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.
The Environmental Working Group recommends against using dental floss made with PTFE. The group states that "Exposure to PFCs has been associated with kidney and testicular cancer, high cholesterol, abnormal thyroid hormone levels, pregnancy-induced hypertension and preeclampsia, obesity and low birth weight . . . . PFCs pollute water, are persistent in the environment and remain in the body for years. Leading manufacturers of PFCs have agreed to phase out some of these chemicals by the end of 2015, including PFOA, the most notorious, which used to be a key ingredient in making Teflon. Unfortunately, there’s no evidence that the chemicals that have replaced PFOA are much safer."
The valve seat in an internal combustion gasoline or diesel engine is the surface against which an intake or an exhaust valve rests during the portion of the engine operating cycle when that valve is closed. The valve seat is a critical component of an engine in that if it is improperly positioned, oriented, or formed during manufacture, valve leakage will occur which will adversely affect the engine compression ratio and therefore the engine efficiency, performance (power and torque), exhaust emissions, and engine life.
Encapsulated o-rings are o-rings consisting of a seamless and uniform Teflon encapsulation which completely encloses a rubber core material. Elastomer/rubber core material are a choice of Silicone or Viton. The combination of these components creates an o-ring that is virtually chemically inert and compression set resistant for use in harsh sealing environments. This combination of chemically resistant polymer jacket over a low-compression set elastomer provides unique properties for a range of demanding applications