Biopolymeric porous structures obtained by supercritical fluids assisted processes

In the last years, biolpolymeric porous structures have acquired an increasing importance in different fields of engineering, ranging from chemical engineering to tissue engineering. Until now, various processes have been implemented for the generation of porous structures, but they are all characterized by several limits, such as long processing times, traces of organic solvents in the final products, low versatility, etc. In this work, we tested a green process assisted by supercritical fluids for the generation of biopolymeric porous structures: the supercritical phase inversion process. We processed different biopolymers such as Polysulfone, Polymethylmethacrylate and Polyvinyl alcohol, and analyzed the effect of process parameters (pressure, temperature, polymer concentration, kind of solvents) on the final morphology. The results confirmed the advantages of the supercritical fluids assisted process with respect to the traditional ones: indeed, dry porous structures were obtained in few hours; moreover, changing the parameters, it was possible to control the kind of structures obtained (from cellular one to bicontinuous) and the size of the pores and porosity (from 70 to 90%); finally, the structures were characterized by residual solvents amount lower than 5 ppm.