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Topic Review
Flame-Retardant Systems for Rigid Polyurethane Foam
The amplified employment of rigid polyurethane foam (RPUF) has accentuated the importance of its flame-retardant properties in stimulating demand. Thus, a compelling research report is essential to scrutinize the recent progression in the field of the flame retardancy and smoke toxicity reduction of RPUF.
  • 978
  • 19 Dec 2023
Topic Review
Glass–fibre–reinforced Polymer
Wind barrier structures are usually installed on railway bridges to reduce wind effects on travelling trains for safety considerations. This however adversely transfers wind loads and causes associated aerodynamic effects to the bridge. An innovative concept of wind barriers using glass fibre reinforced polymer (GFRP) composites is proposed in this work with experimental investigations and numerical modelling. This work provides a solution to mitigate the wind and associated aerodynamic loads. With an appropriate design of bending stiffness, the proposed barriers may deform adaptively in strong wind scenarios and let the wind to pass through their deformed shape and therefore transfer less load to the bridge. Wind-tunnel experiments and numerical studies are conducted on the aerodynamic responses of the train-barrier-bridge system under crosswind with various speeds. The influences of barrier height, air-flow speed and location of the train on the aerodynamic responses of the system were clarified. Both reduced-scale and full-scale finite element models were established for the train-barrier-bridge system and the results were validated with the experimental results to further support the research findings.
  • 976
  • 22 Oct 2020
Topic Review
Weak Polyelectrolytes for Nanoarchitectonic Design Tools
The ionization degree, charge density, and conformation of weak polyelectrolytes can be adjusted through adjusting the pH and ionic strength stimuli. Such polymers thus offer a range of reversible interactions, including electrostatic complexation, H-bonding, and hydrophobic interactions, which position weak polyelectrolytes as key nano-units for the design of dynamic systems with precise structures, compositions, and responses to stimuli. From surface platforms to colloids and gels, weak polyelectrolytes have enabled the development of a wide range of functional materials owing to their intrinsic response to stimuli, including solvents, temperature, pH, and salt.
  • 973
  • 30 May 2022
Topic Review
COF-Based Photocatalysts for Enhanced Synthesis of Hydrogen Peroxide
Photocatalytic synthesis of H2O2 has emerged as a compelling alternative, offering the prospect of harnessing solar energy directly to drive chemical reactions, thereby circumventing the need for energy-intensive processes and deleterious chemicals.
  • 967
  • 11 Mar 2024
Topic Review
Biomedical Applications of Antiviral Nanohybrids
The COVID-19 pandemic has driven a global research to uncover novel, effective therapeutical and diagnosis approaches. In addition, control of spread of infection has been targeted through development of preventive tools and measures. In this regard, nanomaterials, particularly, those combining two or even several constituting materials possessing dissimilar physicochemical (or even biological) properties, i.e., nanohybrid materials play a significant role. Nanoparticulate nanohybrids have gained a widespread reputation for prevention of viral crises, thanks to their promising antimicrobial properties as well as their potential to act as a carrier for vaccines. On the other hand, they can perform well as a photo-driven killer for viruses when they release reactive oxygen species (ROS) or photothermally damage the virus membrane. The nanofibers can also play a crucial protective role when integrated into face masks and personal protective equipment, particularly as hybridized with antiviral nanoparticles.
  • 966
  • 16 Sep 2021
Topic Review
Covalent Organic for Solar Fuel
Harnessing solar energy and converting it into renewable fuels by chemical processes, such as water splitting and carbon dioxide (CO2) reduction, is a highly promising yet challenging strategy to mitigate the effects arising from the global energy crisis and serious environmental concerns. In recent years, covalent organic framework (COF)-based materials have gained substantial research interest because of their diversified architecture, tunable composition, large surface area, and high thermal and chemical stability. Their tunable band structure and significant light absorption with higher charge separation efficiency of photoinduced carriers make them suitable candidates for photocatalytic applications in hydrogen (H2) generation, CO2 conversion, and various organic transformation reactions. 
