Two new catalyst systems for the synthesis of high molecular weight polyethylene and ethylene copolymers with linear 1-alkenes (1-hexene, 1-octene, 1-decene and 3-methyl-1-butene) are described. The catalysts are based on Ti(IV) complexes of the LTiX2 type with a tetradentate bis(phenolate)- piperazine ligand L and with X = Cl or Oi-Pr. The complexes are activated with a bicomponent cocatalyst, a combination of Al(C2H5)2Cl and Mg(C4H9)2 at an [Al]/[Mg] molar ratio of 3. The catalysts afford the synthesis of UHMW resins, both polyethylene and ethylene/1-alkene copolymers with a low 1-alkene content, as well as the synthesis of high molecular weight ethylene/1-alkene copolymers with the 1-alkene content of over 10 mol
This study was related with the synthesis and investigation of the electrochemical behaviors of the electrodes coated pyrrole (Py) and thiophene (Th) on the polymeric membrane (PM). Polypyrrole (PPy) was synthesized by low-cost chemical oxidative polymerization method, and the flexible polymeric membrane electrodes (FPME) doped with the obtained polypyrrole were developed. These electrodes were synthesized via electrochemical polymerization, and also their electrochemical behaviors were analyzed by using cyclic voltammetry (CV). CV analysis results revealed that the polymeric units were strongly attached to the electrode surface and effectively facilitated chemical modification on the electrode surface. The innovative approach of this study was to obtain a membrane by adding of PPy synthesized by oxidative polymerization to alginate, a natural material, and to prove the use of this membrane as an electrode in the electrochemical measurements. Several analyses and tests were conducted to characterize the electrodes. According to Scanning Electron Microscopy (SEM) and Atomic Force Microscopy (AFM) images, the (PME)s had smooth surface structures, with PM having the most homogeneous surface. The pore diameters were measured to be around 1.5 µm according to their SEM images. For capacitor performance, according to the calculation from CV measurements confirmed that the membranes could function at pseudocapacitor levels, with energy densities ranging from 3.7 to 5.4 Wh/g and power densities between 266.515 and 413.125 W/g. These findings suggest that the developed (PME)s have significant application potential in electrochemical energy storage systems, such as pseudocapacitors.
In this work, the influence of a weakly coordinating anion in cationic Pd complexes with N-heterocyclic carbene ligands (NHC ligands) on the activity of these complexes in the addition polymerization of norbornene derivatives with various substituents (alkylidene-, imide-, and ether-containing substituents) was investigated. The key to successful addition polymerization of this type of monomers is the optimal combination of NHC ligand and counterion, which determines the catalytic activity of the complex and the molecular weights of the resulting polymers. The influence of the counterion depends on the nature of the monomer and may differ for norbornenes with different substituents. For example, in the case of polymerization of monomers with nonpolar and low-polarity substituents, (NHC)Pd complexes with the counterion BARF– are more active, whereas monomers bearing highly polar/imide substituents are more efficiently polymerized using complexes with the Sb F_6^ - counterion. This study also demonstrates the possibility of replacing the counterion in the already formed cationic Pd complex, which allows the catalyst to be tailored to the desired monomer. Ultimately, these results open a versatile platform for the design of efficient catalysts for the addition polymerization of norbornene derivatives by optimizing the nature of both the NHC ligand and the counterion, from ligand selection to counterion exchange, allowing for more targeted catalyst design.
By the interaction of p-(2-carboxy)cyclopropyl styrene with butyllithium solution in pentane, a new keto-substituted monomer 2-butanoncyclopropyl styrene has been synthesized and its structure has been determined using IR and NMR spectra. The radical homopolymerization of the obtained monomer in the presence of AIBN in a benzene solution has been carried out. Unlike the IR spectrum of the monomer, in the IR spectrum of the homopolymer, the intensive bands characteristic for the vinyl group are absent, since the homopolymerization proceeds with the opening of the vinyl group. The formal kinetics of the radical polymerization of the synthesized monomer has been studied and the kinetic equation of polymerization of W = k[AIBN]0.5[para-(BCS)], and also the activation energy value (71.8 kJ/mol) has been found. The synthesized homopolymer has photosensitive groups. The cyclopropane and carbonyl groups are cross-linked under UV irradiation. The photosensitivity of the homopolymer is Ψ = 55.5 cm2/C. Poly-(2-butanone)cyclopropyl styrene has prospects for use as a negative photoresist in microelectronics and lithography.
