Design of polyurethane composite foam obtained from industrial PET wastes and MXenes for EMI shielding applications.

The primary aim of this study was to synthesize and characterize polyurethane (PUR) foams derived from the depolymerization products of poly(ethylene terephthalate) (PET) and MXenes (NbAlC). The depolymerized PET products were produced through a zinc acetate-catalyzed glycolysis process using diethylene glycol (DEG) as solvent. These glycolysis products were then reacted with 4,4'-diphenylmethane diisocyanate (MDI), commercial polyols, and MXenes to produce the PUR foams.

Phycocyanin-Loaded Alginate-Based Hydrogel Synthesis and Characterization.

Phycocyanin was extracted from using conventional extraction (CE), direct ultrasonic-assisted extraction (direct UAE), indirect ultrasonic-assisted extraction (indirect UAE), and microwave-assisted extraction (MAE) methods at different temperatures, extraction intervals, stirring rate, and power intensities while maintaining the same algae to solvent ratio (1:15 ). The optimization of the extraction parameters indicated that the direct UAE yielded the highest phycocyanin concentration (29.31 ± 0.

One Reaction: Two Types of Mechanism-SARA-ATRP and SET-LRP-for MMA Polymerization in the Presence of PVC.

This study presents for the first time the polymerization of methyl methacrylate (MMA) in the presence of poly(vinyl chloride) (PVC) that takes place by both SARA-ATRP and SET-LRP mechanisms. The two types of polymerizations that occur in the system are PMMA grafting to the PVC backbone and the formation of a new PMMA polymer, both occurring in the presence of a Cuwire. The polymerizations were controlled as confirmed by the molecular weight evolution, polymerization kinetics, and variations in the dispersity value.

Different morphologies of super-balls obtained to form photonic crystals of cholesteryl benzoate liquid crystals.

The current study highlights the synthesis and characterization of some nanocomposite materials formed by polymer particles and liquid crystals. The liquid crystals used were cholesteryl benzoate (CLB), and the particles were synthesized by emulsion polymerization in the absence of the emulsifier. Through SEM and DLS analysis, the synthesis of particles of the same size was emphasized, and the amount of CLB showed no influence on these parameters.

Experimental Investigations on Shear Thickening Fluids as "Liquid Body Armors": Non-Conventional Formulations for Ballistic Protection.

Shear thickening fluids (STFs) have garnered attention as potential enhancers of protective capabilities and for the optimization of Kevlar armor design. To assess the possible shear thickening properties and potential application in ballistic protection, ten formulations were developed by employing polyethylene glycol (PEG) or polypropylene glycol (PPG), along with fumed silica or Aerosil HDK. Rheological characterization facilitated the identification of formulations displaying shear thickening behavior.

Surface pre-treatment of aluminum alloy for mechanical improvement of adhesive bonding by maple-assisted pulsed laser evaporation technique.

Adhesive joints are widely used for structural bonding in various industrial sectors. The performance of bonded joints is commonly attributed to the cleanliness of the substrate and the pre-treatment of the surfaces to be bonded. In this study, the Matrix Assisted Pulsed Laser Evaporation (MAPLE) deposition technique was used for surface modification of aluminum (Al) plates by the deposition of poly(propylene glycol) bis(2-aminopropyl ether) (PPG-NH) of different number average molecular weights (Mn) of 400 g mol, 2000 g mol, and 4000 g mol, respectively.

State-of-the-Art Polyurea Coatings: Synthesis Aspects, Structure-Properties Relationship, and Nanocomposites for Ballistic Protection Applications.

This review presents polyurea (PU) synthesis, the structure-properties relationship, and characterization aspects for ballistic protection applications. The synthesis of polyurea entails step-growth polymerization through the reaction of an isocyanate monomer/prepolymer and a polyamine, each component possessing a functionality of at least two. A wide range of excellent properties such as durability and high resistance against atmospheric, chemical, and biological factors has made this polymer an outstanding option for ballistic applications.

