Trifluoroethylene properties

Ethylene trifluoroethylene (Tefzel) (ETFE) has good mechanical properties from cryogenic levels to 350°F (177°C). It has an upper continuous working temperature limit of 300°F (149°C). 

Composites of polypyrrole and poly(vinyl chloride) have been prepared by several groups (64-67). Polythiophene-poly(vinyl chloride) composites have also been prepared (68). The electropolymerization of pyrrole on poly(vinyl chloride)-coated electrodes yielded composites with mechanical properties (tensile strength, percent elongation at break, percent elongation at yield) similar to poly(vinyl chloride) (65) but with a conductivity of 5-50 S/cm, which is only slightly inferior to polypyrrole (30-60 S/cm) prepared under similar conditions. In addition, the environmental stability was enhanced. Morphological studies (69) showed that the polypyrrole was not uniformly distributed in the film and had polypyrrole-rich layers next to the electrode. Similarly, poly(vinyl alcohol) (70) poly[(vinylidine chloride)-co-(trifluoroethylene)] (69) and brominated poly(vinyl carbazole) (71) have been used as the matrix polymers. The chemical polymerization of pyrrole in a poly(vinyl alcohol) matrix by ferric chloride and potassium ferricyanide also yielded conducting composites with conductivities of 10 S/cm (72-74). 

Chlorotrifluoroethylene monomer serves as a building block for the CTFE telomer oils as well as the solid higher polymer and various copolymers. CFC-113 also may be used in the production of trifluoroethylene monomer by vapor-phase reduction using hydrogen and a precious metal catalyst, usually palladium [reaction (9)]. Copolymers of trifluoroethylene and vinylidene fluoride show interesting piezoelectric properties. 

Xu H, Cheng ZY, Olson D, Mai T, Zhang QM, Kavamos G (2001) Ferroelectric and electromechanical properties of poly(vinylidene fluoride-trifluoroethylene-chlorotrifluoro-ethylene) terpolymer. Appl Phys Lett 78 2360... 

There are mainly two kinds of piezoelectric polymer materials as mentioned before. First, the polymer materials intrinsically have the piezoelectric effect. This kind of polymer materials mainly are PVDF and its copolymer of trifluoroethylene (PVDF-TrFE) (Furukawa, 1989), nylon-11 (Newman et al., 1980), and polyuria (Hattori et al., 1996). However, most polymer-based piezoelectric generators are fabricated from PVDF and its copolymers. The other polymer materials might endow the generator with thermo-resisting properties, while it has not been verified yet. 

Koga, K. Ohigashi, H. "Piezoelectrisity and related properties of vinylidene fluoride and trifluoroethylene copolymers", J. Appl. Phys., Vol.59, No.6, pp.2142-2150, (1985) Lindner, M., Bauer-Gogonea, S., Bauer, S., Paajanen, M. Raukola, J. "Dielectric barrier microdischarges Mechanism for the charging of cellular piezoelectric polymers", J. Appl. Phys., Vol.91, No.8, pp.5283-5287, (2002)... 

A copolymer of vinylidene fluoride-trifluoroethylene (VDF/TrFE) copolymer is well known as the polymer for which a clear Curie point was found for the first time in an organic material. At this Curie point, the polymer undergoes a solid-to-solid phase transition from paraelectric to ferroelectric phases with decreasing temperature. Therefore, the changes in the physical properties such as crystal structure, electrical and thermal properties upon the ferroelectric phase transition have drawn many researchers interest. Here, the results concerning the ultrasomc spectroscopic mvestigation on acoustic and viscoelastic behaviour around the ferroelectric phase transition region of this copolymer are described [15]... 

Partially fluorinated materials include ECTFE (ethylene trifluoroethylene), ETEE (ethylene tetrafluoroethylene), and PVDE (polyvinylidene fluoride). The partially fluorinated materials have higher mechanical properties but lower temperature ratings (<300°E/149°C), and chemical resistance. 

