The new composites of polylactic acid (D-isomer, PDLA) with arabinogalactan (AG) were obtained using ball milling with subsequent heating and electron beam irradiation of the mixtures of PDLA with AG. The formation of composites was confirmed by gel permeation chromatography and IR spectroscopy. The structure and physicochemical properties of the products were studied by X-ray phase analysis, thermal analysis methods, and dissolution in water. It was shown that heating of the ball-milled PDLA–AG mixture followed by electron beam irradiation led to cross-linking of the polymers, with the formation of water-soluble and water-insoluble adducts. The PDLA–AG composite obtained by irradiation is characterized by resistance to crystallization upon heating.
This study investigates the conformational behavior of compatibilizers at the interface of binary immiscible blends under spatial confinement, using dissipative particle dynamics (DPD) simulations. A planar slit model is constructed to systematically examine the effect of confinement height on the dimensions and interfacial statistics of compatibilizer chains. Results show that chain compression is significant under strong confinement and progressively weakens as the slit height increases, saturating when the height approaches half of that in the unconfined state, after which the interface reaches dynamic equilibrium. Furthermore, reduced slit height markedly enhances compatibilizer density at the interface, indicating that spatial confinement promotes interfacial enrichment. Among different topological architectures, graft compatibilizers exhibit the strongest sensitivity of chain size to binary interaction parameters, outperforming linear and ring structures. These findings provide theoretical insights into the conformational regulation and interfacial distribution of compatibilizers under confined environments.
This study primarily focuses on the development and characterization of a novel nanohybrid interpenetrating polymer network hydrogel composed of chitosan, sodium polyacrylate, and halloysite nanotubes (CS-SA-Hal), designed for potential application in wastewater treatment. This research was motivated by the increasing interest in advanced biomaterials capable of effectively removing contaminants from aqueous media. The synthesized hydrogel was thoroughly characterized using various analytical techniques, including Fourier Transform Infrared Spectroscopy (FTIR), X-ray Diffraction (XRD), Thermogravimetric Analysis (TGA), Differential Thermal Gravimetry (DTG), and Scanning Electron Microscopy (SEM), to elucidate its structural, thermal, and morphological properties. The results confirmed the successful incorporation of halloysite nanotubes within the polymeric matrix, contributing to the formation of a robust, interpenetrating network. Swelling experiments revealed that the CS-SA-Hal hydrogel exhibited a high swelling capacity of approximately 300
This study presents a unified thermo-mechanical analytical framework to investigate the behavior of rotating disks with particular emphasis on polymeric materials, specifically isotropic Natural Rubber. The formulation incorporates centrifugal loading, thermal gradients, and radially graded density within an axisymmetric setting. To better understand the role of material symmetry, a transversely isotropic material is introduced as a reference benchmark, enabling systematic comparison of isotropic polymer response with anisotropic stiffness behavior. Using Seth’s transition theory, closed-form expressions are derived for stress distribution, displacement, and critical angular velocity at the onset of yielding. The results demonstrate that polymer disks exhibit significantly higher deformation and stress sensitivity to thermal loading compared to stiff anisotropic materials. It is further shown that radial density gradation effectively reduces stress concentration and enhances structural stability in polymer systems. The findings provide important insights for the design and optimization of polymer-based rotating components in engineering applications.
The effects of thermally induced residual stresses on the mechanical, thermomechanical, and morphological properties of recycled polyethylene terephthalate (rPET) were systematically investigated. Specimens were subjected to free quenching at controlled bath temperatures (0, 10, 20, and 30°C) and compared against an annealed reference. Quenching at 20°C was identified as the optimal condition, maximizing Izod impact strength ( 8.7 kJ/m2) and elongation at break ( 5.1
PVA-PVP blend films filled with various concentrations of Er (0.16, 0.40, 0.80, 1.58, and 3.125 wt
This paper reports triple-scale raspberry-like composite microspheres synthesized via hydrosilylation, achieving tunable surface roughness. Hierarchical assembly of Dual-Particle-Size SiO2 particles (220 and 84 nm) on silicone rubber microspheres enabled systematic investigation of SiO2 size ratio effects on the wettability of composite. Composite coatings were characterized by FTIR, SEM and contact angle measurements. When the 80 : 20 ratio of 220 nm SiO2 and 84 nm SiO2, the surface of composite achieved maximum water contact angle (157° ± 1°) with robust Cassie–Baxter stability, showing promise for self-cleaning, anti-icing and related applications.
