Prof. Juan Francisco Rodríguez
Prof. Juan Francisco Rodríguez
University of Castilla-La Mancha, Spain

The use of supercritical CO2(scCO2) as polymerization media looks very attractive because ideally makes easier the separation of unreacted monomers, allows a clean and complete removal of co-solvents or reaction additives, improves the mass transfer into a high swelled polymer bulk and permits the tuning of the final physical properties of the polymer obtained. 

Nevertheless not all are advantages, the scCO2 plays a key role into the polymerization process producing multiphase reaction processes of high complexity.In such system, not only the reactivity of CO2 plays a key role on the ring opening polymerizations on scCO2. The matter of question to understand the behaviour of the system is whether in the operative conditions the monomers and/or the polymer are soluble in the scCO2. The formation of particles or foams depends critically on the solubility and on the Tg of the polymer. 

For that reason the knowledge of the complex equilibrium behaviour of monomers, oligomers and polymer into scCO2 is fundamental and also is important to know the changes that the high pressure CO2 exerts on the glass transition temperature, viscosity, surface tension, to understand and control the physical characteristics of the materials that can be obtained: particles, foams, bulks. 

Porous biodegradable polymeric foams loaded with drugs have potential applications in tissue engineering and controlled drug delivery systems. For instance, an environmentally friendly process using scCO2 as foaming and carrier agent was used for the impregnation of 5-fluorouracil and indomethacin in polylactide (PLA) and poly-(lactide-co-glycolide) (PLGA). 

Also, the scCO2 has been employed as green solvent to perform the functionalization of biopolymers by “click” chemistry. The presence of CO2 can favour not only the compatibility and dispersion of the functionalization agent (drug, enzyme, hormone, etc) but also its reactivity with the polymer. The residual reactive are easily removed together with CO2 after the reaction, leaving an absolutely clean and sterilized biomaterial.

Dr. Juan Francisco Rodríguez is Full Professor of Chemical Engineering and theHead of the Institute of Chemical and Environmental Technology (ITQUIMA) from 2007. With about 40 researchers, ITQUIMA is one of the reference research Institutes in the University of Castilla-La Mancha in funding, number of projects, scientific publications and technology transference. More than 180 scientific publications and 190 participations in congress validate the quality of his applied research work. Participant in 3 FP7 projects and NANOLEAP in H2020, he has been the main responsible of more than 20 research projects funded by National and Regional institutions. From lab to pilot plant scale, he has managed more than 100 research projects funded by private companies. He is also the author of seven patents (national and EP). The development of microencapsulation process and the green synthesis of biomaterials in supercritical carbon dioxide are between his main research lines. He has received several national and international research awards and one regional distinction for the creation of the best “spin-off” in the region of La Mancha. Several large pilot plant facilities for the synthesis of biopolymers, microcapsules and for the recycling of polymers are now in operation in ITQUIMA under his supervision. He has been coordinator of the Polyurethanes reference group of the Spanish petrochemical company Repsol for more than 20 years.