Biocompósito ‘pla–casca de cenoura’ como material biodegradável para embalagens

portuguesCom o crescente consumo de embalagens plasticas e o impacto negativo de seu descarte inadequado e a saturacao dos aterros sanitarios e lixoes, as embalagens de alimentos biodegradaveis representam potenciais solucoes. O poli(acido latico) – PLA e ecologicamente correto, biodegradavel e compostavel, mas apresenta fragilidade mecânica. Compositos de PLA contendo bio–residuos (cascas e sementes) podem ser uma estrategia para a diminuicao do descarte dessas materias–primas. Este trabalho tem como objetivo o desenvolvimento de embalagem biodegradavel a base de PLA com a incorporacao de casca de cenoura. Foram confeccionadas amostras PLA–casca de cenoura (0, 5, 10, 15 e 25 p/p% casca) por casting. As amostras foram analisadas por FTIR, teste de textura, teste de degradacao em quatro meios diferentes (acido, basico, agua e solo adubado). Os resultados mostram que as amostras em meio aquoso mantiveram praticamente o peso identico ao inicial, em meio acido e basico houve ganho de massa, embora em solo apresentassem perda de massa consideravel. Houve diminuicao da porosidade do PLA ao adicionar a cenoura, embora a aderencia da casca a matriz PLA tenha sido baixa. A resistencia mecânica aumentou com o aumento da porcentagem de cenoura no PLA. EnglishThe increasing use of plastic packaging and the negative impact of its improper disposal,e saturation of landfills and dumps, led to the development of biodegradable packaging. Poly (lactic acid) – PLA is a polymer widely used in packaging studies, since it is environmentally friendly, biodegradable and compostable, but there are some disadvantages in its properties. The improvement of these properties, using mixtures of peels and seeds, has shown satisfactory results and can be a strategy for the reduction of food residues waste. In this context, the goal of this work was to develop biodegradable packaging based on PLA and carrot peel, aiming at the reuse potential food waste, where the biodegradation of polymeric packaging is a crucial factor. The samples were prepared with 0, 5, 10, 15 and 25 w/w% of carrot peel in PLA. PLA/carrot peel degradation was investigated in four different media: acid, basic, water and composted soil. The results show that the samples in aqueous medium maintained almost the same weight as the initial one, in acidic and basic medium there was mass gain, while in fertilized soil they showed significant mass loss. The results in scanning electron microscopy (SEM) and infrared by Fourier transform (FTIR), showed that there was a decrease in the porosity of the PLA when adding the carrot and little adherence of the carrot to the PLA matrix. The mechanical resistance increased with the increase in the percentage of carrots in the PLA.