Glycerol-(9,10-trioxolane) trioleate (OTOA) is a promising material that combines good plasticizing properties for PLA with profound antimicrobial activity, which makes it suitable for application in state-of-the-art biomedical and packaging materials with added functionality. In this study, the biodegradation kinetics of PLA + OTOA mixed films under soil conditions was assessed over 180 days. Structural and morphological changes that occurred on the surface and in the volume of the films during degradation were scrutinized using DSC, X-ray diffraction, IR, and UV spectroscopy. Morphological changes were assessed using optical and confocal microscopes. The different behavior of the PLA + OTOA blend films during decomposition in soil is explained by their structure and the rate of release of antibacterial OTOA from the PLA matrix. The decomposition rate constants were determined for all films, where kd for PLA samples is 28 µm·year-1, for samples containing 10% and 30% OTOA kd is 2 µm·year-1, and for PLA + 50% OTOA samples kd = 34 µm·year-1. This is explained by changes in the structure and degree of crystallinity of materials during the process of aging in the soil. These results clarify the biodegradation processes of biomaterials containing antibacterial agents in their structure.

Ultrafine fibers from poly(3-hydroxybutyrate) (PHB) and polyvinylpyrrolidone (PVP) and their blends with different component ratios in the range of 0/100 to 100/0 wt.% were obtained, and their structure and dynamic properties were studied. The polymers were obtained via electrospinning in solution mode. The structure, morphology, and segmental dynamic behavior of the fibers were determined using optical microscopy, SEM, EPR, DSC, and IR spectroscopy. The low-temperature maximum on the DSC endotherms provided information on the state of the PVP hydrogen bond network, which made it possible to determine the enthalpies of thermal destruction of these bonds. The PHB/PVP fiber blend ratio significantly affected the structural and dynamic parameters of the system. Thus, at low concentrations of PVP (up to 9%) in the structure of ultra-fine fibers, the distribution of this polymer occurs in the form of tiny particles, which are crystallization centers, which causes a significant increase in the degree of crystallinity (χ) activation energy (Eact) and slowing down of molecular dynamics (τ). At higher concentrations of PVP, loose interphase layers were formed in the system, which caused a decrease in these parameters. The strongest changes in the concentration of hydrogen bonds occurred when PVP was added to the composition from 17 to 50%, which was due to the formation of intermolecular hydrogen bonds both in PVP and during the interaction of PVP and PHB. The diffusion coefficient of water vapor in the studied systems (D) decreased as the concentration of glassy PVP in the composition increased. The concentration of the radical decreased with an increase in the proportion of PVP, which can be explained by the glassy state of this polymer at room temperature. A characteristic point of the 50/50% mixture component ratio was found in the region where an inversion transition of PHB from a dispersion material to a dispersed medium was assumed. The conducted studies made it possible for the first time to conduct a comprehensive analysis of the effect of the component ratio on the structural and dynamic characteristics of the PHB/PVP fibrous material at the molecular scale.

Controlling traps and structural defects in perovskite absorber layers is crucial for enhancing both the device efficiency and long-term stability of perovskite solar cells (PSCs). Here we demonstrate the modification of perovskite films by introducing low-cost green polymers, polysuccinimide (PSI) and polyasparagine (PASP), into the perovskite layer. Structural, morphological and optoelectronic properties of polymer-modified perovskite films were probed by scanning electron microscopy (SEM), X-ray diffraction (XRD), Fourier transform infrared (FTIR) and UV-Vis spectroscopy. The incorporation of PSI triggers interactions between the polymer and perovskite, leading to the passivation of surface defects at the grain boundaries and improved morphology of perovskite films. This defect passivation boosted PSC performance, providing power conversion efficiency (PCE) values up to 20.1%. An optimal polymer concentration of 0.1 mg/mL in the perovskite precursor solution was identified for an improvement in the photovoltaic performance. It was shown that the primary factor leading to the observed enhancement in the power conversion efficiency for PSI-modified PSCs is the increase in the lifetime of charge carriers due to the efficient passivation of surface defects and suppression of recombination losses. Additionally, PSI-modified PSCs demonstrated enhanced stability, retaining over 80% of their initial efficiency after 40 days of storage under ambient conditions without encapsulation. The obtained results highlight the effectiveness of green polymer additives in passivating surface defects in perovskite films and provide a viable approach for improving the stability and performance of perovskite solar cells.

