Emre Baştürk

Antimicrobial agent-free hybrid cationic starch/sodium alginate polyelectrolyte films for food packaging materials

This study aimed to develop polyelectrolyte structured antimicrobial food packaging materials that do not contain any antimicrobial agents. Cationic starch was synthesized and characterized by FT-IR spectroscopy and 1H NMR spectroscopy. Its nitrogen content was determined by Kjeldahl method. Polyelectrolyte structured antimicrobial food packaging materials were prepared using starch, cationic starch and sodium alginate. Antimicrobial activity of materials was defined by inhibition zone method (disc diffusion method). Thermal stability of samples was evaluated by TGA and DSC. Hydrophobicity of samples was determined by contact angle measurements. Surface morphology of samples was investigated by SEM. Moreover, gel contents of samples were determined. The obtained results prove that produced food packaging materials have good thermal, antimicrobial and surface properties, and they can be used as food packaging material in many industries.

Dual-crosslinked thiol-ene/sol gel hybrid electrospun nanowires: preparation and characterization

In this report, we describe the preparation and characterization of cross-linked electrospun membranes by using a reactive electrospinning. A novel methacrylate functional poly(vinyl alcohol) (M-PVA) was synthesized by reacting PVA and isocyanatoethyl methacrylate (2-ICEMA). The crosslinked membranes were achieved in a simple process at a single step using thiol-ene reaction between M-PVA and 3-mercaptopropyl trimethoxysilane (MPTMS) during the electrospinning process. In order to improve theirs the stability, the crosslinked membranes were also thermally treated. The morphology was characterized by scanning electron microscopy (SEM). The structure of M-PVA was characterized by attenuated total reflectance FT-IR. Morphological investigations show that the resulting membranes have nanowires morphology. The thermal analysis of the electrospun membranes was also investigated. Thermal stability of the membranes was improved with the incorporation of the sol gel precursor. The described method provides novel route for organic–inorganic hybrid membranes.

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.

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.

Thermal and Phase Change Material Properties of Comb-Like Polyacrylic Acid-Grafted-Fatty Alcohols

ABSTRACT Poly(acrylic acid)-graft-fatty alcohol are synthesized from the esterification of polyacrylic acid with octadecanol and docosanol. The characterization of poly(acrylic acid)-graft-fatty alcohol was performed by attenuated total reflection–Fourier transform infrared spectroscopy. The thermal stability performances and phase change behaviors of poly(acrylic acid)-graft-fatty alcohol were examined by using thermogravimetric analysis system and differential scanning calorimetry. The results indicate that the poly(acrylic acid)-graft-fatty alcohol polymeric phase change materials possess good phase change properties and provide a suitable working temperature range. The heating process phase change enthalpy is measured between 112 and 122 J g−1, and the freezing process phase change enthalpy is found between 118 and 126 J g−1. The decomposition of poly(acrylic acid)-graft-fatty alcohol polymeric phase change materials started at 177°C and reached a maximum of 380°C. All of the obtained poly(acrylic acid)-graft-fatty alcohol polymeric phase change materials improved latent heat storage capacity in comparison with the pristine poly(acrylic acid) polymer. With the obtained results we conclude that, these materials promise a great potential in thermal energy storage applications. GRAPHICAL ABSTRACT

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

Thermal and morphological characterization of poly(vinyl alcohol) based phenylboronic acid hybrid nanofibers: the effect of experimental parameters on the nanofiber diameter

The aim of this study was to prepare and characterize phenylboronic acid/poly(vinyl alcohol) composite nanofibers. The effects of solution properties and processing parameters on the structure and morphology of the nanofibers were thoroughly investigated. The structure and morphology of nanofibers were examined by SEM, DSC, and FTIR spectroscopy. The nanofiber diameter and the nanostructured morphology depended on solution viscosity, applied electric voltage and tip-to-collector distance. The combination of different materials and processing parameters could be used to fabricate bead-free composite nanofibers. It was found that the solution viscosity have relatively larger effects on the fiber diameter than the other parameters. The thermal properties of polyvinyl alcohol and polymer composite nanofibers were investigated. The analysis revealed that composite containing nanofibers gave higher char yield compared to poly(vinyl alcohol) nanofiber.