Polycaprolactone foams prepared by supercritical CO2 batch foaming of polymer/organic solvent solutions

Abstract

In this work, the batch foaming of polymeric solutions by means of supercritical CO2 (scCO2) is described. The developed process combines the advantages of processing materials from solution in organic solvents and scCO2 batch foaming to prepare foams with uniform and controllable porosity. Polycaprolactone (PCL) was selected as semi-crystalline polymer as a case study and foams from solutions in different scCO2-miscible organic solvents, namely ethyl acetate, chloroform, dioxane and dimethyl sulfoxide, were prepared.Obtained results demonstrate that processing PCL solutions by means of scCO2 batch foaming enables preparing solid polymeric foams with solvent residue close to 1 wt. %, density values in the 0.2–0.5 g/cm3 range, hundreds of microns pore size and pore walls with spherulitic morphology. The advantage of this process is herein demonstrated by the fabrication of composite PCL foams containing 30 w% of either inorganic TiO2 nanoparticles and 5-fluorouracil chemotherapeutic by processing polymeric solutions in a single step.