Biobased composites of poly(lactic acid) melt compounded with bacterial and vegetal nanocelluloses incorporated through different strategies

J. BOVI; J. DELGADO; O. DE LA OSA; M. PELTZER; C. BERNAL; M.L. FORESTI

Polymers

MDPI

Lugar: Basel; Año: 2024 vol. 16 p. 898 - 915

2073-4360

In the current contribution, bacterial nanocellulose obtained from a by-product of Kombuchatea production and vegetal nanocellulose isolated from milled rice husks were employed asfillers of PLA-based composites prepared by intensive mixing followed by compression molding.Given the challenges associated with the incorporation of nanocelluloses—initially obtained as aqueoussuspensions—into melt compounding processes, and also with achieving a proper dispersionof the hydrophilic nanofillers within PLA, three different nanofibrils incorporation strategies werestudied: i.e., direct mixing of dried milled nanocelluloses and PLA; masterbatching by solvent castingof native nanocelluloses followed by melt compounding; and masterbatching by solvent casting ofacetylated nanocelluloses followed by melt compounding. Composites with varying filler content(from 0.5 wt.% to 7 wt.%) were characterized in terms of morphology, optical properties, and mechanicalperformance. Results revealed the relative suitability of each strategy employed to promotenanocelluloses dispersion within the PLA matrix. PLA/nanocellulose masterbatches prepared bysolvent casting proved to be particularly useful for feeding the nanocelluloses into the processingequipment in a dry state with limited hornification. Acetylation also contributed to a better dispersionof both nanocelluloses within the PLA matrix, although no clear positive impact on the mechanicalproperties of the films was observed. Finally, filler loading played an important role in the films’properties by increasing their stiffness while reducing their translucency.