavtaws, feem ntau yog 50 ~ 150 ℃, thiab qhov ntsuas kub rau qee cov roj hmab tshwj xeeb yog siab dua.Piv txwv li, nitrile roj hmab yog siv ntawm 70 ~ 150 ℃, thiab silicone fluorine roj hmab feem ntau yog siv ntawm 200 ~ 300 ℃.Hauv luv, nws yuav tsum tau txiav txim siab raws li qhov kev xeem.
Post lub sij hawm: Feb-14-2022