Macromolecular Symposia最新文献

Industrial wastewater poses a serious threat to human health and the environment. The rising demand for an easy, efficient, environment-friendly, and cost-effective method for wastewater treatment has paved the way for the photocatalytic degradation of wastewater. Organic dyes, which comprise a major portion of organic pollutants in industrial wastewater, are highly toxic and carcinogenic. The hydrothermal method, being economical, easily available, and environmentally friendly, is used to prepare the time-varying KBiFe₂O₅ samples. KBiFe₂O₅ is a lead-free (nonhazardous), low-bandgap brownmillerite-structured crystalline material that can use a wide range of solar spectrum. Their phase purity is also confirmed by powder X-ray diffraction (XRD), UV–Vis diffuse reflectance spectrophotometer (UV–Vis DRS) is done to confirm the bandgap value and Fourier transform infrared (FTIR) spectroscopy is performed to identify the chemical bonds in the material. Degrading textile organic effluent methylene blue (MB) dye under visible light and comparing its photodegradation performance are conducted to investigate the synthesized samples’ photocatalytic properties. The photocatalytic activity is relatively enhanced by adding H₂O₂ in a precise amount. So, the synthesized samples effectively demonstrate photocatalytic behavior, which has been used for wastewater remediation purposes.

This research paper underscores the critical importance of advancing submarine technology by proposing a fully hydrogen-powered submarine integrated with an air-independent propulsion (AIP) system and artificial intelligence (AI)-driven safety measures. Such an innovative approach not only addresses the limitations of traditional diesel-electric submarines but also promises to revolutionize naval operations. The adoption of hydrogen as the primary power source significantly extends the submarine's operational range, reducing its dependence on fossil fuels and minimizing environmental impact. The incorporation of AIP technology enables sustained underwater endurance, reducing vulnerability and enhancing mission effectiveness. Concurrently, AI-driven safety measures provide robust leak detection and safe hydrogen handling, ensuring the well-being of the crew while optimizing operational efficiency. This integrated solution represents a transformative step toward achieving a more sustainable, capable, and stealthy submarine fleet for modern warfare scenarios.

The prospective applications of carbon graphene nanoplatelets (GNPs) reinforced ethylene vinyl acetate (EVA) nanocomposites in flexible electronics, energy storage devices, and thermal management systems have attracted a lot of attention. These nanocomposites offer an effective solution for enhancing the electrical conductivity of interfacing materials in electronic systems and addressing issues related to thermal management. GNPs that possess excellent thermal conductivity of 2000–4000 W m⁻¹ K⁻¹ and an electrical conductivity of 10⁷ S m⁻¹ are utilized in this investigation. The homogeneous dispersion of nanofiller and the effective load transfer between components through strong filler/polymer interfacial interactions are essential for the creation of multifunctional polymer nanocomposites. Particularly, their electrical conductivity and dielectric properties are highlighted in this study, with an emphasis on the synthesis and characterization of nanocomposite materials. This work investigates the utilization of graphene nanocomposites in EVA using a melt-mixing technique assisted by sonication to fabricate multifunctional composites. Incorporating different weight percentages of GNPs (ranging from 0.1 to 0.4 wt.%) within the polymer matrix is carried out. In the present study, the nanocomposites are characterized by scanning electron microscopy investigation and impedance spectrum analysis. The distinctive characteristics of the AC electrical transport in nanocomposites are investigated between 10 Hz and 1 MHz. Excellent interfacial compatibility has been demonstrated by the homogenous distribution of GNPs within the matrix, confirmed by SEM examination. These EVA nanocomposites demonstrate improved electrical conductivity, thereby rendering them very useful for energy storage applications, such as electronic capacitors, wherein supports with a significant dielectric constant and minimal dielectric loss are required.

RETRACTION: V. Ranade, R. J. Choudhary, and K.P. Singh, “Discovering Intrinsic Magnetism of Silk Fibroins” Macromolecular Symposia 1(2024): e2300059, https://doi.org/10.1002/masy.202300059.

The above article, published online on 21 February 2024 in Wiley Online Library (wileyonlinelibrary.com), has been retracted by agreement between author, K.P. Singh; the journal Editor-in-Chief, Alice Jensen; and Wiley-VCH GmbH. The retraction has been agreed following an investigation into concerns raised by author K.P. Singh which was led by the current and former institution (IISER Mohali) of the authors and verified by the Publisher and the Editor-in-Chief. This investigation found that the Corresponding Author V. Ranade used data without authorization for use, listed K.P. Singh as an author without his consent, and published fabricated data. As a result, the data, and the conclusions are considered unreliable and therefore the article must be retracted.

