Utilization of pineapple peel for production of nanocellulose and film application

Abstract

Pineapple peel is a renewable agricultural residue available in abundance whose multipurpose utilization deserves more attention. The present study aimed at the isolation of nanocellulose from pineapple peel and evaluation on its reinforcement capability for gellan gum film. The results from scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR) and X-ray diffraction (XRD) indicated the progressive removal of non-cellulosic components and the non-destruction of cellulose structure following bleaching and alkali treatments. Atomic force microscopy image of the nanocellulose displayed a needle-like structure with averages of 15 ± 5 nm in diameter and 189 ± 23 nm in length. Thermal gravimetric analysis (TGA) indicated that the obtained fibres after bleaching and alkali treatments showed higher thermal stability than the untreated pineapple peel. Although showing an earlier initial degradation temperature, the obtained nanocellulose remained the maximum residue after being heated to 500 °C. The rheological results indicated that the viscosities of the nanocellulose/gellan gum solutions increased slightly with the increase of nanocellulose content. The prepared films were characterized by FTIR, SEM, XRD, TGA, light transmittance and mechanical properties. The introduction of nanocellulose decreased light transmittance values but enhanced the thermal stability of gellan gum film. Compared with the neat gellan gum film, the 4% nanocellulose loaded gellan gum film showed 48.21% improvement in tensile strength.