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Topic Review
Siloxanes
Siloxanes are adaptable species that have found extensive applications as versatile materials for functionalising various surfaces and as building blocks for polymers and hybrid organic-inorganic systems. The primary goal of this review is to report on and briefly explain the most relevant recent developments related to siloxanes and their applications, particularly regarding surface modification and the synthesis of graft copolymers bearing siloxane or polysiloxane segments. The key strategies for both functionalisation and synthesis of siloxane-bearing polymers are highlighted, and the various trends in the development of siloxane-based materials and the intended directions of their applications are explored.
  • 2.7K
  • 08 Sep 2020
Topic Review
pH Responsive Polyurethane for Biomedical and Drug Delivery
pH-responsive polymers are polymers that respond to changes in environmental pH. They can be classified into: (A) polymers with ionizable moieties; and (B) polymers that contain acid-labile linkages. pH-responsive polyurethanes demonstrated good biological response and sustainability in biomedical applications and drug delivery. They have been used as controlled drug delivery systems for oral administration, intravaginal administration, and targeted drug delivery systems for chemotherapy treatment. 
  • 2.7K
  • 12 May 2022
Topic Review
Chitosan-based Flame-Retardant Systems
During the last decade, the utilization of chitin, and in particular its deacetylated form, i.e. chitosan, for flame retardant purposes, has represented quite a novel and interesting application, very far from the established uses of this bio-sourced material. In this entry, chitosan is a carbon source that can be successfully exploited, often in combination with intumescent products, in order to provide different polymer systems (namely, bulky materials, fabrics and foams) with high flame retardant (FR) features. Besides, this specific use of chitosan in flame retardance is well suited to a green and sustainable approach.
  • 2.7K
  • 22 Oct 2020
Topic Review
Remediation of Textile-Dye-Containing Wastewater
Water makes up most of the Earth, although just 0.3% is usable for people and animals. The huge oceans, icecaps, and other non-potable water resources make up the remaining 99.7%. Water quality has declined due to pollution from population growth, industry, unplanned urbanization, and poor water management. The textile industry has significant global importance, although it also stands as a major contributor to wastewater generation, leading to water depletion and ecotoxicity. This issue arises from the extensive utilization of harmful chemicals, notably dyes.
  • 2.6K
  • 09 Jan 2024
Topic Review
Adhesives and Adhesion Mechanism
Adhesives are a preferred choice for binding solid wood and wood composites based on wood strips, chips, fibers, strands, and veneer for manufacturing engineered wood products (EWPs), such as laminated veneer lumber (LVL), laminated strand lumber (LSL), oriented strand board (OSB), cross-laminated timber (CLT), plywood, particle board, medium density fiberboard (MDF), and high-density fiberboard.
  • 2.6K
  • 07 Mar 2022
Topic Review
Supercritical CO2 Foaming Technologies
Poly(lactic acid) (PLA) foaming is divided into physical foaming and chemical foaming; in contrast with the latter, the use of a physical foaming agent for PLA foaming has the characteristic of being green and non-polluting in line with the current carbon-neutral development plan. At the same time, the foam obtained by physical foaming has the properties of lightweight, low density, and more stable. Common physical blowing agents are CO2 and N2. Due to the plasticizing effect of CO2, and its high solubility in PLA, which can promote the crystallization of PLA, the current research on the supercritical foaming of PLA, especially intermittent foaming, mainly uses CO2 as the preferred foaming agent. However, due to the fast diffusion rate of N2, smaller bubbles can be obtained in microcellular injection foaming using N2. Therefore, N2 is commonly used as a blowing agent in the microcellular injection foaming process. In the supercritical foaming process, foaming parameters, such as saturation temperature, saturation pressure, and saturation time have a great influence on the structure and properties of the bubble pores. The cell diameter, cell density, and foam volume expansion ratio are three fundamental parameters for characterizing the cell structure. The variation in the three parameters has a great influence on the cell structure and the performance of the foam. Cell diameter generally refers to the average diameter of at least 100 cell units in the foaming image obtained from electron microscopy. Cell density refers to the number of cells per cubic centimeter of the foamed sample. Volume expansion ratio refers to the density ratio of the unfoamed sample to the foamed sample.
  • 2.6K
  • 14 Nov 2022
Topic Review
Improving the Barrier Properties of the Biodegradable Polymers
Biodegradable polymers have become a topic of great scientific and industrial interest due to their environmentally friendly nature. For the benefit of the market economy and environment, biodegradable materials should play a more critical role in packaging materials. 
