Assessment of the migration potential of phthalate derivatives found in PVC-based wastes into rainwater and soil

Polyvinyl chloride (PVC) is a widely used, durable, and recyclable polymer in the construction industry. However, PVC based construction wastes released after natural disasters such as earthquakes may remain uncontrolled in the environment for long periods and degrade into microplastics through physical and chemical processes. Phthalate type plasticizers added to PVC are not chemically bonded to the polymer matrix and can therefore migrate into environmental media, potentially posing toxic risks. This situation presents a significant concern for environmental and human health.In this thesis, the migration potentials of four different phthalates (dioctyl phthalate (DOP), dioctyl terephthalate (DOTP), diisodecyl phthalate (DIDP), diisononyl phthalate (DINP)) added to PVC and the degradation behavior of the polymer were investigated in both rainwater and soil environments. PVC films prepared using the plastisol method were aged in these environments for 13 weeks. Plasticizer migration was determined by mass loss of the films, while structural changes were analyzed through FTIR spectroscopy for oxidation index and UV visible spectroscopy for conjugated double bond formation. According to the results, DOTP containing films exhibited the highest diffusion coefficients in both environments, while DOP containing films showed the lowest. Overall migration was higher in soil than in rainwater. FTIR analysis indicated increasing oxidation over time and UV data revealed enhanced conjugated double bond density. The findings suggest that PVC waste can act as a source of microplastics and toxic additives in the environment. Keywords : PVC, phthalate, migration, degradation