Articolo in rivista, 2022, ENG, 10.3390/polym14061111

An In Situ Experiment to Evaluate the Aging and Degradation Phenomena Induced by Marine Environment Conditions on Commercial Plastic Granules

De Monte, Cristina; Locritani, Marina; Merlino, Silvia; Ricci, Lucia; Pistolesi, Agnese; Bronco, Simona

CNR; Ist Nazl Geofis & Vulcanol; CNR; Univ Pisa

In this paper, we present two novel experimental setups specifically designed to perform in situ long-term monitoring of the aging behaviour of commercial plastic granules (HDPE, PP, PLA and PBAT). The results of the first six months of a three year monitoring campaign are presented. The two experimental setups consist of: (i) special cages positioned close to the sea floor at a depth of about 10 m, and (ii) a box containing sand exposed to atmospheric agents to simulate the surface of a beach. Starting from March 2020, plastic granules were put into the cages and plunged in seawater and in a sandboxe. Chemical spectroscopic and thermal analyses (GPC, SEM, FTIR-ATR, DSC, TGA) were performed on the granules before and after exposure to natural elements for six months, in order to identify the physical-chemical modifications occurring in marine environmental conditions (both in seawater and in sandy coastal conditions). Changes in colour, surface morphology, chemical composition, thermal properties, molecular weight and polydispersity, showed the different influences of the environmental conditions. Photooxidative reaction pathways were prevalent in the sandbox. Abrasive phenomena acted specially in the sea environment. PLA and PBAT did not show significant degradation after six months, making the possible reduction of marine pollution due to this process negligible.

Polymers (Basel) 14 (6)

Keywords

multi-parametric platform, bioplastics, polymer degradation, marine environment, microplastics, spectroscopy, resin pellets

CNR authors

Ricci Lucia, De Monte Cristina, Merlino Silvia, Bronco Simona

CNR institutes