COpolymers of vinylidene fluoride

As will be seen from Table 13.4 elastomers are also available which are copolymers of vinylidene fluoride and chlorotrifluoroethylene. These materials... 

Elastomeric copolymers of vinylidene fluoride are crosslinked by heating with diamine and basic oxide. Crosslinking involves dehydrofluorination followed by addition of the diamine with the metal oxide acting as an acid acceptor... 

The commercially available materials are copolymers of vinylidene fluoride and hexafluoropropylene, and generally have a fluorine content in the range of 65-69% fluorine. 

Viton Copolymer of vinylidene fluoride and perfluoropropylene (DuPont)... 

A study has been conducted on PBXs based on TATB using various binders such as polyurethane (Estane 5703-Goodrich), Viton-A (copolymer of vinylidene fluoride and hexafluoropropylene Du Pont), silicone resin (Chemlok), Kel-F800 [copolymer (3 1) of chlorotrifluoroethylene and vinylidene fluoride 3M Company] and Teflon [poly (tetrafluoroethylene), PTFE Du Pont] etc. and it was concluded that... 

The copolymer of vinyl ferrocene (VF) and butadiene has also been reported in the literature for use as a binder for composite propellants. It does not require any burn-rate (BR) accelerator because of the presence of iron (Fe) in vinyl ferrocene which is converted to finely divided Fe203 (a well-known BR accelerator) during combustion. A few groups of scientists have also studied fluorocarbon polymers as binders for composite propellants because of their excellent compatibility with oxidizers and fuels coupled with high density. Accordingly, Kel-F elastomer (a copolymer of vinylidene fluoride and chlorotrifluoroethylene, trade name of 3M, USA) and Viton-A (copolymer of hexafluoropropylene and vinylidene fluoride, trade name of Du Pont, USA) have also been reported for this purpose. The structures of Kel-F 800 [Structure (4.13)] and Viton-A [Structure (4.14)] are ... 

Copolymer of styrene and acrylonitrile Copolymer of styrene and butadiene Natural rubber Chlorinated polyethylene Chlorosulfonated polyethylene Polyamides Polyesters Polyurethanes Polysulfones Polyacrylates Polyacrylamides Polydimethylsiloxane Copolymer of vinylidene fluoride and hexafluoropropylene... 

Ferroelectricity has also been found in certain copolymer compositions of VF2 with trifluoroethylene, F3E, [6-11] and tetrafluoroethylene, F4E, [12-15] and in nylon 11 [16]. Specifically, copolymers of vinylidene fluoride and trifluoroethylene (VF2/F3E) are materials of great interest because of their outstanding ferroelectricity [9,17-18], together with a parallel strong piezo- [7] and pyroelectricity [19]. These copolymers exhibit, in addition, an important aspect of ferroelectricity that so far has not been demonstrated in PVF2 the existence of a Curie temperature at which the crystals undergo reversibly a ferroelectric to a paraelectric phase transition in a wide range of compositions [9, 17-18],... 

The most common methods of producing homopolymers and copolymers of vinylidene fluoride are emulsion and suspension polymerizations, although other methods are also used.55... 

The first commercial fluoroelastomer, Kel-F, was developed by the M. W. Kellog Company in the early to mid-1950s and is a copolymer of vinylidene fluoride (VDF) and chlorotrifluoroethylene (CTFE). Another fluorocarbon elastomer, Viton A, is a copolymer of VDF and hexafluoropropylene (HFP) developed by du Pont was made available commercially in 1955. The products developed thereafter can be divided into two classes VDF-based fluoroelastomers and tetrafluoroethylene (TFE)-based fluoroelastomers (perfluoroelastomers).72 The current products are mostly based on copolymers of VDF and HFP, VDF and MVE, or terpolymers of VDF with HFP and TFE. In the combination of VDF and HFP, the proportion of HFP has to be 19 to 20 mol% or higher to obtain amorphous elastomeric product.73 The ratio of VDF/HFP/TFE has also to be within a certain region to yield elastomers as shown in a triangular diagram (Figure 2.2).74... 

