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    Desenvolvimento de compósitos poliméricos de poli(3-hidroxibutirato-co-3-hidroxivalerato)/carbono vítreo para a produção de embalagens antiestáticas biodegradáveis
    (Universidade Federal de São Paulo (UNIFESP), 2020-11-12) Vieira, Leonardo De Souza [UNIFESP]; Passador, Fabio Roberto [UNIFESP]; Universidade Federal de São Paulo
    Antistatic packaging is used to protect electronic components against damage caused by electrostatic discharges and therefore must have sufficiently low electrical resistivity. Poly(3-hydroxybutyrate-co-3-hydroxivalerate) (PHBV) is an interesting option for the production of biodegradable packaging, but it is an electrical insulator. Glassy carbon (GC) is an electrical conductive carbon material that is a promising alternative of an antistatic agent. Thus, PHBV/GC composites can be combined to obtain biodegradable and antistatic packaging. PHBV/GC composites with different GC contents (0; 0.5; 1.0; 2.5 and 5 wt%) and particle sizes (<45 μm and > 75 μm) were prepared by extrusion. Films (0.2 mm) were prepared by hot pressing and characterized by thermal analysis (differential scanning calorimetry - DSC and thermogravimetric analysis - TGA), mechanical properties (tensile test) and electrical characterization (impedance spectroscopy - IS). The effect of the addition of GC and its particle size on the biodegradability of the composites that presented the best electrical results were also evaluated. Before the biodegradation process, samples were subjected to a previous photodegradation test. The effects of the degradation tests on the samples were evaluated by visual analysis, scanning electron microscopy (SEM), measurements of residual weight, surface roughness, contact angle, Fourier-transform infrared spectroscopy and DSC. The results of the IS tests showed that the use of GC contents greater than 2.5 wt% (CV> 75 μm) decreased the electrical resistivity of PHBV/GC composites by 3 decades of magnitude when compared to neat PHBV, resulting in a material suitable for the production of antistatic packaging. Measurements of residual weight, DSC and SEM showed that the GC did not interfere in the biodegradation process, that is, the composites presented a similar behavior to neat PHBV. In this way, GC constitutes an interesting alternative of an antistatic agent, and PHBV/2.5 GC L composite can be considered a promising material for the production of biodegradable antistatic packaging.