Development of amino functionalized POSS based (3-Glycidoxypropyl)trimethoxysilane hybrid sol-gel coatings for aircraft applications

Varan, Dilara Çisel
An amino functionalized and 50 percent amphiphilic polyhedral oligomeric silsesquioxane (POSS) based (3-Glycidoxypropyl)trimethoxysilane (GPTMS) sol-gel reaction was carried out under extreme basic conditions. Amount of POSS per 1 mol of GPTMS was varied at molar ratios of 0.2, 0.4, and 0.6. The sol-gel product was coated on the aluminium 2024 alloy samples with immersion technique and thermally treated to improve corrosion resistance of the alloy. Influence of aging durations (1, 3, and 6 days) on the sol-gel reactions and polymerization of the coating layer were investigated using Fourier Transform Infrared (FTIR) spectroscopy. Thermal properties of the cured samples were analyzed by Differential Scanning Calorimetry (DSC) measurements and Thermo-mechanical analyzer (TMA). Surface properties and corrosion performance of the coatings were tested using contact angle measurement and Electrochemical Impedance Spectroscopy (EIS) techniques, respectively. A 0.6 mole amino functionalized POSS incorporated, and 6 days aged GPTMS revealed better corrosion resistance and hydrophobic features.


Development of pH Sensitive Alginate/Gum Tragacanth Based Hydrogels for Oral Insulin Delivery
Cikrikci, Sevil; Mert, Behiç; Öztop, Halil Mecit (2018-11-07)
Insulin entrapped alginate-gum tragacanth (ALG-GT) hydrogels at different ALG replacement ratios (100, 75, 50, 25) were prepared through an ionotropic gelation method, followed by chitosan (CH) polyelectrolyte complexation. A mild gelation process without the use of harsh chemicals was proposed to improve insulin efficiency. Retention of almost the full amount of entrapped insulin in a simulated gastric environment and sustained insulin release in simulated intestinal buffer indicated the pH sensitivity of ...
Evaluation of neointimal hyperplasia on tranilast-coated synthetic vascular grafts: An experimental study
Karakayali, Feza; Haberal, Nihan; Tufan, Hale; Hasırcı, Nesrin; BaSaran, Ozgur; Sevmis, Sinasi; Akdur, Aydin; Kızıltay, Aysel; Haberal, Mehmet (2007-01-01)
Tranilast is an antiallergic drug that interferes with proliferation and migration of vascular smooth muscle cell induced by platelet-derived growth factor (PDGF) and transforming growth factor-beta 1 (TGF-beta 1). We investigated the local effect of tranilast on neointimal hyperplasia using tranilastcoated prosthetic grafts. The inner sides of the thin-walled polytetrafluoroethylene (PTFE) grafts were coated with chitosan and tranilast containing chitosan solution. Wistar albino rats (32) were used in the ...
Covalent immobilization of invertase on chemically activated poly (styrene-2-hydroxyethyl methacrylate) microbeads
A carrier for invertase enzyme was synthesized from styrene (S) and 2- hydroxyethyl methacrylate (HEMA) in the form of microbeads. These poly (styrene-2-hydroxyethyl methacrylate), P(S-HEMA) microbeads were activated by epichlorohydrin (ECH) treatment for covalent immobilization. The free and immobilized invertase were assayed in the hydrolysis of sucrose to glucose, and the obtained results were compared. The optimum pH was 4.5 for free and 5.5 for immobilized invertase. The optimum temperature of invertas...
Enantioselective reduction of ketones with borane catalyzed by cyclic β- amino alcohols prepared from proline
Demir, Ayhan S; Mecitoglu, Idris; Tanyeli, Cihangir; Gülbeyaz, Volkan (Elsevier BV, 1996-12)
New catalysts have been prepared from (S)- and (R)- proline and the asymmetric borane reduction of prochiral ketones using these catalysts has been studied. The secondary alcohols were obtained in 76-95% yield with 57-96% enantiomeric excesses. Copyright (C) 1996 Elsevier Science Ltd
Synthesis of Phenanthroline-Functionalized Phosphazene Based Metallosupramolecular Polymers and Their Stimuli-Responsive Properties
SEÇKİN, TURGAY; Sezer, Selda; KÖYTEPE, SÜLEYMAN (2018-11-01)
A series of phenanthroline-functionalized phosphazene based metallo-supramolecular polymers (PFP-MSP) was synthesised using a two-step reaction strategy. In first step, three phenanthroline unit containing monomer (PFP-M) was prepared from 5,6-dihydroxy-1,10-phenanthroline and hexachlorocyclotriphosphazene by condensation reaction. Then, this PFP-M was reacted with different metal ion salts (Co, Ni, Cu, Fe, Eu, La, Tb, Lu ions) and resulting for the metallo-supramolecular polymers bearing phosphazene struct...
Citation Formats
D. Ç. Varan, “Development of amino functionalized POSS based (3-Glycidoxypropyl)trimethoxysilane hybrid sol-gel coatings for aircraft applications,” M.S. - Master of Science, Middle East Technical University, 2021.