Bionanocomposites based on pea starch and cellulose nanowhiskers hydrolyzed from pea hull fibre: Effect of hydrolysis time

By hydrolyzing pea hull fibres (PHF) for different times (t) with sulfuric acid, a series of pea hull fibre-derived nanowhisker (PHFNW-t) dispersions was prepared. The PHFNW-t dispersions were then blended with pea starch (PS) to fabricate bionanocomposite films (PS/PHFNW-t). The effect of t on the structure and properties of the PHFNW-t nanowhiskers and those of the corresponding PS/PHFNW-t nanocomposite films were investigated. The length (L), diameter (D) and L/D values of the PHFNW-t ranged from 240 to 400 nm, 7 to 12 nm, and 32.22 to 36.00, respectively. The PS/PHFNW-t nanocomposite films exhibited higher ultraviolet absorption, transparency, tensile strength, elongation at break, and water-resistance than both the neat PS film and the PS/PHF film (as a control with a t of 0 h). The PS/PHFNW-8 film showed the highest transparency, tensile strength, and elongation at break among the PS/PHFNW-t films, due to the high L/D of PHFNW-8. These results revealed that the length of hydrolysis time had a great effect on the structure (including L, D and L/D) of the PHFNW-t nanowhiskers, as well as on the structure and performance of the resulting PS/PHFNW-t films. For preparation of PHFNW-t nanowhiskers and corresponding PS/PHFNW-t films, the most suitable hydrolysis time, in this work, is 8 h.