Hüseyin Yıldırım

Mechanical and Antibacterial Properties of Injection Molded Polypropylene/TiO2 Nano-Composites: Effects of Surface Modification

Polypropylene (PP)/titanium dioxide (TiO2) nano-composites were prepared by melt compounding with a twin screw extruder. Nanoparticles were modified prior to melt mixing with maleic anhydride grafted styrene-ethylene-butylene-styrene (SEBS-g-MA) and silane. The composites were injection molded and mechanical tests were applied to obtain tensile strength, elastic modulus and impact strength. Antibacterial efficiency test was applied on the injection molded composite plaques by viable cell counting technique. The results showed that the composites including SEBS-g-MA and silane coated TiO2 gave better mechanical properties than the composites without SEBS-g-MA. Antibacterial efficiency of the composites varied according to the dispersion and the concentration of the particles and it was observed that composites at low content of TiO2 showed higher antibacterial property due to the better photocatalytic activity of the particles during UV exposure.

Preparation and Characterization of Polyester–Glycidyl Methacrylate PolyHIPE Monoliths to Use in Heavy Metal Removal

Polyester–glycidyl methacrylate (GMA)-based poly(high internal phase emulsion)s (polyHIPEs) with 85% internal phase were prepared by using unsaturated polyester resin (UPR), glycidyl metahacrylate and divinylbenzene (DVB) or styrene (St) with triethanolamine (TEA) as an emulsifier in the presence of a porogen. Porous monoliths were obtained by a removal of internal phase after curing of dispersed phase at 80°C. Morphologies and surface properties of obtained porous monoliths were investigated by scanning electron microscopy (SEM) and Brunauner–Emmet–Teller (BET) molecular adsorption methods. Amine functionalization of epoxy groups of polyHIPEs was achieved by reactions with several amines such as 1,4-ethylenediamine (EDA), 1,6-hexamethylenediamine (HMDA), 4-aminosalicylic acid (ASA), 2-aminothiazole (ATAL), 4-aminobenzothiazole (ABTAL) and 2-phenylimidazole (PIAL), respectively. The functionalized polyHIPEs were characterized by elemental analysis and the best result was obtained with the 1,4-ethylenediamine (EDA) ligand. The adsorption capacities of the modified monoliths for Ag(I), Cu(II) and Cr(III) were determined under non-competitive conditions at room temperature. The results showed that the maximum adsorption capacities of the modified monoliths decrease in order of Ag(I) > Cu(II) > Cr(III) and polyHIPE with 2-phenylimidazole (PIAL) groups is the most effective adsorbent for heavy metal ions.

Effects of compatibilizers on mechanical and antibacterial properties of injection molded nano-ZnO filled polypropylene

Polypropylene (PP)/zinc oxide (ZnO) nanocomposites were prepared by melt compounding. Prior compounding, surface of the particles were modified with different compatilibizers such as silane and stearic acid. Modification was also done by coating the particles with maleic anhydride grafted styrene-ethylene-butylene-styrene (SEBS-g-MA) block copolymer dissolved in toluene. Specimens of tensile test, impact test, and antibacterial efficiency test were obtained by injection molding. The results showed that stearic acid and silane containing composites gave structures with fine distributed particles while the presence of SEBS-g-MA induced agglomerates. The presence of stearic acid increased tensile strength and impact strength but reduced elastic modulus. Silane was more effective in increasing elastic modulus. Despite the elastomeric nature of SEBS-g-MA, it did not rise impact strength due to its limited amount of usage in coating of the particles. Antibacterial properties of the composites reduced with the increment of ZnO loading because of the weak UV absorption and insufficient photocatalytic activity of the particles. On contrary, at low ZnO content, satisfactorily high antibacterial effect was observed especially in well dispersed structures including stearic acid and silane.

Porous functional poly(unsaturated polyester-co-glycidyl methacrylate-co-divinylbenzene) polyHIPE beads through w/o/w multiple emulsions: preparation, characterization and application

Abstract Poly(unsaturated polyester-co-glycidyl methacrylate-co-divinylbenzene) poly high internal phase emulsion (HIPE) beads were synthesized via water-in-oil-in-water (w/o/w) multiple emulsions. HIPEs were prepared by using a commercial unsaturated polyester resin (UPR) and a mixture of glycidyl methacrylate (GMA) and divinylbenzene (DVB) as the cross-linker. The external surfactant was found to be a strong influence on the morphology of the beads. The porosity and the pore morphology of the resulting polyHIPE beads were investigated by scanning electron microscopy (SEM) and Brunauer-Emmett-Teller (BET) molecular adsorption method, respectively. Post-functionalization of the beads was carried out with multifunctional amines such as 1,4-ethylenediamine (EDA), 1,6-hexamethylenediamine (HMDA) and 4-aminosalicylic acid (ASA). Elemental analysis was used to confirm the functionalization. Resulting functional beads were tested on the adsorption of Ag(I), Cu(II), and Cr(III) under non-competitive conditions and atomic absorption spectroscopy (AAS) was used to calculate the adsorption capacities. The maximum adsorption capacities of the functional beads were found to be decreasing in the order of Ag(I)>Cu(II)>Cr(III).

PREPARATION AND METAL SORPTION PROPERTIES OF GMA-MMA-DVB MICROSPHERES FUNCTIONALIZED WITH 2-AMINOTHIAZOLE

Crosslinked glycidylmethacrylate-methylmethacrylate-divinylbenzen (GMA-MMA-DVB) microspheres were prepared by suspension polymerization. The GMA-MMA-DVB microspheres with an average size of 150–300 μm and surface area of 1.51 m2g−1 were functionalized with 2-aminothiazole (ATAL). The affinity of the functionalized microspheres for copper, iron, aluminum, lead, cobalt, and nickel ions was examined. The effects of pH, resin amount, shaking time, type, and volume of the elution solution on the sorption and desorption properties of functionalized microspheres for these metal ions were investigated using the batch method. Sorption capacities (0.97–1.12 mmolg−1), quantitation limits (2.6–3.0 ppb) and recoveries (90–99%) were calculated.

Thermal and Mechanical Properties of Poly(arylene ether ketone)s Based on 5-tert-Butyl-1,3-bis(4- fluorobenzoyl)benzene

An aromatic bishalide, 5-tert-butyl-1,3-bis(4-fluorobenzoyl)benzene (2) was synthesized in high yield and purity by the reaction of 5-tert-butylisophthaloyl chloride (1) and fluorobenzene and polymerized by nucleophilic substitution reaction with commercially available aromatic bisphenols to prepare a series of high molecular weight poly(arylene ether ketone)s containing pendant tertiary butyl groups. The effect of molecular structure on the physical, thermal, mechanical and adhesion properties of the polymers was investigated.

The Study of the Effect of Solvents Absorption in PET Packaging Films

The effects of absorption solvents into poly(ethylene terephtalete) (PET) films, which are used as food packaging materials, was investigated by DSC, SEM and mechanical methods at various temperatures (5, 25 and 40 °C) and for different periods (1–8 weeks), respectively. Due to the interaction of PET films with solvents, there had been serious deformation on the surface morphology of PET films. Plasticizer effects occurrence, because of absorption of solvents, caused weakening of mechanical properties of PET films. As a result, there had been a 42.88 % and 39.20 % decrease in stress at break at 5 °C for 8 weeks, respectively.