Polymeric Compounds Research Articles

Diffraction-limited hyperspectral mid-infrared single-pixel microscopy

In this contribution, we demonstrate a wide-field hyperspectral mid-infrared (MIR) microscope based on multidimensional single-pixel imaging (SPI). The microscope employs a high brightness MIR supercontinuum source for broadband (1.55 upmu hbox {m}–4.5 upmu hbox {m}) sample illumination. Hyperspectral imaging capability is achieved by a single micro-opto-electro-mechanical digital micromirror device (DMD), which provides both spatial and spectral differentiation. For that purpose the operational spectral bandwidth of the DMD was significantly extended into the MIR spectral region. In the presented design, the DMD fulfills two essential tasks. On the one hand, as standard for the SPI approach, the DMD sequentially masks captured scenes enabling diffraction-limited imaging in the tens of millisecond time-regime. On the other hand, the diffraction at the micromirrors leads to dispersion of the projected field and thus allows for wavelength selection without the application of additional dispersive optical elements, such as gratings or prisms. In the experimental part, first of all, the imaging and spectral capabilities of the hyperspectral microscope are characterized. The spatial and spectral resolution is assessed by means of test targets and linear variable filters, respectively. At a wavelength of 4.15 upmu hbox {m} a spatial resolution of 4.92 upmu hbox {m} is achieved with a native spectral resolution better than 118.1 nm. Further, a post-processing method for drastic enhancement of the spectral resolution is proposed and discussed. The performance of the MIR hyperspectral microsopce is demonstrated for label-free chemical imaging and examination of polymer compounds and red blood cells. The acquisition and reconstruction of Hadamard sampled 64 times 64 images is achieved in 450 ms and 162 ms, respectively. Thus, combined with an unprecedented intrinsic flexibiliy gained by a tunable field of view and adjustable spatial resolution, the demonstrated design drastically improves the sample throughput in MIR chemical and biomedical imaging.

Fabrication of Self-Healable, Robust, and Superhydrophobic Nanocomposite Films

Despite the recent advances in nature-inspired superhydrophobic surfaces with multifunctional properties such as self-healing, self-cleaning, antibacterial material, anti-biofouling, and oil-water separation in various industrial applications, there have been very few reports of robust superhydrophobic surfaces fabricated via a low-cost method. Herein, we report a rationally designed, self-healable, robust, and superhydrophobic nanocomposite film, fabricated by a one-step reaction process from a multi-component solution. These superhydrophobic nanocomposite films can be readily fabricated over a large area with high throughput via simple spray coating of the component solution. As the spray-coating materials, we used functionalized hydrophobic silica nanoparticles (hydrophobic-SiO2 NPs) to achieve hierarchical textured structures, and low surface energy. Then, thermal crosslinkers and long hydrocarbon silanes were added to improve the stability and hydrophobicity of the fabricated nanocomposite films. Because of the synergetic effect of the hydrophobic NPs and crosslinked polymeric compounds, the spray-coated superhydrophobic nanocomposite films exhibited excellent superhydrophobicity (static water contact angles > 150°), high transparency (>80%), high stability, and self-healing abilities. Tests confirmed the rationally designed, solution-based spray coating method provides a simple route to construct transparent, robust, and self-healing superhydrophobic surfaces, with high throughput and large area, which can be utilized in various industrial applications, including conventional products and advanced non-wetting surfaces.

Preparation of PLA-TPU-Nanoclay composites and characterization of their morphological, mechanical, and shape memory properties

In this study, a combination of polylactic acid polymer and thermoplastic polyurethane with the addition of nano-clay particles was used. The reason for using clay nanoparticles and their strength is the low price and availability of this material. Adding nano-clay particles to the polymer composition improves the mechanical properties of the composite as they will interact with functional groups of the polymer.The results of the FTIR spectroscopy confirmed the presence of three components in the compound indicating that no chemical reactions occurred among the three components during the compounding process. The FE-SEM images taken from the compounds showed that TPU and nano-clay particles were evenly distributed in the PLA matrix. The DMTA results were utilized to determine the transfer temperature of the compounds as well as the storage and loss modulus and the shape memory properties. The XRD spectroscopy was used to determine the crystallinity and exfoliation of the nanoparticles. The mechanical properties of the fabricated polymer compounds were determined. It was found that the sample with 3% by weight of clay nanoparticles had the highest strength, and the sample with 5 wt% of clay nanoparticles had the highest toughness among nanocomposites. According to the hardness measurement, the sample with 5% by weight of clay nanoparticles has the highest hardness amongst all prepared composites. The memory properties of the prepared nanocomposites showed a significant improvement with increasing the amount of nanoparticles.This study showed the suitability and efficiency of PLA, TPU, and clay nanoparticle melt mixing methods in achieving a relatively tough shape memory composite. At the same time, this method is also inexpensive and scalable.

