Fracture Toughness of Winding Carbon Plastics Based on Epoxy Matrices and Reinforced by Polysulfone Film.

In this work, the fracture mechanism of winding carbon-fiber-reinforced plastics (CFRPs) based on epoxy matrices reinforced by polysulfone film was investigated. Two types of polymer matrices were used: epoxy oligomer (EO) cured by iso-methyltetrahydrophthalic anhydride (iso-MTHPA), and EO-modified polysulfone (PSU) with active diluent furfuryl glycidyl ether (FGE) cured by iso-MTHPA. At the winding stage, the reinforcing film was placed in the middle layer of the CFRP.

Nanocomposites Based on Polyethylene and Nickel Ferrite: Preparation, Characterization, and Properties.

Composite materials based on NiFeO nanoparticles and polyethylene matrix have been synthesized by thermal decomposition to expand the application area of high-pressure polyethylene by filling it with nanoscale particles. The synthesized compositions were obtained in the form of a dark gray powder and compressed for further study According to TEM, the average particle size in composites was 2, 3, and 4 nm in samples with a filling of 10%, 20% and 30%. The concentration dependences of the specific electrical resistivity ρ, dielectric permittivity ε, saturation magnetization M and the parameters of reflection and attenuation of microwave power of the obtained composites were investigated.

Fracture of Epoxy Matrixes Modified with Thermo-Plastic Polymers and Winding Glass Fibers Reinforced Plastics on Their Base under Low-Velocity Impact Condition.

The work is aimed at studying the impact resistance of epoxy oligomer matrices (EO) modified with polysulfone (PSU) or polyethersulfone (PES) and glass fibers reinforced plastics (GFRP) based on them under low-velocity impact conditions. The concentration dependences of strength and fracture energy of modified matrices and GFRP were determined. It has been determined that the type of concentration curves of the fracture energy of GFRP depends on the concentration and type of the modifying polymer.

Catalytic Decomposition of HO in the Aqueous Dispersions of the Potassium Polytitanates Produced in Different Conditions of Molten Salt Synthesis.

It is shown that the potassium polytitanate powder (PPT) synthesized at 500 °C via the treatment of powdered TiO (rutile) in molten mixtures of KOH and KNO is a cheap and effective catalyst of HO chemical decomposition in aqueous solutions. At the same time, the PPT catalytic activity strongly depends on the [TiO]:[KOH]:[KNO] weight ratio in the mixture used for the synthesis, increasing with [KNO] in the order of PPT (30:30:40) < PPT (30:50:20) < PPT (30:70:0). The obtained results are explained by increased [Ti] in the PPT structure (XPS data), which is grown in this order from 0 to 4.

Structure and Thermomechanical Properties of Polyvinylidene Fluoride Film with Transparent Indium Tin Oxide Electrodes.

This paper is devoted to the study of the structure and thermomechanical properties of PVDF-based ferroelectric polymer film. Transparent electrically conductive ITO coatings are applied to both sides of such a film. In this case, such material acquires additional functional properties due to piezoelectric and pyroelectric effects, forming, in fact, a full-fledged flexible transparent device, which, for example, will emit a sound when an acoustic signal is applied, and under various external influences can generate an electrical signal.

Fibrillar biocompatible colloidal gels based on cellulose nanocrystals and poly(N-isopropylacrylamide) for direct ink writing.

Hypothesis: Hydrogels based on cellulose nanocrystals (CNC) have attracted great interest because of their sustainability, biocompatibility, mechanical strength and fibrillar structure. Gelation of colloidal particles can be induced by the introduction of polymers. Existing examples include gels based on CNC and derivatives of cellulose or poly(vinyl alcohol), however, gel structure and their application for extrusion printing were not shown.

Structure and Properties of Epoxy Polysulfone Systems Modified with an Active Diluent.

