Master Degree / Yüksek Lisans Tezleri

Permanent URI for this collectionhttps://hdl.handle.net/11147/3008

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Subject: search.filters.subject.Polymer Science and TechnologyWoS Q: search.filters.wosQuartile.N/A

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  • Master Thesis
    Enhancement of Ultraviolet Resistance of Polyaspartics
    (01. Izmir Institute of Technology, 2024) Karabacak, Bahar Demirtaş; Demir, Mustafa Muammer
    The degradation of polyaspartic ester (PAE) resins under ultraviolet (UV) exposure poses significant challenges for their long-term use in outdoor applications. This study investigates the enhancement of UV resistance of PAE resins through the incorporation of metal oxide particles as UV absorbers. The research aims to determine the efficacy of metal oxide particles in improving the UV protective properties of PAE resins. Experimental results demonstrate that the UV absorption values of resin dispersions containing metal oxide particles significantly increased compared to pure PAE resin. This enhancement may be attributed to the metal oxides' ability to absorb and scatter UV light, thereby reducing the transmission of harmful UV rays through the resin matrix. Various concentrations of metal oxide particles were tested, and the findings underscore the importance of achieving a homogeneous dispersion within the resin for optimal UV protection. The study concludes that the incorporation of metal oxide particles into PAE resins can remarkably enhance the UV resistance of PAE. The improved UV absorption characteristics make these modified resins more suitable for applications exposed to prolonged UV radiation. This research provides a foundation for further exploration into optimizing particle concentrations and dispersion techniques to maximize the UV resistance of polyaspartic ester resins while maintaining their transparency over visible region of the optical spectrum.
  • Master Thesis
    Synthesis and Characterization of Polycaprolactone-Polyvalerolactone Copolymer and Its Use in Melt Electrowriting Applications
    (01. Izmir Institute of Technology, 2024) Dinçkal, Sanem; Yıldız, Ümit Hakan
    This thesis focuses on the synthesis and characterization of Poly(ε-caprolactone) (PCL) and its block copolymers, Poly(ε-caprolactone)-b-Poly(4-hydroxyvalerate) (PCL-b-P4HV) and Poly(ε-caprolactone)-b-Poly(δ-valerolactone) (PCL-b-PVL). These polymers were synthesized through ring-opening polymerization of various lactones (ε-caprolactone, γ-valerolactone, and δ-valerolactone) using biocatalysts such as citric acid, glycolic acid, salicylic acid, boric acid and acetic acid. Detailed analytical and thermoanalytical characterizations were performed. Differential Scanning Calorimetry (DSC) showed that most homopolymers and copolymers exhibited crystallization (Tc) and melting temperatures (Tm) varying between 5-25°C and 50-65°C respectively, confirming successful polymerization. DSC thermograms of block copolymers revealed that solvent choice for precipitation affected crystallinity and thermal properties, with a small second melting point observed due to different crystalline forms. Fourier Transform Infrared Spectroscopy-Attenuated Total Reflectance (FTIR-ATR) confirmed the homopolymerization of Poly(ε-caprolactone) using citric, glycolic, and salicylic acids. Mass spectrometry further revealed characteristic peaks corresponding to expected molecular weights and compositions of the copolymers. The presence of these peaks corroborated the formation of block copolymers with distinct blocks of PCL, P4HV, and PVL confirmed the molecular integrity of the synthesized block copolymers. This thesis provides a comprehensive analysis of the synthesis and characterization of block copolymers, offering insights into their structural properties and potential applications. The findings contribute to the understanding of the polymerization process and the properties of the resulting materials, which are significant for industrial and biomedical applications. The resultant copolymers were utilized in Melt Electrowriting process to provide tissue scaffold. Despite their brittleness, all copolymers were electrowritten without issues, indicating their potential interest in tissue engineering applications.