general reference
VICIAG International
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Properties of polymers
CTFE
Chlorotrifluoroethylene, is thegenericname
for thematerial producedasKel-F®. It isvery
resistant toall chemicalsexceptTHFand some
halogenated solvents,and is resistant toall
inorganiccorrosive liquids, includingoxidizing
acids.CTFEcanbeusedat temperaturesup to
100°C.Swells inketones.
EPDM
EthylenePropyleneDieneMonomer.Ethylene-
propylene synthetic rubbersoffer excellent
heat resistanceaswell as resistance toaging
fromoxidation,ozone,andweatherdue to
their stable,saturatedpolymerbackbone
structure.Asnon-polar elastomers, theyhave
goodelectrical resistivityaswell as resistance
topolar solvents suchaswater,acids,alkanes,
phosphates,esters,andmanyketonesand
alcohols.
ETFE
Ethyltrifluoroethylene is thegenericname for
thematerial suchasTefzel®.Afluoropolymer
used for sealing surfaces, it is resistant tomost
chemical attack;however,somechlorinated
chemicalswill causeaphysical swellingof ETFE
tubing.
FEP
Fluorinatedethylenepropylene isanother
memberof thefluorocarbon familywith similar
chemical properties. It isgenerallymore rigid
thanPTFE,with somewhat increased tensile
strength. It is typicallymore transparent than
PTFE,slightly lessporous,and lesspermeable
tooxygen.FEP isnot as subject tocompressive
creepat room temperatureasPTFE,and
becauseof its slightlyhigher coefficientof
friction iseasier to retain inacompression
fitting.
FFKM
FFKM (perfluorinated rubber) isa
perfluoroelastomer,aclassofmaterials such
asKalrez®. It is chemically resistant topolar
solvents,organic solvents, inorganicand
organicacidsandbases, fuels,oils, lubricants,
inorganic salts,aldehydes,metal halogen
compounds,chlorine,sodiumhydroxide,
aromatics,alcohols,steam,and strongoxidizing
agents.Thenormal temperature service
range is -40°C to315°C,withup to343°C in
intermittent service.
PEEK™
Considered relatively inert andbiocompatible,
polyetheretherketone tubingcanwithstand
temperaturesup to100°C.Under the right
circumstances, .005”- .020”ID tubingcanbe
usedup to5000psi for a limited time,and
0.030”to3000psi.Larger IDsare typicallygood
to500psi.These limitswill be substantially
reducedat elevated temperaturesand in
contactwith some solventsor acids.
Itsmechanical propertiesallowPEEK tobeused
insteadof stainless inmany situationsand in
someenvironmentswhere stainlesswouldbe
too reactive.However,PEEKcanbe somewhat
absorptiveof solventsandanalytes,notably
methylenechloride,DMSO,THF,andhigh
concentrationsof sulfuricandnitricacid.This
tubing ishighlyprone to“kinking”,or sealingoff,
if held ina sharpbendover time.
PFA
Perfluoroalkoxy isafluorocarbonwithchemical
andmechanical properties similar toFEP.More
rigid thaneitherPTFEor FEP.Commonlyused
for injectionmoldedparts.
PPS
Polyphenylene sulphide is thegenericname
for thematerial producedasFortron®,Ryton®,
andTechtron®. It isvery resistant toall solvents,
acids,andbases.
PTFE
Polytetrafluoroethylene is thegenericname for
theclassofmaterials suchasTeflon®. Itoffers
superior chemical resistancebut is limited in
pressureand temperaturecapabilities.Because
it’s soeasy tohandle, it isoftenused in low
pressure situationswhere stainless steelmight
causeadsorption.PTFE tubing is relatively
porous,andcompoundsof lowmolecular
weight candiffuse through the tubingwall.
Polyacetal
Polyacetal orpolyoxymethylene (POM) is the
genericname for thematerial producedas
Delrin®. It isanengineeringpolymerwithhigh
mechanical strengthand rigidity,excellent
dimensional stabilityandexcellent resistance
tomoistureand solvents. Ithasawideuseful
temperature range inairof -50°C to+90°C.
It isnot suitable forusewithacids,alkalis,or
oxidizingagents,andhas limited resistance to
dichloromethaneandmethyl ethyl ketone.
Continued,nextpage.
Properties of polymers
