Papers by Keyword: Weight Loss

Abstract: This study examined the corrosion inhibition characteristics of Launaea taraxacifolia on mild steel in 1M H₂SO₄ solution, considering the demand for environmentally benign and effective corrosion inhibitors in acid media. The work aimed at elucidating the adsorption behavior, inhibition mechanism, and thermodynamic properties of L. taraxacifolia. Gravimetric and potentiodynamic techniques were employed in assessing inhibitor performance for variations in inhibitor concentrations (0.3%–1.2% W/V), immersion time (10–60 minutes), and temperature (303K–323K). The results indicated that corrosion rates increased with temperature, showing that the inhibitory process is dependent on the adsorption of L. taraxacifolia onto the steel surface. Adsorption obeyed Freundlich and Temkin isotherms, and the calculated heat of adsorption was -11 kJ/mol, which indicated physical adsorption. The presence of key phytochemicals, aromatic compounds, and heteroatoms in the inhibitor played an important role in the process, making it a mixed-type inhibitor. The maximum inhibition efficiency of 97.78% was recorded at higher inhibitor concentrations and longer immersion times. The weight loss measurements were within the range of 0.001g to 0.038g across the temperatures. This study illustrates the potential of L. taraxacifolia as a green inhibitor, evidenced by its thermodynamic and kinetic properties. It concludes that L. taraxacifolia might serve as a good substitute for synthetic inhibitors, especially in those industries where environmental considerations are essential.

Abstract: Pipes from industrial process flow diagrams have a predictable risk of failure or damage, so that periodic inspections are carried out. Corrosion that occurs in the pipe can cause a risk of leakage or blockage of the pipe flow which can be fatal to the fluid distribution process. This damage can be anticipated by inhibitors adding and predicting the corrosion rate. This research was conducted to determine the effective concentration of Na₂CrO₄ inhibitor to inhibit the corrosion rate and predict the lifetime of the furnace cooling water circulation pipe using the weight loss method. Na₂CrO₄ inhibitor is a type of anodic inhibitor that works by passively the anode by inhibiting corrosion on a whole metal surface. The study begins with the preparation stage, cutting the pipe into specimens of a certain size, smoothing the surface and weighing the initial weight. The testing phase was carried out by immersing the specimens at various times of 120 h, 240 h and 360 h with Na₂CrO₄ inhibitor variations concentration was 0%; 0,3%; 0,6%; and 0,9%. The corrosion rate was calculated by re-weighing the specimen after the immersion process. The results showed that the most effective inhibitor concentration was 0.6% with a corrosion rate of 0.3021 mmpy and the Remaining Service Lifetime (RSL) was 9.399 years.

Abstract: As a result of the studies of wood flame retardant effect on ignition, the parameters of flame propagation and combustion suppression were established, which makes it possible to influence this process. It has been proven that the creation of a protective layer on the surface of wood prevents it from heating up to a critical temperature. At this moment, a certain amount of combustible gases is released, that is, intense decomposition and ignition occurs. This knowledge makes it possible to establish the dependence of the process of inhibiting the burning rate of wood on the quality of fire protection and the properties of the applied protective mixtures. By experimentally examining wood samples, it was established that the sample without treating caught fire on 52 s and in 100 seconds the flame spread over the entire surface, the sample fire-retardant "FIREWALL-ATTIK" did not catch fire, impregnating solution ВС-13 and "FIREWALL-SV-1", namely a mixture of 271.1 g/m², took 570 and 560 s, the flame spread to the surface only in areas closer to the source, the highest flue gas temperature of 86 and was reached more than 5 times faster, and the flammability index decreased to 4. For the sample protected by "FIREWALL-LAC" ignition occurred in the last second, the flame was recorded at level 0. For the sample fire-protected by "FIREWALL-WOOD" coating no ignition occurred, combustibility index is 0. Due to this, it became possible to determine the conditions for changing the combustion barrier to heat conductivity. Correspondence between the obtained experimental results of the wood burning rate and the analytically calculated equations was found.Taking into account the above, there is a basis for asserting the possibility of purposeful management of the processes of protecting wood from fire by applying fire-retardant mixtures, which under certain conditions are able to create a protective layer on the surface of the material, which restrains the growth of the rate of wood burning.

Abstract: A well-known corrosion parameter is corrosion rate as measured by the electrochemical or the weight-loss methods. The weight loss methods can be measured continuously or intermittently depending on the actual conditions of sample placement and the experimental design. But what distinguishes the measurement method is whether they produce the same corrosion rate value or not. This study aims to study the corrosion rate with a continuous and discontinuous measurement method of weight loss using carbon steel specimens immersed in sodium chloride solution and further compare the two results. For this purpose, 25 sample coupons with the size of 80x23x3.6 mm have been prepared. The measurement of weight loss was carried out on specimens for 10, 20, 30, 40, and 50 days, by immersing the sample in 2 and 3%-wt NaCl, respectively, and one was treated in distilled water according to ASTM G31-72. From the three treatments studied, a percentage of the results was a value that lies between 2.67 and 5.46% with an average value of 4.17%. There is no significantly effect of the data collection method for the three types of the treatment samples immersed for 10 to 50 days in distilled water, 2 and 3%-wt sodium chloride solution.