  • 2.5K
  • 27 Feb 2024
Topic Review
Ceramic-Polymer Composite Membranes
Ceramics and polymers are two main candidate materials for membranes, where the majority has been made of polymeric materials, due to the low cost, easy processing, and tunability in pore configurations. In contrast, ceramic membranes have much better performance, extra-long service life, mechanical robustness, and high thermal and chemical stabilities, and they have also been applied in gas, petrochemical, food-beverage, and pharmaceutical industries, where most of polymeric membranes cannot perform properly. 
  • 2.5K
  • 22 Jun 2021
Topic Review
Injectable Hydrogels
The transfer of some innovative technologies from the laboratory to industrial scale is many times not taken into account in the design and development of some functional materials such as hydrogels to be applied in the biomedical field. There is a lack of knowledge in the scientific field where many aspects of scaling to an industrial process are ignored, and products cannot reach the market. Injectable hydrogels are a good example that we have used in our research to show the different steps needed to follow to get a product in the market based on them. From synthesis and process validation to characterization techniques used and assays performed to ensure the safety and efficacy of the product, following regulation, several well-defined proto-cols must be adopted.
  • 2.5K
  • 12 Mar 2021
Topic Review
Per- and Polyfluoroalkyl Substances
Per- and polyfluoroalkyl substances (PFAS) are a family of synthetic fluorinated organic compounds whose widespread use and resistance to biodegradation have led to their accumulation in the environment, causing growing concerns over their impact on humans.
  • 2.5K
  • 15 Jan 2021
Topic Review
Bound Water and Tissue Stiffness
The mechanical properties of living biological tissues change with aging and commonly can be associated with age-related diseases. Increase of tissue stiffness can be related also with thermodynamically favorable release of tightly bound to biological macromolecules water molecules. 
  • 2.5K
  • 10 Aug 2020
Topic Review
Hydrogen Permeation Test Methods of Polymer Liner Material
Type IV hydrogen storage cylinders comprise a polymer liner and offer advantages such as lightweight construction, high hydrogen storage density, and good fatigue performance. However, they are also characterized by higher hydrogen permeability. Consequently, it is crucial for the polymer liner material to exhibit excellent resistance to hydrogen permeation. International organizations have established relevant standards mandating hydrogen permeation tests for the liner material of type IV on-board hydrogen storage cylinders. 
  • 2.5K
  • 14 Aug 2023
Topic Review
Environmental Ageing of Polymers and Polymer Composites
Polymers and polymer composites are often exposed to elevated temperatures, mechanical stress, water and humid air environments, where their performance is negatively impacted by environmental ageing, reducing their service lifetime.
  • 2.5K
  • 15 Mar 2022
Topic Review
HCN-Derived Polymers
HCN-derived polymers are a heterogeneous group of complex substances synthesized from pure HCN; from its salts; from its oligomers, specifically its trimer and tetramer, aminomalononitrile (AMN) and diaminomaleonitrile (DAMN), respectively; or from its hydrolysis products, such as formamide, under a wide range of experimental conditions. The characteristics and properties of HCN-derived polymers depend directly on the synthetic conditions used for their production and, by extension, their potential applications. These puzzling systems have been known mainly in the fields of prebiotic chemistry and in studies on the origins of life and astrobiology since the first prebiotic production of adenine by Oró in the early years of the 1960s. However, the first reference regarding their possible role in prebiotic chemistry was mentioned in the 19th century by Pflüger. Currently, HCN-derived polymers are considered keys in the formation of the first and primeval protometabolic and informational systems, and they may be among the most readily formed organic macromolecules in the solar system. In addition, HCN-derived polymers have attracted a growing interest in materials science due to their potential biomedical applications as coatings and adhesives; they have also been proposed as valuable models for multifunctional materials with emergent properties such as semiconductivity, ferroelectricity, catalysis and photocatalysis, and heterogeneous organo-synthesis. However, the real structures and the formation pathways of these fascinating substances have not yet been fully elucidated. Several models based on either computational approaches or spectroscopic and analytical techniques have endeavored to shed light on their complete nature.
