Characterisation of different manufactured plastic microparticles and their comparison to environmental microplastics

Abstract

Microplastic particles (MPs) are one of the big problems of our time. What is typically used in MP research, e.g. expositions studies, are spherical primary microparticles. However, these particles do not resemble real microplastics found in the environment. Environmental microplastics are expected to interact differently with the environment than industrially produced primary particles because of their irregular shape and surface morphology. This is a fact relevant for animal feeding studies as well as for separation and analysis studies. Environmental MPs can be roughly categorised into two groups: porous and non-porous particles. Both categories are important for environmental studies on MPs. Here, two production methods of model polymeric microparticles were investigated to simulate environmental microplastics. The first method, which is a typical top-down method, involves grinding granules or films. The second method, which is a typical bottom-up method, involves particle production by precipitation from dissolved polymers. Particles generated by milling exhibit a broad size distribution, an irregular shape and show surface cracks similar to environmental microplastics. Dissolution-precipitation produces highly porous particles with diameters of 15–60 µm. • Investigation of methods for production of microplastics to mimic environmental MPs. • Angular, irregular particles could be produced by milling. • Porous properties of precipitated particle controlled by process parameters. • Adjustment of PSD and SSA of model particles by mixing both types of particles.