Supercritical carbon dioxide extraction of a liquid crystalline additive from polystyrene matrices

Liquid crystalline 4,4′-dibutylazobenzene has been extracted from a polystyrene matrix using supercritical carbon dioxide (scCO2). Extraction efficiency of pure scCO2 is compared with that of Soxhlet extraction. The Simplex method has been used to optimize the time–temperature–pressure parameters. UV–V spectrophotometry has been used to quantify the concentration of the extracted solutions and FTIR to monitor composition. scCO2 allows the extraction of the pure additive significantly improving the yield and strongly reducing time as compared with the conventional method.