Propionylation-modified chitin with improved solubility in green ethanol/water binary solvents for sustainable film and coating applications

摘要

The use of less-toxic solvents is highly desirable for biopolymer processing and applications to meet sustainability while alleviating environmental burdens. In this study, chitin was propionylated to improve its solubility. The highly propionylated chitin exhibited considerably improved solubility (up to 96%) in a binary ethanol/water solution as compared to almost insolubility in a single solvent (either ethanol or water). Transparent films were prepared with acidified solutions and possessed excellent mechanical properties with a tensile strength up to 40 MPa and Young's modulus of 1.3 GPa. When the solution of the chitin propionate solution was employed as a coating on a paper substrate, the chitin propionate coating was found to improve the tensile strength of the paper from 64 MPa up to 84 MPa, and it also significantly decreased the surface energy to improve water resistance. These results suggest that chitin propionate that is dissoluble in ethanol/water binary solvents has potential use for new sustainable bio-based films and coatings in practical applications. Published by Elsevier Ltd.