Starch films containing starch nanoparticles as produced in a single step green route

Abstract

Thermoplastic starch films with glycerol and nanoparticles were prepared from regular cornstarch in a single and quick step using the green chemical principle. Starch nanoparticles (SNPs) were produced by nanoprecipitation with the addition of ethanol as nonsolvent to the hot and room temperature polymeric dispersion. Contact angle increased from 41°, for the control sample, to 67°, for the film produced with glycerol as a plasticizer and by adding alcohol to the hot polymeric dispersion, which indicated a significant decrease in hydrophilicity. SNPs acted as a reinforcing agent and the mechanical properties varied as a function of the presence of plasticizer. Films prepared without glycerol were more rigid presenting the highest Young’s modulus (E = 3640 ± 209 MPa) and the lowest elongation at break (εmax), whereas the films prepared with glycerol were more flexible with the lowest E value and higher εmax around 23%.