Cryogenic Milling of Consumer Plastics for High‐Throughput Characterization of Polydisperse, Amorphous Microplastics
Charlie Maslen, Purnesh Chattopadhyay, Marie Theres Kühne, Gail McConnell, Juliane Simmchen
Abstract
ABSTRACT Microplastics—defined as polymer fragments less than 5 mm in size—pose a clear threat to a wide range of small organisms through ingestion, leading to starvation. In addition, there are many reports of their occurrence in remote geographical areas and in the human body. Although primary microplastics, that is, those manufactured intentionally, have defined characteristics, secondary microplastics resulting from the degradation of larger plastic debris are much less understood. Cryogenic milling has emerged as one of the best ways to generate realistic samples with potential for use as references in studies. Here, we demonstrate the viability of the method for producing microplastics by applying it to a wide range of plastic types including thermoplastics and rubbers. We find that the same milling parameters produce a diversity of size and shape distributions. We present a comprehensive, multi‐methods approach to characterize their chemical and physical properties, providing morphological data across the full size range of microplastics (1 μm–5 mm) and shedding light on the limitations of certain methods.