ELASTOMERIC POLYMER COMPOUNDS FOR PRODUCTION OF SPARE PARTS FOR ROBOTIC MILKING SYSTEM

Currently, the import of spare parts of systems, in particular, nipple rubber and elastomeric parts of the milk pump of the milking unit, has been discontinued. In this regard, the problem of developing technologies for manufacturing elastomeric spare parts for milking machines becomes urgent. One of the possible ways of cost-effective production of spare parts in conditions of small-scale production is free casting or low-pressure casting. To implement such technologies, materials with low viscosity (less than 50 pascals per second) are needed, which include polymer compounds. (Research purpose) The research purpose is determining the brands of elastomeric polymer compounds suitable for the manufacture of spare parts for milking machines. (Materials and methods) Used scientific and technical literature as materials for studying, including articles of indexed periodicals and open sources of information containing information about elastomeric polymer compounds. Research methods are the collection, study and comparative analysis of information. (Results and discussion) It was found that among all polymer compounds, epoxy, polyester, polyurethane and silicone compounds were the most widespread in mechanical engineering and the food industry. It was determined that compounds based on polyurethane or silicone are the most suitable for the manufacture of spare parts for milking machines. These materials provide sufficient mechanical characteristics and high elasticity of the manufactured part. It was noted that silicone-based compounds are used for food purposes, which ensures the chemical and biological inertia of the part. (Conclusions) The most suitable brands of elastomeric silicone compounds are Elastolux Platinum 40 and Silagerm 8040. These materials are manufactured in Russia, have low shrinkage, provide high strength and elasticity of the final parts.

Ecotoxicity of isosorbide acrylate and methacrylate monomers and corresponding polymers

Environmental impact of isosorbide-based monomers and polymers have been evaluated towards bacteria, plants and invertebrates. Isosorbide acrylates show toxicity towards higher organisms while other tested mono- and polymeric compounds are harmless.

Analysis of compressive strength of masonry of ceramic blocks placed with cementitious mortar and polymeric compound

RESUMO O uso dos compostos poliméricos se limita às alvenarias de vedação no Brasil, devido aos critérios da NBR 16590 [1]. No entanto, deve-se avaliar o quanto este material pode contribuir quando aplicado em alvenarias estruturais. Sendo assim, esse estudo investigou o funcionamento de um tipo de composto polimérico, quando aplicado em alvenarias estruturais, realizando ensaios de caracterização química e física do material e de aderência na interface entre bloco e o ligante. Além dessas, foram investigadas a resistência à compressão axial de paredes em escala real, sendo uma amostra executada com as juntas horizontais preenchidas por argamassa cimentícia e outras duas contendo composto polimérico, com 2 e 4 filetes para assentamento dos blocos. Os resultados de caracterização do material ligante e interface mostraram que o composto polimérico possui maior resiliência e melhor desempenho à aderência, quando comparado à argamassa cimentícia. Já na análise global do sistema, verificou-se que a alvenaria construída com 4 filetes de composto polimérico atingiu a mesma resistência à compressão da amostra construída com argamassa cimentícia convencional (~138 kN/m na ruptura), a amostra com 2 filetes apresentou maior deformação vertical, 25 % em relação as demais, mostrando o potencial de utilização do composto polimérico em alvenaria estrutural.

