The influence of an organosilicon modifier on the properties of a compound based on epoxy-urethane oligomer

To improve the performance characteristics of products made of highly-filled polymer compositions, modification of a compound based on epoxy-urethane oligomer was performed. The SH 198 amino functional organosilicon oligomer was used as a modifier. The performed studies established that an organosilicon modifier increases the gel time and the curing time of the composition based on epoxy-urethane oligomer, shows the plasticizing effect on a compound, decreases its glass transition temperature from 16.5 to 9°C, and increases the deformation in the temperature range of from–40 to +50°C.     

Synthesis and curing of epoxy-anhydride polymers modified with an oxirane of the tetrahydroquinoline series

Epoxy-anhydride polymers were prepared from diphenylolpropane diglycidyl ether and isomethyltetrahydrophthalic anhydride in the presence of a chemical modifier, oxirane of the tetrahydroquinoline series. The kinetics of the reaction of the modifier with the anhydride and the curing kinetics of the polymeric compound containing the modifier were studied. The thermal properties and water absorption of the polymers after their curing and structure formation were determined.     

Development of co-continuous morphology in epoxy poly(methyl methacrylate) (PMMA) blends cured by mixtures of phase-separating and non-phase-separating curing agents

The morphology of a quaternary blend containing a diglycidyl ether of bisphenol-A (DGEBA), a thermoplastic modifier (PMMA), a phase-separating curing agent (diaminodiphenylmethane, DDM), and a non-phase-separating curing agent (methylenebis(3-chloro-2,6-diethylaniline, MCDEA) was studied as a function of volume fraction of the thermoplastic modifier and fractional concentration of the curing agents in their mixture. It was found that using mixtures of curing agents a co-continuous morphology could be obtained at PMMA concentrations as low as 2.5 volume percent. Using FTIR spectroscopy it was proved that specific interactions are present between PMMA and individual amine curing agents. On the other hand, there was no detectable specific interaction between PMMA and DGEBA. By analyzing the micro-indentation hardness data of the cryo-fractured samples and putting forward the intrinsic hardness concept, it was proposed that the co-continuous morphology is inherently more effective than the other morphologies in changing the mechanical properties of the above-mentioned multi-component blends.     

HDPE/LDPE共混物形变过程中的结构变化及机理

聚合物熔体结晶由于链缠结等因素的影响,其形态结构非常复杂,这给研究结晶聚合物的微观结构,特别是聚合物在拉伸过程中的形态变化带来很大困难．本文将高密度聚乙烯（ＨＤＰＥ）和低密度聚乙烯（ＬＤＰＥ）两种不相容的组分进行共混,使少量ＨＤＰＥ分散在ＬＤＰＥ中,...     

Thermal deformation properties of oligoepoxide-based binders

Crosslink density and a number of other physicochemical parameters of composites are investigated as functions of the initial mixture composition by the example of materials comprising bisphenol A-based epoxy oligomers with different molecular masses, nitrogen-chlorine-containing oligoepoxide, epoxy novolac block copolymer, epoxyurethane modifier, and amine and anhydride curing agents. It is shown that the incorporation of elasticizers into densely crosslinked polymers reduces the free kinetic volume of the latter. The modification of binder makes it possible to obtain composites that are both well deformed and capable of recovering initial shape at T ≥ T _g. The properties of glass-and carbon-reinforced plastics prepared using the developed elasticized binders by the contact molding are described. This method ensures defect-free bending deformation that exceeds that achieved in the case of compression molding. A rubber-like deformation technology is elaborated that enables one to employ blow molding for the production of open-contour items from cured blanks and closed-contour items that cannot be produced by winding because of their configuration.     

Effect of modifiers on properties and curing of aqueous emulsions of ED-20 epoxy resin in the presence of еpilink 701 cross-linking agent

The dependence of the stability and structural-rheological properties of aqueous emulsions of an epoxy resin on the type and concentration of the modifier was examined. The working time, degree of curing, microstructure, and physicomechanical properties of polymer materials were studied in relation to the modifier type and its concentration in emulsions.     

