Homogeneous phase polymerization of vinylidene fluoride in supercritical CO2:: Surfactant free synthesis and kinetics

Vinylidene fluoride (VDF) polymerizations were carried out in homogeneous phase with supercritical carbon dioxide (scCO(2)) at 120 degrees C and 1500 bar. To control molecular weight perfluorohexyl iodide was used. molecular weight analysis by size-exclusion chromatography indicates that polymers of low polydispersities ranging from 1.5 to 1.2 at the highest iodide concentration Of 0.25 mol . L-1 were obtained. in addition, polymer molecular weight increases linearly with reaction time, indicating that living conditions were established. The "livingness" is based on the labile C-I bond. The weakness of the C-I bond is associated with a fast decomposition of the original hexyl iodide, thus, contributing to initiation and to a significant increase in the initiation rate in the initial phase of the polymerization.