Oksana Tarasyuk

New hydroxyl-functionalized aromatic sulfonamide, N-butyl-4-(3-hydroxypropylamino)benzenesulfonamide (BHPA-BSA), has been synthesized and tested as potential plasticizer for polyamide 12 (PA-12). According to results of quantum-chemical calculations, BHPA-BSA has a higher binding energy with the monomer unit of PA-12 compared to commercial plasticizers N-butylbenzenesulfonamide (BBSA) and N-(3-hydroxypropyl)benzenesulfonamide (HP-BSA). Specific combination of the sulfonamide and hydroxyalkyl groups in BHPA-BSA allows the formation of two hydrogen bonds with the amide group of PA-12 through one of the sulfonamide’s oxygen atom as a hydrogen bond acceptor and hydroxyl group as a hydrogen bond donor. PA-12 films containing 15 and 20 wt% BHPA-BSA or commercial plasticizers have been prepared by compression moulding. IR analysis revealed that both sulfonamide and hydroxyl groups of BHPA-BSA participate in the hydrogen bonding with the amide group of PA-12. Differential scanning calorimetry show that the new sulfonamide lowers the glass transition temperature of PA-12 by more than 40 °C, indicating a plasticizing effect comparable to common plasticizers. The results of dynamic mechanical analysis also revealed the high plasticizing efficacy of BHPA-BSA toward PA-12, which is manifested in the twofold reduction in the storage modulus of the polymer.The volatility of the BHPA-BSA from the PA-12 matrix at 120 °C is five times lower than that of commercial plasticizers. Moreover, the new sulfonamide exhibits excellent resistance to release in hexane, in contrast to BBSA and HP-BSA. Thus, the functionalization of BBSA with the hydroxyalkyl group is an efficient approach to synthesize new low-volatility plasticizers for polyamide resins.

Синтезовано довголанцюговий біологічно активний естер 4-гідроксибензойної кислоти – додецил-4-гідроксибензоат (ДГБ). Отримано композиційні полімерні плівки на основі поліаміду 12 (ПА-12), які містять 25 масових відсотків ДГБ. Методом диференційної сканувальної калориметрії встановлено, що ДГБ знижує температуру склування ПА-12 від 46 до -25 °С і температуру плавлення від 178 до 168 °С. Це свідчить про високу ефективність сполуки як пластифікатора для ПА-12. Згідно з результатами термогравіметричного аналізу, полімерна композиція ПА-12/ДГБ має температуру початку деструкції 324 °С і є термічно стійкою в області температур промислової переробки ПА-12 (220-300 °С). ДГБ є перспективною поліфункціональною модифікуючою домішкою до поліамідів технічного і медичного призначення, яка може суттєво підвищувати гнучність полімерних виробів і надавати їм антимікробних властивостей.

Long-chain imidazolium-based ionic liquids (ILs) possess a broad-spectrum biological activity and are considered promising antifouling agents for protective coatings. A new hydrophobic IL, 1-dodecyl-3-methylimidazolium dodecylbenzenesulfonate (C₁₂C₁IM-DBS), has been synthesized, and a modified epoxy coating material containing 10, 20, and 30 wt% of this IL was prepared by dissolution of C₁₂C₁IM-DBS in commercial DER 331 epoxy resin, followed by a curing phase with diethylenetriamine. Infrared analysis revealed physicochemical interactions between the hydroxyl groups of the resin and the IL. Spectrophotometric studies showed no release of C₁₂C₁IM-DBS after 30 days of exposure of the modified coatings to water. The plasticizing effect of the IL on the epoxy resin was established by differential scanning calorimetry analysis. The introduction of 10 and 20% C₁₂C₁IM-DBS into DER 331 reduced its glass transition temperature from 122.8 °C to 109.3 and 91.5 °C, respectively. The hardness of epoxy resin decreased by approximately 26% after the introduction of the IL. Moreover, DER 331/C₁₂C₁IM-DBS coatings on steel substrates showed significantly improved impact resistance compared to neat resin. The antibiofilm efficiency of DER 331/C₁₂C₁IM-DBS coatings was evaluated by assessing the capability of two biofilm-forming model strains, Staphylococcus aureus ATCC 25923 and Pseudomonas aeruginosa PA01, to form attached biofilms on the surface. The IL effectively inhibited S. aureus surface-associated biofilm development even at the lowest content of 10%. On the contrary, an approximately 50% inhibition of biofilm metabolic activity was detected for DER 331/C₁₂C₁IM-DBS coatings containing 20% and 30% of the IL. Overall, the results of this study indicate that the hydrophobic IL C₁₂C₁IM-DBS is an efficient modifying additive for epoxy resins, which can significantly improve their operational properties for various industrial applications.

