Bacterial Cellulose Acetate: Influence of Degree of Substitution on Structure, Properties and Functional Applications

Abstract

Bacterial cellulose (BC) is a biopolymer characterized by high purity and a highly organized nanofibrillar structure; however, its insolubility and limited processability restrict its use in advanced polymer systems. Acetylation using acetic anhydride has emerged as an effective chemical modification strategy, enabling the controlled substitution of hydroxyl groups with acetyl groups and leading to the formation of bacterial cellulose acetate (BCA), a material with tunable properties. This review critically discusses the main reaction systems based on acetic anhydride, addressing reaction mechanisms, the influence of catalysts, and operational conditions, as well as their relationship with the degree of substitution (DS). Particular attention is given to the correlations between DS and structural, thermal, and morphological properties, including changes in crystallinity, thermal stability, thermoplastic behavior, and solubility in organic solvents. The implications of these modifications for the formation of films and membranes are also examined, highlighting the role of reaction control in materials engineering for applications in separation processes, functional packaging, and biomedical devices. Finally, current challenges related to precise DS control, reproducibility, and industrial scalability are discussed, which are essential aspects for consolidating BCA as a material of interest in applied polymer engineering.