Sustained-Release Performance of Fragrance Agent Based on Palygorskite/Wood Fiber Composite Aerogels

In this work, the palygorskite-based aerogel was used as the carrier of essential oil to prepare high-loading fragrances and achieve long-term controlled release of essential oil. Palygorskite/wood fiber composite aerogels with a high specific surface area, a high porosity and a superior machinability were prepared with palygorskite as a three-dimensional network skeleton and wood fiber as a toughening/ reinforcing material. The loading efficiency of sweet orange essential oil on the aerogels is 96% and the volatile residual oil rate is＜5%. The hydrophobic modification can increase the loading efficiency of aerogels on essential oil, thus prolonging the release time of essential oil. The volatilization rate of essential oil follows a three-stage change law of short-term rapid decline, stable rate and slow decline, showing a good speed control ability of composite aerogels on the volatilization of essential oil. The fragrance agent can maintain a constant release rate of 80 mg/h for 27 h at 60 ℃, and the cumulative release time is 31 h when the aerogels volume is 4 cm³. The controlled release rate of essential oil increases with the increase of aerogels volume. The release behavior of essential oil in aerogels follows the Korsmyer–Peppa model, which belongs to the Non-Fickian diffusion.