Molecular-scale exploration of mechanical properties and interactions of poly(lactic acid) with cellulose and chitin

Poly(lactic acid) (PLA), one of the pillars of the current overarching displacement trend switching from oil- to natural-based polymers is often associated with polysaccharides, to benefit from their increased mechanical properties. This association is, however, greatly hampered by the poor PLA/polysaccharide miscibility, whose underlying nature is still vastly unexplored. This work aims at shedding light into the PLA-polysaccharide interactions and reveal structure-property relationships from a fundamental perspective using atomistic molecular dynamics with amorphous cellulose and chitin as representative polysaccharide molecules. Our computational strategy was able to reproduce targeted mechanical properties of pure and/or composite materials, reveal a lesser degree of immiscibility in PLA/chitin compared to PLA/cellulose associations, assert PLA-oriented polysaccharide reorientations and explore how less effective PLA-polysaccharide hydrogen bonds are related to the poor PLA/polysaccharide miscibility.