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Topic Review
Disentangled Polymers and Composites
Macromolecule entanglements are common in polymers. The chains of macromolecules with carbon skeletons are flexible. The isolated chain easily takes the shape of a coil. When a macromolecule is surrounded by other macromolecules, its coils interpenetrate, and entanglements arise between these macromolecules. The condition of their occurrence is that their molecular weight exceeds a certain limit. The entanglements may be topological (these are common) or cohesive. Entanglement with another macromolecule limits the movement of the macromolecule's chain, so it is an obstacle to this movement.
  • 1.1K
  • 29 Dec 2023
Topic Review
Cellulose Nanocrystal (CNC) Gels: A Review
Cellulose nanocrystals (CNCs) are emerging nanomaterials derived from the most abundant renewable polymer on earth, being widely distributed in plants, bacteria, algae, etc., which can be extracted from these cellulosic sources through mechanical disintegration, controlled sulfuric acid hydrolysis and mixed acid hydrolysis.
  • 1.1K
  • 18 Jul 2023
Topic Review
Characterization of Polymeric Coatings
The development of anti-corrosion polymeric coatings has grown exponentially in the fields of material science, chemistry, engineering, and nanotechnology and has prompted the evolution of efficient characterization techniques. Polymeric coatings represent a well-established protection system that provides a barrier between a metallic substrate and the environment. However, the increase in complexity and functionality of these coatings requires high-precision techniques capable of predicting failures and providing smart protection.
  • 1.1K
  • 22 Jun 2022
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.
  • 1.1K
  • 16 Sep 2021
Topic Review
Reprocessable Photodeformable Azobenzene Polymers
Photodeformable azobenzene (azo) polymers are a class of smart polymers that can efficiently convert light energy into mechanical power, holding great promise in various photoactuating applications. They are typically of crosslinked polymer networks with highly oriented azo mesogens embedded inside. Upon exposure to the light of appropriate wavelength, they experience dramatic order parameter change following the configuration change of the azo units. This could result in the generation and accumulation of the gradient microscopic photomechanical force in the crosslinked polymer networks, thus leading to their macroscopic deformation. Most of the presently developed photodeformable azo polymers have stable chemically crosslinked networks, which make their reprocessing impossible, thus limiting their large scale applications. To solve this problem, reprocessable photodeformable azo polymers have been recently developed by introducing dynamic crosslinking networks (including physically crosslinked and dynamic covalent bond-crosslinked ones) into their structures. In addition, some uncrosslinked photodeformable azo polymers have also been reported and constitute one special type of reprocessable photodeformable azo polymers, whose photodeformation behaviors are mainly induced by the selective reorientation of the azo moieties (become perpendicular to the polarization direction of the polarized light) under the irradiation of either polarized blue light or interfering polarized light.
  • 1.1K
  • 30 Aug 2021
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.
  • 1.1K
  • 19 Dec 2023
Topic Review
Versatile Polyaniline-Based Polymers in Food Industry
Intrinsically conducting polymers (ICPs) have been widely studied in various applications, such as sensors, tissue engineering, drug delivery, and semiconductors. Specifically, polyaniline (PANI) stands out in food industry applications due to its advantageous reversible redox properties, electrical conductivity, and simple modification. The rising concerns about food safety and security have encouraged the development of PANI as an antioxidant, antimicrobial agent, food freshness indicator, and electronic nose. At the same time, it plays an important role in food safety control to ensure the quality of food.
  • 1.1K
  • 14 Dec 2022
Topic Review
Recent Advances in PLA/TiO2 Composites
Polylactic acid/titanium oxide (PLA/TiO2) composites as multifunctional materials havebeen studied extensively by couple of  research groups owing to their outstanding mechanical, thermal, photocatalytic, and antimicrobial properties. This review describes the experimental approaches used to improve the compatibility of PLA/TiO2 composites. The mechanical, thermal, photocatalytic,  and antimicrobial properties of PLA/TiO2 composites are discussed. The potential applications arising from the structural and functional properties of PLA/TiO2 composites were also reviewed. Finally,  it is concluded that a deep understanding of the impacts of TiO2 filler with available improvement approaches in the dispersibility of this filler in the PLA matrix would be the key for the effective usage of PLA/TiO2 composites and to expand their suitability with worldwide application requirements.
