Improvement of polyvinyl alcohol properties by adding nanocrystalline cellulose isolated from banana pseudostems

•Cellulose nanocrystals from banana pseudostem were extracted and characterized.•Nanocomposites of PVOH-nanocrystals were casted and characterized.•The nanocrystals improved thermal, mechanical, and barrier properties of PVOH. Cellulose nanocrystals (CNCs) isolated from banana pseudostems fibers (BPF) of the Pacovan variety were used as fillers in a polyvinyl alcohol (PVOH) matrix to yield a nanocomposite. The fibers from the external fractions of the BPF were alkaline bleached and hydrolyzed under acidic conditions (H2SO4 62% w/w, 70min, 45°C) to obtain CNCs with a length (L) of 135.0±12.0nm and a diameter (D) of 7.2±1.9nm to yield an aspect ratio (L/D) of 21.2. The CNCs were applied to PVOH films at different concentrations (0%, 1%, 3%, and 5% w/w, dry basis). With higher concentrations of CNCs, the water–vapor barrier of the films increased, while the optical properties changed very little. Increasing the concentration of the CNCs up to 3% significantly improved the mechanical properties of the nanocomposite.