For the first time, it has been proposed to use sterically hindered phenoxazinyl radicals and their sources for the reversible deactivation radical polymerization of styrene. Using the example of 2,4,6,8-tetra(tert-butyl)phenoxazin-10-yl, 2,4,6,8-tetra(tert-butyl)phenoxazin-1-one, and a number of paramagnetic tin(IV) complexes, it has been shown that polystyrene with a narrow molecular weight distribution (Đ 1.2) can be synthesized in the reversible inhibition mode in the mild temperature range of 70–90°C.
Conducting polymers (CPs) have attracted considerable interest in the field of supercapacitors due to their excellent electrical conductivity, stability, high pseudocapacitance, environmental compatibility, and cost-effectiveness. Traditional electrode materials include metal oxides, inorganic compounds, carbon-based substances, and conducting polymers. Recent studies indicate that hybridizing CPs with metal oxides can significantly improve electrochemical performance. In this study, polyaniline (PANI) and poly(3,4-ethylenedioxythiophene):polystyrene sulfonate (PEDOT:PSS) were combined with metal oxides (TiO2 and ZnO) via a one-step polymerization process. The resulting composite was analyzed using X-ray diffraction (XRD), X‑ray photoelectron spectroscopy (XPS), ultraviolet–visible (UV–Vis) spectroscopy, and scanning electron microscopy (SEM). Electrochemical evaluations were carried out via cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). The incorporation of metal oxides into the polymer matrix enhanced electrical conductivity and electrochemical behavior, yielding a specific capacitance of 431.51 F/g and a reduced equivalent series resistance of 3.29 Ω. These improvements are likely due to the porous architecture that promotes efficient charge transport and ion diffusion. Theoretical assessment using Dunn’s model indicated a diffusion-controlled charge storage mechanism. The results demonstrate notable enhancements in the structural, optical, morphological, and electrochemical characteristics of the electrode, positioning it as a highly promising material for supercapacitor applications.
This study reports the synthesis and characterization of Poly(N-methyl pyrrole) (PNMPy) and its nanocomposite with molybdenum trioxide (MoO3) prepared via a chemical oxidative in situ polymerization method. The structural, optical, and electrical properties of the synthesized materials were investigated using Fourier Transform Infrared (FTIR) spectroscopy, X-ray diffraction (XRD), UV–Visible (UV–Vis) spectroscopy, and dielectric measurements. FTIR and XRD analyses confirmed strong interfacial interactions and homogeneous dispersion of MoO3 within the PNMPy matrix, forming an ordered hybrid structure. The UV–Vis spectra revealed absorption bands at 380 and 500 nm, corresponding to π–π* and n–π* transitions, with a redshift indicating charge transfer between the polymer and oxide phases. The optical band gap of the PNMPy/MoO3 nanocomposite (2.05 eV) was significantly lower than that of pure PNMPy (3.28 eV) and MoO3 (≈3.0 eV), demonstrating enhanced electronic coupling. Dielectric studies showed that the PNMPy/MoO3 nanocomposite exhibited semiconductor behavior with an electrical conductivity of 1 × 10‒5 S/m and an activation energy of 9.94 × 10–2 eV. These findings indicate that the incorporation of MoO3 nanoparticles effectively enhances the optical and electrical performance of PNMPy, making the composite a promising candidate for use in optoelectronic, sensing, and energy storage applications.
The development of communication systems requires the development of innovative materials capable of limiting the laser radiation power in optical components. One promising approach involves composites based on polyacrylates and astralenes. In our previous study, we demonstrated the successful modification of astralenes for incorporation into acrylates. In this work, we investigate the effect of astralenes on photopolymerization. Photostimulation of these nanoparticles causes the conversion of molecular oxygen to its singlet state, which does not inhibit radical polymerization. Experimental results showed that the introduction of astralenes slows photopolymerization, reducing the reaction rate by approximately half. Furthermore, in situ generation of singlet oxygen by irradiating astralenes with red light makes the polymerization rate comparable to that observed for undoped monomers. Neither the addition of astralenes at concentrations from 0.01 to 0.5
Herein, expandable melamine resin was used as the matrix material, while Na2S2O8 was employed as a formaldehyde scavenger to fabricate low-formaldehyde melamine foam via microwave foaming method. The primary objective was to investigate the determination of Na2S2O8 addition content ratio on the formaldehyde released and the resulting mechanical properties of foam. Our experiments demonstrate that sulfate free radicals ( SO_4^∙ - ) resulted from Na2S2O8 not only can efficiently oxidize free formaldehyde but also promote the cross-linking reaction. The dual effect significantly reduces the residual content of formaldehyde and improves the comprehensive performance of foam. The formaldehyde content of the foam can be decrease to 167 mg/kg—59.2
This study presents a co-assembled gel system based on L-histidine methyl ester-functionalized diacetylene (L-HisDA) and pyrene-1-carboxylic acid (1-Py), designed to achieve ultraviolet-induced enhancement of circularly polarized luminescence (CPL). By incorporating the achiral fluorescent molecule 1-Py into the L-HisDA supramolecular gel, the chiral information from the host matrix was successfully transferred to the guest. Systematic characterization revealed that the co-assembled system undergoes a UV‑induced polymerization transition from the blue to the red phase while retaining its original nanoribbon morphology. A distinct CPL signal emerged at 400 nm during photopolymerization, whose intensity increased progressively throughout the phase transition, reaching a maximum in the red phase with dissymmetry factor glum of 0.85 × 10–2. This enhancement effect can be attributed to the amplification and transfer of chirality within the co-assembled gel during UV irradiation. This work provides a novel co-assembly strategy for developing photo-responsive CPL-active materials.
