Surface acetylation of bacterial cellulose

Bacterial cellulose was partially acetylated by the fibrous acetylation method to modify its physical properties, while preserving the microfibrillar morphology. The overall degree of substitution was varied from 0.04 to 2.77 by changing the amount of acetic anhydride added. X-ray diffraction of the partially acetylated samples showed the crystalline pattern of unmodified cellulose I up to moderate degrees of acetylation, and the change in peak widths indicated that acetylation proceeded from the surface of microfibrils, leaving the core portion unreacted. Scanning electron microscopy revealed that even low levels of acetylation were effective to maintain the original microfibrillar morphology of bacterial cellulose on direct drying from water.