Avaliação de sacolas plásticas utilizando espectometria de absorção atômica e análises térmicas

Abstract

The availability of plastic bags for purchase packing began to popularize in Brazil during the ‘80s. It is use, allied with a fast disposal and a slow decomposition results in a large accumulation in landfills, as well as rivers, lakes and seas. The understanding of these materials composition is essential for one to be able to assess the inherent risks involved in it is use and discartament. In this study, eight samples of plastic bags used for packaging were analyzed, being three of them derivated from naphtha, two from ethanol and the three were oxybiodegradable, in which a chemical additive is added to them so that it’s degradability time decreases. The technique of graphite furnace atomic absorption spectrometry was used to determine cadmium, lead, chromium and antimony. Thermal analyzes were also performed to evaluate the thermal stability and the melting temperature of the different types of samples. It was observed the presence of metals in plastic bags analyzed, and only the chromium could be identified in all samples. The metals and metalloids concentration varied between 0.013 and 2.7 μg g-1, below the maximum limits established by legislation. Through thermal analysis used - thermogravimetric analysis and differential scanning calorimetry - it was observed that all the samples showed the same thermal behavior. Building up the data contents of metals and thermal analysis, it can be inferred that the presence of Cd, Cr, Pb and Sb did not influence the thermal stability of the polymers.