The features of controlled radical polymerization of styrene and its copolymerization with acrylonitrile, proceeding by the atom transfer mechanism under the action of catalytic systems simultaneously containing two copper complexes (CuBr2/TPMA and CuBr2/Me6TREN), have been investigated. The possibility of using low concentrations of the catalyst and the use of sodium potassium tartrate (Rochelle salt), as well as isopropylamine as reducing agents, in the controlled synthesis of the (co)polymers has been evaluated. It has been established that the proposed systems can effectively catalyze the polymerization of styrene and its copolymerization with acrylonitrile. The course of polymerization is accompanied by a linear increase in the molecular weight of samples with conversion, which is characteristic of controlled radical polymerization processes. It has been shown that polar solvents should be used for the process to be efficient. The optimal catalytic systems that allow the process to be carried out at high rate while maintaining control over the process have been identified.
New poly(fluoro-aryl-thiazole) copolymers were synthesized through polycondensation polymerization between aryl-aldehydes (featuring naphthalene, benzene, thiophene, and biphenyl linkers) and dithiooxamide. The successful formation of the polymers was confirmed using spectroscopic techniques, including 1H and 13C NMR, solid-state 13C NMR (CP-MAS), and FTIR. Incorporating thiazole units into the polymer structure increases the sulfur and nitrogen content within the framework. This modification significantly enhances the polymers' thermal stability, as thermogravimetric analysis demonstrates. Additionally, the polymers show improved efficiency in separating Th(IV) and Al(III) ions from aqueous solutions.
For the first time, the controlled synthesis of poly(N-isopropylacrylamide) has been performed in supercritical carbon dioxide via reversible addition-fragmentation chain transfer radical polymerization in the temperature range of 55–70°C. It has been demonstrated that there is a range of CO2 pressures (91–229 bar), in which a polymer with a dispersity below 1.3 can be synthesized in the entire range of monomer conversions, with the number-average molecular weight of the polymer increasing linearly with conversion. As the pressure increases, control over the molecular weight characteristics of the polymer is lost due to separation of the system into two phases; the RAFT mechanism proceeds in one phase, and the conventional radical polymerization mechanism takes place in the second one. These patterns are characteristic of the three trithiocarbonates (dibenzyl trithiocarbonate, S,S'-bis(methyl-2-isobutyrate) trithiocarbonate, and (2‑dodecylthiocarbonothioylthio)-2-methylpropionic acid) and one dithiobenzoate (2-nitro-5-(2-propyl-yloxy)benzyl-4-cyano-4-phenylcarbonothioylthio)pentanoate) studied in the work.
A promising direction in the field of controlled polymer synthesis is photopolymerization via the organocatalyzed atom transfer radical polymerization (O-ATRP), which relies on the use of metal-free organic catalysts. The application of organic compounds as catalysts not only reduces the environmental impact but also enables the use of the obtained polymeric materials in industrial sectors sensitive to trace amounts of metals. Traditionally, heteroaromatic polycyclic compounds with an extended conjugated π-bond system, particularly aryl-substituted phenothiazines, are used as O-ATRP catalysts. This work investigated the possibility of polymerizing a series of methacrylic monomers via the O-ATRP mechanism in the presence of 10-(1-naphthyl)phenothiazine as a catalyst and various bromine-containing initiators under irradiation with 365 nm light. It was shown that the polymerization process is accompanied by an increase in the polymer molecular weight with conversion. The number-average molecular weights are consistent with theoretically calculated values. The use of a bifunctional initiator, ethylene bis(2-bromoisobutyrate), allows for the controlled synthesis of polymers with various molecular weights. The possibility of using the obtained polymer samples as macroinitiators for post-polymerization and block copolymerization, catalyzed by 10-(1-naphthyl)phenothiazine under UV irradiation, was demonstrated.
