PTFE,

The highly crystalline fluoropolymers include fluorinated ethylene polyethylene, perfluoroalkoxyethylene, polychlorotrifluoroethylene and ethylene-tetrafluoroethylene co-polymer but PTFE is perhaps the most widely used and certainly best known as Teflon in non-stick cookware. 

The coefficient of friction of PTFE is lower than almost any other material and it has excellent temperature and mechanical properties although it does have a tendency to creep. The outstanding chemical resistance and electrical properties mean that it is often used in applications that require long-term performance in extreme service environments. 

Like PEEK and POM, this material has a very low surface energy and so will require some form of surface treatment prior to bonding with engineering adhesives (Table 2.17). Cyanoacrylate with primer shows some adhesion but etching kits for the fluoropolymers are also available. 

Notes All shear strengths are given as guidelines only and may vary considerably depending on grade of plastic, fillers, surface finish, etc. 

PVC is the most widely used of all the vinyls and is available in many forms, from soft flexible vinyl (used for car seat covers, medical devices and dinghies) through to rigid vinyl (nsed in toy manufacture, plumbing and pipework fittings and window construction). 

Dimensions of particles reported. From mobility profile. 

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PTFE Polyietrafluoroethene. See also fluorine-containing polymers. 

Fig. ni-19. Trough for dynamic surface measurements A, stainless-steel dish B, aluminum mantle C, inlet thermostatting water D, lower PTFE bars E, oscillating bars F, attachment lower bars G, Wilhelmy plate. (From Ref. 140.)... 

Fig. X-11. Heats of wetting from 0 ( ) and calorimetric heats of immersion (O) of PTFE in n-alkanes. (From Ref. 67.)...

There is no reason why the distortion parameter should not contain an entropy as well as an energy component, and one may therefore write 0 = 0q-sT. The entropy of adsorption, relative to bulk liquid, becomes A5fi = sexp(-ca). A critical temperature is now implied, Tc = 0o/s, at which the contact angle goes to zero [151]. For example, Tc was calculated to be 174°C by fitting adsorption and contact angle data for the -octane-PTFE system. 

Calculate for n-propanol from its contact ancle on PTFE using y = 19.4 mJ/m for PTFE and (a) including and (b) neglecting Tsl-... 

Figure Bl.9.6. A typical Zinnn plot data obtained from a solution of poly (tetrafliioroethylene) (PTFE) M =...

In addition to tire standard model systems described above, more exotic particles have been prepared witli certain unusual properties, of which we will mention a few. For instance, using seeded growtli teclmiques, particles have been developed witli a silica shell which surrounds a core of a different composition, such as particles witli magnetic [12], fluorescent [13] or gold cores [14]. Anotlier example is tliat of spheres of polytetrafluoroetliylene (PTFE), which are optically anisotropic because tire core is crystalline [15]. 

Figure 12.1. Perfluoriiiated resinsulfonic acid similar to Nafion-H, showing clustering of SO3H groups PTFE = poly(tetrafluoroethylene).

Fig. 5.2 Type III isotherms, (a) n-hexane on PTFE at 25°C (b) n-octane on PTFE at 20 C (c) water on polymethylmethacrylate at 20°C (d) water on bis(A-polycarbonate) (Lexan) at 20°C. The insets in (c) and (d) give the curves of heat of adsorption against fractional coverage the horizontal line marks the molar heat of liquefaction. (Redrawn from diagrams in the original papers, with omission of experimental points.)...

A recent innovation in IR sample preparation is the use of disposable sample cards made from thin sheets of either polyethylene (PE) or polytetrafluoroethylene (PTFE). 

Granular material Granular PTFE Granulated sugar Granulating agents Granulation... 

Dry chlorine has a great affinity for absorbing moisture, and wet chlorine is extremely corrosive, attacking most common materials except HasteUoy C, titanium, and tantalum. These metals are protected from attack by the acids formed by chlorine hydrolysis because of surface oxide films on the metal. Tantalum is the preferred constmction material for service with wet and dry chlorine. Wet chlorine gas is handled under pressure using fiberglass-reinforced plastics. Rubber-lined steel is suitable for wet chlorine gas handling up to 100°C. At low pressures and low temperatures PVC, chlorinated PVC, and reinforced polyester resins are also used. Polytetrafluoroethylene (PTFE), poly(vinyhdene fluoride) (PVDE), and... 

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