The Impact of Nanomaterials Modification by Biodegradable Materials in the Food Packaging Industry

In this research work, the mechanical and thermal properties of reinforced films of starch, polylactic acid and cellulose nanofibers for use in the food packaging industry are investigated. Finding the effectiveness of each material by itself and their cumulative effects, studying the effects of starch, polylactic acid and cellulose nanofibers in making films and finding the appropriate portions of materials leading to the best achievable properties have been the objectives of this investigation. In this study, biodegradable nanocomposite films based on polylactic acid, starch and cellulose nanofibers as reinforcing agents were prepared using the solvent casting method. For the produced starch, nanofiber and cell films, the physical properties of thickness, color and structure were studied using the XRD and electron microscopy SEM scanning, whilst the WVP water vapor permeability and mechanical properties including tensile strength, Young modulus and tensile strength at break point, thermal properties including Tg, Tm and the crystallization percentage were investigated by the DSC and FTIR infrared spectroscopy. Scanning electron microscopy results showed the desirable uniform dispersion of starch, cellulose nanofibers with polylactic acid especially in starch and cellulose nanofibers on level (1) and polylactic acid with cellulose nanofibers on level (1.5). In the study of mechanical properties, the addition of cellulose nanofibers to starch films reduced the Young's modulus and increased the tensile strength at the rupture point. The tensile strength increased from 4.5 MPa to 6.63 MPa and 6.89 MPa for starch and cellulose nanofibers films. For polylactic acid and cellulose nanofibers films, the tensile strength increased from 8.76 MPa to 18.56 MPa and 22.69 MPa. For starch and cellulose nanofibers with polylactic acid, the tensile strength increased from 35.33 MPa to 36.99 MPa. It was also observed that the addition of cellulose nanofibers does not have considerable effects on water vapor permeability.