Fluorinated polyurethanes (FPUs) and their composites are promising new barrier materials with a broad range of applications. In particular, they are widely used as effective hydrophobic coatings that perform well under prolonged environmental exposure. Despite their extensive use, the behavior of FPU coatings under specific climatic conditions remains insufficiently studied. In this paper, dynamic mechanical analysis (DMA) is employed to evaluate the structural, mechanical, and relaxation evidence of climatic aging for paint-and-varnish coatings, which protect the surfaces of metallic alloys and polymer composites. Special knowledge of structural and physical-mechanical properties-such as a glass transition temperature (Tg), elastic moduli (E ' and E '') in both glassy and elastic states, degree of crosslinking, and other features relevant to coatings designated for climatic impact prevention-can be reliably obtained by the DMA technique. Along with previously published data, the currently obtained results for FPU have been analyzed for a long time (three years) of exposure in a wide range of climatic regions in Russia.

Glycerol-(9,10-trioxolane) trioleate (OTOA) is a promising material that combines good plasticizing properties for PLA with profound antimicrobial activity, which makes it suitable for application in state-of-the-art biomedical and packaging materials with added functionality. On the other hand, application of OTOA in PLA-based antibacterial materials is hindered by a lack of knowledge on kinetics of the OTOA release. In this work, the release of glycero-(9,10-trioxolane) trioleate (OTOA) from PLA films with 50% OTOA content was studied during incubation in normal saline solution, and for the first time, the kinetics of OTOA release from PLA film was evaluated. Morphological, thermal, structural and mechanical properties of the PLA + 50% OTOA films were studied during incubation in normal saline and corresponding OTOA release using differential scanning calorimetry (DSC), X-ray diffraction (XRD), Fourier-transform infrared (FTIR) spectroscopy and mechanical tests. It was confirmed by DSC and XRD that incubation in the saline solution and corresponding OTOA release from PLA film does not lead to significant changes in the structure of the polymer matrix. Thus, the formation of more disturbed α’ crystalline phase of PLA due to partial hydrolysis of amorphous zones and/or most unstable crystallites in the PLA/OTOA semi-crystalline structure was observed. The degree of crystallinity of PLA + OTOA film was also slightly increased at the prolonged stages of OTOA release. PLA + 50% OTOA film retained its strength properties after incubation in normal saline, with a slight increase in the elastic modulus and tensile strength, accompanied by a significant decrease in relative elongation at break. The obtained results showed that PLA + 50% OTOA film could be characterized by sustained OTOA release with the amount of released OTOA exceeding 50% of the initial content in the PLA film. The OTOA release profile was close to zero-order kinetics, which is beneficial in order to provide stable drug release pattern. Developed PLA + 50% OTOA films showed a strong and stable antibacterial effect against Raoultella terrigena and Escherichia coli, bacterial strains with multidrug resistance behavior. The resulting PLA + OTOA films could be used in a variety of biomedical and packaging applications, including wound dressings and antibacterial food packaging.

Поли-3-гидроксибутират (ПГБ) находит в настоящее время широко при- менение в медицине, биотехнологии, тканевой инженерии, травматологии, ор- топедии, упаковке и др. [1]. Этот полимер обладает уникальным комплексом функциональных свойств: биосовместимостью, гемосовместимостью, гипоал- лергенностью, биодеградацией в природе и живых системах, термопластич- ностью, высокими физико-механическими параметрами [2]. Однако ПГБ имеет некоторые недостатки, связанные с его умеренной гидрофобностью, определя- ющие его плохую смачиваемость водой и низкие диффузионно-транспортные характеристики [3].

Changes in fibrous and film materials based in mixtures of biodegradable polyesters of polyhydrobutyrate, polylactide, and chitosan polysaccharide were studied using structural-dynamic method EPR involving a stable nitroxyl radical—a TEMPO probe—during ozonolysis. The fibers and films were obtained from solutions in chloroform using methods of electroforming and pouring on glass, respectively. It was shown that lower density of packing in amorphous regions of the mixture samples determines an increased rate of their oxidation with ozone as compared with homopolymers. A two-stage kinetic mechanism of ozonolysis was demonstrated, which includes the formation of side groups and subsequent destruction of the polymer chain. It was established that the probe rotation activation energy depends on the amount of the polymer in the mixture, while the activation barrier is minimal for mixtures of polyesters in the same range of concentrations, where the constants of ozonolysis are maximal. It was shown that the presence of chitosan in ternary compositions leads to an increase in the degree and rate of ozonolysis.

