Single-use plastics that are commonly used for packaging and service ware, such as bottles, bags, straws, and wrappers, result in land and marine pollution that as they break down into microplastics. Blending plastics with pro-oxidants could be a promising solution as they accelerate photooxidation to obtain degradable materials whose final ecological and physical footprints are much smaller. In this study, two pro-oxidants, iron stearate (FeSt<sub>3</sub>) and cobalt stearate (CoSt<sub>2</sub>), were melt blended with polypropylene (PP) at concentrations of 1 and 2 wt%. Plates of neat and pro-oxidant-filled PP were kept in an accelerated weathering chamber that simulates the damaging effects of long-term outdoor exposure. Samples were taken out from the test chamber, and their properties were measured at selected time intervals as they undergo photochemical degradation. Physical, thermal, and chemical properties of pristine and pro-oxidant-filled samples were measured using TGA, differential scanning calorimetry, and Fourier transfer IR spectroscopy (FTIR). Within 300 h of aging in the chamber, PP with pro-oxidants were embrittled, cracked, and broken into pieces. After 500 h of aging plastics, plates showed a significant reduction in melting and re-crystallization points, indicating polymer chain breaking, rapid depolymerization. Uv-Vis and GC-mass spectroscopic analysis of wash-water samples indicated water-soluble degradation products are potently biodegradable and can be assimilated by microorganisms. The study offers a successful approach where benign filler could significantly reduce the persistence of plastic pollution without creating undesired by-products

Accelerating environmental degradation of plastics with pro-oxidant additives

ACS Fall 2021

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