Dual-Responsive Hydrogels for Mercury Ion Detection and Removal from Wastewater.

This study describes the development of a fast and cost-effective method for the detection and removal of Hg ions from aqueous media, consisting of hydrogels incorporating chelating agents and a rhodamine derivative (to afford a qualitative evaluation of the heavy metal entrapment inside the 3D polymeric matrix). These hydrogels, designed for the simultaneous detection and entrapment of mercury, were obtained through the photopolymerization of 2-acrylamido-2-methyl-1-propanesulfonic acid (AMPSA) and N-vinyl-2-pyrrolidone (NVP), utilizing N,N'-methylenebisacrylamide (MBA) as crosslinker, in the presence of polyvinyl alcohol (PVA), a rhodamine B derivative, and one of the following chelating agents: phytic acid, 1,3-diamino-2-hydroxypropane-tetraacetic acid, triethylenetetramine-hexaacetic acid, or ethylenediaminetetraacetic acid disodium salt. The rhodamine derivative had a dual purpose in this study: firstly, it was incorporated into the hydrogel to allow the qualitative evaluation of mercury entrapment through its fluorogenic switch-off abilities when sensing Hg ions; secondly, it was used to quantitatively evaluate the level of residual mercury from the decontaminated aqueous solutions, via the UV-Vis technique.

Synthesis and characterization of polyurethane flexible foams provided from PET derivatives, fly ash, and glass wastes.

The aim of this study involved the synthesis and characterization of polyurethane (PUR) foams obtained from poly(ethylene terephthalate) (PET) depolymerization products and two types of filling agents, namely fly ash and glass waste. The depolymerized PET-based products were obtained by zinc acetate-catalyzed glycolysis process in diethylene glycol (DEG) as a co-reactant. The resulting glycolysis products were contacted with methylene diphenyl diisocyanate, castor oil, and reinforcing agents.

Silicone Oil Utilized in Pars Plana Vitrectomy for Patients with Advanced Proliferative Diabetic Retinopathy: Physico-Chemical and Optical Properties.

Objective: Silicone oils have the role in maintaining the attachment of the retina in conditions where the risk of retinal re-detachment is high. However, silicone oils have the tendency to emulsify with subsequent complications. In this work, analyses have been performed to understand changes that occurred to the optical, and physical characteristics of the oil after removal from the vitreous cavity of patients underwent pars plana vitrectomy (PPV) for fibrovascular membranes/tractional retinal detachment (FVM/TRD).

Peelable Alginate Films Reinforced by Carbon Nanofibers Decorated with Antimicrobial Nanoparticles for Immediate Biological Decontamination of Surfaces.

This study presents the synthesis and characterization of alginate-based nanocomposite peelable films, reinforced by carbon nanofibers (CNFs) decorated with nanoparticles that possess remarkable antimicrobial properties. These materials are suitable for immediate decontamination applications, being designed as fluid formulations that can be applied on contaminated surfaces, and subsequently, they can rapidly form a peelable film via divalent ion crosslinking and can be easily peeled and disposed of. Silver, copper, and zinc oxide nanoparticles (NPs) were synthesized using superficial oxidized carbon nanofibers (CNF-ox) as support.

Synthesis and Mechanical Performances of Polyurethane Bio-Based Adhesives Resulted from the Depolymerization of Lignocellulose Biomass.

The purpose of this study is to valorize biomass waste into products with added value for indoor applications. Thus, broadleaf sawdust was chemically processed by the solvolysis reaction in acid catalysis in the presence of diethylene glycol at 160 °C for 4 h. After filtration and removal of the unreacted biomass, the glycolysis product was used in 6 different polyurethane adhesive formulations for wood bonding.

Nanocomposite Hydrogel Films Based on Sequential Interpenetrating Polymeric Networks as Drug Delivery Platforms.