There are essentially two methods used for the production of commercial FTPEs. The first is referred to as iodine transfer polymerization, which is similar to the living anionic polymerization used to make block copolymers such as styrene-butadiene-styrene (e.g., Kraton ). The difference is that this living polymerization is based on a free radical mechanism. The products consist of soft segments based on copolymers of vinylidene fluoride (VDF) with hexafluoropropylene (HFP) and... 

Footnotes (a) Gaskets are also available in other materials, such as hydrogenated nitrile, neoprene, butyl rubber, hypalon, silicon rubber to meet various application requirtnents. (b) Viton is a Du Pont Co. trademark for a series of fluoroelastorners based on the copolymer of vinylidene fluoride and hexafluoropropylene. 

Note ETFE, copolymer of ethylene and tetrafluoroethylene MFA, copolymer of perfluoromethylvi-nylether and tetrafluorethylene PFA, copolymer of perfluoropropylvinylether and tetrafluoroethylene FEP, fluorinated ethylene-propylene copolymer PCTFE, poly(chlorotrifluoroethylene) PVDF, poly(vinylidene fluoride) VDF-HFP, copolymer of vinylidene fluoride and hexafluoropropylene. 

The compns are based upon a copolymer of vinylidene fluoride and perfluoropropylene (Viton A) with polytetrafluoroethylene (Teflon) and various metals and oxidizers. A number of extrudable formulations are listed in Table 15 (Ref 57). The major advantages claimed for these proplnts are high density impulse, compatibility with highly energetic proplnt ingredients and resistance to high centrifugal forces... 

Partially fluorinated fluoropolymers confain hydrogen (H) or other atoms such as chlorine, in addition to fluorine and carbon. The mosf significanf are homopolymers and copolymers of vinylidene fluoride (VDF). There are also copolymers and homopolymers of CTFE, alfhough some have elastomeric properties. Other significant fluoroplastics include ETFE and PVF. 

Polytetrafluoroethylene (PTFE Teflon) was discovered accidently by PlunkettCZ nd commercialized by DuPont in the 1940 s. This polymer has a solubility parameter of about 6H and a high melting point of 327°C and is not readily moldable. Poly-chlorotrifluoroethylene (CTFE, Kel-F), the copolymer of tetrafluoroethylene and hexafluoropropylene (FEP), polyvinylidene fluoride (PVDF, Kynar), the copolymer of tetrafluoroethylene and ethylene (ETFE), the copolymer of vinylidene fluoride and hexafluoroisobutylene (CM-1), perfluoroalkoxyethylene (PFA) and polyvinyl fluoride (PVF, Tedlar) are all more readily processed than PTFE. However, the lubricity and chemical resistance of these fluoropolymers is less than that of PTFE. 

Copolymers of vinylidene fluoride (VDF) (CF2=CH2) and hexafluoro-propylene (HFP) (CF2=CFCF3) were reported 40 years ago by Dixon, et al. [95]. Ferguson [96] carried out a F NMR solution-state analysis of the samples. The gross structure was deduced from the spectral assignments on the assumption that it was a random linear copolymer, except that no adjacent... 

Several wideline NMR experiments were carried out on copolymers of vinylidene fluoride and trifluoroethylene (TrFE) [84,99-112]. Such copolymers are of special interest since TrFE in proportions greater than 10% induces the VDF component to preferentially crystallise in the )8 form. In contrast with neat PVDF, the copolymers exhibit a ferroelectric phase transition at a temperature well below melting. 

Kochervinskii and Murasheva [115] studied the microstructure of copolymers of vinylidene fluoride and tetrafluoroethylene of 71 29 composition using NMR. They showed that there is 5 mol% of diads in the tetrafluoroethylene blocks and 2.5 mol% of head-to-head defects in the VDF blocks. 

Doverspike et al. [66] reported a deuteron NMR orientational lineshape study of perdeuterated (99%) PVDF and the copolymer of vinylidene fluoride with tetrafluoroethylene having 80 mol% VDF. The experiments examined only the crystalline part of the drawn and poled samples (crystallinity of P(VDF-co-TFE) estimated by XRD to be 50%). The maximum remanent polarisation attained with deuterated PVDF homopolymer film was... 

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