Ester-functionalized long-chain pyridinium salt 1-(2-(dodecyloxy)-2-oxoethyl)pyridin-1-ium chloride (1b) has been synthesized. The influence of the substance on morpho-physiological traits of wheat seedlings (germination, shoot and root length and biomass, chlorophylls and carotenoids content, as well as flavonoid content) has been studied. The germination of seeds increased after their exposure to water solutions of pyridinium chloride 1b in the concentration range 0.001-0.1%. However, the concentration 0.1% has a negative effect on plant growth leading to reduced growth parameters in shoots and roots, plant mass, as well as pigments content. The exposure of wheat seeds to water solutions of pyridinium salt with lower concentrations (especially at 0.001%) significantly increased shoot and root length, as well as wet green mass in 7-day-old seedlings. At a concentration of 0.01%, the substance caused a significant increase of chlorophyll a, chlorophyll b, and carotenoids content thus revealing a positive effect on the photosynthetic apparatus of plant leaves. The flavonoid content in a green part of the plants also significantly increased which may indicate activating the plant defense system under mild stress conditions. The high growth-promoting effect of long-chain pyridinium chloride 1b on wheat plants, together with its broad range of antimicrobial activity and biodegradability, makes it an attractive product for various agrochemical applications

A new proton conducting membrane has been developed by impregnation of porous polyimide Matrimid® (PI) with hydrophobic protic ionic liquid triethylammonium bis(trifluoromethylsulfonyl)imide (TEA‐TFSI). According to the results of dynamic mechanical analysis (DMA), PI/TEA‐TFSI membrane has satisfactory viscoelastic properties in the temperature range 25–100°C. However, the sharp drop in storage modulus (E') occurs at higher temperatures that is probably caused by the plasticizing effect of ionic liquid. To improve the mechanical properties of PI matrix, it was impregnated with the solution of polyetheramine Jeffamine® D‐400 in the TEA‐TFSI. This approach allowed to obtain a partially cross‐linked PI which is more resistant to deformation at elevated temperatures. Thus, DMA study revealed a storage modulus around 400 MPa for PI/Jeffamine/TEA‐TFSI membrane up to 150°C, like neat porous Matrimid®. Thermogravimetric analysis results indicate high thermal stability of PI/Jeffamine/TEA‐TFSI composite with thermal degradation point of 343°C. The ionic conductivity of the composite membrane is 4·10⁻³ S/cm at room temperature and reaches the level of 10⁻² S/cm above 100°C. Overall, the results of this study indicate that partially cross‐linked porous PI impregnated with hydrophobic protic ionic liquid is a promising polymer electrolyte membrane for fuel cells operating at elevated temperatures in water‐free conditions.

