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.