Recently, the advancements in energy storage and conversion have surfaced as a critical solution topic currently being discussed in various nations to accomplish a sustainable energy strategy that meets the increasing global energy demands. Therefore, several electrochemists are keen to propose the fabrication of next-generation devices that have boosted electrochemical performance as well as enhanced photochemical conversion efficiency. Polyaniline composite had been chosen for this contemporary study due to its tunable properties and multifunctionality. With a prominence on their practices in renewable energy supply, we have comprehensive topical progressions in research on accurate molecular design grounded on inorganic and organic fillers mixed with polyaniline to form its composite and novel procedures in this investigation. These mixed fillers transform polyaniline into binary and ternary composites by lowering the energy barrier, significantly enhancing the efficiency of next-generation energy supply systems. Wide determination is being reformed to enhance energy efficiency and the accountable usage of energy-active properties. This inclusion of fillers boosts redox reversibility, specific charge capacitance, and photo-conversion efficiency in the chain of polyaniline assembly. The review delivers a comparative scrutiny of multifunctional polyaniline composites, helping readers comprehend how the amalgamation of numerous fillers can enhance the electrochemical performance and photo-conversion efficiency that unlocks its potential in the fabrication of next-generation devices. Such pendant fillers linked to polyaniline assembly unlocked innovative skylines for investigators for sustainable energy resolution, owing to robust charge alteration with boosted efficiency compatible with supercapacitors and next-generation solar devices. This could turn out to be an upcoming transformation that assists administrators in sustaining command and is an integrated approach for satisfying real-world requirements.
Polylactic acid (PLA), a thermoplastic aliphatic polyester derived from renewable resources has garnered considerable attention due to its biodegradability, biocompatibility and favorable processing characteristics. However, inherent limitations such as brittleness, low thermal resistance and suboptimal mechanical performance restrict its utility in high-demand applications. This review critically evaluates recent advancements in reinforcing PLA with a broad spectrum of additives including natural fibers, nanocellulose, inorganic oxides and bioactive herbal/fungal powders. Each reinforcement modality is analyzed in terms of its effect on tensile, flexural and impact properties along with processing compatibility under extrusion, injection molding, compression molding and 3D/4D printing. The synergistic enhancements in stiffness, toughness, biofunctionality and shape-memory response are emphasized. Quantitative comparisons highlight that optimized filler loading typically 1–5 wt
This review addresses current trends in the development of approaches to the modification of epoxy systems with polymers. The use of thermoplastics inert to the components of epoxy systems, including structural thermoplastics, block copolymers, and dendritic and hyperbranched polymers for modifying epoxy resins is considered, as well as combined modification with thermoplastics and fillers. In addition, the review highlights the use of reactive polymers for modifying epoxy systems; these compounds can participate in the curing reaction of epoxy resins under certain conditions, incorporating into the structure of the resulting crosslinked material; the potential advantages of such modifiers are discussed. Particular attention is given to reactive polymers and copolymers containing anhydride groups.
The systematic analytical study of the previously developed nonlinear constitutive equation (CE) for the shear flow of thixotropic viscoelastic-plastic media, which accounts for the interplay of deformation and structural evolution, is continued. For an arbitrary set of six material parameters and an increasing material function governing the model, the basic properties of families of stress relaxation curves (RCs) generated by the CE at instantaneous loading and under ramp loading (taking into account a rise time to a specified strain level), as well as relaxation modulus, structural evolution features and relaxation time under these loading conditions are analytically studied. The analysis focuses on the ramp RCs dependence on material parameters and function of the CE and on a rise time and strain level. The unusual (but observed in tests) properties of RCs arising as a result of structural changes, compared to typical RCs of structurally stable materials (test RCs and RCs generated by linear or nonlinear CEs), are studied. This includes the dependence of RCs and the relaxation modulus on strain level and rise time, as well as the emergence of new relaxation scenarios compared to those observed under step loading. It is proven that for any material parameters and CE function, all ramp RCs decrease with time and have the common zero asymptote. However, RC convexity and increase in RCs family with strain level may be broken due to sufficiently rapid structural changes. This behavior contrasts with experimental RCs for structurally stable materials and RC families generated by the Boltzmann-Volterra viscoelastic CE. The studied CE can describe both convex downward RCs and RCs with inflection points, as well as the growth of RCs and the relaxation modulus with strain level, including the non-monotonic dependence of relaxation curve families on strain level. The initial deformation stage (loading history) significantly affects expression of these effects and the evolution of the relaxation time of the model. It is shown that a high strain rate at the initial stage may induce too high stress in a material and rapid structure break, which will change the material properties drastically, accelerate stress relaxation phase and make RCs with different strain levels to intersect and intertwine. Conversely, a gradual and lasting strain increase to the target level can distort the expected RC properties if the material is structurally mobile and the initial structuredness is significantly less than the equilibrium value. At the initial stage, the material may have time to increase its structuredness (e.g., during processes like gelation or resin curing in composites or 3D printing of photopolymers), which leads to a slowdown of further stress relaxation. The article demonstrates all these effects, which are related to the influence of the initial loading stage, or nonlinearity, or the structural evolution. It explains the possible reasons for families of RCs with unusual properties observed in some experimental studies. It is shown that ignoring the influence of initial loading stage and the possibility of structural changes in a material during deformation may lead to incorrect interpretations of test data and observed phenomena.
