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    Carbyne enriched nanostructures for gas sensing applications: Synthesis and characterization
    (Elsevier Science Sa, 2025) Hejazi, Mohamad-Anas; Zheng, Qing; Yang, Guowei; Lukin, Alexander; Unlu, Caner; Trabzon, Levent
    Among the various forms of carbon nanomaterials, one-dimensional sp-hybridized carbon, known as Carbyne, has been elusive and challenging to synthesize due to its chemical instability. Consequently, the properties of Carbyne have not been fully explored. Recent advancements have allowed the successful synthesis of finitelength Carbyne chains in the laboratory through novel techniques such as ion-assisted pulse plasma deposition (IA-PPD) and laser ablation in liquids (LAL). These methods produced hybrid nanostructures of sp3 and sp2 carbon enriched with Carbyne. In this work, we report the synthesis and characterization of these Carbyne nanostructures to gain a deeper understanding of their unique properties. Their potential as sensing materials in quartz crystal microbalance (QCM) sensors was examined for room-temperature pollutant detection. Characterization results revealed a higher concentration of Carbyne in the LAL samples compared to the IA-PPD samples, which corresponded to superior gas sensing performance. In tests with various analytes, LAL Carbyne exhibited greater selectivity for ammonia gas. The sensor demonstrated a moderate response time of 4.7 min with full recovery in approximately 9.3 min. However, compared to other available carbon materials, the sensitivity of Carbyne was found to be relatively low, highlighting the need for further research to optimize Carbyne synthesis and sensor fabrication.
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    Thermally Conductive Polypropylene Nanocomposites Based on Mechanically Exfoliated Boron Nitride Nanosheets
    (Wiley, 2025) Hejazi, Mohamad-anas; Tavasli, Aybuke; Bader, Sofiene; Trabzon, Levent; Navidfar, Amir
    Thermally conductive (TC) nanocomposites have been used increasingly in miniaturized electronic devices to hinder heat accumulation. By leveraging the lightweight nature of polymeric matrices and incorporating TC fillers, such as hexagonal boron nitride (hBN), high-thermally conductive materials with higher tensile strength can be developed. In this study, mechanically exfoliated hBN (20 wt%) was compounded with polypropylene (PP) to fabricate TC nanocomposites. Parameters such as sonication power, sonication time, and particle size of the hBN were optimized, and the mechanical and thermal properties of the nanocomposites, along with alkyl modification, in comparison to raw and exfoliated boron nitride nanosheets (BNNS), were examined. BNNS-based PP demonstrated improved tensile strength and elastic modulus, accompanied by a decrease in ductility. A high elastic modulus (3386 MPa-ABN/PP20.40-2) was obtained from the alkyl-modified samples. The sample containing 20 wt% BNNS (BNNS/PP20.40-3), which was subjected to 1500 W of sonication for 8 h, demonstrated an improved thermal conductivity of 0.54 W/mK, compared to ABN/PP20.40-2 (0.4 W/mK). This reflects a 125% and 80% enhancement compared to pure PP (0.24 W/mK) and smaller-sized hBN-based samples coded BNNS/PP20.750 (0.304 W/mK), respectively.