This study examines the nature of enzymatic degradation of polyethylene terephthalate (PET) films mediated by a novel recombinant LCCICCG PETase enzyme preparation based on P. verruculosum fungus. The investigation was conducted using amorphous PET samples and PET samples with varying degrees of crystallinity as substrates for PETase-catalyzed hydrolysis under different temperature and pH conditions. Mechanical testing revealed that enzymatic treatment reduced the yield stress by 20-25%, tensile strength by approximately twofold, and elongation at break by 5-10 times, while the deformation mechanism remained unchanged. Enzymatic degradation under acidic conditions was ineffective, whereas increasing the pH to 9-10 markedly accelerated PET degradation and the associated deterioration of mechanical properties. Thermal analysis (TGA, DSC) and microscopy (optical and scanning electron microscopy) demonstrated that degradation was localized at the polymer surface, leading to the formation of cavities, cracks, and submicron-sized pores rather than bulk material disintegration. An inverse correlation was observed between PET crystallinity and susceptibility to enzymatic degradation: samples with crystallinity below 13% could be almost completely degraded, whereas samples with crystallinity above 30% exhibited little or no measurable weight loss over the same period. Low-crystallinity PET underwent rapid degradation accompanied by a transient increase in crystallinity, while highly crystalline PET primarily accumulated surface defects that nevertheless caused a substantial loss of mechanical strength. Consequently, the experimental data obtained in this study provide useful information for understanding PET degradation and for future studies on enzymatic PET recycling. The systematization of feedstock characteristics and the elucidated patterns of enzymatic degradation will enable optimization of pretreatment, enzymatic hydrolysis, and monomer recovery process parameters, thereby facilitating the eventual production of secondary raw materials.

An environmentally friendly method for introducing a hydrophobic pyrene dye into polylactide and polycaprolactone matrices structurally modified through the crazing mechanism has been developed. This method utilizes aqueous dispersions of poly(ethylene glycol) methyl ether-block-poly(D,l-lactide) micelles as dye carriers. The resulting pyrene-containing polymeric materials exhibit fluorescence under UV radiation and have the required mechanical and surface properties.

A series of novel functional polycarbonates, specifically poly(solketal glycidyl ether carbonate-co-propylene carbonate)s with varying compositions, were synthesized through the ring-opening copolymerization of solketal glycidyl ether, propylene oxide, and carbon dioxide. The reaction was catalyzed by rac-(salcy)CoIIIX complexes with bis(triphenylphosphine)iminium salts as co-catalysts, achieving high selectivity. The resulting terpolymers exhibited number-average molecular weights ranging from 2 × 104 to 1 × 105 and a narrow, bimodal molecular weight distribution, with dispersities of 1.02–1.07 for each mode. Interestingly, the addition of a small amount of water to the reaction mixture yielded a terpolymer with a unimodal molecular weight distribution and a dispersity of 1.11. Subsequent acidic hydrolysis of the solketal protective groups produced poly(glyceryl glycerol carbonate-co-propylene carbonate). All terpolymers were amorphous, with Tg near or below room temperature. The hydroxyl-functional polycarbonates underwent cyclodepolymerization under milder conditions compared to polycarbonates with protected hydroxyl groups.

The effectiveness of single-layer actuators based on polymer matrix with branched networks of stimulus-sensitive component is proposed and approved. The study is performed for humidity-driven actuators with polar liquid adsorbing filler. The actuators are produced using a delocalized crazing mechanism to create an interpenetrating pore structure, in which silica gel is formed from ethyl silicate during hydrolysis. The actuator bends towards a lower humidity side and demonstrates a strong response to humidity changes within a few seconds. The enhanced performance of the actuator is realized by adjusting the pore structure and the filler content. The dependencies of the curvature of the bent film and the response time to a humidity change on filler content, show a non-monotonic behavior with a maximum and minimum, respectively. With a solvent polarity increase, the curvature firstly increases and then reaches a plateau. The theory is developed to describe the actuator response to variations in humidity, filler content, crazing strain, temperature. The obtained actuators maintain the initial bending properties for more than 100 cycles and reach the curvature of 2.9 cm-1 at the crazing strain of 200 % and the SiO2-content of approximately 40 wt%. The theoretical model includes a derivation of the free energylike potential within non-equilibrium thermodynamics for steady-state processes, a calculation of the Young's modulus of the actuator based on series-parallel schemes, similar to the Takayanagi model, and the percolation theory. The model parameters are obtained by fitting of theoretical dependencies to the experimental data. The theory and experiment are in quantitative agreement.

