Vinylidene fluoride telomerization

The first reported polymerization of fluoroolefins in carbon dioxide was by Fukui and coworkers [39,40]. Tetrafluoroethylene, chlorotrifluoroethylene,and other fluoroolefins were polymerized in the presence of CO2 using ionizing radiation [39, 40] and free-radical initiators [40]. DeSimone and coworkers reported the homogeneous telomerization of tetrafluoroethylene [41] and vinylidene fluoride [42] in CO2 using AIBN as an initiator. The kinetics of AIBN decomposition in CO2 is well understood [4]. However, peroxide initiators are preferred over azo initiators for producing stable endgroups in fluoroolefins... 

Scheme 93 AIBN - initiated telomerization of vinylidene fluoride and tetrafluoroethylene in sc-COp.

Tetramethyldiphosphine adds photochemically to vinyl and vinylidene fluoride to give the bisphosphines Me2P-CH2-CXF-PMe2 (X H or F), and tetrakis(trifluoromethyl)diphosphine similarly adds thermally (at 50 Q or photochemically to the same olefins and to tetrafluoroethylene. Free-radical additions of trifluorothioacetic acid to the olefins CHF CF2, CHarCFa, and CH2 CHF (see p. 138) have been described only one-way addition was observed. Bis(trifluoromethyl) disulphide adds to fluoro-olefins with u.v. Irradiation in Pyrex or silica apparatus in the vapour phase to yield a variety of 1 1 and telomeric adducts. The products are consistent with the following mechanism ... 

A methacrylate-type poly(vinylidene fluoride) (PVF2) macromonomer was synthesized from vinylidene fluoride via hydroxy-terminated PVF2 obtained by telomerization of vinylidene fluoride. Although homopolymerization of this macromonomer did not proceed completely, it was successfully copolymerized with MMA. 

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