Supercritical CO2 as a solvent for polymeric stone protective materials

The utilization of CO2 as a potential solvent for fluoropolymers used for the protection of civil infrastructures (buildings, bridges, monuments, etc.) is of major environmental as well as economic importance. The cloud points of six perfluoropolyethers at different weight concentrations in CO2 have been measured over a wide range of pressures. The results show that these fluorinated polymers are readily soluble in pure CO2 (no cosolvent or surfactant needed) at temperatures close to 30 degrees C and pressures below 210 bars. The solubilities of the different polymeric products are strongly depend on the polymer hydrogen content and molecular weight. (C) 1999 Elsevier Science B.V. All rights reserved.