Facile one−step preparation of acetylated cellulose nanocrystals and their reinforcing function in cellulose acetate film with improved interfacial compatibility

Abstract

A facile one− step method to fabricate acetylated cellulose nanocrystals (ACNCs) was developed by using mixed sulfuric acid and acetic acid hydrolysis. It could be demonstrated that the esterification of surface hydroxyl groups took place simultaneously with hydrolysis of amorphous regions of cellulose, which was confirmed by transmission electron microscopy (TEM), Fourier transform infrared spectra (FT − IR) and X − ray diffraction (XRD) measurement. The as − prepared ACNCs exhibited typical rod − like morphology with diameter and length of 12 − 18 and 191 − 234 nm, respectively. All − cellulose nanocomposite films were subsequently produced by introducing ACNCs into cellulose acetate (CA) matrix through solution casting technique. The mechanical performance of nanocomposites was significantly enhanced due to the uniform dispersion of ACNCs and favorable CA − ACNC interface. The results showed that the tensile strength, Young’s modulus and elongation at break of nanocomposite film were increased by 78%, 58% and 68%, respectively, with the introduction of 5% ACNCs. Moreover, the nanocomposite films could retain good optical transparency. These results indicated ACNCs have a great potential to be used as reinforcing filler in polymer matrices for extending their industrial applications.