New proton exchange membrane based on polyimide Matrimid® (PI) and hydrophobic protic ionic liquid, 1-methylimidazolium bis(trifluoromethylsulfonyl)imide (MIM-TFSI), has been prepared by casting from methylene chloride/dimethylformamide solution. Infrared analysis revealed physicochemical interactions between 1-methylimidazolium cations and imide groups of PI. The results of mechanical testing indicate significantly reduced tensile strength of PI/MIM-TFSI composite membrane compared to neat polymer. Moreover, the dynamical mechanical analysis results revealed sharp drop in storage modulus (E´) of the polymer film above 60 °C. To improve the elastic properties of the membrane, PI was successively cross-linked with polyetheramine Jeffamine® D-2000 (10 mol. %) in methylene chloride/dimethylformamide solution, as well as in solid film at 100 °C. This approach allowed to prepare PI/Jeffamine/MIM-TFSI (70 wt. %) composite film which has an acceptable E' value of 210 MPa at 140 °C. According to thermal gravimetric analysis data, PI/Jeffamine/MIM-TFSI composite has a thermal degradation point (i.e. 5 % weight loss) of 286 °C. The ionic conductivity of PI/Jeffamine/MIM-TFSI composite membrane is around 10–4 S/cm at room temperature and reaches the minimal level of 10–3 S/cm, required for fuel cell applications, above 100 °C. Overall, the results of this study indicate that the cross-linking of polyimide Matrimid with flexible polyetheramine Jeffamine is an efficient approach for preparing dense composite membrane with high content of the protic ionic liquid. Such polymer-electrolyte membrane has the reasonable combination of good stiffness, thermal stability, and ionic conductivity and therefore is a promising candidate for use in fuel cells operating at elevated temperatures in water-free conditions.

The choice of effective biocides used for routine hospital practice should consider the role of disinfectants in the maintenance and development of local resistome and how they might affect antibiotic resistance gene transfer within the hospital microbial population. Currently, there is little understanding of how different biocides contribute to eDNA release that may contribute to gene transfer and subsequent environmental retention. Here, we investigated how different biocides affect the release of eDNA from mature biofilms of two opportunistic model strains Pseudomonas aeruginosa ATCC 27853 (PA) and Staphylococcus aureus ATCC 25923 (SA) and contribute to the hospital resistome in the form of surface and water contaminants and dust particles. The effect of four groups of biocides, alcohols, hydrogen peroxide, quaternary ammonium compounds, and the polymeric biocide polyhexamethylene guanidine hydrochloride (PHMG-Cl), was evaluated using PA and SA biofilms. Most biocides, except for PHMG-Cl and 70% ethanol, caused substantial eDNA release, and PHMG-Cl was found to block biofilm development when used at concentrations of 0.5% and 0.1%. This might be associated with the formation of DNA–PHMG-Cl complexes as PHMG-Cl is predicted to bind to AT base pairs by molecular docking assays. PHMG-Cl was found to bind high-molecular DNA and plasmid DNA and continued to inactivate DNA on surfaces even after 4 weeks. PHMG-Cl also effectively inactivated biofilm-associated antibiotic resistance gene eDNA released by a pan-drug-resistant Klebsiella strain, which demonstrates the potential of a polymeric biocide as a new surface-active agent to combat the spread of antibiotic resistance in hospital settings.

Guanidine salts are promising proton conductors due to the high content of dissociable protons in guanidinium cation that ensure an efficient proton transfer along hydrogen-bonded network formed by proton donor and proton acceptor sites. However, the high melting point of most guanidine salts is a serious drawback for their application as proton conducting electrolytes. Reducing the symmetry of guanidinium cations by the substitution of hydrogen atoms on alkyl radicals reduces the melting points but also leads to decreased proton conductivity. In this study, monosubstituted guanidine salt, N-butylguanidinium bis(trifluoromethylsulfonyl)imide (BG-TFSI), has been synthesized by a simple two-step method. It is water immiscible room temperature protic ionic liquid. The structure of BG-TFSI was confirmed by nuclear magnetic resonance spectroscopy, as well as infrared spectroscopy. According to thermal gravimetric analysis data, the ionic liquid has the thermal degradation point (5% weight loss) of 348 °C which indicates its excellent thermal stability for use in high-temperature fuel cells. The ionic conductivity of BG-TFSI determined by the electrochemical impedance method was found to be 9·10-4 S/cm at room temperature. This value increased by almost one order of magnitude above 100 °C thus reaching an acceptable level for use in fuel cells. The activation energy Ea calculated from the Arrhenius plot for BG-TFSI is found to be 16.4 kJ/mol which is similar to those reported for other guanidine salts. Based on the obtained results one can assume that the proton transport in BG-TFSI is dominated by Grotthus-type (hopping) mechanism. The results of this study indicated that BG-TFSI is a promising proton conducting electrolyte for fuel cells operating at elevated temperatures in water-free conditions. The hydrophobicity of the ionic liquid is an important advantage since it can prevent its leaching from the polymer electrolyte membrane during the operation of a fuel cell.