Bone tissue restoration requires biomaterials, which combine osteoinductivity and the capability to prevent surgical site infections. Magnesium-substituted biphasic calcium phosphate (Mg-BCP) represents a promising solution, as magnesium substitution increases the biodegradation rate of calcium phosphate ceramics and provides inherent antibacterial properties. This study aimed to achieve wet precipitation synthesis of magnesium-substituted (1–10 mol%) biphasic calcium phosphate and to evaluate its drug delivery potential and antibacterial performance. Porous Mg-BCP granules were fabricated via the gelation of Mg-BCP suspension in sodium alginate followed by polymer removal. Drug delivery potential was evaluated using methylene blue as a model compound, with methylcellulose encapsulation implemented to ensure prolonged release. Magnesium content directly ruled the phase composition: low concentrations (1%) favored hydroxyapatite phase prevalence, while higher concentrations led to the β-tricalcium phosphate formation. Further assessment of drug delivery potential revealed that direct drug loading resulted in burst release, whereas methylcellulose encapsulation successfully enabled prolonged drug delivery. Mg-5BCP formulation demonstrated significant antimicrobial activity with growth inhibition of 17.7 ± 4.1% against C. albicans, 20.8 ± 7.0% against E. faecalis, and 12.9 ± 7.5% against E. coli. Therefore, Mg-5BCP–methylcellulose composite granules present a versatile platform for antibacterial drug delivery for bone tissue engineering applications.

Распространенным подходом к созданию антимикробных полимерных материалов является распределение бактерицидной добавки в объеме материала путем смешения в растворе или расплаве полимера. В работе предложен способ введения сульфата меди (II), обладающего противомикробными свойствами, в пленку из полимолочной кислоты путем силовой импрегнации раствора соли по механизму крейзинга. Установлено, что CuSO4 равномерно распределяется в объеме полимера в виде частиц размером порядка 100 нм. В процессе структурной модификации поверхность полимерной пленки становится более шероховатой и более гидрофобной. Краевой угол смачивания водой увеличивается с 40° до 60–65°. Введение CuSO4 не влияет на поверхностные свойства, но оказывает армирующий эффект на полимерную матрицу при испытаниях на растяжение (увеличение прочности при разрыве в 2.5 раза, относительного удлинения при разрыве в 1.4 раза).

The simple approach of increasing the elastic properties of atactic poly(propylene carbonate) (PPC) with Mn = 71.4 kDa, ĐM = Mw/Mn = 1.86, and predominantly carbonate units (>99%) is suggested by selecting the appropriate hot pressing temperature for PPC between 110 and 140 °C. Atactic PPC is synthesized through ring-opening copolymerization of (rac)-propylene oxide and CO2 mediated by racemic salen complex of Co(III). Hot pressing PPC results in the release of a small amount of propylene carbonate (PC), sufficient to lower the glass transition temperature from 39.4 to 26.1 °C. Consequently, increasing the pressing temperature from 110 to 140 °C generates materials with a reduced modulus of elasticity (from 1.94 to 0.09 GPa), yield strength (from 38 to 2 MPa) and increased tensile elongation (from 140 to 940%). Thermomechanical analysis has shown a significant expansion in sample volume by hundreds of percent within the 80–130 °C range. PPC also displays large, reversible deformations, which can be utilized by creating shape memory materials.

The common approach to creating antimicrobial polymer materials is the distribution of a bactericidal additive in a material by mixing the additive with a solution or a melt of the polymer. This work proposes the method introducing of copper(II) sulfate, which has antimicrobial properties, into a poly(lactic acid) film by forced impregnation of a salt solution via the crazing mechanism. CuSO4 has been found to be uniformly distributed in the bulk of the polymer in the form of particles with sizes of about 100 nm. In the course of the structural modification, the surface of the polymer film becomes rougher and more hydrophobic. The water contact angle increases from 40° to 60°–65°. The incorporation of CuSO4 does not affect the surface properties but has a reinforcing effect on the polymer matrix as is evident from tensile tests (strength and elongation at break increase by 2.5 and 1.4 times, respectively).

The racemic salen complex of cobalt(iii) with pentafluorobenzoate axial ligand provides the synthesis of high molecular weight amorphous polypropylene carbonate and its full conversion into propylene carbonate.

The increasing use of synthetic biodegradable polymers, such as aliphatic polyesters, has led to a greater need to understand their behavior in an end-of-life scenario as food packaging materials. The aim of this work was to investigate the effect on composting of high to 10 wt% concentration of commercial polylactide packaging in food waste during a 98-day pilot-scale test. Members of the genera Bacillus, Geobacillus, Caldibacillus, Compostibacillus, Novibacillus, Planifilum and Aeribacillus accounted for 77 % of the bacterial community at the initial stage. Significant fragmentation of the polylactide packaging was observed after 14 days, and the appearance of low-molecular weight (approximately 5.4 kDa) hydrolytic degradation products led to an increase in biodiversity and a prolongation of the thermophilic stage by 12 days. The results obtained show the possibility of efficient disposal of food waste with high concentration of polylactide packaging under industrial composting conditions.

Powders of copper-, zinc-, manganese-substituted tricalcium phosphates (TCP) are synthesized; the composition and structure of the obtained compounds are studied. It is shown how copper, zinc, and manganese ions affect the phase composition and microstructure of substituted TCP powders. Composite materials based on a blend of polyvinylpyrrolidone with alginate (PVP:ALG) containing copper-, zinc-, and manganese-substituted TCP have been obtained. The thermal stability and mechanical strength of composite films crosslinked with polyvalent metal ions have been studied. The least strong, but at the same time more thermally stable, are composites crosslinked with alkaline earth metal ions. The test for cytotoxicity of extracts of the substituted TCP powders and composites has shown that the powders and composite materials with them are nontoxic and biocompatible. The study of the antibacterial activity of the materials against the Escherichia coli C600 strain has demonstrated that the growth of bacteria was inhibited by the samples co-ntaining copper-TCP and zinc-TCP. The composite with manganese-TCP showed no activity against Escherichia coli C600. The composites based on the PVP:ALG blend with copper- and zinc-substituted TCP can be considered as materials with an antibacterial effect to be used in medicine.

