Mechanical Degradation of Polystyrene Foam by Zophobas Morio Larvae

The present paper describes the formation of microplastics from foamed polystyrene as a result of exposure to insects, namely the larvae of the beetle Zophobas morio in real-life conditions. Larvae were cultured with foamed polystyrene in the absence of food and in control groups with normal nutrition. Most larvae survived and successfully developed into pupae. The effect of larvae on polystyrene is manifested by its mechanical destruction when larvae build tunnels in the volume of polystyrene material, resulting in the formation of a finely dispersed fraction of polystyrene (i.e., microplastics). FTIR, Raman, and NMR spectrometry methods revealed no significant differences in the original polystyrene and polystyrene crushed by larvae; also, according to the GPC data, no significant change in the molecular weight of polystyrene was detected as a result of contact with Z. morio larvae and passage through their gastrointestinal tract. The data obtained confirm that the main result of larvae impact on polystyrene foam is its crushing with formation of microplastic without chemical modification and change of molecular weight.