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Synthesis & Characterization of All-Cellulose Nanocomposites Containing Natural Extracts for Smart Packaging Applications

Azizi Saadatlou, Ghazaleh | 2019

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  1. Type of Document: M.Sc. Thesis
  2. Language: Farsi
  3. Document No: 52451 (07)
  4. University: Sharif University of Technology
  5. Department: Materials Science and Engineering
  6. Advisor(s): Pircheraghi, Gholamreza
  7. Abstract:
  8. In this project, all-cellulose nanocomposites for smart packaging of meat products were synthesized via film casing method. These nanocomposites were aimed to provide visual response to pH change, which occurs due to decay of the meat products. The prepared nanocomposites would be placed inside the packages to be in direct contact with the products and could improve shelf life the products with the help of antibacterial natural extracts incorporated in the samples.Synthesis of the samples started with cellulose nano whiskers synthesis via acid hydrolysis. The prepared nanoparticles were then characterized with XRD, DLS, and Zeta potential analysis. It was shown that a big portion of the nanoparticles have diameters in the range of 70 nm and possess almost 91% crystallinity degree. Also, the surface charge of the particles were measured to be -8.09 mV.XRD analysis showed that presence of nanoparticles in the samples enhance the degree of crystallinity of the nanocomposites. Additionally, DSC results demonstrated that presence of natural extracts caused an increase in the melting temperature of the samples and thus, they might affect the thermal properties of the samples.Study of the samples color change by time and due to variations in pH, showed that presence of nanoparticles improve the performance of the samples. Also, it was shown that CNWG samples showed the best performance from the color change properties point of view. Thus it can be said that prepared nanocomposites have the potential to be used in smart packaging systems. Hydrophilicity of the sample were characterized by the means of contact angle and swelling measurments. It was observed that presence of the extracts increase the hyrophilicity while addition of nanoparticles decreases it. In addition, biodegradability study showed that the samples lose almost 50% of their initial weight by 7 days. Also the presence of both the nanoparticles and the natural extracts increase the rate of the biodegradation. Antibacterial tests, showed that only grape extract demonstrated antibacterial activity and CAG sample was shown to be more effective than CNWG sample
  9. Keywords:
  10. Smart Packaging ; All Cellulose Nanocomposites ; Cellulose Acetate Enzeme ; Cellulose Nanocrystalls ; Natural Extract ; Biodegradability

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