CELLULOSE OXIDATION IN DENSIFIED CARBON DIOXIDE MEDIUM

摘要

When oxidized in a selective way, cellulose becomes resorbable inside human body and, parallelly, develops hemostatic and antibacterial properties, thus leading to the manufacturing of medical devices such as absorbable hemostatics and adhesion barriers. Current industrial processes involve the reaction of cellulose with the oxidative nitrogen dioxide (NO_2), dissolved into chlorofluorocarbons or perfluorinated hydrocarbons, these solvents being chosen because of their inertness in respect to oxidation. We present here a new process, based on the use of supercritical carbon dioxide (SCCO_2) as a solvent for NO_2. This study addresses the influence of reaction time upon the degree of oxidation of the product. In this process, the oxidative reaction is typically performed at 100 bar and 40°C. This procedure yields a material with limited degradation products, a degree of oxidation of 0.6, and with good bioresorbability and mechanical properties.