In this study, approaches to the synthesis of complex compound of gold with cysteine [AuCys]n for measuring absorbed dose in boron neutron capture therapy (BNCT) were developed. The dependence of the complex particle size on pH were established. Nanocomposite materials based on polylactide containing [AuCys]n particles with an average size of about 20 nm were obtained using the crazing mechanism. The structure of obtained materials was studied by electron microscopy. The release kinetics of [AuCys]n from polymer matrix were investigated. Release of [AuCys]n from the volume of the polymeric matrix had a delayed start-this process began only after 24 h and was characterized by an effective rate constant of 1 μg/h from a 20 mg composite sample. At the same time, in vitro studies showed that the concentration of 6.25 μg/mL was reliably safe and did not reduce the survival of U251 and SW-620 cells.

The study of the effect of iodine on the degradation of poly(ε-caprolactone) fibers has revealed a drastic decrease in their molecular weight upon 24 h exposure to a 10% iodine solution in ethanol. It has been assumed that the main mechanism of this degradation is alcoholysis which proceeds with an efficient rate constant of nearly 7.5 × 10–3 h–1

The degradation of polylactide (PLA) films of different structures under conditions of controlled composting has been studied. We have demonstrated that PLA underwent degradation within one month in a substrate that simulated standard industrial composting. Regardless of the initial structure of the samples, the number-average molecular weight (Mn) decreased to 4 kDa while the degree of crystallinity increased to about 70% after 21 days of composting. Addition of an inoculant to the standard substrate resulted in the accelerated degradation of the PLA samples for one week due to an abiotic hydrolysis. These findings have confirmed that industrial composting could solve the problem of plastic disposal at least for PLA.

Approaches to the synthesis of a drug for photon-capture therapy based on the complex compound of gold with cysteine [Au(I)-Cys]n have been developed. The dependence of the particle sizes of the complex on pH was established. Using the crazing mechanism, nanocomposite materials based on polylactide and containing [Au(I)-Cys]n particles with an average size of about 10 nm were obtained. The obtained materials were studied using electron microscopy and their structure was established.

Microorganisms of the genus Bacillus were shown to have different effects on the degradation of polylactide packaging material. The degradation experiment was carried out on an agar medium at a temperature of 55°C and pH 5.9 for 14 days. This is the first report on the abiotic hydrolysis significantly slowing down during incubation with B. licheniformis S8 and occurring in parallel with the main process, enzymatic hydrolysis. The latter involved sequential cleavage of monomer units from the end of the macromolecule and the formation of low molecular weight products used by microorganisms as a substrate; it contributed to a decrease in the mass of polylactide by 5.1

A nanocomposite based on high-density polyethylene with barium titanate (content of 13 – 15 wt. %) was obtained as a result of low-temperature synthesis of the inorganic component directly in the mesopores of an oriented polymer matrix using the sol-gel method followed by hydrothermal treatment in an alkaline medium. Crystallization of barium titanate in nanopores is detected by X-ray phase analysis and electron microscopy to occur mainly in a cubic crystalline modification with an average crystallite size of 16 nm and to form chain structures. A comparative assessment of the dielectric properties of a polymer nanocomposite and powder barium titanate synthesized under similar conditions is carried out.

A number of materials based on biocompatible polymers (polyvinylpyrrolidone and sodium alginate) with hydroxyapatite and dicalcium phosphate dihydrate were developed. The properties of prepared materials were studied by IR and EPR spectroscopies depending on the composition and method of synthesis of calcium phosphates. The introduction of calcium phosphates into the polymer matrix was found to decrease the material porosity from 60–70 to 40–45 vol.% and to decrease the material swelling from 250 to 150%. The results of EPR spectroscopy showed that polyvinylpyrrolidone does not affect the calcium phosphates formation in the synthesis of calcium phosphates in situ. In vitro studies suggest that a composition containing polyvinylpyrrolidone and sodium alginate in a ratio of 1 : 1 obtained ex situ is preferable in connection with its good biocompartability and an absence of cytotoxicity. This material is promising for the application in medicine.

The main problem associated with the use of polylactides (PLAs) in various fields is the requirement for their controlled degradation in the composition of waste. However, the possibilities of biodegradation of PLAs have not been sufficiently studied. It is assumed that microorganisms can decompose a polymer only after its preliminary chemical hydrolysis and reduction of its molecular weight to 10 000 and less. This review examines the influence of various factors on the abiotic and biotic stages of the degradation of PLAs. Special attention is paid to the peculiarities of polymer biodegradation in the conditions of industrial composting as the most promising method of its processing as part of food waste. The microorganisms involved in the degradation of PLAs, as well as their enzymes, are shown.