Evolution of Seal Materials
The evolution of seal materials evolved as seals faced more rugged demands. Early needs could be met using packed hemp or leather, but as the demands became more and more rigorous new materials were sought. This led to the introduction of natural rubber seals, which evolved into synthetic elastomers, and finally engineering polymers like PTFE (Polytetrafluoroethylene).
Four of the most common modern material options for rotary shaft seal lips are nitrile rubber, polyacrylate, FKM, and PTFE. Of these materials, three are elastomers – nitrile rubber, polyacrylate rubber and FKM – and only one is polymer – PTFE. Let’s see how these materials stack up.
Non-stick coatings are all around you, helping you do many of day-to-day things we all take for granted.
In this article we’ll take a look at how your daily life could be very different if non-stick coatings had never been discovered by Roy J. Plunkett in 1938.
The impressive growth of the medical device, biomedical and healthcare industries over the past 15 years continues unabated even as materials such as fluoropolymers are meeting the increasingly challenging demand for new products and procedures.
Adsorption is the adhesion of ions or molecules onto the surface of another phase.Adsorption may occur via physisorption and chemisorption. Ions and molecules can adsorb to many types of surfaces including polymer surfaces. A polymer is a large molecule composed of repeating subunits bound together by covalent bonds. The adsorption of ions and molecules to polymer surfaces plays a role in many applications including: biomedical, structural, and coatings.
Ethylene tetrafluoroethylene (ETFE) is a fluorine-based plastic. It was designed to have high corrosion resistance and strength over a wide temperature range. ETFE is a polymer and its source-based name is poly(ethene-co-tetrafluoroethene). ETFE has a relatively high melting temperature, excellent chemical, electrical and high-energy radiation resistance properties. When burned, ETFE releases hydrofluoric acid.
Fluorinated ethylene propylene or FEP is a copolymer of hexafluoropropylene and tetrafluoroethylene. It differs from the PTFE (polytetrafluoroethylene) resins in that it is melt-processable using conventional injection molding and screw extrusion techniques. Fluorinated ethylene propylene was invented by DuPont and is sold under the brandname Teflon FEP. Other brandnames are Neoflon FEP from Daikin or Dyneon FEP from Dyneon/3M.