Hexafluoropropene, copolymers

In a more specialized approach, IL phases have been immobilized in membrane materials. Although the primary driver of this work was the use of these materials as electrochemical devices, they have also been investigated for catalytic applications [20]. Membrane materials composed of air-stable, room-temperature ILs and poly(vinylidene fluoride)-hexafluoropropene copolymers were prepared with the incorporation of the active catalyst species in the form of palladium on activated carbon. Optical imaging revealed that the prepared membranes contained a high dispersion of the palladium catalyst particles. Studies on the materials included evaluating their gas permeability and their catalytic activity for the hydrogenation reaction of propene. 

Incompatible polymers vinylidene-hexafluoropropene copolymer (Won A) participates in degradation of syntactic PSR Vance, A L Alviso, C T Harvey, C A, Polym. Deg. Stab., 91,1960-63, 2006. 

Crosslinking of CR, chlorobutyl rubber, chlorinated acryl rubber, epichlorohydrin rubber, ethylene-epichlorohydrin copolymer rubber, PVC, chlorinated ethylene and vinylidene fluoride-hexafluoropropene copolymer rubbers in presence of metal compounds such as MgO was studied in detail to elucidate mechanism, variables affecting reaction, points of crosslinking and relative reactivity of rubbers. Control techniques using retarders or accelerators, depending on halogen activity, were proposed. 17 refs. 

FEP plastics Copolymers of tetrafluoro-ethene and hexafluoropropene. Inert and corrosion resistant as Teflon but can be processed by melt techniques. 

B.p. — 29X. Monomer used to form polymers (only under rather drastic conditions) or copolymers with C2F4 and vinylidene fluoride, CH2 = CF2. Hexafluoropropene may be prepared by thermal decomposition of CF3CF2CF2C02Na or is prepared commercially by low pressure pyrolysis of C2F4. 

Fluorocarbon Elastomers. These elastomers were developed by both the Du Pont and 3M companies during the 1950s. They are the most resistant elastomers to heat, chemicals, and solvents known, but they are also the most expensive, ie, between 22 and 35 per kg. The most common types are copolymers of vinyHdene fluoride and hexafluoropropene, thus ... 

Teblina et al. [26] studied the kinetics of radical polymerization of metha-crylic acid in the presence of a hexafluoropropene-vinylidene fluoride copolymer. The polymerization rate increased with conversion. A grafted copolymer was formed by a reaction analogous to eqn. (40) (with F instead of... 

The fluorinated ethenes CF2=Cp2, CF2=CFH, CF2=CH2, CF2=CFC1 and CF2=CFBr each form homopolymers in conventional free-radical initiation procedures [220] and it is notable that the heat of polymerisation for tetrafluoroethene is much greater than for ethene [2]. Indeed, tetrafluoroethene and trifluoropropene are relatively dangerous monomers to handle because of the risk of explosive polymerisation. In marked contrast, quite drastic conditions are required in order to form a homopolymer from hexafluoropropene (HFP) [221], although commercially successful copolymers of CF2=CFCF3 with CF2=CF2 (i.e. FEP) and with CF2=CH2 (Viton rubber) have been developed. 

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]. 

The exact location of the plasticizer is frequently evaluated to better understand the structure of plasticized polymers. In poly[(vinylidene fluoride)-co-hexafluoropropene], VDF/HFP plasticized with dibutyl phthalate, SAXS measurements indicate that DBP resides in the amorphous zone outside the lamellar stacks. If ciystallization is slow the inclusion of DBP inside the lamellar stacks is also possible. In another contribution for the same copolymer, plasticizer was also found in amorphous phase close to the interface with crystalline stmctures which was evidenced by almost constant spacing in the range of tricresyl phosphate studied.In the plasticized PVC, the plasticizer molecules were found in the amorphous area but were also present in the interlamellar, intefibrillar, inter-spheralitic regions and in the amorphous fold surfaces. ... 

They have made contributions on fluoropolymers especially on high-temperature and low-temperature adhesives and elastomers. One interesting copolymer is ethylene and tetrafluoroethylene (1 1), which is emulsion polymerized in the presence of a persulfate catalyst. This copolymer, unlike PTPE, is radiation-resistant. Another fluoropolymer project is the copolymerization between tetrafluoroethylene and hexafluoropropene. One high-... 

In response to a market-driven need, Pennwalt developed a more flexible version of the fluoropolymer for certain applications. This fluoropolymer was introduced in 1984 under the trademark KYNAR FLEX 2800. KYNAR FLEX 2800 is a copolymer of vinylidene fluoride and hexafluoropropene (HFP). 

Thermal decomposition of a y-irradiated poly( vinyl fluoride) occurred in two main steps firstly, elimination of hydrogen fluoride and secondly, main chain scission to yield unsaturated hydrocarbons." Polytetrafluoroethylene and the copolymer of tetrafluoroethylene and hexafluoropropene were degraded in various atmospheres and the decomposition products analysed." - For an inert atmosphere over twenty different fluorinated products were identified. For air the major products were COF, CF , and COj with minor amounts of fluorocarbons. The gaseous and solid decomposition products have also been analysed from the thermal degradation of poly(carbon monofluorides) containing different proportions of fluorine. Kinetic data were also obtained. 

Very few reports have been published on fluorine relaxation times in most cases the results reported for several different molecules indicate that the spin rotation mechanism is dominant at higher temperatures whereas the intermolecular dipole-dipole mechanism is not negligible at lower ones. The chemical shift anisotropy contribution can also be an important factor, whereas the intramolecular dipole-dipole mechanism and scalar coupling contribution seem to be negligible in F relaxation. Some fluorine relaxation times (Tj, T2 and Tj ) have been used for establishing dynamics in a copolymer of tetrafluoroethene and hexafluoropropene. 

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