Physical state of the amorphous phase of polypropylene‐influence on free volume and cavitation phenomenon

Model polypropylene and polypropylene/low molecular weight modifier systems with identical crystalline structure but of different physical state of noncrystalline regions were analyzed. The deformation of reference material was accompanied by a cavitation phenomenon while the deformation of the polypropylene/modifier systems occurred in non‐cavitating manner. Based on X‐ray and PALS measurements the observed change of the intensity of the cavitation phenomenon during the deformation of the analyzed systems was explained. Additionally, the change of interlamellar distance (induced by introducing the modifier molecules and uniaxial stretching) was correlated with the change of average size of the free volume pores of the amorphous phase—this analysis was performed based on experimental data and theoretical estimations. It was proven that the presence of modifier reduce significantly the average size of free volume pores in relation to the system with similar interlamellar distance. Finally, the method enabling specifying the effective content of the modifier in interlamellar regions based on PALS measurements and the observed change of the value of long period was presented. © 2015 Wiley Periodicals, Inc. J. Polym. Sci., Part B: Polym. Phys. 2016 , 54, 531–543     

改性聚乙二醇修饰高交联度不饱和聚酯网络结构的动态力学分析

合成了一系列含有反应活性端基的改性聚乙二醇,并用其对BMC(团状模塑料)专用的高交联度不饱和聚酯进行增韧.结果表明,含有反应性马来酸酐端基的聚乙二醇参与了不饱和聚酯的固化反应,可在交联网络中构成不同长度的柔性链段,在显著提高不饱和聚酯的韧性的同时,基本保持了材料的模量及其它力学性能.用动态力学分析(DMA)对不饱和聚酯交联网络结构进行了系统研究.     

Deformation of magnetosensitive emulsion microdroplets in magnetic and electric fields

A magnetosensitive emulsion comprising an ensemble of nonmagnetic oil droplets suspended in a kerosene-based magnetic fluid is studied. It is found that the droplets of such an emulsion are deformed in both magnetic and electric fields. The character of microdroplet deformation in the electric field depends on the field frequency: at low frequencies, the droplets are flattened; at high frequencies, the droplets are stretched along the force lines of the field. It is established that the deformation caused by the electric field can be compensated for by the imposition of an additional magnetic field, and the conditions of this compensation are determined. It is revealed that, under the action of a magnetic field directed normal to a thin layer of the emulsion, the droplets “split” into branched structures. The action of a similarly directed alternating electric field leads to the transformation of the droplets into tori followed by their rupture. It is concluded that the structure of the emulsion can be efficiently controlled using the combined action of magnetic and electric fields. Original Russian Text ? Yu.I. Dikanskii, O.A. Nechaeva, A.R. Zakinyan, 2006, published in Kolloidnyi Zhurnal, 2006, Vol. 68, No. 2, pp. 161–165.     

Deformation of AUK microporous carbon adsorbent induced by methane adsorption

The dependence of the relative linear deformation of AUK microporous carbon adsorbent on pressure is studied upon the adsorption of methane in the pressure range of 1 Pa to 6 MPa at 177.65, 216.2, 243.3, 273.15, 313, 333, and 393 K. It is found that the curves of adsorption-induced deformation show similar behavior; except for in the initial pressure range (p < 0.2 MPa), the adsorption-induced deformation increases with pressure and drops as the temperature rises. At low temperatures, a shrinkage region is observed in the initial part of the deformation curves that narrows with a rise in temperature. At temperatures above 350 K, the initial shrinkage is absent and the adsorbent expands with an increase in methane pressure. In the pressure and temperature ranges under investigation, the contribution of deformation to the differential isosteric heat of adsorption of AUK carbon adsorbent does not exceed 2%. It is shown that, upon the adsorption of CO₂, N₂, Ar, and CH₄ at 273 K and pressures below 6 MPa, the maximum deformation of AUK adsorbent varies cymbately with variations in the Lennard-Jones (6–12) potential constants for the pair interaction of gas molecules.     

Role of the cure kinetics in morphology control at phase separation of curing multicomponent thermosets and a criterion of equilibrium

The formation of heterophase polymers via phase separation in the course of curing reaction in a blend of a thermosetting oligomer with a rubber modifier is considered. The interference of thermodynamic and kinetic factors that define the morphology of the material being formed is discussed. The need for a kinetic theory of cure-induced phase separation is established, and an approach of this kind is proposed. On the basis of this approach a simple quantitative criterion of deflection of the phase-separating system from the thermodynamic equilibrium is given.     

