Utilization of modified montmorillonite and modified bamboo charcoal power as fillers in chitosan films

Abstract

Chitosan/modified montmorillonite composite films and chitosan/modified bamboo charcoal composite films were prepared by blending chitosan with either modified montmorillonite or modified bamboo charcoal and forming the composite film by using a spin coater machine. The chitosan composite films contained contents of modified montmorillonite or modified bamboo charcoal varying from 0 to 2% (w/w). The morphological, structural and functional properties of these composite films were evaluated. The X-ray analysis showed that the modification of montmorillonite with depolymerized chitosan at molecular weight of 15 kDa appeared to induce the intercalation occurred in the modified montmorillonite. FTIR analysis confirmed that nitric acid oxidized some areas of bamboo charcoal particles during refluxing, leading to formation of carboxylic acid groups on the surface of the bamboo charcoal particles. Investigation of the mechanical properties of these composite films revealed that the tensile strength and rigidity were both found to increase, whilst the elongation at break decreased, with increasing either virgin or modified montmorillonite and bamboo charcoal in chitosan composite films. Inclusion of either unmodified montmorillonite or modified montmorillonite in chitosan films decreased the water and oil absorption of the composite films. Oil, and especially water, absorption of the chitosan/modified bamboo charcoal composite films increased with inclusion of either unmodified bamboo charcoal or modified bamboo charcoal in chitosan films. Inclusion of either modified montmorillonite or modified bamboo charcoal into chitosan films enhanced the thermal stability of chitosan composite films. SEM micrographs showed a good dispersion of modified montmorillonite and bamboo charcoal particles in chitosan matrix up to 0.5% (w/w), while some aggregation of montmorillonite or bamboo charcoal were observed at the content starting of 1% (w/w) of the chitosan composite films. The growth of Colletotrichum gloeosporiodes was completely inhibited by chitosan and chitosan composite films