Effects of reaction conditions on the degree of substitution in acetylated nanocellulose

Abstract

In this study, cellulose nanocrystals (CNC) were chemically extracted from the waste newspapers and acetylated by reacting CNC with acetic anhydride, using sulfuric acid as a catalyst. Response Surface Methodology based on a three-factor factorial design was applied to analyze the interaction effects of reaction temperature, time, and the ratio of nanocellulose and acetic acid (wt/v) on the degree of substitution (DS) which was calculated and compared. Various experimental conditions as reaction temperature (50-70 °C), reaction time (90-150 min), and the ratio of nanocellulose and acetic acid (wt/v) (1:15-1:25) were under investigation. It was found that reaction temperature and its interaction effects have the most significant effects on DS. The acetylated CNC was characterized by FTIR and 1H-NMR spectroscopy. The highest DS (2.997) was obtained in 90 min and the CNC/acetic acid ratio of 1:15 at 70 °C.