Hexafluoropropylene homopolymerized

The major commercial fluoropolymers are made by homopolymerization of tetrafluoroethylene (TFE), chlorotrifluoroethylene (CTFE),vinyhdene fluoride (VF2), and vinyl fluoride (VF), or by co-polymerization of these monomers with hexafluoropropylene (HFP), perfluoro(propyl vinyl ether) (PPVE), per-fluoro(methyl vinyl ether) (PMVE), or ethylene. The polymers are formed by free-radical polymerization in water or fluorinated solvents. 

Copolymers of vinylidine fluoride with hexafluoropropylene are prepared in aqueous dispersions using persulfate initiators. Hexafluoropropylene does not homopolymerize but it does copolymerize. This means that its content in the copolymer cannot exceed 50%. Preferred compositions appear to contain about 80% of vinylidine fluoride. The crosslinking reactions with diamines are not completely understood. It is believed that the reaction takes place in two steps. In the first one, a dehydrofluorination occurs ... 

It does not homopolymerize easily and hence can be stored as a liquid. It undergoes many addition reactions typical of an olefin. Reactions inclnde preparation of linear dimers and trimers and cyclic dimers (21,22) decomposition at 600°C with subsequent formation of octafluoro-2-butene and octafluoroisobutylene (23) oxidation with formation of an epoxide (24), an intermediate for a number of perflu-oroalkyl perfluorovinyl ethers (25,26) and homopolymerization to low molecular weight liquids (27,28) and high molecular weight solids (29,30). Hexafluoropropylene reacts with hydrogen (31), alcohols (32), ammonia (33), and the halogens and their acids, except I2 and HI (31,34-36). It is used as a comonomer to produce elastomers and other copolymers (37-41). The toxicological properties are discussed in Reference 42. 

NMR studies confirm that head-to-tail arrangements predominate in the copolymers. It may be noted that under the conditions normally used to prepare commercial copolymers, hexafluoropropylene does not homopolymerize and so the molar proportion of this monomer in a copolymer cannot exceed 50% whatever the composition of the monomer feed. 

Hexafluoropropylene, in common with the perfluoro derivatives of other alkenes such as 1-butene, 2-butene, isobutene, 1-pentene and 1-nonene, does not homopolymerize but readily copolymerizes with other alkenes (Adams and Bovey, 1952). 

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