Modification of epoxy polymers with small additives of multiwall carbon nanotubes

The effect of small additives of functionalized multiwall carbon nanotubes used as a modifier on the formation and properties of epoxy polymers cured with diaminodiphenyl sulfone is investigated. In the range of additive concentrations 0.01–0.50 wt %, there are extreme dependences of dynamic storage modulus and the glass-transition temperature on modifier concentration. As shown by electron microscopy and X-ray scattering, regions with increased packing densities of macromolecules are formed in the polymers in the presence of the modifier. The effect of the specific surface on the kinetics of curing of epoxy resins is observed. A mechanism controlling the formation of the epoxy matrix that is responsible for the inhomogeneous polymer structuring that defines the final properties of the polymers is suggested.     

The impact of endotrophin on the progression of chronic liver disease

Non-alcoholic fatty liver disease (NAFLD) is the most common liver disease and can lead to multiple complications, including non-alcoholic steatohepatitis (NASH), cirrhosis, and hepatocellular carcinoma. The fibrotic liver is characterized by the pathological accumulation of extracellular matrix (ECM) proteins. Type VI collagen alpha3 (Col6a3) is a biomarker of hepatic fibrosis, and its cleaved form, endotrophin (ETP), plays a critical role in adipose tissue dysfunction, insulin resistance, and breast cancer development. Here, we studied the effects of the Col6a3-derived peptide ETP on the progression of chronic liver diseases, such as NASH and liver cancer. We used a doxycycline (Dox)-inducible liver-specific ETP-overexpressing mouse model on a NAFLD-prone (liver-specific SREBP1a transgenic) background. For this, we evaluated the consequences of local ETP expression in the liver and its effect on hepatic inflammation, fibrosis, and insulin resistance. Accumulation of ETP in the liver induced hepatic inflammation and the development of fibrosis with associated insulin resistance. Surprisingly, ETP overexpression also led to the emergence of liver cancer within 10 months in the SREBP1a transgenic background. Our data revealed that ETP can act as a “second hit” during the progression of NAFLD and can play an important role in the development of NASH and hepatocellular carcinoma (HCC). These observations firmly link elevated levels of ETP to chronic liver disease.Subject terms: Metabolic syndrome, Biological techniques     

Electron tunneling in proteins program

We developed a unique integrated software package (called Electron Tunneling in Proteins Program or ETP) which provides an environment with different capabilities such as tunneling current calculation, semi‐empirical quantum mechanical calculation, and molecular modeling simulation for calculation and analysis of electron transfer reactions in proteins. ETP program is developed as a cross‐platform client‐server program in which all the different calculations are conducted at the server side while only the client terminal displays the resulting calculation outputs in the different supported representations. ETP program is integrated with a set of well‐known computational software packages including Gaussian, BALLVIEW, Dowser, pKip, and APBS. In addition, ETP program supports various visualization methods for the tunneling calculation results that assist in a more comprehensive understanding of the tunneling process. © 2016 Wiley Periodicals, Inc.     

Preparation of highly exfoliated epoxy/clay nanocomposites by "slurry compounding": process and mechanisms

Epoxy/clay nanocomposites with a high degree of exfoliation were achieved using a so-called "slurry-compounding" process with which the dispersed state of clay in water can be successfully transferred to an epoxy matrix. In this process sodium montmorillonite was first exfoliated and suspended in water. This suspension was further treated with acetone to form a clay-acetone slurry followed by chemical modification using silane. The modified slurry was then mixed extensively with epoxy to form epoxy/nanoclay composites. It has been shown that the morphologies of clay before and after curing are quite similar and the exfoliation process is termed "slurry compounding". Furthermore, the amount of organic modifier used is only 5 wt % of clay, in contrast to conventional organoclays which normally contain at least 25-45 wt % of organic surfactant. The resulting epoxy/nanoclay composites exhibit a high degree of clay exfoliation and a better thermal mechanical property.     