  • 965
  • 13 Jul 2021
Topic Review
Polymer Membranes in Contamination Situations
Depending on the type of contamination, various methods are used, including sorption, biodegradation, separation, or ion exchange processes in which membranes play an important role. The type of membrane is selected in respect of both the environment and the type of neutralized pollutants.
  • 964
  • 17 Jun 2021
Topic Review
Mucoadhesive and Mucopenetrating Polymer-Based Adjuvants
Mucus is a viscoelastic gel that acts as a protective barrier for epithelial surfaces. The mucosal vehicles and adjuvants need to pass through the mucus layer to make drugs and vaccine delivery by mucosal routes possible. The mucoadhesion of polymer particle adjuvants significantly increases the contact time between vaccine formulations and the mucosa; then, the particles can penetrate the mucus layer and epithelium to reach mucosa-associated lymphoid tissues.
  • 963
  • 23 May 2023
Topic Review
Solid State Nuclear Magnetic Resonance Investigating Cellulose-Based Materials
Solid state nuclear magnetic resonance (ssNMR) is a powerful and attractive characterization method for obtaining insights into the chemical structure and dynamics of a wide range of materials. Current interest in cellulose-based materials, as sustainable and renewable natural polymer products, requires deep investigation and analysis of the chemical structure, molecular packing, end chain motion, functional modification, and solvent–matrix interactions, which strongly dictate the final product properties and tailor their end applications. In comparison to other spectroscopic techniques, on an atomic level, ssNMR is considered more advanced, especially in the structural analysis of cellulose-based materials
  • 954
  • 15 Apr 2022
Topic Review
Crosslinked nanogel for cancer theranostics
Crosslinked nanogels the structures of which are covalently crosslinked have better physiological stability than micelles and liposomes, making them more suitable for cancer theranostics. The applications of nanogels in drug and gene delivery as well as development of novel cancer therapeutic methods are first introduced, followed by the introduction of applications in optical and multimodal imaging, and imaging-guided cancer therapy. 
  • 948
  • 01 Sep 2020
Topic Review
Carbon Nanomaterials for Electro-Active Structures
The use of electrically conductive materials to impart electrical properties to substrates for cell attachment, proliferation and differentiation, represents an important strategy in the field of tissue engineering. Carbon nanomaterials have great potential for fabricating electro-active structures due to their exceptional electrical and surface properties, opening new routes for more efficient tissue engineering approaches. The concept of electro-active structures and their roles in tissue engineering is discussed in this review, the most relevant carbon-based nanomaterials used to produce electro-active structures are presented. Particular emphasis is put on the electrically conductive property, material synthesis and their applications on tissue engineering. Different technologies, allowing the fabrication of two-dimensional and three-dimensional structures in a controlled way, are also presented. Finally, challenges for future research are highlighted. 
  • 944
  • 18 Dec 2020
Topic Review
Bioactive Polymers via the Biginelli Reaction
Multicomponent reactions (MCRs) have been used to prepare polymers with appealing functions. The Biginelli reaction, one of the oldest and most famous MCRs, has sparked new scientific discoveries in polymer chemistry since 2013. The applications of the Biginelli reaction in developing functional polymers are mainly focusing on polymers that can be used in the biomedical area as antioxidants, anticancer agents, and bioimaging probes.
  • 942
  • 22 Nov 2022
Topic Review
Chemical Recycling for Plastic Waste
Plastics play an integral role in shaping our modern society and are ubiquitous in our daily lives. Their superior material characteristics, performance, and low production cost make them desirable for vast consumer and industrial applications. Chemical or feedstock recycling refers to any reprocessing technology directly affecting the formulation of polymeric waste or the polymer itself.  The recycling plastic waste through chemical means are explored.
  • 941
  • 23 May 2023
Topic Review
Crosslinking Density in Imprinting Polymerization
The crosslinking density of a material determines its physical properties, such as the porosity of the material. In imprinting polymerizations, the porosity determines access to internal binding sites and thus the capacity of the imprinted material. This entry is about effect of the commonly used crosslinking density in imprinting polymerization for a variety of applications.