Expanded perlite is a promising lightweight filler for rigid poly(vinyl chloride) (PVC) composites; however, its inherently hydrophilic surface and weak interfacial affinity limit its reinforcing efficiency. This work investigates the role of surface chemistry in controlling the thermo-mechanical behavior and degradation of PVC containing 3–10 vol
Polymer-based direct radiative cooling (PDRC) materials have attracted increasing attention due to their diverse functional groups and high emissivity within the atmospheric window (8–13 µm). This study introduces a new class of hollow microspheres featuring a multifunctional poly-trimethylolpropane triacrylate (PTMPTA) shell for enhanced radiative cooling. These microspheres are synthesized via radical-initiated interfacial polymerization using heptane as the core and PTMPTA as the shell precursor, followed by thermal evaporation of the n-heptane core. The resulting hollow structures exhibit uniform morphology with 2 μm diameter and 50 nm shell thickness. The inner cavities facilitate strong light scattering and efficient thermal emission. The microspheres are integrated onto fabric substrates through a scalable coating process, forming composite fabrics with superior spectral selectivity. The coatings achieve solar reflectance exceeding 80
Novel aromatic copoly(amide-imides) have been synthesized using 2-(4-carboxyphenyl)-1,3-dioxoisoindoline-5-carboxylic acid and two diamines, 3,3'-dihydroxy-4,4'-diaminodiphenylmethane and metaphenylenediamine, taken at molar ratios of 7 : 3, 1 : 1, and 3 : 7. The structure, thermal, mechanical, morphological, and transport properties of copoly(amide-imide) nonporous membranes have been studied in comparison with similar copoly(amide-imides) containing carboxyl-containing fragments. It has been shown that films of poly(amide-imides) and copoly(amide-imides) with carboxyl groups –COOH in the diamine fragment exhibit higher permeability compared to similar polymers containing metaphenylenediamine fragments in macrochains and are characterized by more pronounced hydrophilicity. This effect is determined by the occurrence of intra- and intermolecular interactions, with the latter predominating for the copolymers containing carboxyl groups, and their virtual absence in copoly(amide-imides) with metaphenylenediamine fragments, as confirmed by thermal analysis and molecular hydrodynamics.
The results of the rheological study of aqueous solutions of poly(N-vinylpyrrolidone) in the shear flow mode at different concentrations and temperatures in a magnetic field and in its absence are presented. The influence of a magnetic field on the enthalpy of activation of a viscous flow process ΔHvisc was studied for the first time; it value was calculated according to the Frenkel–Eyring equation based on data on the temperature dependence of the viscosity of solutions. It was found that in a magnetic field the value of ΔHvisc is higher than that outside the field. This is due to the additional orientation of diamagnetic macromolecules and the strengthening of interchain interaction, which promotes the association of macromolecules. This is confirmed by the increase in viscosity. A nonmonotonic increase in ΔHvisc is observed with increasing concentration of poly(N-vinylpyrrolidone) in solutions.
RAFT polymerization was applied for the synthesis of poly(4-vinylpyridine) and copolymers of 4‑vinylpyridine, containing 5 or 10 mol
Chitosan Portunus trituberculatus (Eschscholtz, 1823) with a molecular mass of 780 kDa and a deacetylation degree of 84
In this study, the optimal degree of polymerization of polyvinyl alcohol (PVA) and appropriate carbonate content necessary to enhance the separation performance of a CO2 separation membrane were determined. The membrane was composed of a composite polymer of PVA, which is known for its gas barrier properties, and sodium polyacrylate (PAANa), which acts as a water-absorbing agent. The PVA/PAANa membranes exhibited pressure resistance even without a cross-linking agent. To further improve the separation performance, membranes were prepared using PVA with four different degrees of polymerization (400–600, 1500–1800, 2000, and 3100–3900), and their separation capabilities were evaluated. Additionally, the optimal amount of caesium carbonate that enhances CO2 permeance was determined. It was found that separation membranes made from PVA with a degree of polymerization of 1500-2000 exhibited higher separation performance. In particular, separation membranes fabricated with PVA with a degree of polymerization of 2000 showed the best separation performance. As a result, a high-performance CO2 separation membrane was successfully developed, achieving a CO2 separation performance of approximately 3.2E-10 (m3(STP)/(m2 s Pa)) and a CO2/He selectivity 700.
Molecular dynamics models of five polyimides (PIs) based on commercially available dianhydrides PMDA, BTDA, ODPA, 6FDA, and BPADA and 1,4-bis-[2′-trifluoromethyl 4′-(4″-aminophenyl)phenoxy] 2,5-di-t-butylbenzene (FMTBDA) were constructed. Intramolecular mobility of these polyimides was investigated via analysis of the distribution of torsion angles values, torsion angle fluctuation amplitude and rotational mobility of aromatic rings. It was demonstrated that two phenyl rings in diamine connected by С–С bond, are forming quite rigid fragments with predominantly uniplanar position of the rings, while two phenyl rings connected by C–N bonds (between diamine and di-anhydride) allow greater variety of conformations. Nevertheless, the imide cycle of the dianhydride fragment conjugated to the diphenyl fragment of diamine tend to form a plane. The mobility of the polymers being investigated ascends in the order: BPADA-FMTBDA < 6FDA-FMTBDA ≅ ODPA-FMTBDA ≅ BTDA-FMTBDA < PMDA-FMTBDA. This trend agrees well enough with previously obtained estimates for their fractional free volume (FFV). Trajectories for the pairs of dihedral angles were estimated, showing that these mainly contain the jumps between the minima of the rotation energy diagrams. Lower rotational mobility of the di-tert-butylbenzene fragment in all the polymers was observed, which is due to the moment of inertia of the bulky tert-butyl groups and due to the restriction of the mobility in a dense amorphous polymer matrix because of these groups.