The work studies self-association behavior of comb-like macromolecules with hydrophobic side chains depending on the distribution of the side chains grafting points, molar mass and the length of side chains. It is shown that the distribution of the side chains grafting points determines the morphology of the globules: sufficiently long macromolecules with a regular grafting points distribution form multidomain globules, while the globules of those with random distribution have elongated or necklace-like morphology. The change in the shape of the globule as the length of the macromolecule increases is reflected by the exponent in the scaling dependencies of the macromolecule sizes on its degree of polymerization. While for short chains this exponent corresponds to the generally accepted 1/3 for compact spherical particles, for long chains this exponent is close to that for elongated objects. Self-association shifts to the area of poor solvent with the decrease in side chains length. The indicator of these associative interactions is the Kraemer parameter. The conclusions of the study are based on the analysis of the experimental literature data, including the works by the authors, as well as novel, previously unpublished experiments and supported by molecular dynamics computer simulation. The experiment compares the hydrodynamic properties of random amphiphilic copolymers of N-methyl-N-vinylacetamide and N-methyl-N-vinylamine iodide (with different lengths of the hydrophobic side pendants (–C12H25, –C10H21, –C8H17, –C6H13)) and a homopolymer sodium polystyrene-4-sulfonate. Viscometric studies of copolymers of N-methyl-N-vinylacetamide and N-methyl-N-vinylamine iodide were carried out in a pure water, water-salt solvent NaCl of different quality.
Due to their ability to combine exceptional electronic and optical properties such as tunable energy levels, high transmittance in the visible to near-infrared (NIR) region, high conductivity, and strong thermal and chemical stability, π-conjugated polymers and molecules have shown great promise as donor and acceptor materials in organic solar cells (OSCs). Indeed, the emergence of these materials offers a promising opportunity to develop high-performance OSCs with outstanding power conversion efficiency (PCE) of over than 20
In recent years, there has been a sustainable advancement of regenerative medicine, including the development of tissue-engineered constructs and their implementation in clinical practice. Current tissue engineering methods and approaches actively use biodegradable materials, among them of protein origin. Silk fibroin, which exhibits superior physicomechanical properties compared to other proteins, holds great high potential for use in this area. To enhance functionality and biocompatibility, silk fibroin can be modified with bioactive additives such as collagen, gelatin, hydroxyapatite, physiologically significant compounds, and drugs. This review addresses methods for the isolation and properties of silk fibroin, analyzes the characteristics of composites containing silk fibroin, and highlights the latest achievements and prospects for the application of silk fibroin-based materials in regenerative medicine.
The paper presents a method for obtaining hydrophilic CdSe/ZnS quantum dots by replacing the initial low-molecular organic stabilizing ligands on the surface of nanoparticles with polymeric ones. For this purpose, hydrophilic homo- and copolymer based on 2-dimethylaminoethyl methacrylate have been synthesized by the method of radical polymerization with reversible chain transfer (RAFT). Due to the presence of the terminal trithiocarbonate residue of the chain transfer agent (CTA) at the polymer chain, functional thio groups for the interaction with the surface of quantum dots have been obtained. For the possibility of further modification of hydrophilic quantum dots, polymer ligands have been additionally modified with tert-butyl acrylate units, which have been hydrolyzed into functional carboxyl groups. In this study, water-soluble CdSe/ZnS quantum dots have been obtained, coated with new polymer stabilizer ligands bearing several reactive carboxyl groups, which significantly expands the possibilities of application of hydrophilic nanoparticles.
