Accelerated environmental degradation of gamma irradiated polypropylene and thermal analysis

Polypropylene (PP) is one of the most important plastic commodities in the world. It can be used in many applications since it has outstanding properties at low cost. However, PP has very low environmental degradation rate; therefore, the discarded PP can accumulate in the environment. The aim of this study is the degradation control of PP using gamma radiation. Dumbbell samples were manufactured by injection molding followed by irradiation using gamma radiation at different doses: 5, 12.5 and 20 kGy. The irradiated samples were exposed to environmental aging during 90 days and characterized by scanning electron microscopy, thermogravimetric analysis, differential scanning calorimetry and X-ray diffraction. The irradiated dumbbell samples PP 5, 12.5 and 20 kGy, exposed to environmental aging, showed intense oxidation with the presence of surface cracks compared with the PP non-irradiated.