Aim. To study the effect of polymeric biocide polyhexamethylene guanidine hydrochloride (PHMG-Cl) on morphophysiological and biochemical parameters of wheat seedlings in the presence of toxic concentration of copper ions. Methods. The growth-stimulating activity of PHMG-Cl in pure state, as well as in the presence of elevated concentrations of copper ions was studied by phytotesting method using wheat seed as a test culture. Physico-chemical interaction between PHMG-Cl and CuSO4 in water solutions was studied by spectrophotometry. Results. Wheat seed treatment with water solutions of polymeric biocide PHMG-Cl in the concentration range of 0.01–0.1 % causes an increase in the length of roots and shoots by over 50 % after 7 days of incubation. The concentration of PHMG-Cl of 1 % was found to have a depressive effect on growth characteristics of the tested plants. This fact indicates that the phytotoxicity of PHMG-Cl is at least two orders of magnitude lower compared with a common pesticide copper sulfate. Thus, wheat seed soaking in 200 μM (0.003 %) water solution of copper sulfate causes reduced length of shoots and roots (by 65 and 34 %, respectively), as well as reduced weight of shoots (by 20 %) and roots (by 74 %) The analysis of green mass showed signifi cantly reduced content of carotenoids (by 26 %) and water soluble fl avonoids (by 37 %), as well as chlorophyll a/b ratio (by 18 %) that indicates decreased plant metabolic activity. However, the toxic effect of copper sulfate ions signifi cantly diminished in the presence of PHMG-Cl (0.01 %). Thus, the length of shoots and roots was found to increase by 24 and 64 %, respectively, compared to the samples treated with CuSO4. Moreover, the content of pigments and fl avonoids in the green mass of seedlings reached the level of control samples. The results of spectrophotometric studies indicate the absence of physico-chemical interaction between PHMG-Cl and copper sulfate in water solutions. Conclusions. The polymeric biocide PHMG-Cl effectively stimulates growth and development of wheat seedlings in the concentration range of its water solutions of 0.01–0.1 %. In the presence of toxic copper sulfate concentration, PHMG-Cl does not possess the growth stimulating activity. However, the polymeric biocide signifi cantly improves copper stress resistance of plants, and normalizes their morpho-physiological indicators, photosynthetic characteristics and secondary exchange.

Four water insoluble room-temperature protic ionic liquids (PILs) based on the N-alkylimidazolium cation with the alkyl chain length from 1 to 4 and bis(trifluoromethylsulfonyl)imide anion were synthesized and their chemical structure was confirmed by the ¹H NMR and ¹⁹F NMR analysis. PILs were revealed to be thermally stable up to 360 and 400 °C. At the same time, the proton conductivity of PILs was found to be dependent mostly on the temperature and, to a less extent, on the type of the cation, i.e., the increase of the conductivity from ~3 × 10⁻⁴ S/cm at 25 °C to 2 × 10⁻² S/cm at 150 °C was observed. The water vapour sorption capacity of PILs was evaluated as a function of relative humidity and the influence of the alkyl chain length on the phase behaviour in the PIL-water system was discussed. The composite polyimide/PILs membranes were prepared by the PIL immobilization in the porous polymer (Matrimid^® 5218) film. The composite membranes showed a high level of proton conductivity (~10⁻³ S/cm) at elevated temperatures (up to 160 °C). The obtained results reveal that the elaborated composite polyimide/PIL membranes are promising candidates for the application as proton exchange membrane at middle and high temperatures.