Properties of Perfluoroalkylvinyl Ethers

Perfluoroalkylvinyl ethers form an important class of monomers in that they are used as comonomers for the modihcation of the properties of homofluoropolymers in addition to their broad nse in copolymers with TFE and other monomers. They are capable of snppressing the crystallization of PTFE efficiently, which imparts usefnl mechanical properties to lower molecular weight of polytetrafluoroethylene polymers. Copolymers of PAVEs and tetrafluoroethylene are thermally stable as PTEE homopolymers. Commercially significant monomers are perfluoropropylvinyl ether and perflnoromethylvinyl ether (PMVE), used for the production of a variety of perflnoroalkoxy resins. 

Perfluoroalkoxy resins are prepared by copolymerization of TFE and perfluoroalkyl monomers in either aqneons or nonaqueous media [58-60]. 

In aqueons copolymerization, which has similar reaction conditions to emulsion polymerization of PTFE, inorganic peroxy compounds (e.g., ammonium persulfate) are used as initiators, and also a perfluorinated emulsifying agent (e.g., ammonium perfluorooctanoate) is added [61]. 

In a nonaqueous copolymerization, fluorinated acyl peroxides are added that are soluble in the medinm [62]. A chain transfer agent may be added to control the molecular weight of the resin. The polymer is separated from the medium and converted into nsefnl forms such as melt-extruded cubes for processes working with melt (e.g., extension, injection molding). The resins are also available as aqueous dispersions, molding powders, and fine powders for powder coating [63,64], 

The commercial process for the synthesis of CTFE has two steps. The first step is hydroflnorination of perchloroethane  

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