Thiol-siloxane oligomers have been produced via the sol-gel process using three different catalysts: barium hydroxide monohydrate, trimethoxyboroxine, and an ammonium salt based on triethylamine and boric acid. The synthesized oligomers have been studied by NMR spectroscopy and mass spectrometry. It has been found that the topology of the resulting oligomers differs depending on the type of catalyst used, and these oligomers are resistant to hydrolytic condensation. Elastic films of hybrid organic-inorganic polymer based on the tetraacrylate monomer and the thiol-siloxane oligomers have been obtained via photopolymerization. The viscoelastic and optical properties of the photopolymer films have been studied, and it has been revealed that the topology of the thiol-siloxane oligomers affects the properties of the hybrid polymer. The values of the modulus of elasticity (0.37–0.48 GPa), glass transition temperature (53–72°C), and refractive index (1.58) of the photocured hybrid films based on different thiol-siloxane oligomers have been determined.
Copolymers of 2,2-diallyl-1,1,3,3-tetraethylguanidinium chloride with ethylene glycol vinyl ether have been synthesized by radical copolymerization in the presence of a radical initiator azobisobutyronitrile. It has been established that, regardless of the medium (in bulk or in ethanol), 2,2-diallyl-1,1,3,3-tetraethylguanidinium chloride is more reactive in the reaction of copolymerization with ethylene glycol vinyl ether, therefore, at any composition of the initial monomers mixture, the copolymers have been enriched with guanidinium units. An increase in the fraction of ethylene glycol vinyl ether in the starting monomers mixture has led to noticeable deceleration of the copolymerization, regardless of the medium. New polymeric salts have been prepared under the action of biologically active acids (benzoic acid or ampicillin) on the copolymer. The structure and antimicrobial properties of the polymeric products have been studied.
The production of soft and flexible products using photopolymer printing in a vat allows for the rapid production of customized products at low cost. However, according to recent research, the resulting materials do not have high strength characteristics. In this work, we investigated the targeted synthesis of oligourethane methacrylates and the influence of their structures on the technological parameters of the vat photopolymerization process. For this purpose, a series of oligomers based on tert-butylaminoethyl methacrylate were synthesized using various isocyanates. The reactivity, viscosity and strength characteristics of materials based on the obtained compounds were studied, and the self-healing ability was also assessed. The nature of the deblocking of isocyanate groups was confirmed using DSC and FTIR spectroscopy methods. Using tert-butylaminoethyl methacrylate and a chain extending agent (diaminodicyclohexylmethane) made it possible to increase the tensile strength σtens up to 9 MPa with a relative elongation at break ε of about 300
Grafted copolymers of chitosan and acrylic acid with a three-dimensional structure were synthesized by a radical mechanism in the presence of potassium persulfate as an initiator. Calorimetric studies have shown that the rate of copolymerization does not depend on the concentration of chitosan. It has been shown that in the presence of a polysaccharide, the enthalpy of polymerization of acrylic acid increases in absolute value, which is probably related to a decrease in the reactivity of the monomer while simultaneously increasing the reactivity of the corresponding radical. Water absorption studies have shown that the obtained materials have superabsorbent properties and can be recommended for use as environmentally friendly water-absorbing materials.
Reactivity ratios have been determined for the free-radical copolymerization of methacrylic acid (r 1) and isoprene (r 2) in 1,4-dioxane. The reactivity ratios calculated according to the extended Kelen–Tüdõs method and the method recommended by IUPAC are found to be r 1 = 1.12 ± 0.26 and r 2 = 0.59 ± 0.22 and r 1 = 1.10 (‒0.15 +0.22) and r 2 = 0.60 (‒0.04 +0.05), respectively. Approaches to determining the configuration of isoprene units using 1H NMR spectroscopy data are considered. It was established that up to 97
Metathesis and hydrogenated oligomers of 5-ethyl-2-norbornene were prepared via tandem synthesis: metathesis polymerization in the presence of first- and second-generation Grubbs catalysts in an ethylene atmosphere and subsequent one-pot hydrogenation. The structure of metathesis and modified products was studied using 1Н and 13С NMR spectroscopy and IR spectroscopy. The effect of the catalyst type on the molecular weight and ratio of components in a mixture of metathesis and hydrogenated oligomers, as well as the effect of the molecular weight on the glass transition temperature of the products, was demonstrated.
