Identification of biodegradable and oxo-biodegradable plastic bags samples composition.

Plastic films used to make market bags are based on polymers such as polyethylene, polystyrene and polypropylene. These materials require a long time to degrade in the environment. Alternative technologies have been developed to reduce the degradation time and the impact on the environment caused by the conventional polymer materials, using pro-degrading additives or by the development of biodegradable polymers. In Brazil, some city?s laws require the use of biodegradable material in the production of market bags, but the absence of specific surveillance policies makes their chemical composition unknown. The plastic bags didn?t show the expected environmental behavior by the manufactures, so it is important to understand the reasons why they are not biodegradable in Brazilian landfills. In this paper, 7 samples that were obtained from a trading company and commercial market of Belo Horizonte were analyzed. The samples were characterized by biodegradable analysis, XRF, FTIR, SEM and TGA/DTA, which allowed the identification and evaluation of the thermal behavior of the material in an inert and oxidizing atmosphere. The results showed that plastic bags were composed by a mixture of PLA and PBAT, with possible presence of TPS and titanium and calcium fillers. All samples presented low biodegradability in compostable environment