Gebe and Runt [47] studied the effects of organically modified layered silicates, such as trioctyl methyl ammonium-modified smetite clays or octadecyl ammonium-modified silicate, on the thermal properties of a 75% polyvinylidene fluoride-co-trifluoroethylene random copolymer. 

The comparison of piezoelectric properties of several of the major piezoelectric ceramics discussed above is given in Table 13.3. hi this table, PZT 4 is hard PZT (PZT doped with acceptor ions, such as K or Na at the A site, or Fe % Al % or Mn at the B site), PZT 5H is soft PZT (PZT doped with donor ions, such as La " at the A site, or Nb or Sb at the B site), LF4T is (K Na Li, ) (Nbj j Ta, jSbj f )Oy and PVDF is piezoelectric polymer synthesized using copolymerization of vini-lydene difluoride with trifluoroethylene (TrFE). 

In the addition to homo-PVF2, a large number of copolymers have also been synthesized which allow to optimize the mechanical properties of fluoropolymers. Most common are copolymers with vinyl fluoride, trifluoroethylene, tetrafluoroethylene, hexafiuoropropy-lene, hexafluoroisobutylene, chlorotrifluoroethylene, and pentafiuoro-propene [521,535, 559-562]. Copolymerization with nonfluorinated monomers is possible [563] in principle but has not yet found commercial use. Fluorocarbon monomers that can help to retain or enhance the desirable thermal, chemical, and mechanical properties of the vinylidene structure are more interesting comonomers. Copolymerization with hexafluoropropylene, pentafluoropropylene, and chlorotrifluoroethylene results in elastomeric copolymers [564]. The polymerization conditions are similar to those of homopoly(vinylidene fluoride) [564]. The copolymers have been well characterized by x-ray analysis [535], DSC measurements [565], and NMR spectroscopy [565,566]. 

Omote, K., Ohigashi, H. and Koga, K. (1997) Temperature dependence of elastic, dielectric and piezoelectric properties of single crystalline films of vinylidene fluoride trifluoroethylene copolymer, J. App. Phys, 81, 2760-9. 

Kawai s (7) pioneering work almost thirty years ago in the area of piezoelectric polymers has led to the development of strong piezoelectric activity in polyvinylidene fluoride (PVDF) and its copolymers with trifluoroethylene and tetrafluoroethylene. These semicrystalline fluoropolymers represent the state of the art in piezoelectric polymers. Research on the morphology (2-5), piezoelectric and pyroelectric properties (6-70), and applications of polyvinylidene fluoride 11-14) are widespread in the literature. More recently Scheinbeim et al. have demonstrated piezoelectric activity in a series of semicrystalline, odd numbered nylons (75-77). When examined relative to their glass transition tenq>erature, these nylons exhibit good piezoelectric properties (dai = 17 pCTN for Nylon 7) but have not been used commercially primarily due to the serious problem of moisture uptake. In order to render them piezoelectric, semicrystalline polymers must have a noncentrosynunetric crystalline phase. In the case of PVDF and nylon, these polar crystals cannot be grown from the melt. The polymer must be mechanically oriented to induce noncentrosynunetric crystals which are subsequently polarized by an electric field. In such systems the amorphous phase supports the crystalline orientation and polarization is stable up to the Curie temperature. 

Wang H, Zhang Q M, Cross L E and Sykes A O, Piezoelectric, dielectric, and elastic properties of poly(vinylidene fluoride/trifluoroethylene), J. Appl. Phys., 74, 3394 (1993). 

PVDF copolymers have been investigated for their piezo properties and for uses in various applications such as sensors. An example of a PVDF copolymer is polyvinylidenefluoride-co-trifluoroethylene [P(VDF-TrFE)], which is a ferroelectric, crystalline polar polymer that exhibits inherent piezoelectric and pyroelectric responses with low acoustic impedance. Such properties provide an optimistic approach towards the use of these polymers for various applications in the near future. Higashihata et al. (1981) compared the piezoelectric craistants of PVDF and P(VDF-TrFE) and observed that much larger values were obtained for P(VDF-TrFE) under the same polarizing conditions. The special interest in this copolymer is also due to the evidence reported by Furukawa et al. (1981) that the PVDF-TrFe copolymer can be annealed to 100% crystallinity, as opposed to 50% in PVDF. Other copolymers have also been explored to determine an enhanced piezo effect (Poulsen and Ducharme, 2010). 

