Abstract
This thesis aims to synthesize and characterize bio-based poly(ethylene furanoate) (PEF), PEF-based nanocomposites, and block copolymers for sustainable food packaging applications. The research focuses on synthesizing high molecular weight PEF from renewable resources, specifically exploring the effects of various monomers, catalysts, and polycondensation techniques on their properties. Additionally, the study seeks to enhance the performance of PEF by incorporating nanoparticles to improve mechanical strength, thermal stability, and antimicrobial activity. Furthermore, the thesis investigates the synthesis block copolymers to assess their potential as flexible and environmentally friendly alternatives to petroleum-derived plastics, ultimately contributing to the advancement of packaging materials in the food industry. In the first part, this work explores the synthesis of high molecular weight bio-based PEF using 2,5-furan dicarboxylic acid (FDCA) or dimethyl 2,5-furan dicarboxylate ...
This thesis aims to synthesize and characterize bio-based poly(ethylene furanoate) (PEF), PEF-based nanocomposites, and block copolymers for sustainable food packaging applications. The research focuses on synthesizing high molecular weight PEF from renewable resources, specifically exploring the effects of various monomers, catalysts, and polycondensation techniques on their properties. Additionally, the study seeks to enhance the performance of PEF by incorporating nanoparticles to improve mechanical strength, thermal stability, and antimicrobial activity. Furthermore, the thesis investigates the synthesis block copolymers to assess their potential as flexible and environmentally friendly alternatives to petroleum-derived plastics, ultimately contributing to the advancement of packaging materials in the food industry. In the first part, this work explores the synthesis of high molecular weight bio-based PEF using 2,5-furan dicarboxylic acid (FDCA) or dimethyl 2,5-furan dicarboxylate (DMFD) for food packaging applications. The investigation evaluates various factors, including monomer type, monomer molar ratios, catalysts, polycondensation time, and temperature, revealing that FDCA is more effective than DMFD in achieving higher molecular weights. The study finds that amorphous samples exhibit a glass transition temperature of (82–87) °C, with crystallinity decreasing in annealed samples as the intrinsic viscosity increases. Increased rigidity and molecular weight enhance the material's suitability for packaging by reducing hydrophilicity and oxygen permeability. Furthermore, low-viscosity samples demonstrate higher hardness and elastic modulus. Application of solid-state polycondensation (SSP) at varying temperatures and times improved melting temperatures, crystallinity, and intrinsic viscosity, underscoring SSP's effectiveness in producing durable, bio-based PEF for food packaging applications. In the second part of the thesis, PEF-based nanocomposites containing Ce-Bioglass, ZnO, ZrO₂, Ag, and TiO₂ nanoparticles were synthesized through in situ polymerization for active packaging applications. The addition of nanoparticles resulted in effective dispersion within the PEF matrix, a slight increase in color intensity, and enhanced thermal stability at higher temperatures. These nanoparticles reduced hydrophilicity, increased surface roughness, and improved surface charge, further enhancing the materials' packaging suitability. Additionally, incorporating nanoparticles imparted antibacterial properties, demonstrating effective inhibition against common bacterial strains. Most nanocomposites also exhibited improved mechanical properties, including increased hardness and elasticity. The incorporation of nanoparticles led to enhanced negative zeta potential and surface charge density. At the same time, the primary thermal degradation pathway was identified as β-hydrogen bond scission, with α-hydrogen bond scission noted in specific nanocomposites. In the third part, PEF/poly(ε-caprolactone) (PCL) block copolymers were synthesized through ring-opening polymerization (ROP) of ε-caprolactone in the presence of PEF at various mass ratios. The results indicated that intrinsic viscosity increased with higher ε-CL content, reflecting longer macromolecular chains. Thermal and mechanical analyses identified the P5050 sample as a homogeneous blend that optimizes flexibility and durability. PCL acts as a plasticizer for PEF to enhance processability. Nanoindentation testing revealed reduced hardness and modulus, for increased ε-CL content, and slight mechanical properties improvements in the highly crystalline PEF1090 sample. Balanced thermal stability and mechanical properties make them suitable materials for flexible packaging applications.
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