PVDF copolymer

Yang, Y. S., Shi, Z. Q. and Holdcroft, S. 2004. Synthesis of sulfonated polysul-fone-block-PVDF copolymers Enhancement of proton conductivity in low ion exchange capacity membranes. Macromolecules 37 1678-1681. 

Cho, K.-Y, Jung, H.-Y., Choi, N.-S., Sung, S.-H., Park, J.-K., Choi, J.-H. and Sung, Y.-E. 2005. A coated Nafion membrane with a PVdF copolymer/ Nafion blend for direct methanol fuel cells (DMFCs). Solid State Ionics 176 3027-3030. 

One particular version of the lithium-ion gel polymer cells, also known as plastic lithium-ion cell (PLION). was developed by Bellcore (now Telcordia Technologies).In this case. Gozdz et al. developed a microporous plasticized PVdF—HFP based polymer electrolyte which served both as separator and electrolyte. In PLION cells, the anode and cathode are laminated onto either side of the gellable membrane. Good adhesion between the electrodes and the membranes is possible because all three sheets contain significant amounts of a PVdF copolymer that can be melted and bonded during the lamination step. 

PVDF copolymer with stainless steel frits... 

PC/PVDF Copolymer of methyl methacrylate and acrylic acid... 

The reader s attention is also drawn to two reviews [146,147] summarising the work of Veeman and Maas, discussed in Section 18.5, on PMMA/PVDF copolymers and blends. 

PVDF film, as produced from the melt, is largely in the nonpolar a-form, the fS phase only being obtained after subsequent processing operations, as described above. If however, vinylidene fluoride is copolymerized with as little as 7% by weight of trifluoroethylene, a copolymer is formed with crystallites completely in the / -form. This obviates the need for stretching after synthesis and the copolymer can be processed byway conventional routes, such as injection molding. Moreover, unlike PVDF, copolymers of vinylidene fluoride and trifluoroethylene have been shown to demonstrate the ferroelectric to paraelectric transition. For a copolymer with a composition of 55% vinylidene fluoride and 45% trifluoroethylene, a phase transition is observed near 70°C, and with 90% vinylidene difluoride, a phase transition at 130°C. 

Electrostrictive polymers have a spontaneous electric polarization. Electrostriction results from the change in dipole density of the material. These polymers contain molecular or nanocrystaUine polarizations that align with an applied electric field. PVDF copolymers with nano-sized crystalline domains, electrostrictive graft copolymers, and liquid crystal elastomers fall under this category. 

Cho KY, Eom JY, Jung HY, Choi NS, Lee YM, Park JK, Choi JH, Park KW, Sung YE (2004) Characteristics of PVdF copolymer/Nafion blend membrane for direct methanol fuel cells (DMFC). Electrochim Acta 50 583-588... 

Cho KY, Jung HY, Sung SJ, Kim WK, Sung SJ, Park JK, Choi JH, Sung YE (2006) Preparation and characteristics of Nafion membrane coated with a PVdF copolymer/recast Nafion blend for direct methanol fuel cell. J Power Sources 159 524—528... 

Asymmetric hydrophobic membranes exhibiting interesting physicochemical properties can be prepared from poly(vinylidenefluoride-C(9-hexafluoropropylene) copolymer (PKF) and PVDF homopolymer (PK) by a phase inversion process induced by a nonsolvent. Membranes from PVDF copolymer generally exhibit lower gas permeance... 

Positive electrode materials are generally mixed with a conductive carbon powder and a polymer binder. Commonly used binders are polyvinylidene fluoride (PVDF) and a PVDF copolymer with hexafluorpropylene (PVDF-HFP). The positive electrode mix is coated as a slurry onto a thin aluminum foil current collector while the carbon negative electrode material, often using the same binders, is coated onto a thin copper foil current collector. 

Another major application area for flexible PVDF copolymers only in the United State at this time. European and rest of the world specifications based upon fire testing may lead to further markets worldwide based upon this technology The compounds usually are mixtures of pol3rmers and additives with PVDF being the major portion. It is the PVDF susceptibility to efficient cross-linking that allows economical processing rates... 

PVDF copolymers at <1000 ppm in typical blown film applications is effective in reducing melt fracture and allowing increased extrusion rates Chemical resistance to bleaching agents and other paper mill process chemicals... 

The analysis made by various researchers working on this topic include several methods. Grafted copolymers are characterized by their molar or mass grafting rates. The latter is generally obtained from the elemental analysis of the elements present in the copolymer. Serdani et al. determined fluorine and carbon in PVDF copolymer grafted by PMMA. The general structure of their copolymer is as follows ... 

Figure 14.22 (80) illustrates the strain response of a PVDF copolymer. At room temperature under an electric field of 150 MV/m, the longitudinal strain (in the film direction) reached some 4% with low hysteresis. 

Burchill, M. T. Diffusion Effects of Carbonate Solvents in PVDF and PVDF Copolymers. In Progress in Batteries and Battery Materials 1998, Vol. 17, pp 144—156, ITE-JEC Press. 

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). 

PVDF Copolymer/acrylic waterborne hybrid masstone paints with mixed metal oxide pigments Fla S45 gloss retention with 10-year chalk values also indicated (10 best)... 

Gaboury SR, Wood KA (2002) Tailoring coating properties through control of PVDF copolymer phase behavior. Surf Coat Inti Part B Coat Trans 85(B4) 243... 

Table 6.13. Properties of Solvay PVDF Copolymers (Vinylidenefluoride and Hexafluoropropylene) Resins ...

Table 6.14. Properties ofSolvay PVDF Copolymers (Vinylidenefluoride and Chlorotrifluoroethylene) Resins t ...

It is known that plasticized rubber, which is made of a copolymer of PVDF and HFP and impregnated with electrolyte solution, shows high ionic conductivity [37]. Thus by increasing the ratio of HFP to PVDF, the ionic conductivity and processability can be improved. A research team as Bellcore Co. Reported that if the HFP content is increased in the HFP/PVDF copolymer used as the polymer matrix, the melting point of the copolymer decreases. At 12% HFP, the copolymer can be processed at 120 to 130°C. A gel is prepared using an electrolyte composition of 1 mol/fLiPFg/EC/DMC, and this gel electrolyte was used for the 4-V... 

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