  • 940
  • 30 Sep 2021
Topic Review
Organic Photorefractive Materials
Photorefractive materials are capable of reversibly changing their index of refraction upon illumination. That property allows them to dynamically record holograms, which is a key function for developing an updateable holographic 3D display. The transition from inorganic photorefractive crystals to organic polymers meant that large display screens could be made.
  • 939
  • 01 Dec 2021
Topic Review
Solid-State Zinc Secondary Batteries with Alkaline Electrolytes
Aqueous zinc-ion batteries (ZIBs) have gained significant recognition as highly promising rechargeable batteries for the future due to their exceptional safety, low operating costs, and environmental advantages. Alkaline electrolytes have a long history of application in zinc-ion batteries. Alkaline electrolytes offer several advantages compared to neutral and acidic electrolytes. The benefits of alkaline electrolytes encompass a high operating voltage, rapid reaction kinetics, and enhanced ionic conductivity. KOH is the preferred alkaline electrolyte in rechargeable zinc batteries due to its notable characteristics such as the high solubility of zinc salt in KOH solution and the superior ionic conductivity of K+ (73.5 S cm−2) compared to Na+ (50.1 S cm−2) and Li+ (38.7 S cm−2). 
  • 934
  • 17 Oct 2023
Topic Review
Simultaneous Production of Cellulose Nitrates and Bacterial Cellulose
The scientific hypothesis about the possibility of simultaneous production of two independent of each other products from Miscanthus giganteus, namely the product of chemical modification of cellulose - cellulose nitrates and the product of biosynthesis - bacterial cellulose was tested.
  • 933
  • 27 Dec 2023
Topic Review
Aliphatic Polyesters by ADMET Polymerization and Hydrogenation
The recent developments of the synthesis of bio-based long-chain aliphatic polyesters by the acyclic diene metathesis (ADMET) polymerization of α,ω-dienes, derived from plant oils and bio-based chemicals, like bis(10-undecenoate) with isosorbide, using ruthenium-carbene catalysts. The development of subsequent (one-pot) tandem hydrogenation produced saturated polyesters under mild conditions.
  • 927
  • 06 Feb 2024
Topic Review
Evaluation of PIL Graft Conjugates
In vitro cytotoxicity of polymer-carriers, which in the side chains contain the cholinum ionic liquid units with chloride (Cl) or pharmaceutical anions dedicated for antituberculosis therapy, i.e., p-aminosalicylate (PAS) and clavulanate (CLV), was investigated. The carriers and drug conjugates were examined against human bronchial epithelial cells (BEAS-2B) and adenocarcinomic human alveolar basal epithelial cells (A549) as an experimental model cancer cell line possibly coexisting in tuberculosis. The cytotoxicity was evaluated by MTT test and confluency index, as well as by the cytometric analyses, including Annexin-V FITC apoptosis assay. The polymer systems showed supporting activity towards the normal cells and no tumor progress, especially at the highest concentration (100 μg/mL). The analysis of cell death did not show meaningful changes in the case of the BEAS-2B, whereas in the A549 cell line, the cytostatic activity was observed, especially for the drug-free carriers, causing death in up to 80% of cells. This can be regulated by the polymer structure, including the content of cationic units, side-chain length and density, as well as the type and content of pharmaceutical anions. The results of MTT tests, confluency, as well as cytometric analyses, distinguished the polymer systems with Cl/PAS/CLV containing 26% of grafting degree and 43% of ionic units or 46% of grafting degree and 18% of ionic units as the optimal systems.
  • 926
  • 11 Oct 2021
Topic Review
Aerogels for the Removal of Heavy Metal Ions
Aerogel is a general term referring to novel nanostructured materials characterized by very high porosity and tunable physicochemical properties that are obtained following a sol–gel process and an appropriate drying method. Such novel materials are entering the market in everyday products and a wide portfolio of properties usable for applications in health care, foods, agriculture, energy, and environmental remediation. Bio-based aerogels obtained from renewable resources and biomass are biodegradable and biocompatible due to the natural origin of the polymers, and for this reason, they greatly contribute to the sustainable concept of the bio-economy, offering promising commodities for environmental remediation.
  • 926
  • 22 Jan 2024
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