An epoxy resin modified with polysulfone (PSU) and active diluent furfuryl glycidyl ether (FGE) was studied. Triethanolaminotitanate (TEAT) and iso-methyltetrahydrophthalic anhydride (iso-MTHPA) were used as curing agents. It is shown that during the curing of initially homogeneous mixtures, heterogeneous structures are formed.

Polymer Nanocomposite Containing Palladium Nanoparticles: Synthesis, Characterization, and Properties.

Composite nanomaterials have been prepared through thermal decomposition of palladium diacetate. The composite contains palladium nanoparticles embedded in high-pressure polyethylene. The materials were studied by a number of different physico-chemical methods, such as transmission electron microscopy, X-ray diffraction, X-ray absorption spectroscopy, electron paramagnetic resonance, and EXAFS.

Radio-Absorbing Materials Based on Polymer Composites and Their Application to Solving the Problems of Electromagnetic Compatibility.

Recently, designers of electronic equipment have paid special attention to the issue of electromagnetic compatibility (EMC) of devices with their own components and assemblies. This is due to the high sensitivity of semiconductor microcircuits to electromagnetic interference. This interference can be caused either by natural phenomena, such as lightning strikes, or by technical processes, such as transients in circuits during fast periodic or random switching.

Thermally Remendable Polyurethane Network Cross-Linked via Reversible Diels-Alder Reaction.

We prepared a series of thermally remendable and recyclable polyurethanes crosslinked via reversible furan-maleimide Diels-Alder reaction based on TDI end-caped branched Voranol 3138 terminated with difurfurylamine and 4,4'-bis(maleimido)diphenylmethane (BMI). We showed that Young modulus strongly depends on BMI content (from 8 to 250 MPa) that allows us to obtain materials of different elasticity as simple as varying BMI content. The ability of DA and retro-DA reactions between furan and maleimide to reversibly bind material components was investigated by NMR spectroscopy, differential scanning calorimetry, and recycle testing.

Dumbbell-Shaped, Graft and Bottlebrush Polymers with All-Siloxane Nature: Synthetic Methodology, Thermal, and Rheological Behavior.

A methodology for synthesizing a wide range of dumbbell-shaped, graft and bottlebrush polymers with all-siloxane nature (without carbosilane linkers) is suggested. These macroarchitectures are synthesized from SiOH-containing compounds-silanol (Et SiOH) and siloxanol dendrons of the first and second generations, with various peripheral substituents (Me or Et)-and from linear siloxanes comprising terminal and internal SiH groups by the Piers-Rubinsztajn reaction. Products and key building blocks are obtained in yields up to 95%.

The Mechanical Properties, Secondary Structure, and Osteogenic Activity of Photopolymerized Fibroin.

Previously, we have described the preparation of a novel fibroin methacrylamide (FbMA), a polymer network with improved functionality, capable of photocrosslinking into Fb hydrogels with elevated stiffness. However, it was unclear how this new functionality affects the structure of the material and its beta-sheet-associated crystallinity. Here, we show that the proposed method of Fb methacrylation does not disturb the protein's ability to self-aggregate into the stable beta-sheet-based crystalline domains.

[Pharmacophysiotherapy in combined treatment of neurosensory hypoacusis in the presence of circulatory disorders in the vertebral arteries].

Basing on the results of ultrasound dopplerography of the vertebral arteries of 337 patients with neurosensory hypoacusis (NSH), we identified 104 (30.9%) patients having vertebrobasilar hemodynamic disorders. We performed endaural phonoelectrophoresis of cavinton in modification, with application of the second electrode with vasoactive drugs on the region of cervical spine.

[Use of non-linearly transformed speech signals for studying the auditory analyzer].

An opportunity to apply non-linearly transformed speech signals for investigation of auditory analyzer in health and disease is analysed. Possible types of non-linear transformations preserving semantics of initial speech signals are discussed and analytic expressions are derived. Some circuitry problems related to performing these types of transformations are examined.