The effects of concentration and surface modification of two Brazilian bentonite clays on nanocomposites' properties based on polylactic acid – (PLA) were investigated. The samples were prepared by the extrusion/injection method to obtain biodegradable packaging plastics. The raw materials and their bionanocomposites were characterized by various techniques. Natural clay samples presented a size of around 2 μm while the modified ones' size was 5–6 μm, probably due to the presence of cetyltrimethylammonium bromide in the interlayer space. The particle size and the contact angle increased with the treatment and the clay's density decreased. The organoclays were homogeneously dispersed in PLA, which can be associated with the interactions between PLA chains' carbonyl groups and the organoclays. The bionanocomposites present modified clay particles axis aligned to the flow direction of the extruder/injector. Chocolate organoclay acts as a nucleating agent to PLA crystal growth, increasing the sample's crystallinity, while Bofe organoclay interferes with the amorphous chain's mobility and diminishes the sample's crystallization. The addition of both organoclays to PLA diminished the sample's elongation at break and strength, although the organoclays increased the sample's Young modulus, even though Bofe organoclay is more active in PLA amorphous phase and Chocolate organoclay on the crystalline one.

Mango seeds from agro‐industry represents an environmental problem due to the amounts of by‐products produced. Conversely, poly (lactic acid) (PLA) is a potential green alternative to conventional plastics. The goal of this study aimed to develop a biocomposite based on PLA and mango’s by‐product for rigid packaging. Six biocomposites are obtained by extrusion/injection processing using formulations with PLA as a matrix and up to 20% by weight of mango seed’s by‐products. The materials are characterized by chemical and physical analysis; scanning electron microscopy/energy dispersive X‐ray, X‐ray diffraction; Fourier transform infrared spectroscopy (FTIR); thermal gravimetric analysis/differential thermogravimetry; differential scanning calorimetry (DSC), and mechanical analysis. FTIR bands and DSC transitions related to starch are higher in the kernel, while more cellulose bands are found in the integument. Kernel presented thermal degradation in the biocomposites, the sample PLA+20 wt% kernel. For the other compositions, it is possible to observe that they could keep their morphology. Significant improvements in both mechanical and barrier properties are found in the formulation with 20 wt% integument (up to 38% in elastic modulus). Therefore, this study suggests that biocomposites developed from PLA / Integument / Kernel have potential as a new biomaterial for rigid food packaging systems.

O aumento do consumo das embalagens de bebidas feitas de PET, trouxe consigo o problema do acúmulo de resíduos pós-consumo no meio ambiente. De modo que a demanda por meios de reuso desses materiais é crescente. Uma alternativa é a obtenção de compósitos com cargas inorgânicas, como a mica. Neste contexto, o presente trabalho teve como objetivo produzir um compósito baseado em poli (tereftalato de etileno) e mica (muscovita). Utilizou-se a mica com granulometria na faixa de -45µm. Para o processamento das misturas de PET/mica em extrusora monorrosca, a mica foi adicionada nas proporções de 3, 5 e 7%, em seguida os compósitos foram prensados para obtenção de filmes planos e as amostras foram caracterizadas. Nos testes de dureza Shore D e densidade, observou-se ligeiro aumento com aumento do teor de mica. O índice de Fluidez (MFI) também aumentou para maiores concentrações de mica, o que pode estar relacionado ao efeito lubrificante apresentado pela muscovita. Em relação às análises térmicas, na termogravimetria (TG) foi observado apenas um evento de perda de massa na faixa de temperatura entre 350 e 500°C correspondente à decomposição do polímero. Já na análise de DSC, foi possível observar um pico endotérmico, a cerca de 250°C referente à fusão do PET. Por meio das análises de microscopia foi possível observar as partículas de mica dispersas na matriz polimérica.