PEEK (polyetheretherketone) muaj qhov zoo heev - qhov kub thiab txias tab sis tsis muaj zog tiv thaiv cov kua qaub. PFA muab cov tshuaj tiv thaiv zoo tshaj rau cov kua qaub thiab cov hauv paus tab sis poob txhua yam muaj zog tshaj 180 degree. Lub coextruded dual- txheej sheath-PEEK txheej sab hauv rau lub zog thiab PFA txheej txheej rau tshuaj tiv thaiv- aims los ua ke kom zoo. Txawm li cas los xij, ntawm 200℃hauv kev daws teeb meem alkaline (piv txwv li, 10-30% NaOH, KOH), PFA / PEEK interface delaminates hauv 100-500 teev vim qhov sib txawv thermal expansion thiab alkaline nres ntawm khi txheej. CTE tsis sib haum yog hnyav: PEEK nthuav dav ntawm 47 ppm / degree, PFA ntawm 110-120 ppm / degree. Nyob rau ntawm 200 degree, lub shear stress ntawm lub interface tshaj 5-10 MPa, tshaj li raug khi txheej adhesion (3-5 MPa). Yog tsis muaj txheej khi zoo, delamination tshwm sim sai. Nrog rau siab -tej txheej kub (piv txwv li, polyetherimide los yog polybenzimidazole), lub neej txuas mus rau 1,000–2,000 teev tab sis tseem ua tsis tau qis dua 5,000 teev. Rau kev pabcuam 200℃alkaline tas mus li, lub tshuab hluav taws xob monolithic PEEK nrog nyias PFA txheej (dip-coated, tsis coextruded) yog qhov txhim khu kev qha, lossis tsuas yog siv lub tshuab rhaub hlau (titanium lossis npib tsib xee alloy).
Kev sib tw Interface ntawm 200 degree
Lub coextrusion ntawm PFA thiab PEEK yog qhov nyuaj vim tias lawv qhov kub thiab txias sib txawv (PFA 350-400 degree, PEEK 380-420 degree) thiab lawv yog cov polymers tsis sib haum. Yuav tsum muaj ib txheej khi. Cov khaubncaws sab nraud povtseg xws li hloov kho polyetherimide (PEI) lossis polybenzimidazole (PBI). Ntawm 200 degree, khi txheej softens (PEI Tg ≈ 217 degree, ze ntawm qhov txwv). Hauv cov tshuaj alkaline, khi txheej hydrolyzes. Txawm tias tsis muaj tshuaj tua kab mob, CTE mismatch tsim cyclic shear stress thaum lub sij hawm thermal cycling (chaw kub txog 200℃). PFA shrinks 6 × ntau tshaj PEEK thaum txias, rub tawm ntawm lub interface. Tom qab 100-500 cycles, delamination pib.
Lub Sijhawm Delamination vs. Ib puag ncig (200 degree)
| Kev tsim kho | Tie Txheej | Ib puag ncig | Sijhawm rau Delamination (teev) | Hom kev ua tsis tiav | Haum rau 200℃Alkaline? |
|---|---|---|---|---|---|
| PFA / PEEK coextruded | Tsis muaj (direct contact) | 20% NaOH | 20–50 | Interfacial sib cais | Tsis muaj |
| PFA / PEEK coextruded | Modified PEI (50 µm) | 20% NaOH | 100–300 | Tie txheej hydrolysis | Tsis muaj |
| PFA / PEEK coextruded | PIB (25 µm) | 20% NaOH | 300–600 | PIB degradation | Marginal |
| PFA / PEEK coextruded | PIB | 10% KOH | 500–1,000 | qeeb delamination | Txais tau rau kev sib tshuam |
| PEEK nrog PFA dip txheej (0.2 hli) | Tsis muaj (mechanical) | 20% NaOH | 1,000–2,000 | Txheej hnav | Txais tau |
| Monolithic PEEK (tsis muaj PFA) | N/A | 20% NaOH | >10,000 (tshuaj tua kab mob) | PEEK degrades | Tsis muaj (tsis zoo alkaline tsis kam) |
| Titanium rhaub | N/A | 20% NaOH | >20,000 | Tsis muaj | Yog (zoo tshaj) |
Tshuaj tiv thaiv ntawm PEEK hauv Alkaline Solutions
PEEK nws tus kheej tsuas muaj kev ncaj ncees tiv thaiv kom muaj zog alkalis ntawm 200 degree. Hauv 10-30% NaOH ntawm 200 degree, PEEK poob 20-30% ntawm nws lub zog tensile tom qab 2,000 teev thiab tsim cov kab nrib pleb. Yog li txawm tias delamination tsis tshwm sim, PEEK txheej sab hauv degrades. Lub dual{11}} txheej tsis daws qhov PEEK qhov tsis zoo. Qhov zoo dua yog tias PFA txheej txheej tiv thaiv PEEK los ntawm kev sib cuag ncaj qha - tab sis PEEK tseem pom alkaline yog tias PFA tawg lossis permeates. Ntawm 200 degree, NaOH permeates los ntawm 1 hli PFA ntawm 0.5–1.0 g / m²·hnub, mus txog PEEK interface hauv lub lis piam.
