Teflon® FEP

Optical Properties. Teflon FEP fluorocarbon film transmits more ultraviolet, visible light, and infrared radiation than ordinary window glass. The refractive index of FEP film is 1.341—1.347 (74). 

Teflon FEP—Fluorocarbon Film, bulletin T-5A, Optical, E. I. du Pont de Nemours Co., Inc., Wilmington, Del. 

The introduction of a perfluoromethyl side chain (Teflon FEP) greatly reduces the crystallinity of PTFE. Crystallinity is reduced even further by replacing the short side chain with a long side chain, such as perfluoropropyl ether. In contrast to Teflon EEP, only a small amount of vinyl ether is requited to reduce crystallinity and develop adequate toughness. 

Unfilled Teflon PFA has been tested in mechanical appHcations using Teflon FEP-100 as a control (24). Tests were mn on molded thmst bearings at 689.5 kPa (100 psi) against AISI 1080, Rc 20,16AA steel, and at ambient conditions in air without lubrication. A limiting PV value of 5000 was found. Wear factors and dynamic coefficients of friction are shown in Table 4. 

These materials were first introduced by Du Pont in 1956 and are now known as Teflon FEP resins. (FEP = fluorinated ethylene-propylene.) Subsequently other commercial grades have become available (Neoflon by Daikin Kogyo and Teflex by Niitechim, USSR). These copolymers may be regarded as the first commercial attempt to provide a material with the general properties of PTFE and the melt processability of the more conventional thermoplastics. 

FEP Teflon FEP (fluorinated ethylene propylene). Teflon is a Du Pont registered trademark. 

Fluorinated ethylene propylene (Teflon) (FEP) is a fully fluori-nated plastic. This polymer was developed to have a combination of unique properties. It combines the desirable properties of PTFE with advantageous melt processing properties. 

Solutions of this and the hexalluoroantimonate salt in hydrogen fluoride, kept for extended periods between —50 and +50°C, burst the Kel-F or Teflon FEP containers. This was attributed to excess pressure of hydrogen fluoride and nitrogen arising from decomposition of the salts. The variable rates of decomposition indicated catalysis by trace impurities. The salts also decompose exothermally after a short period at ambient temperature. 

As example of continued investigation in this report is measurement of induced conductivity of Teflon FEP film after radiation of 35 micrometer films by 50 to 100 kilovolts x-rays (Mo target) and currents between 2.5 mA and 20 mA. Seventy-five kilovolt x-rays, with dosages between 25 rads per second and 220 rads per second, produced conductivity that was studied under 90 volts of applied external field, equivalent to 3.75 x 101 volts per cm. 

The Netherlands Organization of Applied Scientific Research (TNO) carried out a comparative study with Teflon-FEP-bags. Ratios between the dynamic and static method ranged from 0.7 to 1.1 after a storage time of 24 hours (7). These Teflon-bags can be used several times. Normally the sample size is 50 to 100 litres but for ambient air samples of 1600 litres are sometimes necessary. 

To try to separate the oxidation of adsorbate from that of bulk methanol, a droplet cell, shown in Fig. 3-2, was used. A working electrode, platiniun wire, is dipped into an electrolyte droplet on a capillary, which is then connected to the electrolyte reservoir. The top portion of the capillary was covered with Teflon FEP held by Teflon heat shrinking tube. The counter electrode, platinum wire, is in the capillary and its tip reaches just below the droplet. The reference electrode, R. H. E., is constructed between the reservoir and the droplet. 

Algoflon, Dyneon, Fluon, Halon, Hiflon, Hostaflon, Neoflon, Polyflon, Soreflon, Teflon, Teflon FEP, Teflon PFA. 

Wire and cable Teflon FEP Neopflon FEP Fluorinated ethylene/ propylene polymer DuPont, USA Daikin, USA... 

A general discussion of the nature and importance of these chamber characteristics, including wall effects, follows. For detailed descriptions of various types of smog chamber facilities and their operation, one should consult the original literature, including, for example, indoor studies utilizing borosilicate glass cylinders (Joshi et al., 1982 Behnke et al., 1988), chambers made from Teflon (FEP) film with volumes up to... 

Cooper et al. [21, 22] reported in detail the results of their laborious work on the adsorption of four proteins human serum albumin (HSA), fibrinogen (FGN), fibronectin (FN), and vitronectin (VN), on five biomaterials polyethylene (PE), silicone rubber (SR), Teflon-FEP (FEP), poly(tetramethylene oxide)-poly-urethane (PTMO-PU), and polyethylene oxide)-polyurethane(PEO-PU). Hard segments of these polyurethanes are composed of a methylene-bis(p-phenylisocyanate) (MDI) chain extended wih 1,4-butanediol. 

XeF2 was removed from the reactor by pumping the gases through a trap (preferably from Teflon FEP or Kel-F) cooled to — 78 X. Unreacted fluorine as well as SiF4 and other possible contaminants passed through. XeF2 transferred more easily when a warm-water bath was placed around the reactor (after unreacted fluorine was removed) and was siphoned into the water jacket of the lamp well. 

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