MODIFICATION NANO-SIZE OF ZINC OXIDE (ZnO-NS) WITH POLYETHYLENE GLYCOL AND APPLICATION AS ANTIMICROBIAL

Sol-gel is a simple method used to synthesize nano-size ZnO (ZnO-NS) in many applications. It acts as an antimicrobial agent for Escherichia coli and Aspergillus niger infections. The nano-size and patterned nanorods structure of ZnO enhances anti-microbial properties. This study used Polyethylene Glycol (PEG-6000) polymer compounds with variations in their 3, 5, and 10% compositions as templates for the formation of the nanorods. The morphology of the ZnO-NS produced determined the increase in anti-microbial activity. Furthermore, those generated from 5% PEG composition (ZnO/PEG-5) have the smallest size with the greatest anti-microbial activity on inhibition zones against E. coli and A. niger, each of 8.5-10.5 mm. There are morphological differences in each variable in the homogeneity distribution level of the spherical and rod dimension patterns of ZnO-NS. This is based on characterization with UV-VIS-DRS and Fourier-Transform infrared (FT-IR) for the analysis of Zn-O interactions at wave number 500-550 cm-1. Field Emission Scanning Electron Microscopy-Dispersive Scanning Electron Microscope (FE-SEM) and Energy dispersive X-ray spectroscopy (EDX) was used for dimensional pattern analysis, while X-ray diffraction (XRD) was applied for hexagonal wurtzite ZnO structures following the ICSD-65122 standard.

Synthesis, crystal structure and thermal properties of bis-(aceto-nitrile-κN)bis-(3-bromo-pyridine-κN)bis-(thio-cyanato-κN)cobalt(II).

Single crystals of the title compound, [Co(NCS)2(C5H4BrN)2(C2H3N)2], were obtained by the reaction of Co(NCS)2 with 3-bromo-pyridine in aceto-nitrile. The CoII cations lie on crystallographic inversion centers and are coordinated by two N-bonded thio-cyanate anions, two 3-bromo-pyridine and two aceto-nitrile ligands thereby forming slightly distorted CoN6 octa-hedra. In the crystal, these complexes are linked by C-H⋯S and C-H⋯N hydrogen bonds into a three-dimensional network. In the direction of the crystallographic b-axis, the complexes are arranged into columns with neighboring 3-bromo-pyridine ligands stacked onto each other, indicating π-π inter-actions. The CN stretching vibration of the thio-cyanate anions is observed at 2066 cm-1, in agreement with the presence of only N-bonded anionic ligands. TG-DTA measurements reveal that in the first mass loss the aceto-nitrile ligands are removed and that in the second step, half of a 3-bromo-pyridine ligand is lost, leading to the formation of a polymeric compound with the composition [(Co(NCS)2)2(C5H4BrN)3] n already reported in the literature.

Green nanobiopolymers for ecological applications: a step towards a sustainable environment.

To minimize the usage of non-renewable resources and to maintain a sustainable environment, the exploitation of green nanobiopolymers should be enhanced. Biopolymers are generally developed from various microorganisms and plants in the specified condition. This review article discusses the current advances and trends of biopolymers, particularly in the arena of nanotechnology. In addition, discussion on various synthesis steps and structural characterization of green polymer materials like cellulose, chitin, and lignin is also encompassed. This article aims to coordinate the most recent outputs and possible future utilization of nanobiopolymers to the ecosystem with negligible effects by promoting the utilities of polymeric materials like polycaprolactones, starch, and nanocellulose. Additionally, strategic modification of cellulose into nanocellulose via rearrangement of the polymeric compound to serve various industrial and medical purposes has also been highlighted in the review. Specifically, the process of nanoencapsulation and its advancements in terms of nutritional aspects was also presented. The potential utility of green nanobiopolymers is one of the best cost-effective alternatives concerning circular economy and thereby helps to maintain sustainability.

Comparing the filtering efficiency of kombucha SCOBY and nitrocellulose membrane filter