The aim of this study is to develop a new nanobiocomposite based on silver doped hydroxyapatite (AgHAp)/chitosan (CH), AgHAp-CH (x_Ag = 0.15) by an adapted method. The obtained nanobiocomposites are studied by scanning electron microscopy (SEM) and Fourier transform infrared spectroscopy (FTIR) studies. The good stability of AgHAp-CH suspension is established by ultrasound and zeta potential measurements. More than that, the antimicrobial activity of AgHAp-CH nanobiocomposites against Staphylococcus aureus ATCC 25923, Escherichia coli ATCC 25922, and Candida albicans ATCC 10231 microbial strains is evaluated. AgHAp-CH nanobiocomposites demonstrate an effective antibacterial effect against the studied microbial strains. Considering the facile method involved in the development of these nanobiomaterials and their excellent properties, it is suggested that they can be suitable candidates for applications in the biomedical field.

Nanocomposites of sodium alginate (SA) and TiO₂ nanoparticles have gained attention in the last decade for their versatile uses in several applications. Indeed, TiO₂ is particularly appealing for its photocatalytic and antimicrobial activity and inherent safety. In this paper, TiO₂ nanoparticles are successfully embedded, synthesized by a microwave-assisted method, into SA matrix by a simple solvent casting method to form flexible and self-consistent SA/TiO₂ films. FT-IR, XRD, and contact angle measurements confirm the formation of homogeneous and hydrophilic bio-composites films that may be suitable for packaging or life science applications.

The intermolecular forces are of great importance to scientists in a wide field of disciplines as the progress of interactions between molecules determines the bulk properties of substances. It is a matter of fact that the approximation of thermodynamic and transport properties of polymers requires a realistic intermolecular potential associated with the topological constraints of the matter, namely the specific one-to-one secondary interactions between molecular groups. The out-of-equilibrium volume relaxation in glassy polymers remains confined to the phenomenological observation of bulk properties. The Lennard-Jones (LJ)-type potentials and the Tait equation are compared in this communication. It is shown that the subtle relaxation responses observed in glassy polymers can be suitably described using both the local (LJ) interactions and the phenomenological Tait equation for bulk behavior. The approach is based on the oversimplified assumption that the volume relaxation phenomena are the isotropic manifestation of random relaxations of local directional interactions of secondary bonds. The results appear surprisingly appealing, given the straightforward approach.

Gellan gum prepared from the domestic raw materials of Kazakhstan is studied by methods of ¹H NMR spectroscopy, FTIR, GPC, TGA, and compared with characteristics of commercial gellan gum. Fermentation on glucose-fructose syrup of Zharkent and Burunday corn starch plants (Kazakhstan) by Sphingomonas paucimobilis ATCC 31461 produces a biomass containing a high acyl gellan gum (HAG). The average molecular weights, M_w, M_n, M_z, and polydispersity index (PDI) of HAG are determined by GPC. Low acyl gellan (LAG) is obtained by treatment of HAG with alkaline solution. It is shown that the spectral and thermal characteristics of HAG and LAG produced from the glucose-fructose syrup and commercial gellan gum are similar.

Gels are soft materials made of a crosslinked polymer network immersed in a fluid. When water is the main component, these materials (hydrogels) find extensive use in the medical and pharmaceutical fields due to the high biocompatibility given by their high water content. The hydrogel ability to absorb water also makes it interesting for radiation shielding applications in space, since a high hydrogen content is helpful to reduce the damage caused by ionizing radiation on astronauts and electronic devices. In this work, crosslinked hydrogels are prepared using poly(vinyl alcohol) (PVA) with boric acid (BA) as crosslinking agent. Results in terms of chemical composition from Fourier transform infrared (FTIR) spectroscopy, mechanical properties from dynamic mechanical analysis (DMA), and swelling behavior are used to assess the BA capacity to form hydrogen and chemical bonds with the PVA macromolecules.

Microspheres (MSs) made from biocompatible natural polymers with pH-responsive properties, such as alginate and chitosan, are widely exploited as drug delivery systems. In this work, pH-responsive MS based on alginate/chitosan hydrogels is developed and applied as carriers of Ozoile, a stable ozonide. Ozoile is a bioactive formulation obtained by ozonation of biological olive oil, which is capable of inducing the expression of different genes that are involved in the process of tissue regeneration. The MS containing Ozoile is prepared using an electrospray (ES) technique from alginate/Ozoile emulsions. The MSs are optimized with a chitosan coating to improve their stability and degradation behavior, and so to control the release of Ozoile in time. Fourier transform infrared (FTIR) spectroscopy, swelling, and degradation analyses are conducted and results use to assess the potential use of the alginate-based MS for the therapeutic release of Ozoile at specific inflammatory sites.