Thin polyethylene (LDPE) films with controlled crystalline morphology for studying plastic weathering and microplastic generation

Plastic pollution has become one of the most visible environmental issue. Studying the aging and the fragmentation mechanism of polymers therefore raises environmental and health issues. Since it is particularly difficult to monitor all these processes in the real environment, laboratory studies are still necessary to obtain more accurate data and to identify the pathways leading to the outcome of plastic debris in the environment. In this paper we present a new method to prepare micrometer thick LDPE films with different thicknesses and controlled crystalline morphologies (i.e. spherulite size) using dip-coating process. LDPE films presenting different spherulite dimensions were submitted to an accelerated weathering test which indicates that spherulite size has only a weak influence on the rate of photo-oxidation. However, films presenting large spherulites morphologies seem to be more sensitive to surface erosion and crack initiation. We believe that the method developed in this paper can be used to study with more control and more rapidly (i.e. thin film and accelerated weathering) the influence of crystalline morphology on a wide range of semi-crystalline polymers in different aging conditions and thus help to better understand the fragment production of plastics in the environment.