Synthesis and some properties of functionalized film-forming latexes

Semi-continuous emulsion copolymerization was used for preparation different colloid copolymers containig hydroxyl, carboxyl and amide functional groups. Copolymerization of hydroxyethyl methacrylate with styrene and butyl acrylate was investigated. Molecular weight increase in the copolymerization of methacrylamide indicated an extensive branching of macromolecules. Functionalized latexes have been used as binders in water borne paints. In addition to the crosslinking ability the hydrophilic functional monomers positively affect the film formation. The effect of dissociated carboxylic groups on lowering the minimum film forming temperature was much more pronounced if the polymer chains were more polar and softer. Some relationships between the latex flow properties and the film forming ability have been illustrated in this paper.     

New processable polyaromatic ether-keto-sulfones as colorless,clear film-forming materials

New processable polyaromatic ether-keto-sulfones were prepared from 4,4′-diphenoxydiphenyl sulfone, terephthaloyl chloride, isophthaloyl chloride, and bis-p-carboxyphenylacetylene dichloride (IV) in a Friedel-Crafts-type polymerization. The white polymers obtained form colorless, transparent, strong films and can be cast into a glass-fiber laminate. One polymer was prepared which incorporated biphenylene-2,6-dicarboxylic acid dichloride as crosslinking sites; this heat-cured polymer was completely insoluble in sulfuric acid.     

Influence of heteroligand complexation on the thermal, photoluminescent, and film-forming properties of some aromatic terbium(III) carboxylates

With homoligand TbL₃ and heteroligand complexes TbL₃(Q)_n (HL = HSal (salicylic acid) and HPA (2-anilinobenzoic acid); Q = TPPO (triphenylphosphine oxide) and TOPO (tri(n-octyl)phosphine oxide); n = 1 or 2) as examples, it was shown that heteroligand complexation affects not only the thermal and photoluminescent properties but also the quality of films obtained by centrifugation: the root-mean-square roughness changes in the order TbL₃Q > TbL₃(Q)₂ ≈ TbL₃. This is due to different association degrees of the complexes in solution, which was confirmed by MALDI-TOF MS data.     

Relative pKa of some anilinium derivatives in methanol,acetonitrile, and tetrahydrofurane solvents

In this study, the relative pK_a values of nine anilinium derivatives in methanol (MeOH), acetonitrile (AN), and tetrahydrofurane (THF) solutions were successfully calculated with mean absolute deviations of 0.63, 0.68, and 0.75 pK_a units, respectively. To this aim, their gas‐phase basicities were computed using the CBS‐QB3 composite method. Also, conductor‐like polarizable continuum model (CPCM) with UAHF, UAKS and UA0 cavities and SM8 solvation models at HF/6‐31+G(d) level of theory were applied for the calculation of the solvation Gibbs free energies. The obtained results indicate that there is reliable correlation between the experimental and computed pK_a values in the studied solutions. Therefore, to extend the pK_a database for anilines, correlation equations were used to predict the pK_a values in the investigated solvents.     

Thermodynamic characteristics of self-associated solvents

The thermodynamic characteristics of solvents differing by the type of molecular self-assembly through the hydrogen bonds were considered. In the framework of a model approach specific and nonspecific components of the total energy of intermolecular interaction were identified. The solvents with hydrogen bond network are found to belong to a class of liquids, where the strength of non-specific interactions increases with increasing temperature, while in the solvents with a chain of self-association contribution of these interactions is virtually independent of temperature. For this reason, the effect of increasing temperature on the internal pressure and its temperature coefficient were found to be different in these groups of solvents.     

Structural and thermodynamic characteristics of amide solvents

The structural and thermodynamic characteristics of amide solvents are calculated with different types of molecular self-assembly through hydrogen bonding. Under a model-based approach, the specific and nonspecific components of the total energy of intermolecular interactions are identified for primary, secondary, and tertiary amides of carboxylic acids. It is found that similarly to water, primary amides have a network of hydrogen bonds and belong to the class of liquids characterized by an increase in nonspecific interactions with temperature. In secondary amides with the chain self-assembly, the contribution of these interactions is practically independent of temperature, and in tertiary amides it decreases with an increase in temperature. The molar values of the specific and nonspecific components are used to analyze the intermolecular interactions and the structural properties of amides with different degrees of N-substitution.     

