Copolymerization of vinylidene fluoride with hexafluoropropylene in supercritical carbon dioxide

Copolymerization of vinylidene fluoride (VNF) with hexafluoropropylene (HFP) in scCO 2, carried out using perfluorobutyryl peroxide (PBP) initiator over a range of pressures and monomer ratios, was investigated. The PBP initiator was synthesized in Feron 113 and all manipulations were performed in a NaCl/ice bath, and the final product was stored under dry ice. The reactor was purged three times with scCO 2 to remove oxygen. Results show that depending on the initial monomer ratio and reaction pressure, the reaction can proceed heterogeneously, homogeneously initially, becoming homogeneous with increasing reaction time.