Pyroplastics: A new Approach

Pollution of aquatic ecological systems with different kind of plastics, from Nano- to Micro- andMacroplastics is a global problem and is shifting into the area of public interest mainly becausethese plastic particles can be found everywhere in the food chain.Recent scientific publications reported about a new kind of plastic pollution of not well-knownorigin, pyroplastics [1]. Rock shaped and coloured formations of different polymers were found onbeaches in south west England. The current theory of their formation is that plastic litter wasburned incomplete near by the ocean or on the high seas. In comparison to previously publishedplastiglomerates the encapsulated material is usually plastic without a significant amount ofextraneous material [2].In the presented work a Raman microscope equipped with a heating stage was used to determinethe maximum temperature pyroplastic was exposed. It can be seen that the structure of thesamples starts to change above 225°C and above 275°C. The polyethylene bands between 800cm-1 and 1800 cm-1 vanish and the amorphous carbon signal appears (figure 1). Additionalexperiments with the heating stage clearly showed that this effect is not heating time dependentand in combination with a light microscope, it could be shown that at about 80°C differentpyroplastic stone fragments are melting together forming one solid piece.Large area energy dispersive X-ray spectrometry (EDX) elemental mappings (in the cm² range) ona cross section were performed to get additional information about the present chemical elements(see figure 2). In contrast to previously published works no lead, chrome, bromide or antimonycould be found, which would be a hint for special heat and UV stabilisers or flame-retardants.Based on these findings and the fact that stones and sand on a beach can be heated up to 80°C,it can be possible that, additionally to combustion processes, pyroplastic stones are formed by theheat of the sun and the power of tides.