Acetylation of cellulose in ethyl acetate: characterization and thin film applications

Abstract

The study aims to explore the viability of ethyl acetate as a solvent for cellulose acetylation and assess the feasibility of producing films from the acetylated cellulose. Methodologically, the research focused on limited variations in reaction temperature and catalyst amount, specifically two temperatures and four catalyst quantities, while maintaining consistent quantities of EtoAc and acetic anhydride, reaction time, solution concentration, and other factors. The structure and properties of acetylated cellulose were investigated by titration (heterogeneous saponification), viscosity, chemical resistance (solubility), Fourier transform infrared (FT-IR), X-ray diffraction (XRD), proton nuclear magnetic resonance (1H-NMR) and differential scanning calorimetry (DSC). Surprisingly, efficient acetylation in ethyl acetate was achieved with a small catalyst quantity. As the catalyst amount increased, degree of substitution decreased from 2.32 to 0.76. Further investigation involved the production of thin acetate films using the casting method, and evaluating film properties such as ultraviolet (UV) light absorbance, water vapor permeability, tensile strength, and cross-sectional characteristics via scanning electron microscopy (SEM). The films exhibited impressive tensile strengths, reaching up to 76.98 MPa, and demonstrated exceptional transparency. The findings suggest that EtoAc is a suitable solvent for synthesizing cellulose acetate, and adjustments to reaction variables hold the potential to enhance product qualities.