نشریه پژوهش های کاربردی مهندسی شیمی - پلیمر
سال هفتم شماره 1 (پیاپی 23، بهار 1402)

Research subject: 

Electromagnetic heating is one of the new methods of upgrading and increasing heavy oil extraction. In this method, electromagnetic waves will increase temperature, break heavy compounds, reduce viscosity, and improve and increase oil recovery.

Research approach:

 In this research, magnetic iron oxide nanoparticles (Fe3O4) were synthesized by the co-precipitation method, and the efficiency of these nanoparticles in the process of electromagnetic heating and heavy oil upgrading was investigated. Also, a comparison was made between the effect of these nanoparticles in the process of electromagnetic heating and activated carbon. In this process, oil samples containing 0.1% of Fe3O4 nanoparticles or activated carbon were irradiated with microwave (frequency 2.54 GHz and power 400 W) for 0 to 8 minutes, and the temperature and viscosity variation were investigated.

The results showed that microwave radiation increased the temperature of the samples. The temperature of the sample of crude oil, crude oil with activated carbon, and crude oil with Fe3O4 nanoparticles increased from ambient temperature to 70, 82, and 90°C, respectively, under wave radiation for 8 minutes. Also, the most significant decrease in viscosity was reported in 4 minutes: the viscosity of crude oil sample, crude oil with activated carbon, and crude oil with Fe3O4 nanoparticles under wave irradiation for 4 minutes decreased 295 mP.a to 261, 254, and 223 mP.a, respectively. In other words, the viscosity of the samples under wave irradiation for 4 minutes for crude oil, crude oil with activated carbon, and crude oil with Fe3O4 nanoparticles decreased by 11.5, 13.9 and 24.4%, respectively.

Research subject:

 The binder system based on of hydroxyl-terminated polybutadiene resin (HTPB), consist of dioctyl sebacate as a plasticizer (DOS), and toluene diisocyanate as the curing agent. Reaction between the HTPB hydroxyl resin group and the curing agent isocyanate group produces a polyurethane mesh to produce a rubber with the desired properties. In this research, the rheological and mechanical properties of the binder system were investigated and Physical properties compared in the presence of three chemicals retarder polymerization Polyurethane, oxalic acid, maleic acid and tetracycline.

Research approach:

 Oxalic acid, maleic acid and tetracycline alter the properties of the binder system by specific mechanisms. Oxalic acid and maleic acid react with the isocyanate group of the curing agent to produce amides and reduce the viscosity of the binder system. Due to its chemical structure, tetracycline reacts with the curing agent and prevents the development of the main reaction between the HTPB resin and the curing agent TDI and reduces the viscosity. Infrared Fourier transform (FT-IR) test was also used to investigate the functional mechanism of these compounds. In this test, the intensities of the spectra related to each sample were compared with each other and the type of function and mechanism of each of the oxalic and maleic substances and tetracycline were determined.

The structure of the reaction product between HTPB resin and oxalic acid, maleic acid and tetracycline with curing agent was determined and confirmed by FT-IR spectrum. In-situ FT-IR study showed reduction in isocyanate peak intensity after 60/90 min. Chemorheological investigation showed best performance at 0.05% concentration for all retardants, among them tetracycline, oxalic acid and maleic acid depicted 54%, 48% and 47% reduction in viscosity build-up; respectively. Adding 0.05% of tetracycline to binder system resulted in about 20% decrease in cross link density probably due to better interaction with curing agent which emphasized the best performance of 0.05%-tetracycline as retardant.

Contamination of water and soil with heavy metals poses serious risks and threats to human health and the environment, and therefore finding an effective solution to remove these metals is very necessary. In this research, magnetic nanoparticles MnFe2O4 @ SiO2 functionalized with N-phosphonomethyl aminodiacetic acid with core-shell structure were synthesized. These nanoparticles were characterized by scanning electron microscopy, transmission electron microscopy, X-ray diffraction (XRD), Fourier transform infrared (FT-IR) spectroscopy, (TGA) thermal gravimetric analysis, transmission electron microscope (TEM), and (VSM) vibration sample magnetometer. The performance of this synthetic nanoadsorbent for removing Cr (VI), Cu (II) ions from aqueous solutions was evaluated by various parameters such as adsorbent amount, contact time effect on adsorption rate and pH effect. The results show that the adsorption efficiency increases with raising pH (2.5-5) and the best adsorbent performance in the adsorption process of Cr ((VI) and Cu (II) ions at pH 7 was observed. The amount of R in the Freundlich adsorption diagram of copper ion is higher than the Langmuir isotherm. As a result, the adsorption of copper ions on the adsorbent follows the Freundlich adsorption equation. In addition, the amount of R in the Freundlich adsorption diagram for chromium ion is higher than the Langmuir isotherm. Therefore, the absorption of chromium ions on the adsorbent follows the Freundlich adsorption equation. In conclusion, a high n value indicates a favorable and effective absorption in the Freundlich equation. The adsorption data were analyzed by the Langmuir and Freundlich isotherm model. In addition, the recyclability and reuse of the adsorbent was investigated. The results show that no significant reduction in adsorbent activity is observed.

