Preparation and characterization of adipic acid-modified starch microparticles/plasticized starch composite films reinforced by lignin

In this article, starch microparticles (SM) were prepared by delivering ethanol as the precipitant into starch paste solution dropwise. Adipic acid (AA)-modified starch microparticles (AASM) were fabricated using the dry preparation technique. The composites were prepared using AASM as the filler in glycerol plasticized-corn starch (GCS) matrix by the casting process. Two lignins were also compared in terms of structure and reactivity when incorporated within the AASM-GCS matrix. The effects of lignin on the morphology, surface properties, and water sorption, as well as mechanical and thermal properties of starch-lignin composite films were investigated. The surface water resistance and the thermal stability of materials were improved through addition of lignin. Starch-lignin composite materials presented higher tensile strength, but a lower elongation capacity comparatively with those without lignin.