THE INFLUENCE OF CLIMATIC FACTORS ON THE CHANGE IN THE ELASTIC-STRENGTH INDICATORS OF EPOXY POLYMERS BINDERS USED IN LIQUID THERMAL INSULATION COATINGS
Introduction: Thermal insulating coatings are increasingly being introduced into construction practice for internal and external finishing enclosing structures and pipelines. Thermal insulation coatings are usually made based on polymer binder and mineral fillers. The durability and stability of the properties of heat-insulating materials depend on the type of binder. As a rule, polymers are used as a binder: epoxy resin; silicone rubber; urea-formaldehyde resins; aqueous dispersed polymers - styrene-butadiene, polyvinyl acetate, and acrylate (acrylic and styrene-acrylic). The quality indicator of binders can be assessed by the influence of the seasonality of climatic impact, and as a result, the best elastic strength characteristics of binders can be established after one month to a year of field tests. Aim: To determine the influence of climatic factors on the change in the elastic-strength indicators of epoxy polymers binders used in liquid thermal insulation coatings. Methods: A tensile testing machine of the AGS-X series with the TRAPEZIUM X software was used for mechanical tests. The tests were carried out in accordance with GOST 11262-2017 (ISO 527-2: 2012) "Plastics. Tensile test method". Results and Discussion: The paper discusses the results of experimental studies of the compositions of polymer binders and their resistance to various climatic factors, which will later be used as a polymer binder for thermal insulation coatings based on fine mineral granular systems. Conclusions: When analyzing the changes in the characteristics of polymer samples after exposure to climatic factors, it was found that compositions based on Etal-247 epoxy resin, cured with amine hardeners Etal-1440N, Etal-1460, Etal-1472, and Etal-45M, demonstrate the best elastic strength characteristics after one year of full-scale tests. The high stability of the indicators under consideration allows us to conclude that the use of Etal-247 resin as a base leads to creating of the most climate-resistant epoxy coatings.
Read ArticleCOMPARATIVE STUDY ON ANTIOXIDANT ACTIVITY OF SALVIA NEMOROSA L. FROM TWO DIFFERENT LOCATIONS
In order to investigate the antioxidant activity of Salvia nemorosa L. collected from Ahar and Urmia regionsin Iran at different growth stages, aerial parts of sage after collecting were dried, and for measurement, the abilityof scavenge DPPH (2,2-diphenyl-1-picryl-hydrazyl-hydrate) radical in different concentrations (0.025, 0.05, 0.07,0.1, 0.2, 0.04 and 0.6) of methanolic extracts were prepared. The result showed that the ability to scavenge DPPHradical and amount of inhibition percent of vegetative stage leaves, flowering stage leaves, and flowers increasedwith increasing concentrations of methanolic extracts from 0.25 to 0.6 mg/mL. In the region of Urmia, the highestamount of DPPH inhibition there was in vegetative stage leaves, and the lowest amount of DPPH inhibition wasseen in flowers. In Ahar regions, unlike the Urmia region, the highest amount of DPPH inhibition there was inflowers, but the lowest of DPPH inhibition was seen in flowering stage leaves. Also, the content of inhibition ofDPPH in Ahar and Urmia regions similarly increased between two phenological stages (vegetative stage leaves,flowering stage leaves, and flowers) in 0.4 mg/mL and 0.6 mg/mL concentrations.
Read ArticleSTUDY ON THE DPPH FREE RADICAL-SCAVENGING ACTIVITY OF SALVIA NEMOROSA L. AT TWO GROWTH STAGES
This study was designed to examine the DPPH free radical-scavenging activity, in different concentrations (0.025, 0.05, 0.07, 0.1, 0.2, 0.04 and 0.6) of methanolic extracts of Salvia nemorosa L. collected from the northwest of Iran (Zonouz and Ardabil regions) at two-stage of growth (vegetative stage leaves, flowering stage leaves, and flowers). The result showed that the mean of inhibition percentage in the Zonouz region increased in various concentrations and between flowers, vegetative stage leaves, and flowering stage leaves, compared with the plants of the Ardabil region. In each of the regions of Zonouz and Ardabil, the highest amount of DPPH inhibition was observed in the vegetative stage leaves in comparison with flowering stage leaves and flowers. In addition, in the effect of DPPH radical trapping in different concentrations of methanolic extracts of Salvia nemorosa L. was observed that from each of the collected region, methanolic extracts from sage plants were dose-dependent and acted very effective and useful and the best antioxidant activity was in the high concentration of extracts, So in Zonouz and Ardabil regions, the content of inhibition of DPPH increased significantly, by increasing the concentration of 0.025 mg/ml to 0.6 mg/ml and in Zonouz region the content of inhibition of DPPH similarly increased in 0.2, 0.4 and 0.6 mg/ml concentrations. In the Ardabil region, the most content of inhibition of DPPH was seen in 0.4 mg/ml and 0.6 mg/ml concentrations, but in this region, the content of inhibition of DPPH in 0.2 mg/ml concentration there was only in vegetative stage leaves and flowering stage leaves.
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