Polymer Science, Series B最新文献

This study details the synthesis of organic/inorganic hybrid materials by combining the conductive polymer poly(m-aminophenol) (PMAP) with SnO₂ metal oxide. The objective is to broaden the polymer’s environmental applicability and evaluate its adsorption capabilities, focusing on dyes such as Methylene Blue (MB) and Congo Red (CR). The nanocomposite is meticulously formed through in situ polymerization of m-aminophenol in the presence of SnO₂, with varying loading ratios (1, 3, 10%). Extensive characterization, including analytical techniques (IR and XRD), confirms the structural integrity of the synthesized materials. X-ray diffraction (XRD) analyses distinctly show the successful combination of SnO₂ with the polymer matrix. Adsorption kinetics and isotherm were implemented to understand the adsorption mechanism for both dyes. It was found that PMAP/x%SnO₂ nanocomposite materials (with x = 1, 3 and 10) have high adsorption affinity toward MB and low adsorption affinity toward CR. Significantly, the MB removal percentage follows an ascending trend, starting at 85% for pure PMAP and increasing to 89% for PMAP/1%SnO₂, to 92% for PMAP/3%SnO₂, and peaking at 95% for PMAP/10%SnO₂ within 30 minutes. In contrast, CR removal exhibits a lower percentage, with only 54% removal for pure PMAP and a modest increase to 59% for the PMAP/10%SnO₂ nanocomposite, representing a 5% improvement. These outcomes lead to the conclusion that PMAP/x%SnO₂ nanocomposite materials (with x = 1, 3, and 10) exhibit high adsorption affinity for MB and comparatively lower adsorption affinity for CR. The adsorption of MB and CR on the PMAP and on the PMAP/10%SnO₂ nanpcomposite successfully followed the Langmuir adsorption kinetics model, which showed a better fit for the adsorption of MB and CR. The maximum adsorption capacity ({{Q}_{m}}) of MPAP/10%SnO₂ for MB was 76.99 mg/g, while for CR it was 39.56 mg/g.

A series of novel post-metallocene titanium complexes bearing polyfluorinated phenoxy-imines with para-substituents of varying electron-withdrawing (–NO₂, –F) or electron-donating (–OMe, –OEt, ‒OⁱPr, –OPh) properties in N-phenyl fragments were synthesized and used as ethylene polymerization catalysts. Upon activation with modified methylaluminoxane these complexes produce highly crystalline ultra-high molecular weight polyethylene. The resulting catalysts were investigated in terms of the impact of the mesomeric effect of the introduced substituent and the electron unsaturation of the N-aryl fragment on the catalytic activity and molecular weight of the polyethylene produced. A nonmonotonic character of the dependences of the activity of the catalyst and the molecular weight of the synthesized polymers on the electrophilicity of the titanium atom was found. An unexpected increase in polymerization activity was also found in the OAlk series upon the transition from OMe to larger groups. To explain these effects, possible reasons were considered clarifying the details of the studied process. The obtained results demonstrate that fine tuning of electronic features of the phenoxy-imine ligand by altering the para-substituents of N-aryl fragments is a powerful tool for control the activity of titanium catalysts as well as properties of the resulting polymers.

Novel phosphorus–boron–nitrogen-containing products have been developed that promote intumescing and charring of polymer compositions exposed to flame and enhance their fire and heat protective and adhesive characteristics. The structure of these products has been studied, and their fabrication conditions and basic properties have been determined. The results of research and development of a number of fire-and-heat retardant materials, in particular, rubber protection coatings based on polychloroprene and chlorosulfonated polyethylene and perchlorovinyl resin-based protective coatings for fiberglass and elastomeric materials, are summarized. The possibility of using phosphorus–boron–nitrogen-containing products as sizing agents for fillers, such as microfibers and microspheres, is described.

The use of reactive copolymers of glycidyl methacrylate and alkyl methacrylates differing in the length of the alkyl substituent (С6–С18) has been suggested as alternative to fluorinated modifiers to efficiently reduce the surface free energy. The influence of the structure and composition of the copolymers on the surface free energy and the work of adhesion to polar and dispersive test liquids has been demonstrated. At a smooth surface, the polymer coatings based on the functional copolymers have exhibited low surface free energy (down to 19 mN/m) and to ensure the high-hydrophobic wetting state with contact angles up to 105°. The stability of the superhydrophobic state of the polymer coatings at the textured aluminum surface (the AMG2M grade) with initial wetting angles up to 168° has been investigated.

Conditions for the synthesis of polymer–metal complexes incorporating zinc oxide nanoparticles differing in the size and shape, via chemical methods from solutions of purified sodium carboxymethylcellulose (degree of substitution 0.97 and degree of polymerization 850) and zinc nitrate crystal hydrate at temperature 80°C, have been determined. Physico-chemical properties of the samples of sodium carboxymethylcellulose containing stabilized zinc oxide nanoparticles differing in the size and shape have been investigated by means of FT-IR spectroscopy, atomic force microscopy, and X-ray diffraction analysis. It has been found that an increase in initial concentration of Zn(NO₃)₂ in the solutions of sodium carboxymethylcellulose subject to chemical reduction leads to the formation of zinc oxide nanoparticles differing in the size and shape. Solutions of sodium carboxymethylcellulose containing zinc oxide nanoparticles can be widely used in medical practice as biomaterials with antibacterial properties.

