Swelling of cellulose stimulates etherification

Abstract Cellulose has inherent properties that are both hydrophilic and water-insoluble, which can create challenges in certain technical applications. One solution to these challenges is derivatization, however, the crystalline structure of cellulose limits its chemical reactivity. This study explores the reactivity of highly swollen cellulose produced by dissolving and reprecipitating microcrystalline cellulose. This extreme swelling of cellulose is expected to increase the accessibility and reactivity, however, upon drying the cellulose becomes hard and inflexible a phenomenon known as hornification. Different drying methods were used to overcome the problems of hornification, including freeze-drying, acetone-drying, and drying with glycerol as a spacer. The samples were carboxymethylated and the degree of substitution (DS) was used to assess reactivity, with freeze-dried samples showing the highest DS. The findings suggest that preserving the swollen structure through appropriate drying methods enhances cellulose reactivity, offering potential improvements in industrial cellulose ether production.