聚酯型扩链脲改性环氧树脂E-51/DDS体系反应活性研究

提高二氨基二苯砜(DDS)固化环氧树脂体系的反应活性,降低反应温度、提高反应速率,具有重要的研究意义和实用价值.本研究以聚酯(PEGA1000,2000,PNGA1000,2000)、甲苯-2,4-二异氰酸酯(TDI)、二甲胺为原料合成了含有聚酯型柔性间隔基的扩链脲U-PEGA1000,2000,U-PNGA1000,2000,用其改性环氧树脂E-51/DDS体系,采用DSC系统考察了改性体系的固化反应活性.结果表明,改性体系固化反应活性明显提高,固化反应表现活化能降低,固化反应峰顶温度从230℃降至170℃,固化反应的表观活化能由67.74kJ/mol降至47.80kJ/mol.     

Normal and Lateral Deformation of Lyotropically Ordered Polymer Brush

Summary: Planar polymer brush formed by semirigid chains of freely jointed rigid segments and immersed into a solvent is considered. Brush collapse induced by deterioration of the solvent quality and its deformation by external normal or lateral force is studied. It is demonstrated that these three different situations can be described in the framework of the common approach. It is shown that the collapse is accompanied by liquid‐crystalline (LC) ordering within the brush. The LC transition can be jump‐like (the first order) or continuous, depending on the segment's aspect ratio and grafting density. Transition point is investigated in detail, the corresponding phase diagrams are calculated. It is shown that the phase diagrams of a normally deformed brush have different structures, with a narrow ‘leg’ in the good solvent region for sparsely grafted brush, with two coexistence regions and a triple point, in addition, for shorter segment length or without these features if the chains are densely grafted. For the laterally deformed brush, phase diagrams have similar structures with a critical point in the good solvent regime.

Polymer brush subjected to deformation by normal (top) and lateral (bottom) external force.     

Deformation of Individual Aggregates and Flocs

Abstract

The production of flocs or aggregates is important to many solid–liquid separation processes; well‐known examples are found in water treatment and mineral processing. When sedimentation is used to remove these aggregates from suspension, a voluminous sludge results. Reduction of the liquid content of such sludges may be key to process economics, either through improved product quality or decreased disposal charges. Although consolidation of sludge blankets has been studied extensively, the deformation of individual aggregates and flocs has not. Indeed, little quantitative information is available regarding the force required to alter the physical conformation of an aggregate or floc. In this study, a technique has been developed to measure compressive force and aggregate volume simultaneously during deformation. These data show that different compression strategies can significantly affect the work requirement per unit volume of interstitial fluid expelled. The technique reported here makes it possible to quantify the force and work requirements for floc deformation, and also to identify changes in the physicochemical environment (for flocculation) that improve overall process efficiency.     

Deformation behavior of oriented UHMW-PE fibers

The mechanical behavior of gel-spun, ultra-drawn, UHMW-PE fibers was investigated as a function of temperature, stress, and time under static and dynamic loading conditions. From a phenomenological point of view, two separate contributions to the deformation behavior could be distinguished, i.e., a reversible (viscoelastic) contribution and an irreversible plastic flow component. It was investigated whether or not this distinction can be rationalized on a molecular basis. The fibers were studied using static (creep) and dynamic mechanical analysis (DMA), dilatometry, and wide-angle x-ray scattering (WAXS). The results of the combined experimental observations are discussed in an attempt to relate the deformation behavior of highly oriented PE fibers to events occurring on a molecular scale.     

Adsorption-Induced Deformation of Adsorbents

Adsorption-induced deformation of AR-V and AUK carbon adsorbents and NaX zeolite has been studied upon adsorption of n-С₅Н₁₂, n-С₆Н₁₈, n-С₇Н₁₆, and CO₂ at temperatures of 193?423 K. It has been shown that adsorption-induced deformation is positive upon the physical adsorption of gases and vapors on the surface of a nonporous (macroporous) solid when the excess adsorption is positive. When calculating the adsorption-induced deformation in the region of the capillary-condensation filling of mesopores, the additional pressure in capillaries, which is negative (contraction of an adsorbent), must be taken into account in the case of wetting a solid surface with a liquid adsorbate. The compressibility of AUK microporous carbon adsorbent as a porous solid is almost independent of the temperature and the properties of an adsorbate, and, for adsorption of n-C₅H₁₀ and n-C₇H₁₆ hydrocarbons and CO₂, it is γ_а = (5.6 ± 0.6) × 10^?6 bar^?1. The compressibility of AUK adsorbent appears to be 87% higher than that of nonporous graphite.