Vinylidenefluoride- copolymers

Copolymer ethylene and tetrafluoroethylene Copolymer from ethylene and vinyl acetate Ethylene-vinyl acetate-acrylic acid graft copolymer Ethylene-vinyl acetate-carbon monoxide copolymer Copolymer from ethylene, vinyl acetate, and vinyl chloride Copolymer of ethylene and vinyl alcohol also EVOH Fluorinated EPR tetrafluoroethylene/hexa-fluoro propylene rubber Hexa-fluoro propylene-vinylidenefluoride copolymer... 

THV (tetrafluoroethylene-hexafluoropropylene-vinylidenefluoride copolymer) foil has very high transparency and elasticity, but low strength, so it is mostly used as a covering for load-carrying nets. As a fluoropolymer, THV foil may be welded and is non-combustible and not susceptible to contamination, nor is it affected by UV radiation or chemicals. 

In the article by Balta Calleja et al., the latest results of investigations into the structure of poly(vinylidenefluoride)and its copolymers withpoly(trifluoroethylene) are summarized and extensively dicussed. These polymers are the most important ferroelectric materials. Special emphasis is placed on the relation between the change of structure and the transition from the ferroelectric into the paraelectric phase. 

Various copolymers of the fluorinated monomers have been prepared [243]. Copolymers of tetrafluoroethylene and hexafluoropropene have under vacuo a stability close to that of teflon (Fig. 66). Copolymers with trifluoronitroso me thane have a lower stability than PTFE (Figs. 66 and 67). The copolymer of vinylidenefluoride and hexafluoropropene is one of the most stable elastomers available at the present time (Fig. 66 and Table 12). For a typical copolymer containing 70% vinylidene fluoride, the rate of weight loss is 0.04% per min at 350°C and the activation energy is 57 to 46 kcal mole"1, according to Wright [243]. 

Synonyms FPM Vinylidenefluoride/hexafluoropropylene copolymer IMinUon Elastomer consisting of 60-85% vinylidene fluoride gt thermal props, and chem. resist. 

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... 

Fine, E. G., Valentini, R. F., Bellamkonda, R., and Aebischer, P. (1991), Improved nerve regeneration through piezoelectric vinylidenefluoride-tiifluoroefliylene copolymer guidance channels. Biomaterials 12(8) 775-780. 

Piezoelectricity appears in natural crystals such as quartz, tourmaline, rochelle salt as well as in artificially produced ceramics and polymers such as e. g. nylon or copolymers of vinylidenefluoride (VDF) with trifluoroethylene (TrFE) or with tetrafluorethylene (TeFE). Most of the piezoelectric materials used for commercial sensor applications are synthetically produced polycrystalline ferroelectric ceramics such as e.g. lead-zirconate-titanate (PZT). 

Hayashi, K., TsubaJdhara, H., Kubo, U. Doping effect on the electric current and molecular structure of a vinylidenefluoride-trifluoroethylene copolymer. Japanese Journal of Applied Physics 36, 1176-1177 (1997)... 

Most of the other fluorine-containing monomers such as trifluoroethylene, hexafluoropropylene, and pentafluoropropylene are used only for copolymerization with vinyl fluoride, vinylidene fluoride, and tetrafluoroethylene [506,521,535,559-562]. Those copolymers, after a convenient vulcanization procedure using peroxides, diisocyanates, or amines, can be applied as fluorocarbon elastomers [564]. Due to the fluorine content, they have high chemical resistance and often a broad temperature range for application [612]. Polymers of interest are the vinylidenefluoride/hexafluoropropylene copolymer and the... 

The most common process to manufacture MTV is the so-called shock gel process also called coacervation process. According to Douda, it had been first used in 1959 [3]. It is an adaptation of the well-known coagulation process of nitrocellulose binder practiced since the 1920s to vinylidenefluoride-hexafiuoropropene-copolymer (70 30mol%) binder (marketed as either Viton or Fluorel ) [4]. 

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

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

A styrene copolymer cross-linked with DVB was lightly sulfonated and the product incorporated into poly(vinylidenefluoride) and ethylene-propylene-diene with addition of antimonic acid (HSb). The resultant composites were sulfonated using chlorosulfonic acid and the procedure afforded membranes showing good physical properties (Chapter 8, Section 6). 

Other kinds of copolymers include poly(vinylidene fluoride) (PVDF), poly(vinylidenefluoride-hexafluoro propylene) (P(VDF-HFP)), and polyethylene glycol dimethyl ether. The ionic conductivity of polymer electrolytes using LiCFjSOj as lithium salt can reach 10 S/cm at room temperature [1]. 

In the early 1980s, Sony Corporation initiated research on polymer lithium-ion batteries. At that time there was no such term as "polymer lithium-ion battery." The main idea is to use a block copolymer of poly vinylidenefluoride-hexafluoro propylene (P(VDF-HFP) as a gel carrier for the organic electrolytes. The composition of this polymer lithium-ion battery is shown in Figure 14.7 [3]. Later, Samsung Corporation coated a polymer on the traditional separators to act as a host for the organic electrolytes to prepare gel polymer electrolytes. Sanyo Corporation added precursors of PEO and plasticizers (organic... 

There are a few other fluorocopolymers, besides PVDF, which can be used as membrane materials, such as poly(vinylidenefluoride-co-hexafluoropropylene) and poly(vinylidene difluoride-co-chlorotrifluoroethylene). The chemical structure of these copolymers is presented in Figure 8.1. 

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