Gulzhakhan Zh Yeligbayeva

A polyethylene/acrylic copolymer was synthesized using a grafting technique with benzoyl peroxide as a catalyst and xylene as a solvent. Acrylic acid (AA) was grafted onto polyethylene (PE) in a 1:5 ratio. The resulting grafted copolymer, characterized by FTIR, was blended with rice straw at varying percentages of 3%, 5%, and 7% to produce biodegradable films. The properties of these films in water were evaluated through analyses of viscosity, tensile strength, elongation at break, water contact angle, and solubility. Incorporating rice straw enhanced the grafted copolymer's biodegradability, resulting in increased viscosity, tensile strength, and elongation at break of the films, while reducing the water contact angle and solubility. However, incorporating 7% rice straw in the grafted copolymer-based on PE (1.0%) and AA (5.0%) resulted in increases in viscosity, tensile strength, and elongation at break by 29.5%, 46.1%, and 9.6%, respectively, while reducing the contact angle and biodegradability solubility time at 45°C by 25.8%.

Polyurethane coatings were synthesized through polyaddition polymerization using various polyols. These polyols included polypropylene glycol with different molecular weights, such as PPG-2000, and PPG-1200, as well as 1,4- butanediol. Additionally different contents of bisphenol F; namely 4.5, 11.5, and 24.2%, as well as methylene diphenyl diisocyanate at an NCO/OH ratio of 2.0. The prepolymer polyurethane films were analyzed to study their characteristics using techniques such as Fourier transform infrared spectroscopy, viscosity measurements, thixotropic index analysis, and mechanical property evaluations. The pot life and dry times of polyurethane coating containing 11.5% bisphenol F were 90 minutes and 10 hours (time to touch), respectively, with full hardening achieved at 28 hours. Furthermore, the coating exhibited excellent mechanical properties: tensile strength of 80 N/m², elongation of 260%, adhesion strength of 10 MPa (cross-hatch), hardness of 95, and a contact angle of 118°. These properties, coupled with its strong adhesion (10 MPa) to metal surfaces, contributed to its outstanding chemical and corrosion resistance. The coatings obtained from the prepolymer polyurethane based on 11.5% bisphenol F exhibited the highest mechanical properties and water, chemical, and corrosion resistance followed by 4.5%, and 24.2%, respectively.

A polyethylene (PE)/starch copolymer was prepared by a grafting technique in the presence of benzoyl peroxide as a catalyst and xylene as a solvent. The ratio of PE grafted onto starch was in ratio 1:5, respectively. The obtained grafted copolymer was characterized by Fourier transform infrared (FTIR) spectroscopy. The obtained grafted copolymer was mixed with rice and wheat straw as well as calcium carbonate (CaCO₃) as a filler to form biodegradable films. Various analyses such as viscosity, tensile strength, elongation at break, water contact angle, thermogravimetric analysis (TGA), scanning electron microscopy (SEM), and solubility tests have been used to study the properties of biodegradable films in water and soil. CaCO₃ and rice and wheat straws improved the biodegradability of the grafted copolymer. The presence of CaCO₃ in the presence of rice and wheat straws increased the viscosity, tensile strength, thermal stability, and weight loss of the film in the soil. While elongation at break, the water contact angle and solubility in water decreased. According to the study, samples that were between 380°C and 400°C showed the highest polymer breakdown values and adding CaCO₃ resulted in the lowest water contact angle.

Blend copolymers (PVA/S) were grafted with polyethylene glycol methyl methacrylate (PEGMA) with different ratios. Potassium persulfate was used as an initiator. The blend copolymer (PVA/S) was created by combining poly(vinyl alcohol) (PVA) with starch (S) in various ratios. The main idea was to study the effect of different ratios of the used raw materials on the biodegradability of plastic films. The resulting polymers (PVA/S/PEGMA) were analyzed using FTIR spectroscopy to investigate the hydrogen bond interaction between PVA, S, and PEGMA in the mixtures. TGA and SEM analyses were used to characterize the polymers (PVA/S/AA). The biodegradability and mechanical properties of the PVA/S/PEGMA blend films were evaluated. The findings revealed that the mechanical properties of the blend films are highly influenced by PEGMA. The time of degradation of the films immersed in soil and Coca-Cola increases as the contents of PVA and S and the molecular weight (MW) of PEGMA increase in the terpolymer. The M8 sample (PVA/S/PEGMA in the ratio of 3:1:2, respectively) with a MW of 950 g/mol produced the lowest elongation at break (67.5%), whereas M1 (PVA/S/PEGMA in the ratio of 1:1:1, respectively) with a MW of 300 g/mol produced the most (150%). The film’s tensile strength and elongation at break were improved by grafting PEGMA onto the blending polymer (PAV-b-S). T_g and T_m increased when the PEGMA MW increased from 300 to 950. T_g (48.4 °C) and T_m (190.9 °C) were the lowest in M1 (300), while T_g (84.8 °C) and T_m (190.9 °C) were greatest in M1 (950) at 209.3 °C. The increased chain and molecular weight of PEGMA account for the increase in T_g and T_m of the copolymers.

