Solvent-free Rapid Microwave Esterification of Bamboo Lignocellulose for Biodegradable Composite Films Fabrication

The poor compatibility between hydrophilic bamboo powder and hydrophobic biodegradable polymers poses a major challenge for developing high-performance biomass composite plastics. Herein, a rapid, solvent-free, and heterogeneous esterification method for the efficient esterification modification of bamboo powder using microwave assistance was proposed. Maleic anhydride (MAH) and bamboo powder were subjected to a solvent-free reaction in a microwave reactor for 30 min, achieving efficient esterification of bamboo lignocellulose. The esterified bamboo powder required no further purification and can be directly used to fabricate PBAT composite films. The esterification reaction between MAH and the hydroxyl groups of lignocellulose to reduce the polarity of bamboo and the unreacted MAH shields hydroxyl groups of surfaces cooperatively and improved the interfacial compatibility of bamboo powder with PBAT. The composite sample with 40 wt % PBAT substitution exhibited mechanical properties far superior to those reported in comparable studies, achieving a tensile strength of 16.56 MPa and an elongation at break of 428.5%, while reducing the overall cost by 22.55%. Furthermore, the film exhibits excellent barrier properties against water vapor and UV radiation. This study provides a feasible pathway for the high-value utilization of lignocellulosic resources, such as bamboo, in applications including packaging materials and agricultural mulch films.