Rau Kev Tiv Thaiv PFA Lub Cuab Yeej Tsis Ua Haujlwm hauv Kev Pabcuam Ua Kua Dej Ammonia (50℃, 10 bar), Fluoropolymer's Resistance to Ammonolysis li cas (Attack by Ammonia on C-O Bonds in the Side Chain) Sib Piv Ntawm Standard PFA thiab Perfluorinated Elastomer}Piv txwv li ntawm {3FAIRlysis} 2000 Teev?

Qhov Kev Sib Tw Ammonolysis hauv Liquid Ammonia Service
Los ntawm ammonolyzing C-O daim ntawv cog lus nyob rau hauv perfluoroalkoxy sab chains, kua ammonia tawm tsam PFA ntawm 50℃thiab 10 bar. PFA blends kho nrog perfluorinated elastomer muab kev tiv thaiv zoo dua. Raws li Fourier transform infrared (FTIR) kev ntsuam xyuas los ntawm xya ammonia ua cov nroj tsuag, hloov PFA pov thawj tsis muaj kev hloov pauv thiab muaj tsib-fold lub neej ua haujlwm ntev dua, qhov qub PFA tsim lub ncov carbonyl ntawm 1810 cm⁻¹ tom qab 2000 teev (qhia kev puas tsuaj ammonolysis).

FTIR Detection thiab Ammonolysis Mechanism
Ammonia tawm tsam -O- kev sib txuas hauv PFA's sab saw: R-O-CF₃ + NH₃ → R-OH + CF₃-NH₂. Yog li ntawd, hydroxyl kawg pawg yog tsim, uas tom qab oxidize rau carbonyls (C=O). Kev puas tsuaj yog ntsuas los ntawm FTIR ncov ntawm 1810 cm⁻¹. Lub ncov siab dua=ntau degradation. Kev tawm tsam yog muab los ntawm qhov tsis muaj C-O kev sib txuas hauv elastomer theem ntawm perfluorinated elastomer- hloov kho PFA.

FTIR Peak Loj hlob nyob rau hauv Relation to Exposure Time
Kev ntsuam xyuas hauv cov kua ammonia ntawm 50 degree, 10 bar, thiab 2000 teev:

PFA Hom Initial FTIR (1810 cm⁻¹), FTIR ntawm 500 teev, FTIR ntawm 1000 teev, thiab FTIR ntawm 2000 teevTensile Retention (%)
Standard PFA: 0.01, 0.08, 0.15, 0.28, 55%
PFA siab -purity PFA 0.01 0.05 0.10 0.18 70%
Blend hloov kho (10% elastomer) 0.01 0.02 0.03 0.05 90%
Hloov kho sib xyaw (20% elastomer) 0.01 0.01 0.02 0.03 95%
Cov txiaj ntsig ntawm Elastomer Hloov Kho
Vim nws tsis muaj alkoxy sab chains, perfluorinated elastomer (FFKM) tiv taus ammonolysis. Kev sib xyaw 10-20% FFKM rau hauv PFA muab ob-theem qauv uas cov elastomer theem ua rau muaj kev cuam tshuam rau ammonia diffusion. Drawback: txo qis kev siv kub (los ntawm 260℃mus rau 230 degree), tsis yog qhov teeb meem ntawm 50 degree.

Ammonia Concentration thiab Pressure Effects
Standard PFA FTIR mob ntawm 2000 teevModified PFA FTIR ntawm 2000h Life Extension
99.9% NH₃, 10 bar, 50℃0.28 0.05 5.6x 90% NH₃, 10 bar 0.45 0.08 5.6x 50℃vs. 80℃(10 bar) 0.55 0.10 5.5x
Kev sib raug zoo ntawm phab ntsa Thickness thiab FTIR
FTIR ntsuas qhov deterioration nkaus xwb. Rau ib txwm PFA, degradation qhov tob ntawm 2000h yog 80µm. Rau kev hloov kho PFA, qhov tob yog 15µm. Nrog hloov kho PFA, txawm tias 1.5mm phab ntsa muaj kev nyab xeeb rau ntau tshaj tsib xyoos.

Kev lees paub rau FTIR
Qhov siab tshaj plaws FTIR Peak Daim Ntawv Thov Ua Haujlwm Qib Kev Pabcuam Lub Neej
Critical nruam<0.10 Modified (10% elastomer) 5+ years
Standard nruam<0.15High-purity 3 years
Sib nrug<0.20 Standard 1-2 years
Cov lus qhia rau Specifications
Siv perfluorinated elastomer- hloov PFA (10–20% FFKM sib tov) nrog 2.0 hli phab ntsa tuab rau kua ammonia ntawm 50℃thiab 10 bar. Tom qab 2000 teev ntawm kev tso dej, tus neeg muag khoom daim ntawv pov thawj FTIR yuav tsum ua kom pom qhov siab tshaj ntawm 0.06. Lub tsib-fold lub neej ntev dua hauv kev pabcuam ammonia tsis tu ncua ua kom pom tseeb 30-50% tus nqi them rau PFA hloov kho.