Research Subject:

 In recent years, smart water flooding has gained attention regarding enhanced oil recovery, and one of its driving mechanisms is wettability alteration. However, the effect of acid presence on smart water performance needs to be clarified. Thus, the main question is whether the presence of acid and potential determining ions can lead to further wettability alteration and interfacial tension (IFT) reduction. Additionally, in this study, trivalent cations were added to smart water for the first time, and the results were compared with those of divalent cations. 

Research approach: 

In this study, seawater (SW), 4-times diluted SW, and 8-times diluted SW were prepared in distilled water, 0.001 normal HCl and 0.01 normal HCl, and the contact angle and IFT experiments were carried out. In addition, concentrations of Ca2+, Mg2+, and Fe3+ were adjusted in 8-times diluted SW prepared in 0.01 normal HCl, and the IFT and contact angle tests were conducted.

The results showed that the presence of acid in distilled water could decrease the IFT values; however, it did have a marginal effect on contact angle reduction. Also, because of synergistic effects between acid and potential determining ions, IFT significantly declined. While adding acid to brines with different salinities resulted in contact angle reduction, the glass surface remained oil-wet. Regarding divalent and trivalent cations, the results revealed that increasing Fe3+ concentration in smart water made the glass surface water-wet. However, adjusting Ca2+ and Mg2+ concentrations changed the wettability from oil-wet to neutral-wet. Moreover, divalent and trivalent cations showed similar behavior in IFT reduction, and a four-times increase in the concentration of each mentioned ion reduced IFT by about 2 mN/m.

Research subject:

 Polycarbonate/acrylonitrile butadiene styrene alloy is one of the most widely used polymer alloys in the world, which has become very widespread due to the excellent properties and characteristics of these alloys as well as other advantages. However, it seems that strengthening the properties and efficiency of these alloys can increase their scope of application. Typically, polymers have a high resistance to the passage of electricity. In recent years, increasing the electrical conductivity or reducing the electrical resistance of polymers by using conductive nanoparticles has received much attention.

Research approach:

 For this purpose, first, alloys of polycarbonate and acrylonitrile butadiene styrene were prepared by melt mixing method and were tested and evaluated in terms of physical and mechanical properties, thermal properties and behavior of the melt. Next, by adding nanographene to the best alloy, the electrical, mechanical and morphological properties of nanocomposites were investigated. In order to increase the electrical conductivity of nanocomposites, different amounts of nanographene (1, 2 and 3%) were used.

By increasing the amount of polycarbonate, tensile strength and modulus, flexural strength and modulus, and HDT of the alloys increased. The results showed that the alloy with 68% polycarbonate generally has better properties than other alloys, so this alloy was considered as the polymer base of nanocomposites. The results of the mechanical test show an increase in the tensile strength and tensile modulus of the samples with an increase in the percentage of nanoparticles. Also, the examination of the electrical resistance of nanocomposites showed that in all samples, nanographene has been able to reduce the electrical resistance of the polymer to a very significant extent. By examining the mechanical and electrical properties of the samples, it was determined that the Percolation threshold of nanoparticles is equal to 2%. The FE-SEM images of the nanocomposites showed that the graphene nanoparticles were well dispersed in the polymer matrix and no traces of clumps or clusters resulting from the accumulation of nanoparticles were observed.

Hypothesis: 

One potential method for improving nanocomposite mixed matrix membranes is through the use of nanoparticles and compounds containing hydroxyl and carboxyl groups, which may aid in the penetration of CO2 gas. In this study, we investigated the selectivity and permeability of a polyether block amide/polyvinyl alcohol (Pebax/PVA) nanocomposite membrane containing magnesium oxide (MgO) nanoparticles. Previous research has shown that the addition of MgO to the Pebax/PVA matrix can increase CO2 permeability by creating an intermolecular space.

Prepared a Pebax/PVA nanocomposite membrane with a weight ratio of 80:20, containing 10% MgO nanoparticles, through a solution casting method. Evaluated the performance of the Pebax/PVA/MgO nanocomposite membrane for separating CH4 and CO2 gases using various tests.

Characterized the membranes through Fourier transform infrared (FTIR), X-ray diffraction (XRD), and field emission scanning electron microscopy (FESEM) tests. FESEM images showed increased surface roughness with the addition of nanoparticles, and the nanoparticles were well dispersed within the polymer matrix. XRD analysis indicated that MgO nanoparticles had more interaction with PVA chains than with Pebax chains, and peaks at 42° and 62° regions were formed due to the placement of MgO nanoparticles among the polymer chains. We studied various parameters, including polyvinyl alcohol and MgO nanoparticle content, pressure, and temperature, as independent variables and examined their effects on the permeability of CH4 and CO2 gases. We measured the permeability of the constructed membranes and found that the addition of MgO significantly increased the permeability of CH4 and CO2.