  • 2.5K
  • 29 Apr 2021
Topic Review
Antimicrobial Polymers
Antibiotic resistance has increased markedly in Gram-negative bacteria, causing severe infections intractable with traditional drugs and amplifying mortality and healthcare costs. Consequently, to find novel antimicrobial compounds, active on multidrug resistant bacteria, is mandatory. In this regard, cationic antimicrobial peptides (CAMPs)—able to kill pathogens on contact—could represent an appealing solution. However, low selectivity, hemolytic toxicity and cost of manufacturing, hamper their massive clinical application. In the recent years—starting from CAMPs as template molecules—less toxic and lower-cost synthetic mimics of CAMPs, including cationic peptides, polymers and dendrimers, have been developed. Although the pending issue of hemolytic toxicity and biodegradability is still left not completely solved, cationic antimicrobial polymers (CAPs), compared to small drug molecules, thanks to their high molecular weight, own appreciable selectivity, reduced toxicity toward eukaryotic cells, more long-term activity, stability and non-volatility. With this background, an updated overview concerning the state of the art of the main manufactured types of CAPs, active on Gram-negative bacteria, is herein reported, including synthetic procedure and action’s mechanism. Information about the antibacterial activity, advantages and drawbacks of the most appealing compounds was also provided.
  • 2.5K
  • 12 Jan 2021
Topic Review
Durability Performance of Geopolymer Concrete
Geopolymer concrete is produced from the geopolymerization process, in which molecules known as oligomers integrate to form geopolymer networks with covalent bonding. Its production expends less thermal energy and results in a smaller carbon footprint compared to Ordinary Portland Cement (OPC) concrete. It requires only an alkaline activator to catalyze its aluminosilicate sources such as metakaolin and fly ash, to yield geopolymer binder for the geopolymerization to take place. Because of its eco-friendly technology and practical application, current research interest is mainly concentrated on the endurance of geopolymer concrete to resist heat and chemical aggressions. 
  • 2.5K
  • 07 Mar 2022
Topic Review
Polymeric Hydrogels
Polymeric hydrogels (PolyHy) have been extensively explored for their applications in biomedicine as biosensors, in tissue engineering, diagnostic processes, and drug release. The physical and chemical properties of PolyHy indicate their potential use in regulating drug delivery. 
  • 2.4K
  • 31 May 2021
Topic Review
Mechanism of Self-Healing Hydrogels
Polymeric hydrogels have drawn considerable attention as a biomedical material for their unique mechanical and chemical properties, which are very similar to natural tissues. Among the conventional hydrogel materials, self-healing hydrogels (SHH) are showing their promise in biomedical applications in tissue engineering, wound healing, and drug delivery. Additionally, their responses can be controlled via external stimuli (e.g., pH, temperature, pressure, or radiation). Identifying a suitable combination of viscous and elastic materials, lipophilicity and biocompatibility are crucial challenges in the development of SHH. Furthermore, the trade-off relation between the healing performance and the mechanical toughness also limits their real-time applications. Additionally, short-term and long-term effects of many SHH in the in vivo model are yet to be reported.
  • 2.4K
  • 09 Nov 2022
Topic Review
Agricultural Applications of Superabsorbent Polymer Hydrogels
Although natural polymers, such as various polysaccharides, have undoubted advantages related to their biocompatibility, biodegradability, and low cost, they are inferior to synthetic polymers in terms of water absorption and water retention properties. In this regard, the most promising are semi-synthetic polymeric superabsorbents based on natural polymers modified with additives or grafted chains of synthetic polymers, which can combine the advantages of natural and synthetic polymeric hydrogels without their disadvantages. Such semi-synthetic polymers are of great interest for agricultural applications, especially in dry regions, also because they can be used to create systems for the slow release of nutrients into the soil, which are necessary to increase crop yields using environmentally friendly technologies.
  • 2.4K
  • 02 Mar 2023
Topic Review
Polyvinyl Chloride in the Environment
Plastics have recently become an indispensable part of everyone’s daily life due to their versatility, durability, light weight, and low production costs. The increasing production and use of plastics poses great environmental problems due to their incomplete utilization, a very long period of biodegradation, and a negative impact on living organisms. Decomposing plastics lead to the formation of microplastics, which accumulate in the environment and living organisms, becoming part of the food chain. The contamination of soils and water with poly(vinyl chloride) (PVC) seriously threatens ecosystems around the world. Their durability and low weight make microplastic particles easily transported through water or air, ending up in the soil.
  • 2.4K
  • 12 Jan 2024
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