Solubility of ozone in some flourocarbon solvents

The solubilities of ozone 0-6 Wt% in air or oxygen, in 14 Fluorocarbon solvents have been determined at ambient temperature. Solubilities ranged from 50 to 700 ppm (wt) for a gas phase 0₃ concentration of 6 Wt%. Compounds with 0₃ solubilities <130 ppm (wt), exhibited approximate Henry's Law behavior, whereas those compounds with O₃ solubilities >200 ppm (wt) showed apprarent marked Henry's Law deviations.     

Epoxy and polyurethane adhesive materials of elad,aquapol, and acrolat brands and their components

Different groups of chemical products developed and produced at the Macromer Scientific and Manufacturing Company are described and recommended for use in adhesive compositions, including reactive diluents for epoxy compositions, urethane prepolymers, binders for photocurable materials, aqueous polyurethane dispersions. The main characteristics of binders for glues are presented, as well as the prospects for their application in formulas of adhesive compositions.     

Interaction of superhydrophobic materials with aqueous solutions and organic solvents

The interaction of a fluorine-containing superhydrophobic (SHP) coating on the surface of a siloxane rubber with aqueous solutions and organic solvents was studied by wettability analysis. The long-term durability of the coating against the damaging action of atmosperic precipitates saturated with salt ions, acid rains, as well as a number of organic solvents was demonstrated. The resistance of the coating to highly alkaline media is lower than to a neutral medium because of the hydrolysis of Si—O—Si bonds and amide groups. The low resistance of the fluorine-containing SHP coating to acetone is due to the swelling of the substrate and mechanical destruction of the fluoroorganic component.     

Molar extinction coefficients of some commonly used solvents

Molar extinction coefficients of some commonly used solvents (ethanol (C₂H₅OH), methanol (CH₃OH), propanol (C₃H₇OH), butanol (C₄H₉OH), water (H₂O), toluene (C₇H₈), benzene (C₆H₆), carbontetrachloride (CCl₄), acetonitrile (C₄H₃N), chlorobenzene (C₆H₅Cl), diethylether (C₄H₁₀O) and dioxane (C₄H₈O₂)) have been determined by a well-collimated narrow beam transmission geometry at 279, 356, 662, 1173, 1252 and 1332 keV γ rays. The total γ ray interaction cross sections of these solvents have also been determined. A good agreement has been obtained between the experimental results with the theoretical values evaluated through XCOM calculations.     

Pressure-sensitive adhesive materials for operational maintenance of equipment

The properties of pressure-sensitive adhesive materials, namely, an adhesive-based film protective coating, a pressure-sensitive aluminum foil, and an aluminum foil-based pressure-sensitive material with a permanent tacky layer are described. The materials are shown to be applicable for occasional maintenance of damages (scratches, chips, or peels of lacquer coatings) on external surfaces of aircraft frames.     

Properties of composite materials based on adhesive prepregs

The properties of composite materials based on a wide range of adhesive prepregs from glass and carbon fillers are described. The advantages and features of the technological production process of structures made from PCM, including honeycomb structures of single and double curvature with the use of adhesive prepregs designed for operation from ?130 to 175°C, are shown.     

Properties of adhesive materials used in repair-and-renewal operations

Advantages of repair technologies based on the use of adhesive materials are shown. Basic properties are given for adhesive materials used in repair operations, namely, epoxy-based metal-filled materials; film adhesives and adhesive prepregs; anaerobic repair compositions based on caoutchoucs and acrylates; and epoxy, acrylate, and urethane acrylates used for adhesion under conditions of increased humidity and under water. Some operation technologies for repair and renewal based on the use of adhesive materials are considered, namely, technologies that deal with breakdowns and preventive repairs on oil and gas pipelines, in the aviation industry (repair of honeycomb sandwiches included), in power engineering, and in the chemical and petrochemical industry, as well as those that solve relevant problems of car repair.     

