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A functionalization process has to occur in order to employ carbon nanotubes, generally by using certain types of acids. Multiwalled carbon nanotubes synthetized from benzene and ferrocene were oxidized at different temperatures between 270-600 °C through thermal treatment at atmospheric conditions. Samples were characterized by SEM, EDS, XRD, FTIR and Raman. The weight loss is shown with fluctuations from 0-78% according to different temperature conditions. FTIR analysis demonstrated presence of carbonyl groups and decrease of CHx. [ABSTRACT FROM AUTHOR]

TiAl x N y O z coatings were prepared by DC reactive sputtering on AISI D2 tool steel substrates, using a target of Ti-Al-O fabricated from a mixture of powders of Ti (22.60 wt.%), Al (24.77 wt.%), and O (52.63 wt.%). The coatings were deposited on substrates at room temperature in a reactive atmosphere of nitrogen and argon under a pressure of 8.5 × 10−3 mbar. X-ray diffraction, electron dispersive spectroscopy, Raman scattering, and nanoindentation techniques were employed to investigate the coatings. The results show that the increment in the nitrogen flow affects the structure and the mechanical properties of the coatings. The sample with the lowest nitrogen flow presented the highest hardness (10.5 GPa) and the Young’s modulus (179.5 GPa). The hardness of the coatings TiAl x N y O z as a function of crystalline grain size shows a behavior consistent with the Hall–Petch relation. [ABSTRACT FROM AUTHOR]

A stainless steel core catalyst with several green precursors, butanol, diethyl ether, ethyl acetate and hexane, were used to obtain multi-walled carbon nanotubes via chemical vapor deposition. Argon was used as carrier gas at 50-90 ml/min rates. Samples were synthetized at 680-850 °C, according to the precursor used. The characterization techniques were scanning electronic microscopy, X-ray diffraction, energy dispersive, Fourier transformed infrared and Raman spectroscopy. The micrographs showed tangled carbon nanotubes formation with different diameters from 50-300 nm. Elemental analysis indicated carbon atomic percentages ranging from 93-99%, 1.0-4.5% iron and less than 1% of manganese, chrome and silicon. X-Ray diffraction demonstrated the characteristic carbon nanotubes peak (002) at 26°. G and D carbon nanotubes distinctive bands were confirmed by Raman spectra for all samples. [ABSTRACT FROM AUTHOR]

Background: Folic acid (FA), a synthetically produced compound analogous to vitamin B9, also referred to as vitamin folate, is an essential compound in human health and faces challenges in stability during food processing. This study explores the incorporation of FA into carboxymethylcellulose (CMC) nanofibers using electrospinning to enhance its stability., Results: In this study, optimization of both electrospinning and solution parameters facilitated the fabrication of nanofibers. Furthermore, incorporating FA into CMC/polyethylene oxide (PEO) nanofibers resulted in thinner fibers, with an average diameter of 88 nm, characterized by a flat shape and smooth surface. Fourier transform infrared spectroscopic analysis demonstrated substantial hydrogen bonding interactions between FA and the polar groups present in CMC. This interaction contributed to an encapsulation efficiency of 94.5%, with a yield exceeding 87%. Thermal analysis highlighted mutual interference between CMC and PEO, with FA enhancing the thermal stability and reducing the melting temperatures and enthalpies of PEO, while also increasing the reaction heats of CMC. The encapsulated FA remained stable in acidic conditions, with only 6% degradation over 30 days, demonstrating the efficacy of CMC/PEO nanofibers in safeguarding FA against acidic environments. Moreover, the nanofibers provided a protective barrier against UV radiation, thereby preserving the stability of FA., Conclusion: This study emphasizes the efficacy of CMC/PEO nanofibers as a protective matrix against FA degradation. The findings indicate that this innovative approach could significantly diversify the applications of FA in food fortification, addressing concerns regarding its vulnerability to temperature and hydrolysis reactions during food processing. © 2024 Society of Chemical Industry., (© 2024 Society of Chemical Industry.)

The synthesis, characterization and degradation of a hybrid chitosan (CTS)/glycidyl methacrylate (GMA) material are reported. These versatile materials (natural-synthetic materials) are potential candidates for dental restoratives. All materials were characterized by infrared spectroscopy (FT-IR), X-ray diffraction and thermal (DSC) analysis. Particular attention was paid to the thermal stability and chemical resistance of the hybrid CTS materials. From dynamical rheological tests, it was concluded that CTS-GMA solutions behave as physical hydrogels. These pH-sensitive gels are an example of stimuli-responsive polymers, also known as 'smart polymers'.