Improving gas barrier properties of sugarcane‐based LLDPE with cellulose nanocrystals

Abstract

AbstractThis study was aimed at improving the gas barrier property of sugarcane based LLDPE using cellulose nanocrystals (CNCs). Specifically, this study evaluated the effect of CNC content on the crystallinity, tortuosity factor, carbon dioxide permeability (PCO2), and/or oxygen permeability (PO2) of bio‐LLDPE sheets and films. All nanocomposites showed considerable improvement in gas barrier irrespective of the CNC content. The PCO2 coefficient of LLDPE sheets decreased by 36% by adding 10 wt% of CNCs into the sheet. Similarly, a significant decline in both PO2 (about 50%) and PCO2 (about 33%) coefficients of LLDPE films was obtained by adding 2.5 wt% of CNCs into the films. Nevertheless, no correlation was established between gas permeability and percent crystallinity of LLDPE sheet since the PCO2 coefficient decreased almost linearly with increasing CNC content whereas the percent crystallinity of LLDPE increased only up to 2.5% CNC content and remained constant thereafter. In contrast, the tortuosity factors calculated from the gas diffusion coefficients increased almost linearly with CNC contents and correlated well with the gas permeability improvement in bio‐LLDPE‐based nanocomposites. Consequently, the enhanced gas barrier in the nanocomposite was assigned to the tortuosity effect created by the impermeable CNCs rather than the changes in percent crystallinity.