Green synthesis has gained a wide recognition as clean synthesis technique in the recent years. In the present investigation, silver nanoparticles were prepared by a novel green synthesis technique using Mangifera indica (Mango leaves) and found to be successfully used in dental applications. The prepared samples were spectroscopically characterized by XRD, PSA, SEM with EDS, and UV–Vis spectroscopy. The crystalline size and lattice strain were analyzed from the XRD data which were counter-verified by W–H plots and particle size analyzer. The XRD peaks revealed that average crystalline size of the as-synthesized Ag nanoparticles was of 32.4 nm with face-centered cubic structure. This was counter-verified by particle size analyzer and Williamson–Hall plots and found to be 31.7 and 33.21 nm in the former and latter, and the crystalline size of Ag NPs could be concluded as 32 ± 2 nm. The morphological structure of the prepared sample was studied through SEM images and the chemical composition was analyzed by the EDS data. The band energy was calculated as 393 nm from UV–Vis, which confirmed the synthesized sample as Ag nanoparticles. To improve the mechanical bonding and hardness of the dentally used glass ionomer cement (GIC), the synthesized silver nanoparticles were incorporated into GIC in 2% weight ratio. The morphology of the prepared specimens was studied using optical microscope images. Vickers microhardness and Monsanto hardness tests were performed on GIC, GIC reinforced with microsilver particles and GIC reinforced with nanosilver particles and the latter derived a promising results. The results of the Monsanto tests confirmed the increase in hardness of the GIC reinforced with AgNps as 14.2 kg/cm2 compared to conventional GIC and GIC reinforced with silver microparticle as 11.7 and 9.5 kg/cm2. Similarly the Vickers hardness results exhibited the enhanced hardness of GIC-reinforced AgNps as 82 VHN compared to GIC as 54 and GIC-reinforced silver microparticles as 61 VHN. The antibacterial activity of AgNPs was tested by a well-diffusion method on Escherichia coli and Staphylococcus aureus bacteria, and the obtained results exhibited a promising antibacterial activity of the as-synthesized nanoparticles.
In this work, MoO3-CuO metal oxide composite nanopowders are prepared by simple mechanochemical assisted synthesis technique with the stoichiometric weight ratios of MoO3 and CuO as 2.3:1 and 3.3:1, respectively. The structural and spectroscopic properties of the as-synthesised samples are characterised by XRD, SEM with EDS, FT-IR, Raman spectroscopy and TGA/DTA. X-ray diffraction pattern demonstrates the peaks correspond to orthorhombic phase of α-MoO3 and monoclinic phase of β-CuO. The average crystalline sizes of the 2.3:1 and 3.3:1 samples were found to be 16 and 24 nm, respectively, which are supported by Williamson–Hall (W–H) calculations. The correlations between the milling rotational speeds with morphological characteristics are revealed by the SEM images. The fundamental modes of Mo=O and Cu–O were analysed by FT-IR. Raman analysis has provided the qualitative information about the structure of the mixed oxide composite. Thermogravimetry analysis and Differential Thermal Analysis (DTA) of MoO3-CuO have revealed that the dual phase mixed oxide composite is stable up to 709 °C with a negligible weight loss. Based on the above, it can be inferred that the synthesised mixed lubricous oxide nanocomposite could be used as a solid lubricant at elevated temperatures
In this work, we report the spectroscopic, thermal, and mechanical outcomes of epoxy reinforced sisal/flax (S/F) hybrid natural fiber composites. This work is intended to enhance the mechanical and thermal properties of the sisal fibers in addition of the flax fibers. In recent years, natural fiber composites gained inclusive credit as a supernumerary to conventional synthetic composites for their superior ecological properties. Five different varieties of composite slabs i.e., 60% epoxy matrix and 40% of sisal/flax fibers were fabricated unidirectionally through a simple hand layout method by varying sisal and flax ratio as (40/0, 30/10, 20/20, 10/30, and 0/40) with a constant weight fraction as 0.4Wf. The X-ray Diffraction analysis was performed on the 50S/50F specimen and the crystallinity index is calculated as 42.84%. The spectroscopic and thermal studies were conducted on the 50S/50F sample and the chemical imprint of the composite is revealed by the strong peaks of cellulose, hemicellulose, and lignin along with amorphous and crystalline content of the FTIR data and is confirmed through the XRD data. The addition of flax fibers to sisal fibers showed a constructive improvement of thermal stability which is shown by the TG/DTA graph. In a three-stage degradation of sample, a maximum is observed at 334oC. The tensile, flexural, and impact tests of all the fabricated composite samples are performed and ultimate tensile strength of 165.2 N/mm2 for the 40S/0F composite with an elongation of 9.2% is noted. The ultimate flexural stress of 8.1 N/mm2 is observed in composite 10S/30F and composite 10S/30F has an excellent ability to absorb impact force of 1.2J energy. Based on the above results the manufactured composites exhibited higher thermal and mechanical properties showing a unique characteristic for different concentrations of flax fibers. Thus, the developed composites can be used individually for various applications based on the requirement of the end-user.
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