Qee yam tseem ceeb rau polyester txheej degradation

Polyester degradation yog cuam tshuam los ntawm hnub ci hluav taws xob, photocatalytic admixtures, dej thiab noo noo, tshuaj, oxygen, ozone, kub, puas, sab hauv thiab sab nraud kev nyuaj siab, thiab pigment fading.Tawm ntawm tag nrho cov, cov nram qab no yam, tag nrho cov tam sim no nyob rau hauv sab nraum zoov huab cua, yog Qhov tseem ceeb tshaj plaws rau txheej degradation:

noo noo, kub, oxidation, UV hluav taws xob.

ya

Hydrolysis tshwm sim thaum cov yas raug dej los yog cov av noo.Qhov tshuaj tiv thaiv no yuav yog ib qho tseem ceeb ntawm kev degradation ntawm condensation polymers xws li polyesters, qhov twg ester pawg yog hydrolyzed.

Kub

Thaum ib lub polymer raug rau lub zog thermal ntau dua li cov khoom siv hluav taws xob uas tuav cov atoms ua ke, nws tau yooj yim cleaved. Yog li ntawd, ob macroradicals, los yog electron-deficient molecules, yog generated.
Cov yas feem ntau yog cov noobrally soj ntsuam nyob rau hauv peb tej yam kev mob ntawm elevated-temperature exposure: elevated kub nyob rau lub sij hawm ntev ntawm lub sij hawm, siab kub nyob rau hauv lub sij hawm luv luv, los yog cyclic raug rau siab thiab qis kub, xws li tej zaum yuav tshwm sim thaum lub sij hawm alternating hnub thiab hmo ntuj raug. Qhov kub thiab txias tau nce ntxiv, qhov cuam tshuam puas tsuaj ntxiv los ntawm kev raug UV ntxiv.

oxidation

Vim muaj cov pa oxygen hauv huab cua, feem ntau hom hluav taws xob degradation, photooxidation, tshwm sim ntawm tag nrho cov organic polymers. Ib zaug ntxiv, cov txheej txheem yuav nrawm dua los ntawm UV hluav taws xob thiab kub dua. Cov tshuaj tiv thaiv tshuaj tuaj yeem piav qhia los ntawm cov pa oxygen nres ntawm daim ntawv cog lus hauv cov saw hlau polymer, uas tuaj yeem tsim cov pawg carbonyl lossis crosslink.Different stabilizers tuaj yeem siv los txo cov polymer degradation: antioxidants, thermostabilizers, photostabilizers, thiab lwm yam.

UV hluav taws xob

Thaum nws los txog rau kev siv sab nraum zoov, qhov kev txhawj xeeb tseem ceeb hauv kev ntsuam xyuas cov khoom yog qhov muaj peev xwm lub hnub ci degradation thaum cov yas siv rau sab nraum zoov. Ntawm tag nrho cov hluav taws xob uas ncav cuag lub ntiaj teb saum npoo, txog 5-6% ntawm lub teeb yog nyob rau hauv cheeb tsam UV. ntawm cov spectrum thiab feem ntau yuav txawv nrog txhua hnub ib puag ncig huab cua.
Cov nyhuv photochemical ntawm lub hnub ci ntawm cov khoom siv yas yog nyob ntawm cov khoom siv sab nraud thiab cov khoom siv hluav taws xob ntawm cov khoom siv hluav taws xob. Lub teeb wavelengths uas muaj feem cuam tshuam rau cov yas muaj li ntawm 290 txog 400 nm. Lub wavelength ntawm UV hluav taws xob uas nws lub zog photon sib raug rau ib qho kev sib cog lus lub zog hauv cov saw hlau polymer tuaj yeem rhuav tshem cov khoom siv tshuaj (los ntawm cov saw hlau), hloov cov khoom, thiab yog li ntawd qhov kev ua tau zoo ntawm cov polymer.6 Qhov kev puas tsuaj loj tshaj plaws rau cov polyesters yog xav 325nm