Proces vzniku mikroplastů při degradaci plastů v modelových podmínkách

Abstract

The presented dissertation focuses on the study of microplastic (MPs) formation generated by the degradation of plastic materials. The aim of the work was to design and build a laboratory apparatus for plastic degradation. Using this apparatus, degradation processes were simulated under model conditions on selected types of plastics, specifically a PE bag, PET bottle, PS cup, 2 biodegradable bags from different manufacturers and a biodegradable HDPE bag. The plastics were exposed to combined effects of UV radiation, distilled water and its movement for one year. A secondary objective was to detect and identify the generated microparticles. Samples of macroplastics and water containing microparticles were sampled every three months and analyzed using macroplastic weight loss, microscopy and μ-FTIR analysis of extracted microparticles from the water. The weight loss of macroplastics was negligible for conventional plastics (less than 2%) and significant for bioplastics (up to 36%). A total of 240 microparticles were collected, of which 101 were identified as microplastics, i.e., synthetic polymers and additives. The results showed that conventional plastics generally generate fewer microparticles than bioplastics, with HYTREL 7246 material being the most common in the samples. Additionally, microplastics of different compositions than the main polymer of the original product were often generated in conventional plastics. The color of the microparticles generally matched the colors of the original materials, but in a small number of cases, microparticles of completely different colors were found. The most commonly found shapes of microparticles were fragments and fibers. This dissertation provides valuable information and new insights into the degradation of plastics and bioplastics, a field with a limited number of comprehensive scientific studies to date.