Sustainable use of cassava (Manihot esculenta) roots as raw material for biocomposites development

- Cassava peel and bagasse were characterized and used as natural fillers of TPS films.
- Processing conditions favored cassava starch-filler interactions.
- Fillers particle size and chemical composition affect their reinforcing abilities.
- Composites TPS films exhibited higher UV barrier capacity than cassava TPS.
- Byproducts reinforce TPS matrices despite the low concentrations used.

This work is focused on the use of cassava roots peel and bagasse as natural fillers of TPS materials based on cassava starch. A deep insight into biocomposites microstructure was performed in order to support mechanical and barrier properties of the final materials. Cassava byproducts chemical composition and particle size distribution helped to explain TPS SEM morphology, mechanical and barrier properties modifications. Processing conditions favored starch-filler interactions leading to lower mixing energy requirements. The matrix-filler compatibility was demonstrated by FTIR and thermal analysis of TPS composites. Filler addition increased UV-barrier capacity and opacity of TPS materials, though water vapor permeability was maintained. Both byproducts reinforce TPS matrices even though low filler concentrations were used. Bagasse addition (1.5%) increased 260% elastic modulus and 128% maximum tensile stress of TPS composites, being the most efficient reinforcing agent due to its high residual starch content and lower proportion of smaller particles.