Structural Interpretation of Plasma-polymerized Tetrafluoroethylene

Structural interpretation of plasma-polymerized tetrafluoroethylene produced in a glow discharge chamber is given by referring to 19F-NMR and IR spectroscopy, elemental analysis, and number-average molecular weight determination. The polymer is hardly soluble in the usual organic solvents because of its highly branched structure, making NMR spectroscopy and molecular weight determination impossible. However, the polymer is soluble in 1,2-dibromo-1,1,2,2-tetrafluoroethane and the following structural interpretation could be obtained. The number-average molecular weight is 3600 for the majority of the polymer, consisting of 96 carbon and 129 fluorine atoms within a unit molecule. The IR spectrum shows evidence of some C=C groups and the 19F-NMR spectrum a highly branched and cross-linked structure in which a large number of quaternary carbons are involved in the polymer matrix as compared with CF2 and CF carbons. The plasma-polymerized tetrafluoroethylene has been characterized in a somewhat different way from the plasma-polymerized ethylene, involving a small number of quaternary carbons.