Mechanical Properties of Silver-Clay Nanofilms for Food Packaging

In this research, the mechanical properties of seven types of nanofilm with differing amounts of silver and silver-clay particles were studied. The elasticity of modulus, tensile strength, toughness, elongation at break, tear strength and color of nanofilms were compared with those of ordinary LDPE film. Results showed that the inclusion of nano particles increased the modulus of elasticity, tensile strength and tear strength 1.1 to 2.5 times. However, elongation at break point and toughness of the films decreased 1.4 to 4 times. The effect of film type on modulus of elasticity, tensile stress and tear strength was significant at the 0.01 level and for elongation at break point and toughness was significant at the 0.05 level. An investigation of film color parameters and ∆E showed that the 1000 ppm nano silver film had more color than the other films. The smallest ∆E was for the control film. The ∆E value of the nano silver films increased as nano particle content increased and, in nano composite films, decreased as clay content increased. Overall, the nano film with 1000 ppm nano silver content was the best film and the control film was the worst. In conclusion, the nano composite film (SC3) with 500 ppm nano silver and 450 ppm nano clay content was the best film in terms of its mechanical properties. The dark color of this film, however, is an undesirable aspect for food packaging. This may be alleviated by color-removing procedures or by use of the films with lower nano particle content.