Kombucha is a fermented tea made from tea broth 5-8% Sucrose (granulated sugar) and SCOBY (symbiotic culture of bacteria and yeast), it is an alcoholic drink with 0.5 -2.5% alcohol. The origin of kombucha tea is said to be from China. The kombucha tea takes about 7-10 days for its fermentation. The fermentation takes place in two stages, wherein the first stage takes about 7-10 days, and the pellicle is formed in the air-water interface and in the second stage the flavoring of the kombucha is done with the fruit pulp and it is left for 10 days. In the first stage of fermentation, it forms a polymeric cellulose pellicle (SCOBY) with the help of certain species of bacteria and yeast-like lactic acid bacteria, Acetic acid bacteria and Saccharomyces species. The consumption of kombucha is good for health. The SCOBY is a biofilm formed by the action of acetic acid bacteria, lactic acid bacteria, and yeast and it is made of cellulose polymeric compound which can trap the microorganisms to a certain extent and retain them on the filter pad (SCOBY). The increased use of nitrocellulose membrane filter is used for filtering microorganisms from the sample is used extensively as it gives out efficient results, but the continuous and increased use of nitrocellulose filter is not good for the environment and for the human population who live near the industries where it is made. This study focuses on the use of SCOBY as a filter pad on various samples and finding out its efficiency when compared to the nitrocellulose membrane filter pad.

Recovery of spinal cord functions after experimental complete crossection under the effect of chitosan polymeric compounds

To study clinical and functional recovery in experimental animals with transected spinal cord after management with photo-cross-linked chitosan in a homogeneous mixture with polyethylene glycol. We studied 20 rabbits with a model of complete spinal cord transection at the level of Th9. There were control and experimental groups (n=10; n=10). In the experimental group, we intraoperatively injected photo-cross-linked chitosan in a homogeneous mixture with polyethylene glycol. Neurological status was assessed using the modified Basso Beattie Bresnahan scale. Histological examination was performed after removing the animals from the experiment. In the experimental group, significant regression of neurological disorders was accompanied by partial recovery of movements, sensitivity and control of pelvic functions by the 30th day of the experiment. There was no mortality in the experimental group. Paraplegia and anesthesia persisted in the control group while mortality was 40% (n=4). Histological analysis in the main group revealed axonal «bridges» in the area of injury and spread of DiI dye through this area. These phenomena confirm the positive effect of chitosan and polyethylene glycol on functional recovery after experimental spinal cord injury. These data are consistent with histological findings.

Graphene Oxide Nanoparticles Influence on the Electrical Properties of (PVA– PEG ) Blend

In this study, we preparation polymer blend (PVA-PEG) for three samples in different Molecular weight of PEG ( 4000-8000- 20000 g/mol) then preparation anther three samples polymer Nanocomposites (PVA-PEG-GO) by adding Graphene oxide nanoparticles (GO) concentrically (0.01wt) to blend polyvinyl Alcohol (PVA) and Polyethylene colacyl by using casting method after that study the Electrical properties (A-C) and structure (FTIR) and Optical Microscope enlargement (10x). The results of the study showed the effect of the addition of Graphene oxide on the alternating electrical properties have shown that the insulation constant. The electrophoresis and isolation loss of polymer compounds (PVA-PEG-) are reduced with increasing frequency of the electric field dominant and dielectric loss increases with increasing PEG concentration. The results showed that the alternating electrical conductivity of polymeric composite increased with increasing frequency and molecular weight of all prepared composite. It was also shown that the increase of electrical conductivity significantly with samples of poly nanoparticles (PEG-PVA-GO) by increasing the molecular weight of PEG and be at the highest molecular weight (20000g / mol).

Ultrasensitive sensing performances of amphiphilic block copolymer induced gyrus-like In2O3 thick films to low-concentration acetone.

In the present work, an inducible assembly of di-block polymer compounds approach was employed for the synthesis of mesoscopic gyrus-like In2O3 by using lab-made high-molecular-weight amphiphilic di-block copolymer poly(ethylene oxide)-b-polystyrene (PEO-b-PS) as a revulsive, with indium chloride as an indium source and THF/ethanol as the solvent. The obtained mesoscopic gyrus-like In2O3 indium oxide materials exhibit a large surface area and a highly crystalline In2O3 nanostructure framework, and the gyrus distance is about 40 nm, which can facilitate the diffusion and transport of acetone vapor molecules. By using this material as a chemoresistance sensor, the obtained gyrus-like indium oxides were used as sensing materials, showing an excellent performance to acetone at a low operating temperature (150 °C) due to their high porosity and unique crystalline framework. The limit of detection of the thick-film sensor based on indium oxides is appropriate for diabetes exhaled breath acetone concentration detection. Moreover, the thick-film sensor shows a very fast response-recovery dynamics upon contacting acetone vapor due to its abundant open folds mesoscopic structure, and also to the large surface area of the nanocrystalline gyrus-like In2O3.

