Thesis Title: Modeling of the weathering of plastic film (LDPE, PP, PET) by UV irradiation

Monday 18 February  2019, at: 13:00, Venue: Hall Κ2.A7

Examination Committee

• Professor Nicolas Kalogerakis (advisor)
• Associate Professor Tryfon Daras
• Dr. Evdokia Syranidou

Abstract

A vast amount of plastic items worldwide ends up to the marine and terrestrial environment and theis presence pose a great long-term threat to the entire ecosystem. Mesoplastics are a widespread litter which are accumulated in world’s ocean and beaches. One kind of mesoplastics are plastic films which are widely used in numerous fields such us packaging. Once they are exposured to the environment’s oxidizing conditions such as sunlight and moderate temperatures, they undergo natural weathering. The most important factors, oxygen and UV irradiation trigger a photooxidation and new oxygen-rich functional groups are generated. Hence the surface structure of the exposured material altered.

The purpose of this dissertation is to study the mechanism of abiotic weathering degradation of the plastics when are exposured in a simulated marine and coastal environment. LDPE, PP and PET films were placed in marine and coastal simulated mesocosms and they were exposure to UV irradiation. The coastal experiment lasted 180 days while the experiment in the aquarium lasted 90 days. The plastic films were free of additives in order to investigate the chemical modification of their surface due their different polymeric structure. Modeling and statistical analysis of the indices of the new functional groups, gave the ability to determine the rate of the abiotic degradation and to make predictions for LDPE and PP films. In parallel, the threshold when the degradation took place was examined in order to determine which type o film was weatherd faster.