In this study, novel materials have been obtained via a dual covalent and ionic crosslinking strategies, leading to the formation of a fully interpenetrated polymeric network with remarkable mechanical performances as drug delivery platforms for dermal patches. The polymeric network was obtained by the free-radical photopolymerization of N-vinylpyrrolidone using tri(ethylene glycol) divinyl ether as crosslinker in the presence of sodium alginate (1%, weight%). The ionic crosslinking was achieved by the addition of Zn, ions which were coordinated by the alginate chains.

Nafcillin-Loaded Photocrosslinkable Nanocomposite Hydrogels for Biomedical Applications.

Skin infections are frequently treated via intravenous or oral administration of antibiotics, which can lead to serious adverse effects and may sometimes contribute to the proliferation of resistant bacterial strains. Skin represents a convenient pathway for delivering therapeutic compounds, ensured by the high number of blood vessels and amount of lymphatic fluids in the cutaneous tissues, which are systematically connected to the rest of the body. This study provides a novel, straightforward method to obtain nafcillin-loaded photocrosslinkable nanocomposite hydrogels and demonstrates their performance as drug carriers and antimicrobial efficacy against Gram-positive bacteria.

"Green" PBX Formulations Based on High Explosives (RDX and HMX) and Water-Soluble pH-Sensitive Polymeric Binders.

The increasingly harsher and more complex international and European environmental legislation drives the current development of "greener" energetics materials and munitions. The aerospace and defense industries rely on extensive research in the formulation and scale-up production of polymer-bonded explosives (PBX). In this context, this paper aims to present a versatile method for obtaining "green" PBX formulations based on two high explosives (hexogen (RDX) and octogen (HMX)) and acrylic acid-ethyl acrylate copolymeric binders.

Surface Modification Using MAPLE Technique for Improving the Mechanical Performance of Adhesive Joints.

The adhesive bonds that ensure the appropriate mechanical properties for metal joining imply the surface chemical and wetting modification characteristics of the substrates. In this work, matrix-assisted pulsed laser evaporation (MAPLE) was used for the surface modification of Al via the deposition of two chemical compounds, polyvinyl alcohol (PVA) and triethanolamine (TEA), from frozen aqueous solutions. The deposition of the TEA and PVA layers was evidenced by FT-IR, SEM, and AFM analysis.

Effect of Aromatic Chain Extenders on Polyurea and Polyurethane Coatings Designed for Defense Applications.

The present work describes the synthesis of new versatile polyurea (PU) and polyurethane (PUR) matrices, including different chain extenders, which facilitate the design of distinct, tunable properties, and high-performance derivatives. These polymers can be used for various defense and security applications, such as coatings for ballistic protection, CBRN protection, binders for energetic formulations, etc. Combining aliphatic and aromatic molecules in PU or PUR structures enables the synthesis of polymers with improved and controllable thermo-mechanical properties.

Lignocellulose Biomass Liquefaction: Process and Applications Development as Polyurethane Foams.

One of the main strategies for sustainable human society progress is the development of efficient strategies to limit waste production and maximize renewable resource utilization. In this context, this review highlights the opportunity to transform vegetable biomass residues into valuable commercial products. Biomass conversion entails the depolymerization of lignocellulosic biomass towards biopolyols and the synthesis and characterization of the valuable products obtained by using them.

The Influence of Potassium Salts Phase Stabilizers and Binder Matrix on the Properties of Novel Composite Rocket Propellants Based on Ammonium Nitrate.

The environmental impact and availability of ingredients are vital for the new generation of rocket propellants. In this context, several novel composite propellants were prepared based on the "greener" oxidizer (PSAN), a micronized aluminum-magnesium alloy fuel, iron oxide powder burn rate modifier, triethylene glycol dinitrate (TEGDN) energetic plasticizer and a polyurethane (PU) binder. The novelty of this study is brought by the innovative procedure of synthesizing and combining the constituents of these heterogeneous compositions to obtain high-performance "eco-friendly" rocket propellants.

Peelable Nanocomposite Coatings: "Eco-Friendly" Tools for the Safe Removal of Radiopharmaceutical Spills or Accidental Contamination of Surfaces in General-Purpose Radioisotope Laboratories.