Опыт ФГУП «РАДОН» по кондиционированию радиоактивных отработавших ионообменных смол Калининской АЭС

The paper discusses the practice applied by FSUE Radon, namely, by the NPK — Sergiev Posad branch to the conditioning of spent ion exchange resins from the Kalinin NPP: they are immobilized within a polymer waste form using a purposely designed and manufactured pilot unit. Based on the laboratory and methodological capacities of the enterprises, the study demonstrates the compliance of the obtained polymer compound and the waste packages with relevant quality indicators and acceptance criteria provided for by the regulatory requirements.

Resonance‐Based Directional Light Emission from Organic Light‐Emitting Diodes: Comparing Integrated Nanopatterns and Color Conversion Waveguide Gratings

Tailoring the angular emission pattern of organic light‐emitting diodes (OLEDs) is a promising approach to increase device performance in many applications. In miniaturized point‐of‐need sensor systems using organic light sources and photodetectors, directional illumination of specific sensing spots may enhance overall sensitivity by improved light utilization. Periodically nanopatterned waveguides forming photonic crystal slabs are oftentimes employed to obtain directional resonant light outcoupling from OLEDs. This work compares emission directionality for two types of devices utilizing the same polymer compounds as the emissive material: OLEDs comprising a nanopatterned bottom electrode and conventional OLEDs featuring a dedicated nanopatterned color conversion layer (CCL) for directional light outcoupling. Simulated and experimentally measured emission characteristics show that resonant outcoupling effects from a separate CCL are significantly stronger due to spatial separation from the lossy electrode layers as well as high optical contrast at the waveguide interfaces. While OLEDs with nanopatterned electrodes exhibit only small deviations from the Lambertian emission profile, the nanopatterned CCL induces high outcoupling peaks at specific viewing angles leading to increased emission directionality.

Structural Properties Covalent Organic Frameworks (COFs): From Dynamic Covalent Bonds to their Applications

AbstractCovalent organic frameworks (COFs) are classified as lightweight, ordered, porous organic polymeric compounds. COF‐based materials are comprised of the covalent bonds of lightweight elements, such as C, B, O, Si, and N, with structural units. They can be used in various industrial applications. There have been significant advances in the design and synthesis of covalent organic frameworks and their applications in gas storage, catalysis, adsorption, purification of small molecules, optoelectronics, molecular sensing, biomedical, targeted drug delivery, conductive membrane, and energy storage. COFs demonstrate fascinating optical and electrical properties. This review has endeavored to categorize and investigate the essential physicochemical properties of COFs for further studies and investigations.

Self-growing photonic composites with programmable colors and mechanical properties

Many organisms produce stunning optical displays based on structural color instead of pigmentation. This structural or photonic color is achieved through the interaction of light with intricate micro-/nano-structures, which are “grown” from strong, sustainable biological materials such as chitin, keratin, and cellulose. In contrast, current synthetic structural colored materials are usually brittle, inert, and produced via energy-intensive processes, posing significant challenges to their practical uses. Inspired by the brilliantly colored peacock feathers which selectively grow keratin-based photonic structures with different photonic bandgaps, we develop a self-growing photonic composite system in which the photonic bandgaps and hence the coloration can be easily tuned. This is achieved via the selective growth of the polymer matrix with polymerizable compounds as feeding materials in a silica nanosphere-polymer composite system, thus effectively modulating the photonic bandgaps without compromising nanostructural order. Such strategy not only allows the material system to continuously vary its colors and patterns in an on-demand manner, but also endows it with many appealing properties, including flexibility, toughness, self-healing ability, and reshaping capability. As this innovative self-growing method is simple, inexpensive, versatile, and scalable, we foresee its significant potential in meeting many emerging requirements for various applications of structural color materials.