Abstract—Nonwoven fibrous materials based on polylactide (PLA) and ozonide of oleic acid triglyceride (glycero-(9,10-trioxolane)-trialeate) in a range of concentrations of 1–5 wt

Abstract—The review presents publications devoted to a promising biopolymer, poly-3-hydroxybutyrate, and composite materials based on it. The structure and properties of the materials are considered. The main focus is on the biomedical application of these biopolymer materials. The main advantage of poly-3-hydroxybutyrate is its biodegradability in nature and living systems, biocompatibility, hemocompatibility, and thromboresistance. This biopolymer also possesses processability. The products and materials based on it can be processed by solution and melt production methods. The review pays great attention to the production of ultrathin fibers by electrospinning. Materials based on poly-3-hydroxybutyrate even now find wide application in medicine, hygiene, packaging, and ecology.

The product of ozonolysis, glycero-(9,10-trioxolane)-trioleate (ozonide of oleic acid triglyceride, [OTOA]), was incorporated into polylactic acid/polycaprolactone (PLA/PCL) blend films in the amount of 1, 5, 10, 20, 30 and 40% w/w. The morphological, mechanical, thermal and antibacterial properties of the biodegradable PLA/PCL films after the OTOA addition were studied. According to DSC and XRD data, the degree of crystallinity of the PLA/PCL + OTOA films showed a general decreasing trend with an increase in OTOA content. Thus, a significant decrease from 34.0% for the reference PLA/PCL film to 15.7% for the PLA/PCL + 40% OTOA film was established using DSC. Observed results could be explained by the plasticizing effect of OTOA. On the other hand, the PLA/PCL film with 20% OTOA does not follow this trend, showing an increase in crystallinity both via DSC (20.3%) and XRD (34.6%). OTOA molecules, acting as a plasticizer, reduce the entropic barrier for nuclei formation, leading to large number of PLA spherulites in the plasticized PLA/PCL matrix. In addition, OTOA molecules could decrease the local melt viscosity at the vicinity of the growing lamellae, leading to faster crystal growth. Morphological analysis showed that the structure of the films with an OTOA concentration above 20% drastically changed. Specifically, an interface between the PLA/PCL matrix and OTOA was formed, thereby forming a capsule with the embedded antibacterial agent. The moisture permeability of the resulting PLA/PCL + OTOA films decreased due to the formation of uniformly distributed hydrophobic amorphous zones that prevented water penetration. This architecture affects the tensile characteristics of the films: strength decreases to 5.6 MPa, elastic modulus E by 40%. The behavior of film elasticity is associated with the redistribution of amorphous regions in the matrix. Additionally, PLA/PCL + OTOA films with 20, 30 and 40% of OTOA showed good antibacterial properties on Pseudomonas aeruginosa, Raoultella terrigena (Klebsiella terrigena) and Agrobacterium tumefaciens, making the developed films potentially promising materials for wound-dressing applications.

Antibiotic resistance of pathogens is among the major concerns in various medical applications. Therefore, the search for the novel antimicrobial agents that could prevent pathogen’s resistance, while maintaining efficient treatment, is one of the most important issues for biomedicine nowadays. One of the relevant methods for the development of functional non-woven materials possessing antimicrobial properties is the use of ozone and ozonolysis products for the modification of fibrous materials. This approach has recently attracted both academic and industrial interest and has found various biomedical applications. Several methods providing antimicrobial properties to textiles using ozone or ozonolysis products were proposed, including encapsulation and/or direct introduction of ozone-generated antimicrobial agents into the fibrous polymer matrix and ozone treatment of non-woven fiber materials. For the latter, the ozonolysis products are uniformly distributed predominantly on the polymer surface but could be also formed inside the polymer bulk due to ozone diffusion through the amorphous areas or defects. It was found that ozone modification of fibrous materials could lead to increase in hydrophilicity and improvement in their functional properties (smoothness, elasticity, strength, antimicrobial activity). In this chapter, various aspects of ozone modification of non-woven fiber materials for biomedical applications are reported and discussed.