Zhang, S. Zhang, N. Huang, C. Ren, K. Zhang, Q. Microstructure and electromechanical properties of carbon nanotube/poly(vinylidene fluoride-trifluoroethylene-chlorofluoroethylene) composites. Adv. Mater. 2005, 17, 1897-1901. 

Buckley GS et al (2002) Electrostrictive properties of poly(vinylidenefluoride-trifluoroethylene-chlorotrifluoroethylene). Chem Mater 14(6) 2590-2593... 

Huang et al (2004) Poly(vinylidene floride-trifluoroethylene) based high performance electroactive polymers. IEEE Trans Dielec Elec Insul 20 299-311 Jayasuriya et al (2001) Crystal-structure dependence of electroactive properties in differently prepared poly(vinylidene fluoride/hexafluoropropylene) copolymer films. J Polym Sci Part B Polym Phys 39(22) 2793-279... 

In semicrystalline dipole electrets, polar crystallites are present in addition to the polar amorphous phase (Fig. 2b). In die technically most interesting semicrystalline dipole electrets such as polyvinyhdene fluoride (PVDF) and its copolymers with trifluoro ethylene (P(VDF-TrFE)) (Lovinger 1983) or hexafluoropropylene (P(VDF-HFP)), odd Nylons 7 and 11, polyureas, polyureflianes (PU), and some liquid crystalline polymers, the crystallites are ferroelectric (Vasudevan et al. 1979 Hattori et al. 1996). The terpolymer poly(vinyhdene-fluoride-trifluoroethylene— chlorotrifluoroethylene) (P(VDF-TrFE-CTFE)) has been shown to have relaxor ferroelectric properties as the CTFE group destabilizes die long-range order of the ferroelectric phase (Xu et al. 2001). 

Y. Higashihau. T. Yagi, and J. Sako, Piezoelectric properties and applications in the composite system of vinylidcne fluoride and trifluoroethylene copolymer and PZT ceramics, Ferroeketries 68 63 (1986). 

Another widely used approach is the in situ polymerization of an intractable polymer such as polypyrrole onto a polymer matrix with some degree of processibil-ity. Bjorklund [30] reported the formation of polypyrrole on methylcellulose and studied the kinetics of the in situ polymerization. Likewise, Gregory et al. [31] reported that conductive fabrics can be prepared by the in situ polymerization of either pyrrole or aniline onto textile substrates. The fabrics obtained by this process maintain the mechanical properties of the substrate and have reasonable surface conductivities. In situ polymerization of acetylene within swollen matrices such as polyethylene, polybutadiene, block copolymers of styrene and diene, and ethylene-propylene-diene terpolymers have also been investigated [32,33]. For example, when a stretched polyacetylene-polybutadiene composite prepared by this approach was iodine-doped, it had a conductivity of around 575 S/cm and excellent environmental stability due to the encapsulation of the ICP [34]. Likewise, composites of polypyrrole and polythiophene prepared by in situ polymerization in matrices such as poly(vinyl chloride), poly(vinyl alcohol), poly(vinylidine chloride-( o-trifluoroethylene), and brominated poly(vi-nyl carbazole) have also been reported. The conductivity of these composites can reach up to 60 S/cm when they are doped with appropriate species [10]. 

Cardoso, V.F., Lopes, A.C., Botelho, G., Lanceros-Mdndez, S., 2015. Poly(vinylidene fluoride-trifluoroethylene) porous films tailoring microstructure and physical properties by solvent casting strategies. Soft Mater. 13 (4), 243-253. 

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