Master Degree / Yüksek Lisans Tezleri
Permanent URI for this collectionhttps://hdl.handle.net/11147/3008
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Master Thesis Surface Modified Halloysite Nanotubes Incorporated Polyl-Lactide Nanocomposites for Food Packaging Applications(Izmir Institute of Technology, 2019) Tüzün, Ece Zeynep; Tıhmınlıoğlu, Funda; Tıhmınlıoğlu, Funda; 03.02. Department of Chemical Engineering; 03. Faculty of Engineering; 01. Izmir Institute of TechnologyBiodegradable Poly (L-lactide) (PLA) can replace petroleum based packaging materials to solve environmental problems. PLA lacks of ductility and have moderate barrier properties. In this study, halloysite nanotubes (HNTs) possessing unique surface chemistry and tubular structure were incorporated into PLA matrix to overcome drawbacks of PLA. Firstly, HNT surface was modified with aminopropyltriethoxysilane (APTES) to enhance interfacial adhesion between HNTs and PLA matrix by decreasing the hydrophilicity of HNTs. Modified HNTs (m-HNTs) were characterized by SEM, FTIR, TGA, N2 adsorption-desorption analysis, XRD and XPS. FTIR, XRD and XPS results revealed that APTES was successfully grafted onto HNTs. The optimum pH and APTES concentration for the silanization of HNTs were determined as 3.50 and 1%, respectively. HNT/PLA and m-HNT/PLA nanocomposite films with different wt% of nanofiller loadings were prepared by solution casting. The films were characterized by FTIR, XRD, tensile test, water vapor permeation, DSC, TGA, contact angle and SEM analysis and color measurements. Better dispersion and consequently better mechanical properties were obtained with m-HNT addition compared to unmodified ones. Tensile strength at break of PLA was increased by 4.7% and 16.6% with 2 wt% HNT and m-HNT addition, respectively. m-HNT/PLA nanocomposites had better water vapor barrier properties than unmodified HNT/PLA nanocomposites while both of them improved the barrier property. Best mechanical and water vapor barrier properties were achieved with 2% modified HNT (1% APTES) containing PLA nanocomposites. Therefore, nanocomposite films produced in this study with high transparency and good barrier property can be a suitable candidate for fresh food packaging.Master Thesis Preparation and Characterization of Corn Zein Nanocomposite Coated Polypropylene Films for Food Packaging Applications(Izmir Institute of Technology, 2010) Özçalık, Onur; Tıhmınlıoğlu, Funda; Tıhmınlıoğlu, Funda; 03.02. Department of Chemical Engineering; 03. Faculty of Engineering; 01. Izmir Institute of TechnologyFeasibility of prepared novel corn zein nanocomposite (CZNC) coated polypropylene (PP) film (CZNC-PP) structures for food packaging applications was investigated. Excellent barrier properties of corn zein nanocomposites were successfully combined with mechanically strong PP as an eco-friendly promising alternative to conventional barrier packaging systems. In this study, the effect of nano-sized layered silicate amount, type and processing of CZNC layer on the barrier, mechanical, optical and surface properties of the CZNC-PP films were investigated. Incorporation of organomodified montmorillonite (OMMT) by solution intercalation into zein coating matrix improved barrier and mechanical properties of PP films. The properties of single CZNC layers and interactions between layered silicates and zein matrix were also investigated. Fine delamination of OMMT in zein coating was found to be responsible for the improvements in oxygen and water vapor barrier of single corn zein layers due to more tortuous path formed for permeation of oxygen and water vapor. Prepared CZNC-PP films achieved nearly 4 times reduced oxygen permeability while WVP of the films were reduced by 30% with 5 wt% OMMT content in 5.9 m corn zein coating. Meanwhile, improvements were less significant for unmodified nanoclay loadings due to the incompatibility between unmodified MMT and corn zein. Hydrophobicity of CZNC surface increased with increasing OMMT loading in accordance with WVP results. Permeation data was fitted to various phenomenological models predicting the permeability of polymer nanocomposites as a function of clay concentration and aspect ratio of nanoplatelets. While significant improvements in mechanical properties including doubled elastic modulus and 75% higher yield strength of PP films were obtained, incorporation of OMMT in CZNC layer did not change the color of CZNC-PP films significantly.