Obtenção e caracterização de compósitos poliméricos biodegradáveis obtidos via extrusão a partir de PLA (ácido polilático), amido de mandioca, glicerol e bagaço de cana-de-açúcar

Abstract

For a long time is perceived the importance of polymeric materials in the society daily life, once they have several applications. However, we can say that the vast majority of these materials are plastic material transformations originated from oil. In addition to the use and depletion of natural resources (oil), the greatest concern related to these materials is the destination and disposal of these materials. Facing such a problem it can be cited the study and development of new biodegradable polymeric materials, such as a proposal to minimize environmental impacts. Therefore, this work had as objective to obtain of biodegradable polymeric composites through extrusion, produced by different formulations of PLA (polylactic acid), cassava starch, sugar cane bagasse (lignocellulosic residue) and glycerol, as well as the characterization of their physico-chemical and biodegradable properties. The composites were prepared with a laboratory extruder and used varying amounts of starch and fiber and fixed amounts of glycerol and PLA, which resulted in 3 types of formulations (FC, F1 and F2). The results indicated that: (i) it was possible to prepare both composites of cassava starch as well as with fibres from sugar cane bagasse; (ii) FT-IR spectra showed the structures of the formulations after incorporation cassava starch, bagasse of sugar cane and glycerol; (iii) the average density of FC was 0.0148, F1 and F2 0.0130 0.0175. Only the FC has a coefficient of variation greater than 10 per cent, representing an average dispersion of good accuracy, and F1 and F2 presented CV less than 10 per cent, where the value of the error is minimal; (iv) The F2 formula presented the highest water absorption capacity at all intervals when compared to the other samples (FC and F1); (v) the biodegradability test, despite being simple and fast (14 days), presented results of mass loss and the visual analysis of composites showed that all the formulations showed signs of degradation based on their thinner and brittle structure, but the formulation was presented the F2 more points or regions of fragmentation and signs of biodegradation, the prepared specimens of PLA showed no changes. This study was important because it was possible to obtain a biodegradable material, with adequate and excellent biodegradation rate, in addition to being composed of industrial waste of low added value.