Hexafluoro propylene

The fluororubbers also form an important class of speciality elastomers and although the market is dominated by the vinylidene fluoride-hexafluoro-propylene copolymers a wide range of materials has been produced over the past 40 years. 

Tetrafluoromethane, hexafluoroethane, tetrafluoroethylene. difluoropropane, hexafluorocyclopropane, and n-hexafluoro-propylene... 

Other halogenated copolymers, in which an isomorphous replacement is observed, were studied by Leshchenko, Karpov, and Kargin (19, 20) and later by Natta, Allegra, and Bassi (21). The former authors show that copolymers obtained from vinylidene fluoride and tetrafluoro ethylene are crystalline and show a tendency to altemance between the two types of monomer units (19). The same authors studied the vinylidene fluoride/hexafluoro propylene and the vinylidene fluoride/ trifluorochloro ethylene copolymer systems. In the former case crystallinity is observed up to contents of about 10% of the second component, the crystal structure being that of polyvinylidene fluoride. In the latter case crystallinity disappears for vinylidene fluoride contents in the order of 16%, the observed structure being that of polytrifluorochloro ethylene (20). 

Synthetic methods have limited the preparation of saturated perfluoropolyethers. The most successful perfluoropolyether synthetic chemistry has been DuPont s anionic polymerization of perfluoroepoxides, particularly hexafluoro-propylene oxide and tetrafluoroethylene oxide (39). Their synthetic procedure is a three-step scheme for saturated perfluoropolyether production involving oxidation of perfluoroolefins to perfluoroepoxides, anionic polymerization to acyl fluoride terminated perfluoropolyethers, and conversion of acyl fluoride end groups to unreactive end groups by decarboxylation reactions or chaincoupling photolytic decarboxylate reactions. 

A study of internal friction in copolymers of tetrafluoroethylene and hexafluoro-propylene. Die Makromol. Chem. 34, 50—66 (1959 b). 

Indeed, free radical polymerization of fluoroolefins continues to be the only method which will produce high-molecular weight fluoropolymers. High molecular weight homopolymers of TFE, CFC1 = CF2, CH2CF2, and CH2=CHF are prepared by current commercial processes, but homopolymers of hexafluoro-propylene or longer-chain fluoroolefins require extreme conditions and such polymerizations are not practiced commercially. Copolymerization of fluoroolefins has also led to a wide variety of useful fluoropolymers. Further discussion of the subject of fluoroolefin polymerization may be found elsewhere and is beyond the scope of this review [213-215]. 

PROPYLENE OXIDE (DOT) OXIRANE, TRIFLUORO-(TRIFLUOROMETHYL)- PERFLUORO(METHYLO-XIRANE) PERFLUOROPROPYLENE OXIDE PROPANE, l,2-EPOXY-l,l,2,3,3,3-HEXAFLUORO- PROPYLENE OXIDE HEXAFLUORIDE (TRIFLUORO-xMETHYL)TRIFLUOROOXIRANE TRIFLUORO-(TRIFLUOROMETHYL)OXIRANE... 

Figure 6.3.11. Variation of weight % loss fora poly(vinylidene fluorlde-co-hexafluoro-propylene) sample in a TGA experiment at a heating rate of 1(f C/min.

A pyrogram for poly(vinylidene fluoride-co-hexafluoro-propylene) is shown in Figure 6.3.12. The copolymer has M , = 455,000 and has the idealized formula (-CH2CF2-)x [-CF2CF(CF3)]y. The pyrolysis was done similarly to that of PVC (see Table 4.2.2). 

Figure 6.3.12. Result for a Py-GC/MS analysis of poly(vinylidene fluoride-co-hexafluoro-propylene), M = 455,000. Pyrolysis done at 60CP C in He, with the separation on a Carbowax type column.

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... 

PPE with poly(hexafluoro propylene- thermoformable, high HDT, Snodgrass Lauchlan,... 

Figure 4.5-6 Amide end-capped poly(hexafluoro-propylene oxide) used for Ae inverse emulsion polymerization of acrylamide in CO2 [119].

Jayasuriya AC, Schirokauer A, Scheinbeim JI (2001) Crystal-structure dependence of electroactive properties in differently prepared poly(vinylidene fluoride/hexafluoro-propylene) copolymer films. J Polym Sci Part B Polym Phys 39 2793... 

Figure 5- A plot of flie CED for a number of different polymers as a function of the temperature. The polymer types are indicated in the legend where the abreviations have the following meaning. PE polyethylene- PEG poly(ethylene oxide) aPP, atatic polypropylene PMMA, poly(methyl mefliacrylate)- PDMS polyfdimethyl siloxane) PTMeO, poly(tetra-methylene oxide) PPG, polvfpropvlen e oxideV PHFP, poly(hexafluoro propylene) PHFPO, polyfhexafluoro propylene LiS 3GT, polyt piylene t PCPT, polycaprolactone PS, polystyrene PEKK,...

Trade Name Synonyms Cyracure UVR-6216 t[Dow http //www.dow.com] 1,2-Epoxy-1,1,2,3,3,3-hexafluoropropane CAS 428-59-1 EINECS/ELINCS 207-050-4 Synonyms Acetone, hexafluoro Hexafluoroepoxypropane Hexafluoro-1,2-epoxypropane Hexafluoropropene epoxide Hexafluoropropene oxide Hexafluoropropylene oxide Oxirane, trifluoro (trifluoromethyl)- Perfluoro (methyloxirane) Perfluoropropylene oxide Propane, 1,2-epoxy-1,1,2,3,3,3-hexafluoro-Propylene oxide hexafluoride ... 

Varcoe and coworkers were pioneers in synthesizing AEM for DMFC by radiation grafting vinylbenzyl chloride (VBQ onto poly (vinylidene fluoride) (PVDF), and poly (tetrafluoroethene-co-hexafluoro propylene) (FEP), followed by quatemization in trimethylamine and immersion in KOH solution to obtain the hydroxide ion forms [203], as indicated in Fig. 6.12. 

Kumar GG, Kim AR, Nahm KS, Yoo DJ (2011) High proton conductivity and low crossover of polyvinylidene fluoride-hexafluoro propylene-silica sulphuric acid cmnposite mcanbranes for direct methanol fuel cells. Curr Appl Phys 11 896-902... 

VF2/HFP n. Abbreviation for vinylidene fluoride-hexafluoro-propylene co-polymer. 

A large number of by-products are formed in this process, mostly in trace amounts more significant quantities are obtained of hexafluoro-propylene, perfiuorocyclobutane, l-chloro-l,l,2,2-tetrafluoroethane, and2-chloro-1,1,1,2,3,3-hexafluoropropane. Small amounts of highly toxic perfluoroisobuty-lene, CF2=C(CF3)2, are formed by the pyrolysis of chlorodifluoromethane. 

The physical and electrochemical properties of a new class of hthium ion conducting polymer electrolytes formed by dispersing nanosized C CPO ) in the poly (vinyhdene fluoride-hexafluoro propylene) (PVDF-HFP) - LiClO complexes have been reported. The prepared membranes were subjected to XRD, SEM, TG-DTA, and FT-IR analysis. Ionic conductivity measurements have been made as a function of temperature and hthium salt concentrations. The polymeric film with a ratio of PVDF-HFP Ca3(PO )2 LiC10 75 15 10 offered maximum ionic conductivity. The interfacial property of Li/NCPE was also analyzed. The interaction that exists between the polymer and lithium salt species has been confirmed by FT-IR analysis. 

---