Preparation of Esterified Bacterial Cellulose for Improved Mechanical Properties and the Microstructure of Isotactic Polypropylene/Bacterial Cellulose Composites

Bacterial cellulose (BC) has great potential to be used as a new filler to reinforce isotactic polypropylene (iPP) due to its high crystallinity, biodegradability, and efficient mechanical properties. In this study, esterification was used to modify BC, which improved the surface compatibility of the iPP and BC. The results indicated that the cellulose octoate (CO) changed the surface properties from hydrophilic to lipophilic. Compared to the pure iPP, the tensile strength, charpy notched impact strength, and tensile modulus of the iPP/BC composites increased by 9.9%, 7.77%, and 15.64%, respectively. However, the addition of CO reinforced the iPP/CO composites. The tensile strength, charpy notched impact strength, and tensile modulus of the iPP/CO composites increased by 14.23%, 14.08%, and 17.82% compared to the pure iPP. However, the elongation at break of both the composites is decreased. The SEM photographs and particle size distribution of the composites showed improvements when the change of polarity of the BC surface, interface compatibility, and dispersion of iPP improved.