Development of biodegradable films of poly(lactic acid) and isolated soy protein produced by flat extrusion

ABSTRACT

With the worsening of environmental problems caused by poor solid waste management, biodegradable polymers emerge as alternatives for sustainable materials that can minimize environmental impact. In view of the urgent demand for sustainable products, this study aimed to develop films based on poly (lactic acid) (PLA) and isolated soy protein (SPI) via flat extrusion for study as a potential application in food packaging. The films were produced in five different formulations: the pure PLA matrix as a control film; PLA with 3 and 5% of the isolated soy protein, PLA with 3 and 5% of the isolated soy protein with the addition of 1.5% glycerol, and analyzed via thermogravimetry, infrared spectroscopy, UV-vis transmittance and angle contact. The results indicated that the insertion of the components in the PLA matrix led to a reduction in the thermal stability of the films, which also did not show chemical interaction between their components. The soy particles, better dispersed in the matrix due to the presence of plasticizers, helped in reducing the transmittance of the films, and in the formation of hydrophilic systems.

Keywords
Biodegradable Polymer; Vegetable Protein; Glycerol; Extrusion