The influence of the composition of hybrid hydrogels based on macromonomeric unsaturated derivative of sodium alginate and diethylacrylamide synthesized by radical copolymerization with redox initiation on their structure and properties was studied. It was shown that the introduction and an increase in the content of alginate macromonomer lead to significant changes in the supramolecular structure of the hydrogels and cause a decrease in their swelling degrees. At the content of the alginate component in the hydrogels above 10 wt
The study demonstrates new opportunities for improving the prediction of gas transport properties of glassy polymers based on their chemical structure using the Database of the Topchiev Institute of Petrochemical Synthesis, Russian Academy of Sciences. A generalized linear model has been developed to predict permeability coefficients for any gas-polymer system based on structural descriptors of the polymer and gas properties, such as tabulated effective kinetic diameters of gas molecules and effective Lennard–Jones potential parameters. This model significantly expands the dataset available for predictions and the application of modern machine learning methods. The feasibility of using small residual neural networks to enhance the accuracy of linear model predictions is shown, and training such neural networks does not require significant computational resources.
The polycondensation of norbornane-2,3,5,6-tetracarboxylic acid dianhydride with various diamines has been studied for the first time in order to synthesize new polyimides based on cycloaliphatic dianhydride. Norbornane-2,3,5,6-tetracarboxylic dianhydride (NBDA) has been synthesized from cis-5-norbornane-exo-2,3-dicarboxylic anhydride. The possibility of obtaining polyimides based on norbornane-2,3,5,6-tetracarboxylic dianhydride has been studied by carrying out synthesis under different conditions. Chloroform-soluble, film-forming polyimides based on norbornane-2,3,5,6-tetracarboxylic dianhydride have been obtained by one-step catalytic polycyclocondensation of norbornane-2,3,5,6-tetracarboxylic dianhydride with aromatic diamines in a benzoic acid melt. According to the second method, the polyimide based on norbornane-2,3,5,6-tetracarboxylic dianhydride has been produced using a two-step procedure: low-temperature polycondensation of silylated cycloaliphatic diamine (N,N′-bis(trimethylsilyl)isophoronediamine) in an amide solvent to form a soluble prepolymer with its subsequent imidization in the solid phase. The heat treatment conditions have been optimized for the prepolymer, allowing the production of a polymer with a composition corresponding to the target polyimide. The obtained polymers have been characterized by IR spectrometry, 1H NMR and solid-state 13C NMR spectroscopy, elemental analysis, and DSC and TGA techniques.
Metathesis oligomerization of norbornene in the presence of the first-generation Grubbs catalyst and ethylene used as a chain transfer agent yielded an oligomeric product, which was then hydrogenated over a palladium catalyst. After oligomerization and modification, the yield of the products was over 80 and 90
Crosslinking process kinetic parameters of mixtures based on low-molecular polyisoprene and MQ‑copolymers have been investigated by means of rotational rheometry. The rheological method allows tracking of the changes in the principal parameters of the system, such as viscosity, dynamic moduli, and the mechanical loss tangent during the entire chemical curing process. The evolution of viscous and viscoelastic properties of the system have been recorded under isothermal conditions as well as under conditions of continuous increase in temperature. Duration of the gelation in the systems has been determined under conditions of shear deformation via extrapolation of the dependence of reciprocal viscosity on time as well as from the crossover of the loss factor in a wide frequency range. Rheological properties of the filled systems about the gelation transition have revealed the power dependence of the dynamic moduli on the frequency, the critical parameter being equal to 0.54 at 100°C. The increase in the fraction of the inorganic component in the MQ-copolymers from 1 : 2 to 1 : 4 has led to an increase in the gelation time.
The modification of addition poly(5-vinyl-2-norbornene) by the hydrogermylation reaction has been studied for the first time. Modification is carried out using triethylgermane as a model germane and an (NHC)Pt complex, which previously proved to be one of the most efficient catalysts of the hydrosilylation of such objects, as a catalyst. Optimization of the modification conditions of poly(5-vinyl-2-norbornene) allows the synthesis of high molecular weight soluble polymers containing 60‒65
The influence of solvent vapor on the dielectric properties of films of polystyrene, poly(2-vinylpyridine), and poly(4-vinylpyridine) has been investigated. A procedure for the measurement of dielectric permittivity via the capacitor method under conditions of strong swelling of the films has been elaborated. It has been found that the swelling in chloroform vapor is the most prominent and leads to noticeable increase in the real part of the dielectric permittivity of the samples. This effect can be used to enhance the dielectric contrast between the domains of a block copolymer. It has been demonstrated that the observed decrease in the polymer glass transition temperature under condition of swelling can be approximated by the group contributions method.
