Reinforcement Effects of Microfibrillated Cellulose on Chitosan-Polyvinyl Alcohol Nanocomposite Film Properties

The objective of this research was to analyze the reinforcement effect of microfibrillated cellulose (MFC) on chitosan-polyvinyl alcohol (chitosan-PVA) nanocomposite films in terms of their morphological, physical, chemical, thermal, biological, and mechanical properties. Chitosan-PVA blend films reinforced with MFC filler loadings at 0.5 to 5 percent had smoother, more regular, and more uniform external surface morphology compared with chitosan-PVA reinforced with MFC filler loaded at 7.5 percent. With regard to the physical properties, incorporation of MFC into chitosan-PVA polymer blends reduced nanocomposite film transparency. Furthermore, the films had three different diffraction peaks: crystalline peak, amorphous peak, and small ancillary peak. Compared with the neat chitosan-PVA blend, the addition of MFC to chitosan-PVA polymer blends shifted Fourier-transform infrared spectroscopy peaks at 3,500 to 3,000, 2,918, 1,440, 1,101, and 850 cm(-1), indicating a chemical interaction between chitosan-PVA polymer blends and MFC. According to differential scanning calorimetry, thermogravimetric analysis, and differential thermal analysis, the addition of MFC enhanced the thermal stability of chitosan-PVA compared with neat chitosan-PVA composite films. Most nanocomposite films reinforced with MFC had a higher tensile strength than films made from neat chitosan-PVA and chitosan-PVA-MFC 7.5 percent because of percolation formation. However, neither neat chitosan-PVA composite film nor chitosan-PVA-MFC nanocomposite films showed a zone of inhibition or had a zone of inhibition index against Escherichia coli, Staphylococcus aureus, Candida albicans, and Ganoderma sp.