Effects of environmental conditions on latex degradation in aquatic systems

Following use polymer materials may be released to the natural environment distributed to various environmental compartments and may undergo a variety of mechanical and chemical weathering processes. This study characterised the degradation of a latex polymer of different thicknesses under a range of environmental conditions in outdoor microcosms. Samples were immersed in either demineralised water, artificial freshwater and marine water media and exposed for a period of 200-250 days with exposure starting at different times of the year. Effects of pH, agitation and the exclusion of light on degradation were also studied. At the end of the exposure period, recovery of polymer material ≥ 1.6 μm ranged from a low of 22.04% (± 16.35, for the freshwater treatment at pH 5.5) to a high of 97.73% (± 0.38, for the exclusion of light treatment). The disappearance of the bulk material corresponded to an increase in nanoparticles and dissolved organic material in the test media. Modelled degradation kinetics were characterised by multi-phasic degradation patterns and the results indicated degradation rate is affected by light intensity and polymer thickness. Mass balance analysis indicates that losses of volatile materials to the air compartment may also be occurring.

► We characterised the degradation of latex in outdoor aquatic microcosms. ► Degradation rate was dependent on light and material thickness. ► Photooxidation is shown to be the primary degradation pathway. ► Degradation products include the formation of nanosized particles. ► Mass balance indicates that loses to the atmosphere occur.