Síntese e caracterização de nanocompósitos poliméricos biodegradáveis para aplicação no setor de embalagens

Abstract

The search for more effective methods for food preservation has improved in recent years, which has led to the development of technologies that aim to extend the durability and ensure the stability of food products. Emerging solutions include the use and development of active packaging, which interacts directly with food, tending to increase its shelf life. And with the growing focus on sustainability, films made from blends of natural polymers together with more versatile polymers, with the addition of reinforcements, are becoming a promising alternative for the production of food packaging. In this scenario, this study seeks to produce and characterize nanocomposites composed of arrowroot starch, carboxymethyl cellulose (CMC), glycerol and citric acid, reinforced with zinc oxide nanoparticles in different concentrations (0%, 0.5%, 2% and 5% w/w), with the aim of evaluating their potential for applications in more sustainable and efficient food packaging. The films were obtained by the casting solution technique (solvent evaporation) and characterized by experimental techniques such as Fourier transform infrared spectroscopy (FTIR), X-ray diffractometry (XRD), scanning electron microscopy (SEM), thermogravimetric analysis (TGA), tensile test to analyze their mechanical properties, moisture percentage, swelling and solubility were analyzed, in addition to performing tests to study their biodegradability behavior in natural soil and their practical application as bread packaging. In the visual aspect, all the films obtained presented considerable optical transparency. The results demonstrated that in a period between 18 and 20 days buried in natural soil, total degradation was observed in all the films produced. The addition of ZnO NPs as a reinforcing agent in arrowroot starch and CMC films promoted an improvement in tensile strength from 1,75 to 35,84 MPa and in the elastic modulus from 5,79 to 1142,29 MPa. Finally, during the nine weeks of application of the films as bread packaging, no macroscopic changes characteristic of colonization by microorganisms, such as fungi, were observed. Thus, the results demonstrate that the nanocomposite films increased the shelf life of bread for a considerable period and can be effectively used as active packaging for bread storage.