  • 1.1K
  • 06 Apr 2021
Biography
Mahmoud A. Hussein
M.A. Hussein is a professor of Polymer Chemistry, Polymer Chemistry Lab, Chemistry Department, Faculty of Science, Assiut University (AU), Egypt. He obtained his PhD in Organic Polymer Synthesis from Assiut University, Egypt in 2007. He got a position at Chemistry Department, King Abdulaziz University (KAU), Jeddah, Saudi Arabia from 2010 – till now. He got a postdoctoral position in the Unive
  • 1.1K
  • 13 Mar 2023
Topic Review
Membrane-Based Direct Air Capture Application
Direct air capture (DAC) is an emerging negative CO2 emission technology that aims to introduce a feasible method for CO2 capture from the atmosphere. Unlike carbon capture from point sources, which deals with flue gas at high CO2 concentrations, carbon capture directly from the atmosphere has proved difficult due to the low CO2 concentration in ambient air. Current DAC technologies mainly consider sorbent-based systems; however, membrane technology can be considered a promising DAC approach since it provides several advantages, e.g., lower energy and operational costs, less environmental footprint, and more potential for small-scale ubiquitous installations. Several recent advancements in validating the feasibility of highly permeable gas separation membrane fabrication and system design show that membrane-based direct air capture (m-DAC) could be a complementary approach to sorbent-based DAC, e.g., as part of a hybrid system design that incorporates other DAC technologies (e.g., solvent or sorbent-based DAC). 
  • 1.1K
  • 05 Feb 2024
Topic Review
Sulfonimide-Based Dendrimers
Dendrimers are multifunctional polymer compounds with a tree-like shape and a high branching degree. 
  • 1.1K
  • 25 Feb 2021
Topic Review
Fiber–Hydrogel Composites for Wound Healing
The structural resemblance of fiber–hydrogel composites to natural tissues has been a driving force for the optimization and exploration of these systems in biomedicine. Indeed, the combination of hydrogel-forming techniques and fiber spinning approaches has been crucial in the development of scaffolding systems with improved mechanical strength and medicinal properties.
  • 1.1K
  • 11 Mar 2021
Topic Review
Recycling of High-Molecular-Weight Organosilicon Compounds in Supercritical Fluids
The main known patterns of thermal and/or catalytic destruction of high-molecular-weight organosilicon compounds are considered from the viewpoint of the prospects for processing their wastes. The advantages of using supercritical fluids in plastic recycling are outlined in this entry. They are related to a high diffusion rate, efficient extraction of degradation products, the dependence of solvent properties on pressure and temperature, etc. A promising area for further research is described concerning the application of supercritical fluids for processing the wastes of organosilicon macromolecular compounds.
  • 1.1K
  • 14 Dec 2022
Topic Review
Stimulus-Responsive Polymers and Polypeptoid Skeletons
Polypeptoids have low cytotoxicity and good biocompatibility because of their structural similarity to polypeptides. Different from polypeptides, however, polypeptoids show thermal transformation similar to synthetic thermoplastics, making them suitable for various heat treatment methods. Polypeptoids combine the properties of natural macromolecules and synthetic polymers, and become great candidates as stimulus-responsive biopolymers.
  • 1.0K
  • 05 Aug 2021
Topic Review
Natural and Modified Cyclodextrins as Packaging Additives
Cyclodextrins (CDs) have been used by the pharmaceutical and food industries since the 1970s. Their cavities allow the accommodation of several hydrophobic molecules, leading to the formation of inclusion complexes (ICs) increasing the guest molecules’ stability, allowing their controlled release, enhancing their water solubility and biodisponibility.
