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We investigated the occurrence of plastic contamination in sediments collected in the area of Pianosa Island (Adriatic Sea). In November 2015, 20 sediment samples were collected at depth varying between 119 and 142 m. At the laboratory, plastic debris in samples were weighted, measured and classified into dimensional groups, and categorized according to shape. Polymer types were identified using FT-IR analysis. All sediment samples contained plastics. In terms of numerical abundance, microplastics accounted for 64.4% of the total amount found. Filaments (66%) were the most common shape category. Identification through FT-IR spectroscopy evidenced the presence of 6 polymer types. Considering abundance, the majority of plastic debris were nylon (53.2%), followed by polyethylene (18%). By weight, polyethylene (61.4%) was the most represented polymer type, followed by polypropylene (19.6%). Because the distance from the coast, we hypothesize that plastics could be originated from marine-based sources including fishing vessels, merchant vessels and recreational boats.

The photooxidation of poly[bis(4-isopropylphenoxy)phosphazene] under accelerated conditions has been followed by FTIR and UV visible spectroscopic techniques. The main photooxidation products are acetophenone and phenol groups. In addition, acetone vapors have been detected by GC MS combined techniques concomitant with the IR spectral changes in the CH stretching region, suggesting a significant decrease in the isopropyl moieties. The presence of polymeric sequences having phenol groups under our conditions gives origin to further oxidation reactions due to electron transfer or radical recombination or to hydrogen abstraction reactions promoted by unhindered phenoxyl radicals. In addition, the absence of UV visible light, i.e., under thermooxidation reaction at 60° C has demonstrated that phenol groups are the main responsible of secondary oxidation products. The complexity of the photooxidation mechanism in the solid state for this polymer makes it difficult to determine a definitive degradation mechanism under both thermo- and photooxidative conditions.

In this paper we present results on the photolysis of poly[bis(4-benzylphenoxy)-phosphazene] in solution and in film, both in the presence and in the absence of molecular oxygen. Light irradiation of the polymer in oxygen-saturated CH2Cl2 solutions results in a remarkable degradation of the polyphosphazene, while in argon-purged solutions no appreciable variations of the polymer structure could be detected. The photolysis of poly[bis(4-benzylphenoxy)phosphazene] in films induces the cross-linking of the polymer regardless of the presence or the absence of molecular oxygen. The main process observed during the photochemistry both in solution and in the solid state of the polymer is the oxidation of the 4-benzylphenoxy group on the polyphosphazene, without involvement of the inorganic -P=N- backbone. The effect of temperature on the photolysis of the polyphosphazene substrate in film is also reported.