One of the biggest challenges in oil and gas production projects is dealing with the various types of corrosion to which certain parts of field equipment are exposed. Selecting the right corrosion inhibitor for the specific environment is extremely important. Choosing inhibitors for a particular location can be a difficult task because there are many factors to be considered. Understanding the corrosion problems that can arise is important in the oil and gas industry, and knowledge of which inhibitors to use to deal with general and localized corrosion will save time and money in the long run. This article presents the results of studies of various brands of domestic and foreign corrosion inhibitors for use in the Uzen field: physical and chemical characteristics (density, viscosity, freezing temperature, mass fraction of active substance, compatibility with field waters, amine number), efficiency of corrosion inhibitors in laboratory conditions and on a bench simulating field reservoir conditions, taking into account pressure, temperature, fluid flow rate, as well as aggressive components - hydrogen sulfide and carbon dioxide. In addition, studies of corrosion inhibitors' effect on the process of preparation of production are also given. The works were carried out in the center of scientific and laboratory research of KMG Engineering branch " KazNIPImunaygas" LLP.

Thermosensitive hydrogels based on N‐isopropylacrylamide (NIPAAm) and 2‐hydroxyl ethyl acrylate (2‐HEA) were synthesized with different composition ratios at 50:50 and 70:30 mol% using ammonium persulfate as free radical initiation system. The hydrogel was characterized by Fourier transform infrared spectroscopy (FTIR). The interpolymer complex between hydrogels and linear with poly(acrylic acid) (PAA) with different molecular weight was studied. The effect of pH, molecular weights, inorganic salt (NaCl) as well as surfactants concentrations on the complexation was investigated. The swelling behavior of the thermosensitive hydrogels in PAA solutions went up with increasing pH and molecular weight of PAA. However, the decreasing the concentration of surfactants sodium dodecyl sulfate (SDS) and cetylpyridinium bromide (CPB) increased the swelling behavior of hydrogels.

An advanced methodology of phase transition determination in aqueous solutions of thermo-sensitive polymers by using of the phase portraits method has been suggested. The methodology allows highly accurate determining the temperature when exactly a half of molecules loses solubility (from the maximum number that can go to another phase state under given conditions). It is shown that since phase transition passes usually in a wide enough temperature interval this indicator should be used as a quantitative parameter that characterizes phase transition process. Additionally the suggested methodology allows introducing one more quantitative parameter that reflects a sharpness of phase transition. The methodology is verified by an example of phase transitions study in aqueous solutions of thermo-sensitive copolymers based on N-vinylpyrrolidone and vinyl propyl ether.

New thermosensitive hydrogels based on N ‐isopropyl acrylamide and 2‐hydroxyethyl acrylate were prepared in the presence of ammonium persulfate as an initiator using a free‐radical technique. The thermal stability as well as the physical and chemical properties of the obtained hydrogel were studied by thermogravimetric analysis, differential scanning calorimetry and scanning electron microscopy. The swelling of the hydrogels was investigated by the cathetometer method. In order to use thermosensitive hydrogels as a carrier of antibiotics (lincomycin and gentamicin), several biological tests were performed. All samples of thermosensitive poly( N ‐isopropyl acrylamide) and 2‐hydroxyethyl acrylate hydrogels containing medical substances exhibited antibacterial activity. The antibacterial activity of temperature‐sensitive hydrogels naturally increases with increasing concentration of antibiotics in the carrier. The results obtained indicate a large amount of drug was released from the hydrogels with full retention of antimicrobial properties. These copolymers can be used as an antibacterial material in the field of medicine. © 2020 Society of Chemical Industry

The present study investigates the effect of blend copolymers on the physico-mechanical properties of mortar mixes. Blend copolymers were synthesized based on poly vinyl alcohol (PVA) and urea (U) in aqueous solution with different blend ratios 65/35, 50/50 and 35/65 respectively, using glacial acetic acid as crosslinking. Physico-mechanical properties of mortar examined included water/cement ratio, setting time, workability, water absorption and compressive strength. The addition of blend copolymers to the mortar affected the physico-mechanical properties of mortar mixes. As the content of PVA increases in the blend copolymers, the water of consistency decrease, whereas the setting times (initial & final) were shortened. The compressive strength of the hardened cement pastes was increased at all ages of hydration while water absorption decreased.