Gilson 333 - Appendix E | Reference Information; Liquid Contact Materials

Appendix E
APPENDIX E | REFERENCE INFORMATION
Liquid Contact Materials
The information provided in the following table is accurate to the best of our knowledge and
belief, but it is intended for general information only (classified by alphabetical order).
Liquid Contact Materials
Material Description
ETFE
Ethyltrifluoroethylene (ETFE) is the generic name for the material such
as Tefzel®. A fluoropolymer used for sealing surfaces, it is resistant to
most chemical attack; however, some chlorinated chemicals will cause a
physical swelling of ETFE tubing.
FEP
Fluorinated ethylene propylene (FEP) is a member of the fluorocarbon
family with similar chemical properties as PTFE. It is generally more rigid
than PTFE, with somewhat increased tensile strength. It is typically more
transparent than PTFE, slightly less porous, and less permeable to oxygen.
FEP is not as subject to compressive creep at room temperature as PTFE,
and because of its slightly higher coecient of friction is easier to retain
in a compression fitting.
PCTFE
This material is a homopolymer of chlorotrifluoroethylene which has many
of the properties similar to other fluoropolymers such asPTFE or FEP,
but is mechanically superior in rigidity (does not deform easily), and has
very low gas permeability. Its dimensional stability makes it attractive
for use as a component of a structural part where the high temperature
and chemical resistance of fluoropolymers is required. PCTFE shows high
compressive strength and low deformation under load.
PTFE
Polytetrafluoroethylene is the generic name for the class of materials
such as Teflon®. It oers superior chemical resistance but is limited in
pressure and temperature capabilities. Because it’s so easy to handle, it
is often used in low pressure situations where stainless steel might cause
adsorption. PTFE tubing is relatively porous, and compounds of low
molecular weight can diuse through the tubing wall. Use the black PTFE
piston seals with organic solvents.
LIQUID CONTACT MATERIALS CONTINUED ON PAGE 94
IN THIS CHAPTER
● Liquid Contact Materials | 93
● Solvent Miscibility | 95
93
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