Degradation of poly(ε-caprolactone) under laboratory conditions during exposure to air and soil
E.S. Shirokova, E.V. Tovstik, A.V. Sazanov
Section: Remediation and rehabilitation
Various aliphatic polyesters are used to provide biodegradable compostable packaging materials. They are a group of materials with a wide range of thermal, mechanical and biodegradability properties that can be easily adapted to a specific application. However, when using such materials for packaging solutions,their release into the environment after the end of the product’s service life is not excluded. In this regard, the assessment of changes occurring with polymeric material in soil and in air is of interest. The paper presents the results of assessing the degradation of films made from poly(ε-caprolactone) (PCL), one of the representatives of polyesters used for the production of flexible packaging, as well as high-density polyethylene (HDPE), which served as a reference sample. The experiment was carried out in laboratory conditions (natural light; temperature 20±2 оC) with exposure of the samples in the soil and in the air for 12 months. The changes in the polymer materials assessed by the appearance of the samples, the loss of their absolute mass, as well as IR spectroscopy and thermogravimetry data. The number of micromycetes in the soil in which the polymer samples were kept was indirectly judged to be biodegradable. The safety of degradation products was judged by the results of contact biotesting of soil us- ing radish (variety Zhara), carried out according to certified methods, taking into account international standards. The ability of polymeric materials to biodegrade under the action of micromycetes was confirmed in a fungus resistance test. A strain of mycelial fungus Fusarium proliferatum AC was a test culture. Degradation in the soil over the studied period was typical only for samples of PCL films. At the same time, the phytotoxic effect of PCL degradation products in the soil was not established. Signs of HDPE oxidation were indicated on the 3rd month of its air incubation. HDPE showed resistance to degradation in the soil. Based on the results of the work, a conclusion was made about the need to create special conditions for the disposal of PCL, despite its biodegradability proven in laboratory experiments.
ISSN 1995-4301
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