Polyfvinylidene fluoride properties

Of greater interest in recent years have been the peculiar piezolectric properties"" of polyfvinylidene fluoride). In 1969 it was observed" that stretched film of the polymer heated to 90°C and subsequently cooled to room temperature in a direct current electric field was 3-5 times more piezoelectric than crystalline quartz. It was observed that the piezolectric strain coefficients were higher in the drawn film and in the normal directions than in the direction transverse to the film drawing. 

Although Tyrann-M/E and even conventional membranes are superior to the new polyamide and polyfvinylidene fluoride) membranes with respect to flow rates and filtration capacities, the latter two are more suitable for filtration of most (but not all) organic solvents and, partially as a result of their lower void volumes (Table IV) exhibit mechanical and thermal properties which are generally superior to those of the cellulosics. It should also be noted that in the special case of fiber-reinforced membranes, the mechanical properties are predominantly functions of the embedded fibers rather than of the membrane structu reverse. 

Structure and Properties of Ferroelectric Copolymers of PolyfVinylidene Fluoride)... 

Costa, C.M., Rodrigues, L., Sencadas, V, Silva, M., Rocha, J.G., Lanceros-Mndez, S., 2012. Effect of degree of porosity on the properties of polyfvinylidene fluoride-trifluorethylene) for Li-ion battery separators. 

Baltd-Calleja, F. Gonzalez Arche, A., Ezquerra, T. A., Santa Cruz, C., Batalldn, F., Frick, B. and Ldpez Cabarcos, E. Structure and Properties of Ferroelectric Copolymers of Polyfvinylidene) Fluoride. Vol. 108, pp. 1-48. 

Nasef, M.M., Saidi, H. and Dahlan, K.Z.M. 2010b. Radiation grafted polyfvinylidene fluoride)-gra -polystyrene sulfonic acid membranes for fuel cells Structure-property relationships. Chin.. 1. Pohm. Sci. 28 761-770. 

The inability to process PTFE by conventional thermoplastics techniques has nevertheless led to an extensive search for a melt-processable polymer but with similar chemical, electrical, non-stick and low-friction properties. This has resulted in several useful materials being marketed, including tetrafluoro-ethylene-hexafluoropropylene copolymer, polyfvinylidene fluoride) (Figure 13.1(d)), and, most promisingly, the copolymer of tetrafluoroethylene and perfluoropropyl vinyl ether. Other fluorine-containing plastics include poly(vinyl fluoride) and polymers and copolymers based on ClFE. 

Present researdi on physical properties, performance, and passible applications of electroactive polymers has oonceatraled < cooducting potymers because of their peculiar electrical properties, but the interest in polymers originally arose firom the rlieleciric ones. The strong piezoelectric effect in polyfvinylidene fluoride) (PVDF or PVFi) poled under high electric field was observed the first time by Kawai (1) in 1969, while its pyro-... 

Kim GH, Hong SM, Seo Y. Piezoelectric properties of polyfvinylidene fluoride) and carbon nanotube blends P-phase development. Phys Chem Chem Phys 2009 11(44) 10506-12. 

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