Synthesis of indoleacetic acid modified cellulose nanocrystals and their enhanced effect on the physical properties of pectin film

Cellulose nanocrystals (CNCs) is extensively applied in bio-based biodegradable materials due to its unique properties. In this paper, an efficient oxidation method was proposed for the preparation of CNCs at mild reaction conditions (room temperature, 3 h) using a sodium bisulfite (NaHSO 3 ) activated potassium permanganate (KMnO 4 ) system. Subsequently, indoleacetic acid (IAA) modified CNCs (CNCI) were prepared by reacting CNCs with IAA, and the physical and chemical properties of CNCI were investigated by scanning electron microscope (SEM), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), thermogravimetric analyser (TGA) and X-ray photoelectron spectroscopy (XPS). The modification of CNCs broadened the applications of CNCs, and the incorporation of CNCI into pectin-based films improved the physical properties (including mechanical property, UV resistance, hydrophobicity) of pectin film (P). Besides, the obtained P-CNCI film showed good antibacterial property and it could be used for strawberry preservation. This study provided an efficient, environmentally friendly and economical method for the preparation and modification of CNCs, which showed potential applications in the manufacture of advanced functional materials.