Physical properties (thermal,thermomechanical, magnetic,and adhesive) of some smart orthodontic wires

Thermal, thermomechanical, and caloric properties of commercial orthodontic wires (produced by Natural Orthodontics Corp., USA) with cylindrical and rectangular geometry were studied. Depending on the applied forces, there were identified the range of elasticity, the elasticity–viscoelasticity coexistence domain and the domain in which a maximum force of 18 N is applied, for the orthodontic wires. When increasing the thickness of orthodontic wires, deformation decreases. The Controlled Force Module, in the tension mode, was used for the determination of the orthodontic wires elongation at application of the stretching forces from 0 to 13 N, at 35 °C, maintaining each static force value for 3 min. The increase in the cross-sectional area of the orthodontic wires disfavors the process of elongation of the sample, at the same applied static force. Using the Multi-Frequency–Strain–Stress modulus, in the tension mode, DMA cyclic heating–cooling measurements were performed. The measured physical quantities for orthodontic wires were Storage Modulus, Loss Modulus, Tanδ and Stiffness, at heating and cooling. Thus, the characteristic temperatures of the phase transitions (A_s, A_f, M_s, M_f), of all the studied orthodontic wires were identified. Also, the values of the elasticity modulus (Young’s Modulus) of the orthodontic wires were calculated at 35 °C. With the DSC Q200 device, using temperature-modulated differential scanning calorimetry method, a multi-step temperature variation program, was applied to a rectangular wire, in three stages (cooling–heating–cooling). Through the interpretation of heat fluxes (reversible, irreversible and total), the phase transitions in the formation of martensite, austenite, but also of the rombohedral phase (R-phase), were identified. Formations of austenite and martensite were also evidenced by the classical DSC method, but the classical DSC method also enabled the R-phase identification. The adherence of some food dyes on the orthodontic wires, as well as the modification of the surface roughness of the orthodontic wire after the deposition of the food dye, was also studied. By magnetic measurements, it was established that the orthodontic wires had paramagnetic properties at room temperature, and nitinol was a mixture of 49.2% austenite and 50.8% martensite.

     

Effect of some components of photosensitive composition on the sensitometric characteristics of the materials for recording holograms

Effect of ingredients of the light sensitive composition of registering layer on the photographic parameters of halosilver photographic materials for recording holograms is considered.     

Properties of adhesives and adhesive materials used in aviation industry

Methods for developing adhesives and adhesive material used in the structures of almost all units of aviation machinery are described step by step. The properties of high-strength film-forming adhesives; adhesive prepregs; sandwich-type aluminum-polymer materials (SIALs); cold- and hot-setting adhesives intended for gluing metals, different nonmetallic materials, and combined joints; and self-adhesive film materials of ZPPK and FAS grades are given. It is also shown where and for which purposes these adhesives are applied.     

Optical sensor materials for the detection of amines in organic solvents

A new optical polymer-based sensor was developed, which is able to recognize amines in organic solvents with high sensitivity. Thin polymer membranes were prepared and investigated, which contain a chromogenic functional dye (reactand) that shows a significant colour change during a reversible chemical reaction with the analyte. For that purpose the azo dye 4-trifluoroacetyl-4′-[N-(methacryloxyethyl)-N-(ethyl)amino]-azobenzene (CR-465) was synthesized, which contains a trifluoroacetyl moiety (receptor for interaction with amines) and in addition, a polymerizable methacrylate group. The methacrylate group links the dye covalently to the polymer matrix and the receptor recognizes the analyte via covalent binding. For immobilisation of the dye cross-linked methacrylate polymers with different composition were used. The highly cross-linked polymer network was stable against most organic solvents and exhibited enhanced stability against mechanical strain compared to plasticized PVC. The sensitivity of the reaction between the analyte and the dye was tailored by the choice of the solvent in which the analysis of the sensor layer was performed, with equilibrium constants for 1-butylamine ranging from 80 to 2000 M⁻¹ in chloroform and DMSO, respectively. In toluene as the solvent, sensor layers typically exhibited equilibrium constants of 100 M⁻¹ for 1-butylamine, 1300 M⁻¹ for 1,4-diaminobutane and 20,000 M⁻¹ for tris-(2-aminoethyl)amine. We have also investigated the cross-linked sensor layers with respect to molecular imprinting and did not find any enhancement in selectivity through imprinting in the presence of different analyte molecules.     

Application of adhesive materials for the repair of acting gas pipelines

The materials and equipment developed to eliminate damage in the pipelines that transmit hydro-carbons are presented. The properties of the adhesive materials and processing methods used in the repairs are described.