To reduce the flammability of polymers, functional flame retardants have become widespread, among which phosphorus-containing methacrylates occupy a special place. Despite the well-developed issues of their synthesis and use, the search for new monomers of this class remains a demanding task due to their efficiency, environmental friendliness, and a number of other reasons. This review systematizes the results of recent research concerning phosphorus-containing polymerizable monomers of the methacrylate series, the use of which makes it possible to reduce the flammability of the resulting materials and composites.

In recent years, magnetic-responsive hydrogels, alongside other smart hydrogel materials, have emerged as a focal point of research owing to their exceptional responsive properties and their wide array of biomedical applications. This study introduces an innovative approach involving the use of a biocompatible, carboxymethyl cellulose (CMC) hydrogel crosslinked with non-toxic fumaric acid and loaded with iron oxide nanoparticles (Fe₃O₄) as a novel carrier for magnetic-responsive curcumin drug delivery. Structural characterization of the CMC hydrogel and Fe₃O₄ nanoparticles was conducted through rigorous analysis, utilizing techniques such as Fourier-transform infrared spectroscopy, scanning electron microscopy, and dynamic light scattering. Our results indicate an intriguing inverse relationship between Fe₃O₄ nanoparticle concentration and the swelling ratio of the hydrogel, revealing an interesting relationship between nanoparticle concentration and hydrogel properties. Furthermore, our investigation revealed that the 3.3% Fe₃O₄-loaded magnetic CMC hydrogel exhibited a notably higher curcumin release percentage in comparison to other magnetic CMC hydrogel formulations. This underscores the efficacy of our magnetic CMC hydrogel nanocomposite as a vehicle for curcumin drug delivery, especially when subjected to external magnetic field stimulation. Significantly, our data substantiates that the presence of Fe₃O₄ nanoparticles within the hydrogel network results in a sustained and prolonged release of curcumin when exposed to magnetic stimulation and underscores the potential of magnetic CMC hydrogel nanocomposites as a promising platform for controlled drug delivery.

A two-step nucleophilic substitution mechanism was used and described to prepare liquid amine-terminated fluoroelastomers (LTAFs) by using liquid hydroxy-terminated fluoroelastomers (LTHFs) as raw materials, benzenesulfonyl chloride as an activator, and hexanediamine as an amine source. A reaction time of 24 h at 18°C and a molar ratio of groups –NH₂/–OH = 6.00 is an optimal condition for obtaining LTAFs with a yield of amino groups of 51%. The resulting LTAFs has a higher viscosity and lower thermal stability than LTHFs, while the molecular weight and distribution, as well as the glass transition temperature, remain essentially similar. Aziridine cured LTAFs has the best comprehensive mechanical properties and excellent chemical solvent resistance.

For the first time, it was proposed to use aniline derivatives with a skeleton monoterpene fragment at the nitrogen atom (N-(het)aryl-substituted camphan-2-amines and N-aryl-substituted fenchan-2-amines) as antioxidants for rubbers. Using nitrile butadiene rubber as an example, the kinetics of accumulation of carbonyl groups in macromolecules was studied using IR spectroscopy and the potential ability of these compounds to inhibit the process of thermal-oxidative aging was revealed. N-[(1RS,2RS)-Camphan-2-yl]-4-methoxyaniline and N-[(1RS,2RS)-camphan-2-yl]-4-ethoxyaniline, which differ in the presence of polar ethoxy and methoxy substituents at the p-position at aniline and characterized by the lowest bond energy >N–H. The results of a comprehensive assessment of the retention of elastic-strength properties, hardness, and degree of cross-linking of samples after thermal-oxidative aging in laboratory conditions, as well as long-term full-scale climatic tests in the tropical climate of southern Vietnam, allow us to conclude that after additional testing these compounds can be used as antioxidants in rubber formulations.

Molecular imprinting technology is a specialized technique used to create selective recognition sites within synthetic polymers. It has been employed in the removal of environmental contaminants like pesticides. In this research, a magnetic molecularly imprinted polymer (MMIP) centered on chlorpyrifos as the template molecule was successfully synthesized. Ethyleneglycol dimethacrylate (EGDMA) was the crosslinker, functional monomer used was methacrylic acid (MAA) and initiator was AIBN (2,2′-azobis-isobutyronitrile). The MMIP was successfully characterized using Fourier-transform infra-red (FTIR), scanning electron microscope (SEM), energy dispersive X-ray (EDX), and X-ray diffraction (XRD). The MMIP recorded a high adsorption capacity and selectivity for chlorpyrifos. The MMIP was then used as a dispersive solid phase extraction (D-SPE) adsorbent for isolating and extracting chlorpyrifos from water samples. A gas chromatograph coupled with an electron capture detector (GC-ECD) was used to quantify the extracts. When compared to C-18 solid phase extraction (SPE), the MMIP recorded spiked chlorpyrifos recoveries between 82 and 104% while that for C-18 SPE ranged between 64 and 81%. The limits of quantification (LOQ) and detection (LOD) were 4.91 and 1.62 mg/L respectively.