  • 1.0K
  • 18 Nov 2021
Topic Review
Fluoropolymer Membranes for Membrane Distillation and Membrane Crystallization
Fluoropolymer membranes are applied in membrane operations such as membrane distillation and membrane crystallization where hydrophobic porous membranes act as a physical barrier separating two phases. Due to their hydrophobic nature, only gaseous molecules are allowed to pass through the membrane and are collected on the permeate side, while the aqueous solution cannot penetrate. However, these two processes suffer problems such as membrane wetting, fouling or scaling. Membrane wetting is a common and undesired phenomenon, which is caused by the loss of hydrophobicity of the porous membrane employed. This greatly affects the mass transfer efficiency and separation efficiency. Simultaneously, membrane fouling occurs, along with membrane wetting and scaling, which greatly reduces the lifespan of the membranes. Therefore, strategies to improve the hydrophobicity of membranes have been widely investigated by researchers. In this direction, hydrophobic fluoropolymer membrane materials are employed more and more for membrane distillation and membrane crystallization thanks to their high chemical and thermal resistance. 
  • 1.0K
  • 03 Jan 2023
Topic Review
Microplastics Derived from Food Packaging Waste
Plastics are commonly used for packaging in the food industry. The most popular thermoplastic materials that have found such applications are polyethylene (PE), polypropylene (PP), poly(ethylene terephthalate) (PET), and polystyrene (PS). Unfortunately, most plastic packaging is disposable. As a consequence, significant amounts of waste are generated, entering the environment, and undergoing degradation processes. They can occur under the influence of mechanical forces, temperature, light, chemical, and biological factors. These factors can present synergistic or antagonistic effects. As a result of their action, microplastics are formed, which can undergo further fragmentation and decomposition into small-molecule compounds. During the degradation process, various additives used at the plastics’ processing stage can also be released. Both microplastics and additives can negatively affect human and animal health.
  • 1.0K
  • 29 Jan 2023
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.
  • 1.0K
  • 11 Mar 2024
Topic Review
Supercritical Carbon-di-Oxide Technology for Polymeric-Particles
Supercritical carbon dioxide (SC-CO2)  based techniques can be exploited for the formulation of polymeric nanocarriers, limiting the use of toxic organic solvent. The currently approved FDA pharmaceutical polymers like PLA and PLGA particles can be obtained in the micro-and nanometer range by techniques that involve SC-CO2 as solvent (RESS, RESOLV), anti-solvent (SAS, SEDS, SAILA) or extractant (SFEE), depending on the SC-CO2 compatibility with the system materials and the final product.
  • 1.0K
  • 27 Apr 2021
Topic Review
Silicones Renewed for Emerging Applications
Polydimethylsiloxane (PDMS) is the basis of the vast majority of silicone products that have found use in almost all areas of human activity, from cosmetics to the nuclear or aerospace industry. After 80 years from the first direct synthesis of silicones (2020), they still enjoy great interest, both scientific and applicative, being extremely versatile. Polydimethylsiloxane (PDMS), in spite of its well-defined helical structure, is an amorphous fluid even at extremely high molecular weights. The cause of this behavior is the high flexibility of the siloxane backbone and the lack of intermolecular interactions attributed to the presence of methyl groups. These make PDMS incompatible with almost any organic or inorganic component leading to phase separation in copolymers and blends. The material itself is hydrophobic and permeable to gases, with low viscosity, solubility parameters, low glass transition temperature and very low surface tension. This makes the silicones spread very easily, distinguished by their ability to form temporary films and thin coatings to more substantial durable films or with self-leveling and adhesive capacities as stand-alone sheets of different sizes and thickness, from a few micrometers to a few millimeters. One application that is based on this property is the formation of free standing, flexible submicrometric films of interest as active elements in certain devices, such as dielectric elastomer transducers (DETs). Dielectric elastomers (DEs), three-dimensional networks of long and flexible polymer chains, are soft active materials showing promising properties that mimic natural muscle for use in advanced robotics and smart prosthetics, as well as in haptic and microfluidic devices. They enjoy great interest due to their inherent flexibility, large strain, high efficiency, high energy density, and fast response of the material. In addition, some of their properties can be adjusted as required by chemical, physical or combined approaches. 
  • 1.0K
  • 23 Jun 2021
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