The introduction of hydrophilic fillers in the matrix of hydrophobic thermoplastic polymers is a complicated issue, due to thermodynamic incompatibility of the components and poor adhesion properties. These complications are the most pronounced in the case of a hydrophilic polymer which cannot melt without decomposition (as polysaccharides) used as the filler. In this study, we have taken advantage of the solvent-free extrusion method both to modify the chitosan chemical structure in order to impart amphiphilic properties and to mix the obtained derivatives with polyethylene. The influence of the processes parameters, the presence of plasticizer, and the filler content on the thermal and mechanical properties of the composite film materials as well as their morphology has been investigated. It has been found that the introduction of hydrophobic fragments in the structure of chitosan insignificantly improved the mechanical properties of the materials in comparison with the pristine polysaccharide. A more significant effect has been caused by simultaneous introduction of the plasticizer, affording the materials with uniform morphology and improved plasticity.
The review provides information about the initial and modern phases of creating methods and stages of technologies for producing powdered cellulose, as well as microfibrillar, microcrystalline, and nanocellulose. The raw materials for powdered cellulose are waste from the woodworking and agricultural industries, as well as processed products from the pulp, paper, and textile industries. Historically established mechanical, physical, chemical, and biological methods are presented in the review with information on the possibilities of using additional stages, for example, the steam-explosive method. Information is provided on comparative structural studies of the presence of functional groups of lignocellulosic raw materials and powdered celluloses obtained from them, taking into account the supramolecular structure and residual lignin. It is shown that powdered cellulose can be widely used in sovereign technologies of the pharmaceutical and cosmetic industries as binders and emulsifiers and can be processed into ethers and esters, as well as into fibers (through solutions). Nonaqueous solutions of cellulose and mixtures of cellulose with synthetic polymers open up the possibility of creating carbon fiber materials and composites (uniquely combining high strength, chemical and heat resistance, as well as electrical conductivity and low density), which are important in scientific and practical terms in expanding the range of products of the textile and medical industries, as well as a variety of equipment with unique properties for the automotive industry, rocket and missile engineering, and various special-purpose equipment. The development of these technologies is, of course, interdisciplinary.
Processes of polymer modification in a supercritical carbon dioxide environment leading to the production of new materials intended primarily for medicine, pharmacology, and conducting polymer systems are analyzed. The processes of polymer impregnation in a supercritical carbon dioxide environment with carbon nanotubes to produce heat- and electrically conductive polymer materials and the processes of polymer micronization used in the development of polymer–polymer composite materials are considered. The processes of obtaining aerogel materials based on polysaccharides (sodium alginate) for use as matrices for biocompatible heterogeneous catalytic systems, the processes of impregnation of thermoplastics with photochromic and luminescent compounds leading to the corresponding photoactive polymer materials, and the processes of immobilization in natural polysaccharide matrices of biologically active compounds allowing the production of prolonged medicinal products are described. Particular attention is paid to the features of graft copolymerization, which allows obtaining biocompatible products for additive technologies and completely nontoxic materials with high adhesion to cells.
On the basis of furfuryl glycidyl ether, the product derived from furfural, diol chain extenders have been synthesized. Using these chain extenders and bismaleimide as a crosslinker polyurethanes with thermally induced self-healing effect have been prepared by the reversible Diels–Alder reaction. The structure of the synthesized polymers is studied by IR spectroscopy. Thermal and physicomechanical properties of the materials are also investigated. Differential scanning calorimetry measurements revealed the cyclic nature of direct and retro-Diels–Alder reactions. Visual assessment of the self-healing ability of the material is carried out using scanning electron microscopy. Quantitative evaluation (the self-healing efficiency of the Young’s modulus and strength) is performed by means of dynamometric analysis of initial and recovered polymer samples. It has been demonstrated that the content of dynamic bonds affects the properties of polyurethanes, as well as the efficiency of self-healing.
