The Diffusion of TEMPONE Radical in the Graft Copolymer of N-Isopropylacrylamide with Oligolactide in the Presence of Supercritical Carbon Dioxide by In Situ EPR Method

Abstract

Impregnation of the thermoresponsive graft copolymer of <i>N</i>-isopropylacrylamide and oligolactide, (P(NIPAM-<i>co</i>-PLA)), with the composition 83.8 : 16.2 wt % with a stable nitroxyl radical, 4-oxo-2,2,6,6-tetramethyl-piperidine-1-oxyl (TEMPONE), in SC-CO₂ medium using a high-pressure reactor that allows recording electron paramagnetic resonance (EPR) spectra <i>in situ</i> is performed for the first time. The diffusion coefficient of TEMPONE in P(NIPAM-<i>co</i>-PLA) swelled in SC-CO₂ is estimated.