The Influence of Protein and Elastomer Waste Mixture on the NBR-Based Elastomer Compound

The paper presents the influence of a mixture of elastomeric and protein waste from the footwear industry on the properties of elastomeric compounds based on NBR (butadiene-co-acrylonitrile) rubber, as well as their obtaining and characterization. The mixture of leather and rubber waste was cryogenically ground, in three grinding cycles, and the selected size was 0.35 mm, and the rotation speed of 14,000 rpm. After grinding, the leather and rubber waste mixture was functionalized with potassium oleate at a temperature of 60°C. The polymer compounds based on butadiene-co-acrylonitrile rubber (NBR) and the mixture of protein and elastomeric waste (in the ratio of 15, 20, 40, 50%) from the footwear industry were processed by mixing on an internal Brabender mixer, tested from a rheological, physical and mechanical point of view (hardness, elasticity and tensile strength) after conditioning for 24 h at room temperature according to the standards in force, but also by FT-IR spectroscopy performed with a double beam IR molecular absorption spectrometer, in the range 4000-400 cm-1, using the FT-IR Thermo Nicolet iS 50, equipped with ATR with diamond crystal. Following characterisation, it can be said that they present optimal values that fall within the standards for the footwear industry.

An Efficient and Precipitant-Free Approach to Selectively Recover Lithium Cobalt Oxide Made for Cathode Materials Using a Microwave-Assisted Deep Eutectic Solvent

The recovery of cathode materials using deep eutectic solvents (DESs) still requires a long leaching time and relatively high temperatures. The poor selectivity of the leaching process leads to the low purity of the precipitate. Herein, a microwave-assisted choline chlorine–oxalate–water system was designed to selectively leach Li and recover high-purity cobalt oxalate simultaneously, which could greatly shorten the extraction time and decrease the leaching temperature. Fourier transform infrared spectroscopy, X-ray diffraction, inductively coupled plasma–mass spectrometry, and X-ray photoelectron spectroscopy methods were used to explore the mechanism of microwave-assisted DES leaching of valuable metals from lithium cobalt oxide (LCO). It was found that 99.05% of Li could be selectively leached and 99.21% of Co could be precipitated as cobalt oxalate at 100 °C in 10 min simultaneously. The purity of cobalt oxalate precipitated was 95.36% without any purification procedures. A new polymer compound Co2+[(Ch+)x(Cl–)y(HC2O4–)z] was formed during the microwave-assisted leaching process. The compound could be hydrolyzed, and the cobalt oxalate precipitate appeared by increasing the water content in the DES. Finally, the DES for the recovery of LCO could be cycled four times with favorable selectivity. A low-pollution, efficient, process-simple, and precipitant-free technology using a microwave-assisted DES for selective recovery of LCO was proposed, which provided an important reference method for large-scale recovery of valuable metals from spent lithium-ion batteries.

Replenishment in the Family of Rhenium Chalcobromides; Synthesis and Structure of Molecular {Re4S4}Br8(TeBr2)4, Dimeric [{Re4S4}Br8(TeBr2)3]2, and Polymeric {Re4S4}Br8 Compounds Based on the {Re4S4}8+ Tetrahedral Cluster Core.

We have obtained three new rhenium(IV) chalcobromides belonging to the homologous series {Re4S4}Br8(TeBr2)n (n = 0, 3, 4): a molecular complex {Re4S4}Br8(TeBr2)4 (1), a dimeric complex [{Re4S4}(TeBr2)3Br7(μ-Br)]2 (2), and a two-dimensional (2D) polymeric compound {Re4S4}Br8 (3). Compound 1 is isotypic to the already known {Re4Te4}(TeBr2)4Br8, while 2 and 3 exhibit a new type of binding of tetrahedral clusters via μ-Br bridges. Compounds were characterized by X-ray single-crystal diffraction, X-ray powder diffraction, and thermal and elemental analyses. In compound 2, two tetrahedral cluster cores {Re4S4}8+ are linked together forming a dimer through two Re-μ-Br-Re bridges. Calculations of the electron localization function (ELF) showed that there is no covalent interaction between rhenium atoms of neighboring clusters. In compound 3, each rhenium atom of the {Re4S4}8+ core is coordinated by three Br ligands: one terminal Br and two bridging μ-Br ligands. As a result, eight bridging bromine atoms link {Re4S4}8+ cluster cores into goffered layers. {Re4S4}Br8 is the new stable rhenium(IV) thiobromide, the first discovered in the Re-S-Br system, along with the already known octahedral rhenium(III) thiobromides Re6S4+xBr10-2x (x = 0-4).