Properties of alginate-based films reinforced with cellulose fibers and cellulose nanowhiskers isolated from mulberry pulp

Cellulose fibers (CF) and cellulose nanowhiskers (CNW) were isolated from the mulberry pulp and blended with alginate to prepare alginate-based composite films. Different concentrations (2, 4, and 6 wt% based on alginate) of CF and CNW were used to test the effect of filler concentrations on the mechanical, water vapor barrier, and thermal properties of the alginate-based composite films. The CNW was in needle shape with the length of 200–400 nm and the diameter of 15–30 nm. The mechanical properties of alginate films were improved by blending with the CNW. The elastic modulus and tensile strength of alginate films were increased by 35% and 25%, respectively, however, water vapor permeability remained at the same level as the neat alginate films by blending 4 wt% of CNW. The CNW obtained from the mulberry pulp can be used as a reinforcing filler for the preparation of bio-nanocomposites for the development of completely biodegradable food packaging materials.