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 (M_n) 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.

An alternative method for production of hybrid organic–inorganic nanocomposites based on porous polyolefin films (isotactic polypropylene, high density polyethylene), deformed via crazing mechanism in physically active media, and calcium phosphates is proposed. Film composite materials of different structure and containing 10–25 wt % of filler are obtained. Particles of calcium hydroxyapatite with a diameter of 15–50 nm are formed in these films at once in the pores of the polymer matrices with the development of a layer, the morphology of which is determined by the structure of the original porous films, and its parameters can be controlled by the reaction conditions. It is found that the composites obtained are characterized by anisotropy of mechanical properties, and the introduction of the calcium phosphate particles results in some increase in the mechanical characteristics of the polymer matrices. High-temperature heating (up to 700°C) of nanocomposites leads to burning out of the polymer matrix and formation of porous calcium hydroxyapatite residues consisting of nanoparticles with different morphology depending on the initial porous structure of polymer (from needle-shaped crystals with a length of 100–150 nm and about 10 nm in diameter to spheres with a diameter of 50–90 nm). The results obtained are relevant for the directional regulation of the structure and properties of bioactive substances and creation of modern materials for biomedical use.

This study examines the nature of enzymatic degradation of polyethylene terephthalate (PET) films mediated by a novel recombinant LCC^ICCG 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.