RESEARCH OF FUEL- AND WATER RESISTANCE OF COATINGS BASED ON THE FILLED EPOXY-THIOKOL POLYMERIC COMPOSITIONS

The article provides the results of studies of fuel- and water resistant priming coatings based on the filled fuel-resistant compositions based on the E-41 epoxy modified with liquid Thiokol 1 brand and cured with ASOT-2 organic-silicon amine. There was examined the microstructure of coating surface of fuel resistant primer 1 by means of optical and scanning electron microscopy after tests in TS-1 fuel and distilled water. It has been determined that availability of a filler with lamellar structure as a part of fuel-resistant primer promotes the decrease in fuel-swelling and moisture absorption that can be connected with manifestation of a barrier effect.

Preparation and Evaluation of Ternary Polymeric Blends for Controlled Release Matrices Containing Weakly Basic Model Drug

Objective: The objective of this study was to evaluate the suitability of ternary mixture of smart polymers comprised of Eudragit®E100, Eudragit®L100, and sodium alginate to serve as a carrier for sustained drug release for weakly basic drugs. The model drug chosen in this part of the study is Metronidazole. Methods: Matrix tablets formulations were prepared by either direct compression or by wet granulation. Dissolution studies were conducted using USP XXΠ rotating paddle apparatus in three different consecutive stages (pH 1.2, 4.8 and 6.8). Tablets made of low to intermediate proportions of sodium alginate and an approximately equal proportions of Eudragit®E100 and Eudragit®L100 were found to have significant modification of drug release rates. Result: Thus, indicating a potential for controlling the drug release for 12 hours depending on polymers ratios in the formulation. The ratio of sodium alginate to total Eudragit® polymers and the ratio of Eudragit®E100 to Eudragit®L100 within the ternary polymeric composition were found critical in determining the controlled release performance. Conclusion: Results of swelling studies were in agreement with the dissolution behaviors of the tablets. The findings suggest the significance of the ternary polymeric compositions in controlling the release of weakly basic drug.

Application of Computational Methods for Creating and Selecting Polymeric Compositions with Given Properties

The article discusses current mathematical methods (probabilistic, regression, correlation, fuzzy, graph, and others) used in the study of the structure and property dependencies of polymer compositions and polymer composite materials. The authors consider the methodology and theoretical aspects of modeling these dependencies, give technological calculations using models. The paper provides examples of the analysis of the particular case of complex chemical and chemical-technological systems, polymer compositions and composite (polymer) materials. The authors show a possible solution to the problems of assessing the quality of composite polymer materials and the rational choice of the composition in homogeneous sets using fuzzy sets.

The flow curves of nitrocellulose solutions on Hoppler viscosimeter

For the first time a possibility of an application of a Hoppler viscosimeter with the pressing ball for obtaining of the flow curves of 5-50% bipolymeric cellulose nitrates – polyvinyl nitrate (NC-PVN) solutions based on the measurements of the stationary velocity of a ball displacement along the wall of the cylindrical vessel has been checked experimentally. The relationships, rearranging the equations of the shear stress and rate by means of the correlation coefficients, underlie the method. The time of the ball immersion into the polymeric solution has been used as the main parameter, which is experimentally determined. The rheological flow law and the rheological parameters of reprocessing of 5-50% NC-PVN solutions in EA: a flow index, a consistency coefficient, have been established. It has been shown that 30-50% NC-PVN solutions in EA display properties of the non-Newtonian liquid to a greater degree and they are more structural ones in comparison with 5-20% NC-PVN solutions; the greater deviation of the flow index from 1 indicates on it. The values of the limit shear stresses that characterize the plastic (strength) properties of the polymeric compositions and allow to evaluate preliminary a possibility of a reprocessing of the nitrocellulose solutions, including the solutions, which are filled to the powders using the aqueous-dispersing, the lacquer-extrusion and the extrusion technologies, were found by the extrapolation of the rectilinear section of the flow curve to the axis of stresses. In the course of reprocessing of NC-PVN solutions in EA according to the aqueous-dispersing, the lacquer-extrusion and the extrusion technologies, the limits of a plasticity, corresponding to 90-1950 Pa, 1950-2750 Pa and 2750-5600 Pa, have been established. It has been shown, that the plasticity of NC-PVN die (50:50), filled with the octogen in the amount of 40 % by mass, increases ~1.7 times in comparison with the die, which is not filled, and it results in descreasing of a “brittleness” of the filled NC-lacquer.

The Influence of Inorganic Fillers on the Protective Properties of Epoxy Polymer Composite Materials

The influence of regularities of the chemical-mineralogical nature, the dispersity, and the surface properties of inorganic fillers on the protective properties of epoxy polymer composite materials have been investigated. Polymeric compositions based on epoxy resin of ED-20 brand and aliphatic amine curing agent of diethylenetriamine of DETA brand have been chosen as the research materials. The fillers were the air-dry dispersed materials of different nature: oxide, clay and quartz. The resistance of the composites to water and aqueous solutions (absorbency) was investigated by dipping the samples into an aggressive aqueous medium. For the received samples of the filled composites, thermogravimetric (TG) and differential scanning calorimetry (DSC) method were used using the SDT Q600 device manufactured by TA Instruments (USA). It has been found that the thermal stability and the absorbing capacity of the filled composites in water and aqueous acidic and alkaline mediums correlate with each other. It has been shown that to obtain materials with improved protective characteristics, it is necessary to use oxide or clay fillers with the basic (alkaline) surface function.

PREPARATION AND INVESTIGATION OF SOME MECHANICAL PROPERTIES OF UNSATURATED POLYESTER RESIN REINFORCED BY HYBRID NANOPARTICLES

In this study, nano-composite of polymeric materials, prepared from unsaturated polyesterresin (UP). Two groups of nanocomposites were prepared by Hand Lay-up method. The firstgroup consists from (UP) reinforced by hybrid nanoparticles consisting of a mixture ofzirconium oxide and yttrium oxide (30 mol%Y2O3- ZrO2) with particles size (83.98nm). Thesecond group consists of (UP) reinforced by zirconia nanoparticles (ZrO2) with particle size(47.23nm). The effect of volume fraction (0.5%, 1%, 1.5%, 2%, 2.5%, 3%) of thenanoparticles additives on some mechanical properties of composites materials was studiedalso. The results shown that the values of the flexural modulus, impact strength and fracturetoughness increased, as the volume fraction ratio of the nanoparticle increased for bothgroups of nanocomposites, while flexural strength values decreased with the increased thevolume fraction ratio of the nanoparticles for both groups of nanocomposites also. As wellas, the unsaturated polyester resins reinforced by hybrid nanoparticles has higher mechanicalproperties as compared with their counterparts of composites reinforced by zirconiananoparticles only. The morphological formation of the fracture surface showed a closeinterconnection between all components of the prepared polymeric compositions. Thisreinforce a good compatibility between unsaturated polyester resins and reinforcementnanoparticles, which enhancement the mechanical properties.