Extraction and application of cellulose microfibers from Washingtonia palm as a reinforcement of starch film

Abstract

This work aims to optimize the industrial extraction conditions of cellulose microfibers (CMFs) from Washingtonia palm fiber for application in starch bio-composite films. The CMF extraction was a mixed process that combines caustic soda treatment with hydrogen peroxide bleaching in a stirred thermostatic bath. To study the yield, whiteness index and α-cellulose content, three variables were selected; NaOH and H2O2 concentrations and treatment time. The optimum was determined using a Response Surface Methodology (RSM) approach for samples treated for 70 min with 5.21% NaOH and 5.54% H2O2. The optimized CMF was used to produce Starch/CMF bio-composite films with higher mechanical and barrier performance, which increased by 300% and 31%, respectively. Moreover, its moisture absorption and water solubility decreased by about 24% and 26%, respectively after adding 20 wt% CMF. In fact, morphological results showed that the higher CMF in the Starch/CMF20 leads to the heterogeneous CMF distribution and agglomerates resulting in weakened starch films. As a result, the extracted CMF can be a competitive nanofabrication filler.