The crystallization behavior of semicrystalline polymers is crucial for tailoring material properties for industrial and scientific applications, particularly when traditional methods such as differential scanning calorimetry (DSC) are precluded by cost, inaccessibility, or sample size. We investigated the potential of digitally extracted pixel intensity using Polarized Optical Microscopy (POM) as a quantitative substitute for DSC for assessing polymer melting and crystallization behaviors. Using isotactic polystyrene (iPS) as a model polymer, rigorous calibration established a correlation between illuminance and digitally extracted pixel intensity (DPI). Calibration enables real-time in situ monitoring of crystallization and melting processes. Comparative analyses of melting endotherms and crystallization exotherms obtained using DPI and DSC demonstrated a strong correlation, validating DPI as an effective thermal analysis method. This study also highlights the non-destructive nature of DPI, its morphological visualization capabilities, and its potential for integration with automated digital imaging and machine-learning techniques. These findings offer a promising pathway to accessible, cost-effective, and real-time polymer characterization, which transcends limitations of conventional calorimetry. When rigorously calibrated against illuminance, DPI can track melting and crystallization trends that correlate with DSC heat flow features. However, DPI does not measure heat flow and should be interpreted as an optical surrogate, not a calorimetric equivalent.
This study investigated pore growth during stretching of polymerization-filled composites based on Al2O3 particles coated with ultra-high-molecular-weight PE, HDPE, or a dual-layer ultra-high-molecular-weight PE/HDPE coating. The particles were spherical in shape with an average diameter of 20 μm. When the composite was stretched, the particles exfoliated, creating pores. During stretching, the spherical pores were elongated, first becoming elliptical and then conical. The sharp angles of the rhomboid pores are due to the plastic flow of the polymer, not its degradation. Pore volume increases linearly with the material extension ratio. This increase in pore volume is due to the presence of rigid particles within the pores, which limit the lateral contraction of the composite. Bands representing transverse interactions between the particles and the polymer are visible in the equatorial region of the pores. Presumably, polymer elongation is greatest in these microregions and the polymer degradation process begins in them. It has been hypothesized that at a temperature of 190°C, the tensile stresses generated during composite pressing do not relax in the ultra-high-molecular-weight PE melt. This is explained by a molecular entanglement network.
Expressions have been obtained to trace the time (t) dependence on the concentration of radicals ([R]) created by a short radiation pulse, taking into account the chain-length dependence of propagation and termination rate coefficients. These expressions have been used to test the accuracy of determining the parameters of the composite model of the termination rate coefficient by single pulse-pulsed laser polymerization-electron paramagnetic resonance (SP-PLP-EPR) method using in silico modeling. Testing has shown that to find the transition chain length Lf of the composite model, it is correct to search for the inflection point of the dependence of log( ρ/[R] - 1) on log(t), rather than determining the break point of this dependence. Also, due to the influence of the chain-length dependence of the propagation constant for short radicals, the parameters of the composite model of chain termination are determined with a significant systematic error.
Unwanted icing on solid surfaces presents a critical challenge in a wide range of technological applications due to its detrimental effects on functional stability, energy efficiency, and overall system reliability. To address this phenomenon, multiple strategies have been explored, including the development of icephobic surface coatings, mechanical deicing techniques, thermal deicing systems, deployment of chemical deicing agents, and other advanced mitigation methods. In this study, novel nano-magnetically functionalized polyvinylidene fluoride (PVDF)/Fe3O4 fibrous films were engineered, exhibiting enhanced potential for use as icephobic materials. The electrospinning process was employed to fabricate highly aligned ferromagnetic nanofibers, with the incorporation of magnetite (Fe3O4) nanoparticles into the PVDF matrix leading to a significant increase in the electroactive β-phase fraction. The application of a directional magnetic field during electrospinning facilitated the production of uniformly oriented nanofiber architectures, enabling comprehensive evaluation of their morphological characteristics and anti-icing performance. Advanced characterization techniques, including wettability and icephobicity assessments, infrared spectroscopy, Fourier-transform infrared (FTIR) spectroscopy, atomic force microscopy (AFM), and scanning electron microscopy (SEM), were employed. The findings demonstrate that the precisely oriented nano-fibrous magnetic coatings exhibit superior icephobic performance, underscoring their suitability for next-generation anti-icing and deicing applications in critical technological systems.
Magnetic microparticles with silicon shells of varying thickness have been obtained by modifying the surface of carbonyl iron. The structure and magnetic properties of the particles have been studied using scanning electron microscopy and vibrational magnetometry. The original and modified particles have been used as fillers to create magnetoactive elastomers based on polydimethylsiloxane. The concentration of magnetic particles in the magnetoactive elastomers varied from 40 to 80 wt
