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- MakaleAçık Erişim2025Scopus SJRQ2Tungsten carbide-based shape memory biopolymer nanocomposites as a promising new gamma radiation shielding material
Pekdemir, Mustafa Ersin; Yılmaz, Demet; Selçuk Pekdemir, Sibel; Taşgın, Yahya; Ekmen, Busenur
In this study, structural, thermal and radiation shielding properties of Polylactic acid (PLA)/polyhydroxyalkanoates (PHAs)/Tungsten Carbide (WC) nanocomposite films were investigated. PHA/PLA/WC composite films were prepared by using different amounts of WC (5%, 10%, 18%, 28%). Characterization of the composite films was carried out by Attenuated Total Reflection Infrared Spectroscopy (ATR-IR), Thermogravimetric Analysis (TGA), Differential Scanning Calorimetry (DSC), X-ray Diffraction (XRD) and Scanning Electron Microscopy (SEM). The linear and mass attenuation coefficients (LAC and MAC), mean free path (MFP), Half-Value Layer (HVL), Tenth Value Layer (TVL), effective atomic numbers (Zeff), and effective electron densities (Nel) of the synthesized composite films were experimentally measured from 53.16 to 383.85 keV. Also, the neutron equivalent dose rates for the prepared film samples were determined. Exposure buildup factor (EBF) and fast neutron removal cross section (ΣR) were theoretically calculated. The particle shielding characteristics of the composite films were evaluated. The MFP values at 356.01 keV are 8.211 cm, 7.772 cm, 7.360 cm, 6.710 cm and 5.942 cm for PLA/PHA, PLA/PHA/5%WC, PLA/PHA/10%WC, PLA/PHA/18%WC and PLA/PHA/28%WC, respectively. It was observed that an increase in WC content enhances the gamma shielding abilities in PHA/PLA films. The results revealed that PHA/PLA/WC composite materials can be used as protective coating materials.
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İncele - MakaleYalnız künye2022Scopus SJRQ2Dielectric Biodegradable Biopolymer-Based Graphene Nanocomposites for Use in the Packaging Industry and Capacitor Application
Gürler, Nedim; Torğut, Gülben
In this study, polyhydroxyalkanoate (PHA) and polylactic acid (PLA)-Graphene (G) nanocomposite films were synthesized by taking different concentrations of G via the solution casting process, and their structural, mechanical, opacity, thermal and dielectric properties were examined for the first time. Scanning electron microscopy (SEM) was used for investigating surface morphology. Films containing graphene were more opaque than films without graphene. The incorporation of graphene into the polymer matrix improved the mechanical property. The tensile strengths of the control PHA/PLA film and the graphene-reinforced 1 %G-PHA/PLA nanocomposite films were 18.98 and 24.34 MPa, respectively. Thermogravimetric analysis results showed that PHA/PLA−G nanocomposites had good thermal stability below 300 °C. Considering the dielectric measurements, it is seen that the dielectric constant (έ) and dielectric loss (ϵ”) decreased with increasing frequency and less changed at higher frequencies. The developer feature of graphene is remarkable in both parameters. The electrical conductivity of PHA/PLA−G nanocomposites was also examined as a function of frequency at room temperature. As the amount of G increased from 1 %wt to 5 %wt, the conductivity of the composites increased.
AtıfScopus9WoS8OpenAlex11İncele - MakaleYalnız künye2021Scopus SJRQ2Nanofiller reinforced biodegradable PHA/PLA composites: physico-chemical, thermal and dielectric properties
Torğut, Gülben; Gürler, Nedim
In this study, the electrical, thermal, morphological and physical properties of polyhydroxyalkanoate (PHA) and polylactic acid (PLA) blends and its nanocomposites prepared in different content of montmorillonite (3%wt, 5%wt, 7%wt) were investigated. Biodegradable blends of PHA/PLA were prepared in different compositions ranging from 30–70%. Nanocomposite films were analyzed by Fourier Transform Infrared (FTIR), Thermogravimetric Analysis (TGA), Differential Thermal Analysis (DTA) and scanning electron microscopy for morphology (SEM). The effects of the amount of MMT used as a reinforcing filler on the morphology, color, opacity, thermal stability, and dielectric properties of PHA/PLA films were investigated. SEM analyses showed good interaction between MMT and PHA/PLA film. As the MMT concentration increases, the transparency of the films decreases. In addition, MMT has improved thermal stability. Also, the dielectric properties and electrical conductivity of nanocomposite films were studied. The measurements were performed at frequencies between 100 Hz to 10 kHz at room temperature. As the frequency increased, dielectric permittivity (έ), the dielectric loss (ε'') and the electrical conductivity (σ) decreased and remain constant at high frequencies. έ, ε'' and the σ increased with increasing MMT content.
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