Tetrafluoroethylene oligomers

Commercial telomerization usually involves the reaction of pentafluoroethyl iodide (telogen) with tetrafluoroethylene oligomers (taxogen) in the presence of a catalyst, to produce a perfluoroalkyl iodide polymer (telomer) ... 

Coe, P.L. Ray, N.C. Tetrafluorethene oligomers. Part 14. Reactions of perfluoro-3-methylpent-2-ene (tetrafluoroethylene trimer) with nucleophiles. J. Fluorine Chem. 1998, 88, 169-178. 

Uses. The variety of fluoropolymers and fluoroelastomers incorporating VDF in the main chain is extensive. The commercially important thermoplastic copolymers are based upon hexafluoropropylene HFP (10,11) chlorotrifluoroethy-lene (CTFE) (12,13) and co- or ter-polymers with tetrafluoroethylene (14). Telomer-ization of VDF to form fluorinated oligomers by radical addition has been reviewed (15). 

While partially fluorinated alkenes such as vinyl fluoride and vinylidene fluoride polymerize with the same facility as tetrafluoroethylene, the latter is unique in the class of the perfluoroalkenes with the respect to the ease of polymerization as will be described later. Perfluoroalkenes such as hexafluoropropylene (HFP) and hexafluorobutadiene polymerize only with great difficulty as the result of the steric inhibition in the propagation step [598]. HFP can be converted to high-molar-mass polymer only at pressures above 1000 atm. The polymerizations are carried out most conveniently in a perfluorinated solvent using perfluorinated free-radical initiators [599]. For the polymerization of hexafluorobutadiene, similar conditions are reported [600]. Due to these very drastic polymerization conditions, these oligomers/polymers are not yet commercially applied. 

Oligomers of tetrafluoroethylene (particularly pentamer) are prepared by oligomerization of tetrafluoroethylene in an organic solvent in the presence of a fluoride compound and a crown ether [280],... 

Other recent applications of ToF-SIMS without XPS include the examination of PS [6, 17-19], polyethylene (PE) [20], carbon fibre reinforced epoxy resins [21], polyalkyl methacrylates [22], alkylketene dimers [23], perfluorinated polymers [24], perflnorinated ethers [25], polyethylene glycol (PEG) oligomers [15, 25-29], rubber [30], ethylene-tetrafluoroethylene copolymer [30], Nylon-6 [31], PC [32,33], PDMS [34], polypyrrole coated PS [35], poly-p-phenylene vinylene [36], butyl rubber [37], poly(4-vinyl phenol)/poly(4-vinyl pyridine blends) [38], polypyrrole-silica gel composites [39], y-glycidoxypropyl trimethoxy silane [40], triblock copolymer poly(ethylene glycol)- 3 poly(phenylene ethylene)- 3 poly(ethylene glycol) [41], ethylene-terephthalate-hydroxybenzoate copolymer [42], PS-polyvinyl methyl ether, polycarbonate - PS blends [43] and PDMS-urethane [44],... 

Haszeldine [62,63] allowed trifluoromethyl iodide to react with ethylene and obtained oligomers of the type CF3[CH2CH2] I (n = 1, 2, and 3). The reaction of trifluoromethyl iodide with tetrafluoroethylene, catalyzed by ultraviolet (UV) irradiation, yielded short-chain polymers of the general formula CF3[CF2CF2] I, where n = 1-10. Some of the members of the telomeric series were isolated. 

A process developed by ICI [95-97] is based on anionic polymerization of tetrafluoroethylene. Unlike high-molecular-weight poly(tetrafluoroethylene) produced by free-radical polymerization, anionic polymerization catalyzed by a fluoride (e.g., cesium, potassium, or tetraalkylammonium fluoride) produces highly branched oligomers. The main products are a tetramer, a pentamer, and hexamers (Fig. 2.7). 

A process developed by ICI [119] is based on anionic polymerization of tetrafluoroethylene pioneered by Graham [120]. The branched oligomers produced can be reacted with phenol and then with chlorosulfonic acid to form sul-fonyl chlorides useful as intermediates ... 

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