Cov ntaub ntawv ua tau zoo (200 degree, 20% NaOH)
| Khoom siv | Tensile Strength Retention tom qab 2,000 teev (%) | Surface condition | Permeation Rate ntawm OH⁻ (tus txheeb ze) | Pom zoo Max Temp |
|---|---|---|---|---|
| PFA monolith | 85–90 | Me ntsis daj | 1.0x | 180 degree |
| PEB monolith | 65–75 | Nto crazing | 5–10x | 200℃(limited lub neej) |
| PFA / PEEK coextruded (PBI khi) | 70-80 (tag nrho) | Delamination ntawm interface | 1.0x (los ntawm PFA) | 190 degree |
| PTFE (raws li siv) | 60–70 | o | 0.5x | 200℃(tab sis mos) |
| Titanium (Qib 2) | 100 (hlau) | Passivated | N/A | 200℃+ |
Lwm txoj kev daws teeb meem rau 200℃Alkaline cua sov
Rau kev txhim khu kev qha cua sov ntawm 200℃hauv concentrated alkalis:
Titanium rhaubQib 2 lossis Qib 7 titanium resists 30% NaOH ntawm 200℃indefinitely. Tsis xav tau polymer. Tus nqi nruab nrab (2–3 × PFA). Qhov kev xaiv zoo tshaj plaws.
Nickel 200 los yog Hastelloy C-276: Kuj tiv taus kub alkalis. Tus nqi qis dua titanium me ntsis.
Sab nraud cua sov: Ua kom sov lub tank los ntawm sab nraud siv lub nkoj los yog lub tshuab cua sov. PFA (los yog PTFE) hauv ob sab phlu hauv lub tank tuav tshuaj tiv thaiv; lub rhaub yeej tsis tiv nrog alkali.
Qhov kub thiab txias: Ua haujlwm ntawm 160℃tsis yog 200 degree. PFA ib leeg ua haujlwm ntawm 160℃(10+ xyoo lub neej). Cov tshuaj tiv thaiv tus nqi yuav qeeb dua, tab sis kev ntseeg tau zoo heev.
Piv txwv teb
Ib tsob nroj tshuaj xav tau 200 degree, 30% NaOH immersion rhaub. Lawv sim coextruded PFA / PEEK cua sov (PBI khi txheej). Tag nrho delaminated hauv 4 lub hlis (≈1,500 teev). Cov nroj tsuag hloov mus rau titanium Qib 7 rhaub (3 hli sheath, 6 kW). Lub tshuab cua sov titanium tau ua haujlwm rau 5 xyoos yam tsis muaj kev saib xyuas. Tus nqi yog 3 × PFA, tab sis kev tshem tawm ntawm kev ua tsis tiav thiab kev poob qis them rau tus nqi them hauv 1 xyoo.
Xaus: PFA/PEEK Delaminates hauv Kub Alkaline Service
Lub coextruded PFA/PEEK dual{0}} txheej txheej tsis tuaj yeem tiv taus 200℃raug cuam tshuam rau hauv cov tshuaj alkaline (10–30% NaOH) yam tsis muaj delamination. CTE mismatch thiab khi txheej degradation ua rau interface tsis ua hauj lwm nyob rau hauv 100-1,000 teev. PEEK nws tus kheej degrades hauv kub alkalis. Rau kev txhim khu kev qha 200℃alkaline cua sov, siv lub titanium los yog nickel rhaub - tsis muaj polymer. Rau qhov kub qis (tsawg dua lossis sib npaug li 160 degree), PFA ib leeg txaus. Tsis txhob sim txuas ntxiv PFA qhov kub thiab txias los ntawm kev thim rov qab nrog PEEK. Lub interface ua tsis tau, ces PEEK degrades. Nws yog ib qho kev poob ua ke. Mus rau hlau, mus rau sab nraud, lossis mus qis dua. Delamination tsis yog qhov txaus ntshai - nws yog qhov tseeb. Zam ob- txheej hauv kub alkalis. Titanium yeej.
