Research Outputs

Now showing 1 - 3 of 3
  • Publication
    Poly(lactide) and Ni nanoparticles supported thermally reduced graphene oxide nanoarchitecture for magnetic stimuli‐responsive material
    (Society of Plastics Engineers, 2025) ;
    Moreira Dos Santos, Leonardo
    ;
    Ullah, Hameed
    ;
    Barrera Galland, Griselda
    ;
    Geshev, Julian
    ;
    Bergmann, Carlos
    ;
    Quijada, Raúl
    In recent years, biodegradable plastics have gained significant attention as a strategy to reduce environmental contamination. However, achieving uniform dispersion of magnetic nanoparticles (MNPs) in polymers remains challenging due to magnetic aggregation. Core-shell encapsulation has emerged as an effective method to address this issue. In this study, nickel (Ni) nanoparticles (NPs) were supported on thermally reduced graphene oxide (TrGO), reduced at two distinct temperatures (600 and 1000°C), and used as nano-fillers to fabricate PLA nanocomposites. The mechanical, thermal, and magnetic properties of these composites were systematically investigated. X-ray diffraction (XRD) analysis displayed characteristic peaks for both graphene and Ni, with an estimated Ni NP size of 3.59 nm. Raman spectroscopy confirmed the D and G bands of graphene, along with distinct peaks of Ni. Surface area and elemental analyses indicated an increase in surface area and carbon content with thermal reduction, followed by a predictable decrease after supporting Ni NPs. Atomic absorption spectroscopy revealed that 8–12 wt.% of MNPs were successfully loaded onto the TrGO surface. Fourier transform infrared spectroscopy (FT-IR) demonstrated that the polymer's chemical structure remained unchanged after nanoparticle incorporation. Uniform dispersion of the filler was observed through fracture interface scanning electron microscopy (SEM) and transmission electron microscopy (TEM). Thermogravimetric analysis (TGA) showed a slight improvement in the initial degradation temperature of the PLA nanocomposites upon NP addition, although the final thermal stability was lower compared to neat PLA. Differential scanning calorimetry (DSC) showed a small increase in crystallinity, while the melting temperature remained unchanged. The addition of the filler led to a slight improvement in the elastic modulus. The hydrophilic nature of the nanocomposites was confirmed by water contact angle measurements. Notably, the incorporation of TrGO-Ni nanoparticles converted the original diamagnetic PLA matrix into a ferromagnetic material.
  • Publication
    Optical response of Zr2CO2/MoS2 2 CO 2 /MoS 2 van der Waals heterostructures calculated using first-principles calculations
    (Elsevier, 2024) ;
    Aziz, Hafsa
    ;
    Shah, Tahir Abbas
    ;
    Rahman, Altaf Ur
    ;
    Jabeen, Nawishta
    ;
    Abdul, Muhammad
    ;
    El-Bahy, Zeinhom
    ;
    Alomar, Taghrid
    ;
    AlMasoud, Najla
    In the field of material science, the search for a material with an optimal bandgap of approximately 1.40 eV that can act as an efficient photocatalyst for water splitting using solar spectrum irradiation is a noble mission. In this article, we explore the structural, electronic structure, optical and photocatalytic properties of Zr2CO2/MoS2 vdW heterostructures. Our results demonstrates that the Zr2CO2/MoS2 vdW heterostructure can be reliably synthesized. This is due to a minimal lattice mismatch of less than 3%, a negative adhesion energy of -4.23 meV/Å 2, and inherent dynamic stability. The electronic band structure calculations indicate that the Zr2CO2/MoS2 vdW heterostructure is an indirect bandgap semiconductor. We found that the conduction band minimum (CBM) and valance band maximum (VBM) of the heterostructure are located in different monolayers. Furthermore, under −2 % biaxial strain a transition from type-I to type-II (staggered) band alignment occurred. Stacking 2D MoS2 on the Zr2CO2 monolayer results in a vdW heterostructure, and as a result, the HSE calculated bandgap of the Zr2CO2/MoS2 vdW heterostructure in most stable configuration lying in the ideal range for photocatalytic applications. We also studied the heterostructure’s optical properties to understand its response to incident photons with energies up to 14 eV. Based on our findings, Zr2CO2/MoS2 heterostructures are desirable for optoelectronic device applications operated in visible range. Our research offers fresh recommendations for developing novel, highly effective photocatalytic compounds with numerous optical device applications.
  • Publication
    Different aspects of polymer films based on low‐density polyethylene using graphene as filler
    (Wiley, 2023) ;
    Medeiros, Gabriela
    ;
    Peter, Jakub
    ;
    Andrade, Ricardo
    ;
    Fechine, Guilhermino
    The focus of the present work is to prepare low‐density polyethylene (LDPE)‐graphene (G) nanocomposite films with improved gas barrier properties by melt extrusion. A narrow range of the graphene (0.05–0.3 wt.%) as filler was used in the LDPE matrix. The rheological analysis indicating that there is no significant influence on the LDPE chains mobility with the addition of filler. The nanocomposites percent crystallinity (Xc%) increase from 25.0% to 31.6% compared to neat LDPE. The X‐ray diffractogram shows a change in width half height of the peak positioned at 26° ((002) plane) from 0.69 (graphite) to 1.24 (graphene), revealing the asymmetry of this plane. The optical microscopy images show a good dispersion of the nanoparticles in the polymer matrix. The mechanical properties of the nanocomposites in longitudinal direction demonstrate better improvement with addition of the filler as compared to the transverse direction. The contact angle measurements of nanocomposites for water and ethylene glycol do not shows a significant variation in comparison to neat LDPE. The nanocomposites show 26% enhancement in the oxygen barrier property. Thus, here we present the cost‐effective LDPE‐graphene nanocomposites with improve oxygen barrier property, which can be used in different industrial application especially in food packaging.