Synthesis of Fluoropolymers in Supercritical Carbon Dioxide

TLDR

Fluoropolymers are prized for high‑performance properties but are generally insoluble in common solvents, limiting variant synthesis to chlorofluorocarbons. The study aims to avoid the environmental hazards of CFCs by synthesizing these materials in supercritical fluids. The authors perform homogeneous solution polymerization of highly fluorinated acrylic monomers in supercritical CO₂ using free‑radical initiation. Decomposition rates and efficiency factors of azobisisobutyronitrile in supercritical CO₂ were quantified and found to differ from those in conventional liquid solvents.

Abstract

Fluoropolymers are used in many technologically demanding applications because of their balance of high-performance properties. A significant impediment to the synthesis of variants of commercially available amorphous fluoropolymers is their general insolubility in most solvents except chlorofluorocarbons (CFCs). The environmental concerns about CFCs can be circumvented by preparing these technologically important materials in supercritical fluids. The homogeneous solution polymerization of highly fluorinated acrylic monomers can be achieved in supercritical carbon dioxide by using free radical methods. In addition, detailed decomposition rates and efficiency factors were measured for azobisisobutyronitrile in supercritical carbon dioxide and were compared to those obtained with conventional liquid solvents.