Abstract

The controlled photooxidation process of polypropylene J-643 microplastics (MP) was experimentally evaluated under the incidence of UV-B light up to a maximum exposition time of 75 days, by determining the carbonyl index (IC) from analysis by FTIR spectroscopy. Likewise, the morphological changes in the oxidized polypropylene microplastics were analyzed using an Olympus optical microscope model BX50. Morphologically, an increase in roughness and the appearance of blackened areas was evident in the oxidized PP MPs, not observed in the non-chemically modified MP; This is due to the increase in the exposure time of the samples to UV radiation. In turn, there was a decrease in the mechanical resistance of the material and an increase in its fragility. These changes can be explained from a macromolecular point of view, by the fragmentation of the polymer chains that generates cracks and surface irregularities. Additionally, the calculated IC values suggest a relationship between the longer exposure time to UV radiation and the increase in oxidation of the MP.