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Study of Biodegradation of Polyethylene (PE), Polyethylene Therephthalate (PET) and Oxo–Biodegradable Plastics Package
D.S. Stefan and I. Meghea

The disposal of plastics, especially those used in packaging, represents a serious challenge to waste management. Biodegradable plastics are now emerging as one of the available options to solve such environmental issues. The industrial development of new biodegradable plastics and compostable plastics has been accompanied by the parallel development of suitable standard test methods. This paper presents the studies regarding the compliance with specific biodegradation conformity assessment criteria for three types of packages: polyethylene, oxo-biodegradable and polyethylene therephtalate plastics. It were studied the degradation and biodegradation level for plastics samples in aqueous conditions, by composting and exposure at UV irradiation. For the conformity assessment the following parameters have been determined: volatile organic compounds, total content of heavy metals (Cd, Cr, Hg, Pb), moisture, ash content, total organic carbon and the degree of biodegradability in aqueous medium for oxo-biodegradable plastic and polyethylene. For the biodegradation processes conducted by composting in monitoring conditions a mixture has been used consisting in mature compost, vegetal waste resulted from fruits mark distillation, sawdust and the studied plastics. The parameters monitored are: moisture, total organic carbon, ash content, Kjeldhal nitrogen, pH and temperature. To identify the structural modifications in time IR spectra have been registered. The plastics tested meet the conformity conditions regarding composition (volatile organic compounds and heavy metals content) but not those referring to the conformity conditions for biodegradability.

Keywords: biodegradation, polyethylene, polyethylene therephtalate, oxo-biodegradable plastic, composting.

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