Properties of polymers

CTFE

Chlorotrifluoroethylene, is the generic name for the material produced as Kel-F^® and as Aclar^®. It is very resistant to all chemicals except THF and some halogenated solvents, and is resistant to all inorganic corrosive liquids, including oxidizing acids. CTFE can be used at temperatures up to 100°C. Swells in ketones.

For Cheminert fittings, Cheminert valve stators and rotors, and Valco ferrules.

ETFE

Ethyltrifluoroethylene 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.

For tubing.

FEP

Fluorinated ethylene propylene is another member of the fluorocarbon family with similar chemical properties. 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 coefficient of friction is easier to retain in a compression fitting.

For Valco ferrules and tubing.

PAEK

Polyaryletherketone is the generic name for the family of polyketone compounds. (See PEEK.) PAEK includes PEK, PEEK, PEKK, and PEKEKK, which differ in physical properties and, to a lesser degree, in inertness.

VICI utilizes a range of proprietary PAEK-based composites (PEEK and others) for valve and fitting components. These composites resist all common HPLC solvents and dilute acids and bases. However, concentrated or prolonged use of halogenated solvents may cause the polymer to swell. Avoid concentrated sulfuric or nitric acids (over 10%).

For Cheminert valve stators.

PEEK

Considered relatively inert and biocompatible, poly-etheretherketone tubing can withstand temperatures up to 100°C. Under the right circumstances, .005” - .020” ID tubing can be used up to 5000 psi for a limited time, and 0.030” to 3000 psi. Larger IDs are typically good to 500 psi. These limits will be substantially reduced at elevated temperatures and in contact with some solvents or acids.

Its mechanical properties allow PEEK to be used instead of stainless in many situations and in some environments where stainless would be too reactive. However, PEEK can be somewhat absorptive of solvents and analytes, notably methylene chloride, DMSO, THF, and high concentrations of sulfuric and nitric acid. This tubing is highly prone to ”kinking”, or sealing off, if held in a sharp bend over time.

We do not recommend PEEK tubing for critical, hazardous, or long term use, particularly at high pressures..

For Cheminert fittings, Valco fittings and ferrules, and tubing.

PFA

Perfluoroalkoxy is a fluorocarbon with chemical and mechanical properties similar to FEP. More rigid than either PTFE or FEP. Commonly used for injection molded parts.

For Cheminert fittings and Valco ferrules,

PPS

Polyphenylene sulphide is the generic name for the material produced as Fortron^®, Ryton^®, and others. It is very resistant to all solvents, acids, and bases.

For Cheminert valve stators.

PTFE

Polytetrafluoroethylene is the generic name for the class of materials such as Teflon^®. It offers 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 diffuse through the tubing wall.

For Valco ferrules, and tubing.

PTFE, glass-filled

This form of PTFE is nearly as inert as the virgin but is much more mechanically stable.

For Valco ferrules.

Polyimide, graphite

A graphite-filled polyimide. Due to its brittle nature, it is usually used only for reducing ferrules.

For Valco reducing ferrules.

Polyimide, virgin

Not recommended for general use due to its tendency to be sticky and brittle at high temperatures. Often used as a high temperature electrical insulator.

Use virgin polyimide Valco ferrules and fused silica adapters as electrical insulators for capillary electrophoresis.

Polyimide, Valcon

A high temperature (350°) graphite-reinforced polyimide composite used for all FS and FSR ferrules (fused silica adapters) and many standard ferrules. Valcon polyimide is specially prepared by a process know as Hot Isostatic Pressing (HIP) prior to being machined into individual adapters. This two step process yields a fused silica adapter with high temperature stability far exceeding that of parts produced by molding. It cannot be used with steam or with bases such as strong alkali and aqueous ammonia solutions.

For Valco ferrules, and fused silica adapters - FS and FSR.

Polypropylene

Widely used polymer for non-wetted parts. Attacked by strong oxidizers, aromatic and chlorinated hydrocarbons.

For Cheminert fittings.

PVDF

PVDF, polyvinylidene fluoride, has excellent resistance to most mineral and organic acids, aliphatic and aromatic hydrocarbons, and halogenated solvents. Poor resistance to acetone, MEK, THF, and potassium and sodium hydroxide. Often supplied as Kynar^®.

For Cheminert valve stators.

Read about properties of metals.