1, 1, 4, 4, 1 1 Федеральное государственное бюджетное учреждение науки Федеральный исследовательский центр химической физики им. Н. Н. Семенова Российской академии наук 2 Российский экономический университет им. Г. В. Плеханова 3 Институт биохимической физики им. Н. М. Эмануэля Российской академии наук 4 Российский университет дружбы народов Тип: статья в сборнике трудов конференции Язык: русский Год издания: 2024 Страницы:

The porosity of fibrillar scaffolds plays a pivotal role in the regeneration of living tissue, significantly influencing cell spreading, proliferation, and differentiation, thereby impacting the overall efficiency of regenerative processes. A genuine fibrillar scaffold comprises fibers and pores of diverse sizes and scales. The interconnectivity of the fiber network is intrinsically linked to its mechanical properties. When the scaffold material exhibits piezoelectric characteristics, the application of an electric field to enhance regeneration induces microelectromechanical movement among the fibers, both in relation to one another and in alignment with the applied field. This results in alterations to the connectivity parameters of the network, with notable fluctuations in the distances between electroactive fibers and pore sizes. Consequently, the pathways for signal transduction within the piezoelectric scaffold adapt according to changes in the equivalent circuits of the network. Therefore, a straightforward mathematical approach (time-resolved) is essential for assessing field-induced variations in interfilament distances, network connectivity parameters, and the orientation of fiber ensembles composed of various filaments. This extends to the formation of multiscale networks and tree-like structures with lateral branches for signal routing, which is critical for the engineering and optimization of electroactive scaffolds. We propose employing multifractal analysis for this purpose. We recommend utilizing the multifractal spectra parameters D(q) and f(α), while advising against direct analysis of the scaling behavior for the dynamics of fiber structures for scaffold engineering applications.

Electrospun ultrathin fibers based on binary compositions of polylactide (PLA) and poly(ε-caprolactone) (PCL) with the various content from the polymer ratio from 0/100 to 100/0 have been explored. Combining thermal (DSC) and spectropy (ESR) techniques, the effect of biopolymer content on the characteristics of the crystal structure of PLA and PCL and the rotative diffusion of the stable TEMPO radical in the intercrystallite areas of PLA/PCL compositions was shown. It was revealed that after PLA and PCL blending, significant changes in the degree of crystallinity of PLA, PCL segment mobility, sorption of the Tempo probe, as well as its activation energy of rotation in the intercrystalline areas of PLA/PCL fibers, were evaluated. The characteristic region of biopolymers’ composition from 50/50 to 30/70% PLA/PCL blend ratio was found, where the inversion transition of PLA from dispersive medium to dispersive phase where an inversion transition is assumed when the continuous medium of the PLA transforms into a discrete phase. The performed studies made it possible, firstly, to carry out a detailed study of the effect of the system component ratio on the structural and dynamic characteristics of the PLA/PCL film material at the molecular level.

In our study, we investigated the accelerated aging process of PLA under 253.7 nm UV-C irradiation with the use of the GPC, NMR, FTIR, and DSC methods and formal kinetic analysis. The results of GPC and DSC indicated a significant degree of destructive changes in the PLA macromolecules, while spectroscopic methods NMR and FTIR showed maintenance of the PLA main structural elements even after a long time of UV exposure. In addition to that, the GPC method displayed the formation of a high molecular weight fraction starting from 24 h of irradiation, and an increase in its content after 144 h of irradiation. It has been shown for the first time that a distinctive feature of prolonged UV exposure is the occurrence of intra- and intermolecular radical recombination reactions, leading to the formation of a high molecular weight fraction of PLA decomposition products. This causes the observed slowdown of the photolysis process. It was concluded that photolysis of PLA is a complex physicochemical process, the mechanism of which depends on morphological changes in the solid phase of the polymer under UV radiation.

Silver-based metal–organic decomposition inks composed of silver salts, complexing agents and volatile solvents are now the subject of much research due to the simplicity and variability of their preparation, their high stability and their relatively low sintering temperature. The use of this type of ink in inkjet printing allows for improved cost-effective and environmentally friendly technology for the production of electrical devices, including flexible electronics. An approach to producing a silver salt-based reactive ink for jet printing has been developed. The test images were printed with an inkjet printer onto polyimide substrates, and two-stage thermal sintering was carried out at temperatures of 60 °C and 100–180 °C. The structure and electrical properties of the obtained conductive lines were investigated. As a result, under optimal conditions an electrically conductive film with low surface resistance of approximately 3 Ω/square can be formed.

Проблема загрязнения окружающей среды промышленными отходами и бытовым мусором привела к необходимости создания новых материалов, спо- собных разлагаться под действием окружающей среды на безвредные для при- роды вещества. В этой связи разработка полимерных композиций на основе по- лимеров природного происхождения становится в настоящее время все более актуальной. Особый интерес представляют синтезируемые из природного сырья, соответственно химическим и микробиологическим путем, алифатиче- ские полиэфиры полилактид (ПЛА) и полигидроксибутират (ПГБ).