Аннотация:Microplastic pollution is currently considered as one of the most important issues that requires thorough research. The largest number of studies focus on collecting microplastic particles and determining their concentration and chemical composition. In addition to the polymer matrix, which is usually inert, microplastic particles may contain pollutants of different types. They are often chemical additives, such as plasticizers, flame retardants and dyes, which are added during the manufacturing process to give plastic products their desired properties. Additionally, once in the environment, microplastic particles, which have a large specific surface area, tend to adsorb on their surface and accumulate other environmental pollutants, such as surfactants and metal ions. Therefore, one of the important tasks is to develop methods for obtaining model systems of microplastic particles containing various fillers, as well as to study the processes of sorption-desorption of these potential pollutants. Of particular interest are polymer systems that contain toxic water-soluble additives, which can be released in a humid environment or within a living organism and cause harm.Monodisperse polystyrene latex particles, whose sizes can be easily varied and controlled, are often used as a model for microplastic systems. The disadvantage of these systems is their ideal spherical shape and the possibility of contamination with emulsifiers. Other method is to break down polymer macro-samples into smaller particles using laser ablation, ultrasonication, or mechanical processing. The result is a mixture of particles with different sizes and irregular shapes, which have surface defects similar to those found in real microplastics. However, the problem of obtaining model microplastics based on a wide range of industrial polymers containing a specific low-molecular additive has not yet been solved. This work proposes an original method for obtaining these filled microplastic particles. Crazing was used to introduce additives, which could potentially be pollutants, into the polymer. This process involves the uniaxial stretching of the original polymer film in a liquid medium that contains the required additive dissolved in it. During stretching, zones of plastic deformation with a nanoscale fibrillar-porous structure, known as crazes, form in the polymer and become filled with the surrounding solution. As the tensile strain increases, the proportion of the polymer material that transforms into crazes and volumetric porosity increase. The non-volatile additive remains in a highly dispersed form in the polymer volume after the liquid medium has been removed. Then the resulting films with filler can be crushed using mechanical processing, and thereby obtain model microplastic particles based on the desired polymer and containing the required additives, including water-soluble ones. The report examines the morphological characteristics of polylactide microplastic particles, as well as the kinetics of the release of additives, including copper nitrate, brilliant green dye, and surfactant sodium dodecylbenzene sulfonate, into the aquatic environment.