Radioactive materials are potentially harmful due to the radiation emitted by radionuclides and the risk of radioactive contamination. Despite strict compliance with safety protocols, contamination with radioactive materials is still possible. This paper describes innovative and inexpensive formulations that can be employed as 'eco-friendly' tools for the safe decontamination of radiopharmaceuticals spills or other accidental radioactive contamination of the surfaces arising from general-purpose radioisotope handling facilities (radiopharmaceutical laboratories, hospitals, research laboratories, etc.

Epoxy Coatings Containing Modified Graphene for Electromagnetic Shielding.

This study presents the functionalization and characterization of graphene and electromagnetic interference (EMI) attenuation capacity in epoxy-nanocomposites. The modification of graphene involved both small molecules and polymers for compatibilization with epoxy resin components to provide EMI shielding. The TGA and RAMAN analyses confirmed the synthesis of graphene with a different layer thickness of the graphene sheets.

Bisphenol A Adsorption on Silica Particles Modified with Beta-Cyclodextrins.

This study presents the synthesis of silica particles bearing two beta-cyclodextrin (BCD) (beta-cyclodextrin-BCD-OH and diamino butane monosubstituted beta-cyclodextrin-BCD-NH). The successful synthesis of the BCD-modified silica was confirmed by FT-IR and TGA. Using contact angle measurements, BET analysis and SEM characterization, a possible formation mechanism for the generation of silica particles bearing BCD derivatives on their surface was highlighted.

Strippable Polymeric Nanocomposites Comprising "Green" Chelates, for the Removal of Heavy Metals and Radionuclides.

The issue of heavy metal and radionuclide contamination is still causing a great deal of concern worldwide for environmental protection and industrial sites remediation. Various techniques have been developed for surface decontamination aiming for high decontamination factors (DF) and minimal environmental impact, but strippable polymeric nanocomposite coatings are some of the best candidates in this area. In this study, novel strippable coatings for heavy metal and radionuclides decontamination were developed based on the film-forming ability of polyvinyl alcohol, with the remarkable metal retention capacity of bentonite nanoclay, together with the chelating ability of sodium alginate and with "new-generation" "green" complexing agents: iminodisuccinic acid (IDS) and 2-phosphonobutane-1,2,4-tricarboxylic acid (PBTC).

Eco-Friendly Peelable Active Nanocomposite Films Designed for Biological and Chemical Warfare Agents Decontamination.

In the context of imminent threats concerning biological and chemical warfare agents, the aim of this study was the development of a new method for biological and chemical decontamination, employing non-toxic, film-forming, water-based biodegradable solutions, using a nano sized reagent together with bentonite as trapping agents for the biological and chemical contaminants. Bentonite-supported nanoparticles of Cu, TiO, and Ag were successfully synthesized and dispersed in a polyvinyl alcohol ()/glycerol () aqueous solution. The decontamination effectiveness of the proposed solutions was evaluated by qualitative and quantitative analytical techniques on various micro-organisms, with sulfur mustard () and dimethyl methylphosphonate () as contaminants.

Novel Polyurethanes Based on Recycled Polyethylene Terephthalate: Synthesis, Characterization, and Formulation of Binders for Environmentally Responsible Rocket Propellants.

Novel polyurethane-based binders, specifically designed for environmentally responsible rocket propellant composites, were obtained by employing the polyester-polyols that resulted from the degradation of polyethylene terephthalate waste. A new class of "greener" rocket propellants, comprising polyurethanes (based on recycled PET) as the binder, phase stabilized ammonium nitrate (PSAN) as the eco-friendly oxidizer, and triethylene glycol dinitrate (TEGDN) as the energetic plasticizer, together with aluminum as fuel and FeO as the catalyst, is herein reported. The components of the energetic mixtures were investigated (individually and as composite materials) through specific analytical tools: H-NMR, FT-IR, SEM-EDX, DTA and TGA, tensile and compression tests, DMA, and micro-CT.