Utilizing foxtail millet husk waste for sustainable new bioplastic composites with enhanced thermal stability and biodegradability.

Foxtail millet husk (FMH) is a byproduct that is not suitable for consumption and is often discarded as solid
waste. However, it can be used as a raw material to develop novel bioplastic composites that transform agrobased
leftovers into value-added goods. Herein, new bioplastic composites were developed from poly(lactic
acid), poly(butylene adipate-co-terephthalate) and FMH based granules by Injection Molding. The required
granules were generated via a solvent evaporation method. The resulted bioplastic composites were analyzed for
their morphologies, mechanical properties, crystal structures, thermal stability, and melting and crystallization
behaviors using various techniques, such as scanning electron microscopy, universal testing machine, X-ray
diffraction, thermogravimetric analysis, and differential scanning calorimetry. Expressly, chemical bonding between
FMH fibers and poly(lactic acid)/poly(butylene adipate-co-terephthalate) PLA/PBAT was confirmed
through Fourier Transform infrared spectroscopy analysis. The inclusion of FMH lowered the impact strength of
the PLA/PBAT combination, which was confirmed by mechanical analysis. Morphological findings confirmed
that the PLA/PBAT combination had FMH aggregation. DSC thermograph revealed negligible differences in glass
transition and melting temperatures of PLA/PBAT blend with and without FMH. The thermogravimetry results
exhibit that the FMH can improve bioplastic thermal stability. The addition of FMH improved the biodegradability
of the PLA/PBAT bioplastic composites. Overall, FMH waste can be repurposed for bioplastic composites
with enhanced thermal stability and biodegradability. This reduces solid waste from agricultural practices and
creates eco-friendly products. Further research could lead to more sustainable alternatives.