دانلود رایگان مقاله افشای بالقوه نانوکامپوزیت صمغ گوار / نقره و مس

ABSTRACT

Guar gum (GG) based nanocomposite (NC) films were prepared by incorporating silver-copper alloy nanoparticles (Ag-Cu NPs)through solution casting method. Effect of NP loadings (0.5–2%) on the thermomechanical, optical, spectral, oxygen barrier and antimicrobial properties of the GG/Ag-Cu NC films were investigated. Tensile testing showed an improvement in the mechanical strength, and a decrease in elongation at break for all NP loadings. NP incorporation into GG films showed a marked influence on the color values. The NC films showed excellent UV, light and oxygen barrier capability. Thermal properties of the NC films were improved as evidenced from the differential scanning calorimetry and the thermal conductivity data. NC films became rough and coarse over neat GG film as visualized through the scanning electron microscopy. A strong antibacterial activity was exhibited by NC films against both Gram-positive and Gram-negative bacteria, and therefore, the film could be considered as an active food packaging.

4. Conclusion

In this study, GG based nanocomposite films were developed by incorporating different levels of Ag-Cu nanoparticles. Properties of the GG films were greatly influenced by the level of NPs reinforced into film forming matrix. A significant improvement in the mechanical properties of the GG NC films achieved by introducing NPs where a uniform distribution of NP was visualized through SEM.Visual color and optical properties of GG films were influenced by the reinforcement of Ag-Cu NPs. The NC films had the excellent barrier property against the light in the UV range. The permeability ofthe GG films to oxygen significantly dropped with NP loading into the film. Thermal properties of GG films improved with incorporation of NPs. The developed NC films showed excellent antimicrobial activity against L. monocytogenes and S. thyphimurium. Overall, based on the findings in this work, the GG/Ag-Cu nanocomposite films had potential for development of active packaging to inhibit the growth of microorganisms, extending food shelf-life and ensure food safety. Moreover, it could be used as UV defensive packaging material for UV-sensitive foods to prevent lipid oxidation. Before commercialization of the nanocomposite films, a sincere evaluation of nanoparticle migration to food samples and exposure levels to human health are required to measure which are crucial for such newly developed materials.