PFA and MFA

FIGURE 4.16 Extruded pipes from PEP. (Courtesy of DuPont.) 

FIGU RE 4.17 Variety of parts for chemical industry from MFA. (Courtesy of Solvay Solexis.) 

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In general, mechanical properties of PFA are very similar to those of PTFE within the range from -200 to +250°C (-328 to +482°F). The mechanical properties of PFA and MFA at room temperature are practically identical differences become obvious only at elevated temperatures, because of the lower melting point of MFA. 

PFA and MFA exhibit considerably better electrical properties than most traditional plastics. In comparison with the partially fluorinated polymers, they are only slightly affected by temperature up to their maximum service temperature.54... 

PFA and MFA have an outstanding chemical resistance even at elevated temperatures. They are resistant to strong mineral acids, inorganic bases, and inorganic oxidizing agents and to most of the organic compounds and their mixtures common in the chemical industry. However, they react with fluorine and molten alkali.55... 

Aqueous dispersions of these two melt-processible perfluoropolymers are processed in a way similar to PTFE dispersion. FEP dispersions can be used for coating fabrics, metals, and polyimide films. They are very well suited for bonding seals and bearings from PTFE to metallic and nomnetallic components and as nonstick and low-friction coatings for metals [20]. FEP can be fused completely into a continuous film in approximately 1 min at 400°C (752°F) or 40 min at 290°C (554°F) [21]. PFA and MFA dispersions are used to coat various surfaces, including glass fabric, glass, and metals. 

Figure 3.36 A comparison of tensile strength of PFA and MFA as a function of temperature.> i...

Abrasion resistance is usually measured by the Taber Test procedure described by ASTM D1044. Abrasion resistance of unfilled semicrystalline polymers is linked to the degree of crystallinity that is itself related to the molecular stmcture and weight of the resin and its processing. Table 3.54 includes the results of testing two types of perfluoroalkoxy polymers, PFA and MFA, and ECTFE. Notice the large difference between wear index (weight loss by abrasion in 1000 cycles) of ECTFE which is a partially... 

Some of the thermal properties of perfluoro-alkoxy polymers (PFA and MFA) and FEP have been listed in Tables 3.62 and 3.63. Table 3.64 and Fig. 3.93 provide similar data for PVDF and Tables 3.65 and 3.66 for ETFE and ECTFE. 

Figure 3.106 A comparison of transmittance of FEP, PFA, and MFA in the UV and visible light regions.

Tables 12.1 and 12.2 summarize the effect of a number of representative organic and inorganic compounds on tetrafluoroethylene-perfluoropropyl vinyl ether polymer (PFA). Figure 12.2 gives a comparison of PFA and MFA (copolymer of tetrafluoroethylene and perfluoromethyl vinyl ether).

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