Abstract: Intumescent fire-retardant coatings based on epoxy resins, compared to traditional fire-retardant compositions, have improved performance properties – high strength, chemical and atmospheric resistance, adhesion to many materials. However, unmodified epoxy polymers are combustible and to obtain IFR based on them, flame retardants and mineral fillers are added to their composition. Intumescent systems for flame retardant coatings based on epoxy oligomers (non-halogen-containing) usually consist of ammonium or ammophos polyphosphate as an acidic agent and a wide range of fillers, both inert and gaseous, or which are an additional source of carbon. Each component of the fire-retardant intimate coating in different ways affects the processes of coke formation, which determines the requirements for their choice. Thus, the aim of this work is to conduct experimental studies of the dependence of the characteristics of the expanded coke layer on the composition of the intumescent epoxyamine composition. The results of experimental studies of the effect of ammonium polyphosphate and binary mixtures of ammonium polyphosphate (APP) with aluminum hydroxide (AH), sodium tetraborate decahydrate (STD), titanium oxide TiO₂ (TO), pentaerythritol (P), aerosil (A) and expandable graphite are presented (EG) on the multiplicity of expanding and weight loss of epoxy compositions at study temperatures of 350, 400 and 450°C. Studies have shown that the production of intumescent flame retardant coatings based on epoxy oligomers is possible provided they are filled with ammonium polyphosphate in an amount of more than 20 mass parts. The most effective in terms of expanding are additives titanium oxide and aluminum hydroxide in an amount of 20 mass parts, which allows to obtain intumescent fire-retardant coatings with a linear coefficient of expanding 30-32 and 24-27, respectively, throughout the range of temperatures. The obtained data are useful in the development of fire-retardant coatings based on epoxy oligomers.

Abstract: The results of researches of wood burning parameters and influence of fire-retardant substances on them are given. Studies have shown that the process of heat insulation of a wooden structure is the formation of soot-like products on the surface of natural combustible material. Under the action of the burner flame on the protected sample treated with impregnating solutions based on a mixture of ammonium phosphate with antiseptic, the temperature of gaseous combustion products was 230 oC, and weight loss did not exceed 9%, while wood treated with a composition of urea and phosphoric acids and starch showed temperature of 160 oС with a weight loss of 3.6%. It is established that fire protection by coatings provides a low rate of burnout of wood samples and with increasing temperature exposure and translates into a non-flammable material that does not spread the flame on the surface.

Abstract: Novel extracted natural stabilizer for the polymer was investigated in this study. The natural anti-aging was extracted from plants and it is demonstrated that this type of stabilizers are suitable for biodegradable polymers. Gynostemma pentaphyllum (0.01–0.03 wt%) were extracted and added to the poly(vinyl chloride) blend. The achieved polymeric films were exposed to an accelerated UV light aging process for 300 hours at ambient temperature. The efficiency of tested natural stabilizer was linked to blank PVC films. FTIR spectroscopy, weight loss, electronic microscope and scanning electron microscopy were performed. Using small amount of natural stabilizer is significantly beneficial because it does not influence the PVC properties.

Abstract: In the present work, corrosion inhibition of low carbon steel in a 1M H2SO4 solution by pectin nanoparticles extract was studied by potentiostatic and weight loss methods. Increasing the acid concentration leads to an increase in the corrosion rate of the electrode. The variable conditions of the pectin nanoparticles used in this investigation are (2 to 10g/l at 25oC). It was found that the concentrates acts as a compelling consumption inhibitor for gentle steel in an acidic medium. The hindrance process is credited to the adsorbed film development of the inhibitor on the metal surface of that protects the metal against corrosion. It was observed that the efficiency of the inhibition rose with increased inhibitor concentration up to the maximum level of 92% for 10 g/l at 25 oC. The results showed that the corrosion rate without the inhibitor was 2.263mpy while with the inhibitor 0.179 mpy, meaning that the rate of corrosion improved more than 90%. The results of the immersion time (1 h) at 25oC on the inhibition of the corrosion also indicated improved corrosion resistance. The results demonstrated that an extract of pectin nanoparticles could serve as an excellent eco-friendly, green corrosion inhibitor. Fourier- transform infrared spectroscopy (FTIR) results indicate that these nanoparticles contain various chemical bonds (C-C, CH2, C-O-C, and cellulose) with metal surfaces, lead to producing a barrier layer that protects the surface.

Abstract: Fireproof coatings at the time of operation of the building structure is a separate and complex task, covering both the stages of the process protection from moisture, and subsequent fire protection formed during the swelling of the coating. They have been proven to create a layer of material on the surface that prevents moisture from penetrating the wood when the destruction of the coating begins. This makes it possible to determine the effect of flame retardants and the properties of the protective compositions on the process of slowing down the rate of water absorption. The process of moisture transfer by flame retardant coating in the presence of a polymeric shell is simulated, the diffusion and mass transfer dependences are obtained, and the diffusion coefficient is determined, which is 7.08·10^-12 m²/s, which allow to obtain a change in the dynamics of moisture upon washing out of the flame retardant. The results of determining the weight loss of the coating sample during exposure to water indicate the ambiguous effect of the nature of the leaching agent. In particular, this implies the availability of data sufficient for qualitatively conducting the process of inhibition of moisture diffusion and detection on its basis of the moment from which the fall of the coating efficiency begins. Features of slowing down the process of moving the moisture to the material that is treated with flame retardant, are in several aspects. Namely, the use of water-insoluble flame retardants and other components, as well as polymer binder, which are characterized by the formation of polymer shell on the surface of the wood.

Abstract: The possibility of using polymers based on epoxyphenolic binders to obtain fiberglass with an intense level of carbonization has been investigated. The correlation between the pyrolytic transformations intensity and the fire hazard indicators of polymers is shown. It is established that the conditions for the intensive passage of pyrolytic reactions are facilitated by the presence in the matrix system of conjugated aromatic (naphthalene) radicals. The C/H ratio in the carbonized layer is confirmed by the data of IR spectroscopy both at the preparation stage and after exposure to characteristic temperatures.