Cov khoom siv tshuaj ntawm FEP zoo ib yam li PTFE thiab PFA.
PFA Properties
PFA polymers yog tag nrho fluorinated thiab yaj-processible.Lawv muaj tshuaj tiv thaiv thiab thermal stability piv rau PTFE.Lub ntiajteb txawj nqus tshwj xeeb ntawm perfluoroalkoxy resins yog nyob rau hauv thaj tsam ntawm 2.12e2.17.PFA muaj qhov kub siab siv tas li ntawm 260 C.
Crystallinity thiab lub ntiajteb txawj nqus tshwj xeeb ntawm PFA qhov chaw txo qis thaum qhov cua txias ntawm cov molten polymer yog nce.Qhov qis tshaj crystallinity tau los ntawm quenching molten PFA hauv dej khov yog 48% (qhov tshwj xeeb lub ntiajteb txawj nqus 2.123).
Zoo ib yam li PTFE, qhov hnyav molecular ntawm PFA tsis tuaj yeem ntsuas los ntawm cov txheej txheem ib txwm siv.Ib qho tsis ncaj qha hu ua melt flow rate (MFR) kuj hu ua melt flow index (MFI) yog siv uas yog tus nqi ntawm cov polymer yaj uas yuav ntws los ntawm lub capillary rheometer ntawm qhov kub thiab txias nyob rau hauv ib qho kev ntsuas (feem ntau hauv grams hauv 10 feeb) .MFR yog inversely proportional rau viscosity;viscosity yog ncaj qha proportional rau molecular hnyav ntawm lub polymer.
PFA nthuav tawm ib qho kev hloov pauv thawj zaug ntawm 5 C hauv qhov sib piv rau ob qhov kub thiab txias rau PTFE ntawm 19 thiab 30 C. Nws muaj peb qhov kev hloov pauv thib ob ntawm 100, 30 thiab 90 C.
PFA muaj cov khoom siv hluav taws xob zoo heev xws li kev rwb thaiv tsev siab, tsis tshua muaj hluav taws xob tsis tu ncua (2.1), thiab tsis tshua muaj qhov cuam tshuam.Dielectric tas li thiab dissipation yam tseem zoo li tsis hloov nyob rau hauv thaj tsam ntawm 40 mus rau 250 C thiab 102 Hz rau 2.4 1010 Hz.Dielectric tawg zog (lub sij hawm luv luv) yog 80 kV / mm rau 0.25-mm-thick zaj duab xis.
Cov khoom siv tshuaj lom neeg ntawm PFA zoo ib yam li cov PTFE.PFA raug tawm tsam los ntawm hluav taws xob, thiab degradation hauv huab cua pib ntawm qhov koob tshuaj me ntsis ntau dua li ntawm PTFE uas pib degrade ntawm 0.02 Mrad.
FEP Properties
Fluorinated ethylene-propylene copolymer yog tag nrho fluorinated thiab yaj-processible.Lawv muaj cov tshuaj tiv thaiv zoo heev thiab thermal stability.Lub ntiajteb txawj nqus tshwj xeeb ntawm FEP resins yog nyob rau hauv thaj tsam ntawm 2.13e2.15.FEP muaj qhov kub siab siv tas li ntawm 200 C.
Zoo ib yam li PTFE, qhov hnyav molecular ntawm FEP tsis tuaj yeem ntsuas los ntawm cov txheej txheem ib txwm siv.Zoo li PFA, MFR yog siv los ntsuas qhov hnyav molecular ntawm FEP.MFR thiab qhov hnyav molecular yog inversely cuam tshuam.
Molecular hnyav tis yog txiav txim los ntawm kev ntsuas lub dynamic module ntawm polymer yaj siv rheological analyses.Crystallinity ntawm nkauj xwb (unmelted) FEP yog 65e75%.
FEP nthuav tawm ib qho kev hloov pauv thawj zaug uas yog nws qhov chaw melting.Relaxation kub ntawm FEP nce nrog HFP cov ntsiab lus ntawm cov copolymer.FEP muaj qhov hloov pauv dielectric ntawm 150 C uas tsis cuam tshuam los ntawm cov monomer muaj pes tsawg leeg lossis crystallinity (qhov tshwj xeeb lub ntiajteb txawj nqus).
Cov khoom siv tshuaj ntawm FEP zoo ib yam li PTFE thiab PFA.
FEP raug tawm tsam los ntawm hluav taws xob, thiab nws qhov degradation hauv huab cua pib ntawm ib koob ntawm 0.2 Mrad (10 npaug siab dua li ntawm PTFE).
Post lub sij hawm: Mar-04-2018