Seyfullah Madakbaş

Preparation, characterisation, and dielectric properties of polypyrrole-clay composites

In this study, polypyrrole-clay (PPy-clay) composites were prepared by the in situ chemical oxidative polymerisation of pyrrole in the presence of clay. The chemical structures of the composites were characterised by FTIR and XRD analysis. The thermal properties of these novel composites were analysed by TGA and DSC measurements. Glass-transition temperatures and char yields increased with the increase in clay content in the nanocomposites. The interactions between PPy and clay were mainly between polypyrrole and the layers of clay. It was observed that, as the amount of clay in the composites increased, the dielectric permittivity decreased while the dielectric conductivity of the composite materials increased.

Determination of methylparaben by differential pulse voltammetry using a glassy carbon electrode modified with polypyrrole

A new modified glassy carbon electrode (GCE) based on a synthesized polypyrrole (PPy) was developed for the determination of methylparaben by differential pulse voltammetry (DPV). PPy was covalently immobilized on GCE surface using tetraethyl ammonium perchlorate (TEAP) and acetonitrile (ACN). Methylparaben was oxidized by differential pulse voltammetry and a peak was observed at 1.20 V. The calibration curve obtained with differential pulse voltammetry was linear in the concentration range from 0.01 to 5 mM methylparaben with a limit of detection of 8 ×10−3 mM and RSD of 0.11%. The improved method was applied to the determination of methylparaben in cream samples using the differential pulse voltammetry method.

Improved Thermal Stability and Wettability Behavior of Thermoplastic Polyurethane / Barium Metaborate Composites

In this paper, it was targeted to the enhance thermal stability and wettability behavior of thermoplastic polyurethane (TPU) by adding barium metaborate. TPU-Barium metaborate composites were prepared by adding various proportions of barium metaborate to TPU. The chemical structures of the composites were characterised by fourier transform infrared spectroscopy (FTIR) and X-ray diffraction (XRD) analysis. All prepared composites have extremely high Tg and thermal stability as determined from DSC and TGA analysis. All composite materials have the Tg ranging from 15 to 35 °C. The surface morphologies of the composites were investigated by a scanning electron microscopy. Mechanical properties of the samples were characterized with stress-strain test. Hydrophobicity of the samples was determined by the contact angle measurements. The obtained results proved that thermal, hydrophobic and mechanical properties were improved.

Thermal and Morphological Properties of Organo Modified Nanoclay/Polyethylene Terephthalate Composites

The purpose of this study is polyethylene terephthalate (PET) and modified organo-nanoclay with different masses and to contribute to the different areas of use and literature by examining these nanocomposites physical, chemical and thermal features. In this study, nanocomposite films, which work in PET that is a type of polymeric material, and work into modified organo-nanoclays with different percentages, obtained with the method called as in situ polymerization. The chemical structures of nanocomposites prepared were investigated by fourier transform infrared spectroscopy. The surface morphologies of this nanocomposites were examined by scanning electron microscope. Their thermal properties were analyzed by differential scanning calorimetry and thermogravimetric analysis. According to the results obtained, the thermal stabilities of modified nanoclay composites got better than PET. Besides, while the percent of clay in the doped PET was rising, its fragility increased. At the same time, high mass of clay formed when the percent of contribution developed. Thus, the surface interaction of polymer–clay decreased, because the composed aggregations prevented the polymer matrix from going into the layer of clay.

Bisphenol A (BADCy)/bisphenol P (BPDCy) cyanate ester/colemanite composites: synthesis and characterization

The aim of this study was to improve thermal stability, mechanical, and surface properties of bisphenol A dicyanate ester (BADCy) with the addition of bisphenol P dicyanate ester (BPDCy) and colemanite. The cyanate esters (BADCy and BPDCy) were prepared from diphenol compound (bisphenol A or bisphenol P) and cyanogen bromide in the presence of triethylamine. The chemical structure of the synthesized cyanate esters was investigated by fourier transform infrared spectroscopy and nuclear magnetic resonance spectroscopy (1H-NMR and 13C-NMR) techniques. The cyanate esters/colemanite composites having various ratios of BADCy, BPDCy, and colemanite were prepared. Thermal stability of the samples was evaluated by thermogravimetric analysis and differential scanning calorimetry. The samples were characterized with the following analyses: gel content, water absorption capacity, and stress–strain test. Hydrophobicity of the samples was determined by the contact angle measurements. Moreover, the surface morphology of the samples was investigated by a scanning electron microscopy—energy dispersive spectrometer mapping. Finally, the obtained results prove that the prepared composites have good thermal, mechanical, and surface properties and that they can be used in many applications such as the electronic devices, materials engineering, and other emergent.

Structural and Dielectric Properties of Two Different BaTiO3/Polyaniline Nanocomposites

Barium titanium oxide/polyaniline (BaTiO3/PANI) nano-composites were obtained in two different processes by the use of PANI and BaTiO3 nano-particles synthesized by the sol–gel technique. FT-IR, XRD, SEM and TGA measurements were taken for structural properties of all samples. The molecular interaction between BaTiO3 nanoparticles and PANI was between the H atoms in the N–H bond and the OH molecules in the solution environment. The said interaction was coordinated with BaTiO3 molecules over O atoms. XRD results confirmed that the synthesized BaTiO3 had a characteristic cubic perovskite structure and that its structure had not changed. TGA results revealed that the composites became more stable as the BaTiO3 amount increased. The dielectric measurement results are consistent with the structural results at higher frequencies. Dielectricity increased as BaTiO3 ratio increased in the environment. The change in the real part of the dielectric permittivity by frequency was stable at high frequencies. According to these results, it is concluded that the composite samples could have very high electromagnetic wave absorption values at higher frequencies (GHz).

Effect of Barium Titanate on the Thermal, Morphology, Surface, and Mechanical Properties of the Thermoplastic Polyurethane/Barium Titanate Composites

ABSTRACT The aim of this study was to improve thermal stability, mechanical, and surface properties of thermoplastic polyurethane (TPU) with the addition of BaTiO3. The TPU/BaTiO3 composites having various ratios of TPU and BaTiO3 were prepared. The chemical structure of the prepared composites was investigated by FTIR. Thermal stability of the samples were evaluated by thermogravimetric analysis and differential scanning calorimetry. Mechanical properties of the samples were characterized with stress–strain test. Hydrophobicity of the samples was determined by the contact angle measurements. Moreover, the surface morphology of the samples was investigated by a scanning electron microscopy. GRAPHICAL ABSTRACT

Preparation and Characterization of Polyaniline/Hexagonal Boron Nitride Composites

Abstract Polyaniline (PANI) is one of the most studied conductive polymer with several unique properties and good conductivity. In this study it was aimed to prepare Polyaniline (PANI)/Hexagonal boron nitride (h-BN) composites. Chemical structures of the composites were characterized by FTIR analysis. Thermal properties of these novel composites were analyzed by TGA and DSC measurements. Glass transition temperatures and char yields of the composites increased with increasing h-BN percentage. FTIR, XRD and UV measurements indicated that the boron atoms in h-BN particles interact with the unpaired electrons in nitrogen atoms of PANI. Dielectric measurements revealed dipolar polarization behavior of the composites.