Aproveitamento sustentável da lignina kraft para desenvolvimento de filmes com proteção ultravioleta

Abstract

Lignin nanoparticles (LNPs) stand out as a green approach to processing and converting renewable natural resources into high value-added products, being increasingly studied within the scientific community. With potential for various applications, biopolymer-based plastics, such as pectin, have the capacity to be transformed into films with specific associated properties. Therefore, developing pectin-based films that combine their intrinsic characteristics with additional functionalities, such as UV radiation blocking, is of great interest. By incorporating nanoparticles into pectin-based films, it is possible to obtain a material with complementary characteristics. This combination enhances mechanical properties, hydrophobicity, and UV radiation resistance in pectin films. In this study, Kraft lignin nanoparticles (KLNPs) were synthesized via antisolvent precipitation, followed by the preparation of pectin-based films incorporating KLNPs with UV-blocking properties. The composite films showed excellent UV radiation blocking capacity, reaching 0% transmittance without compromising film transparency. They also exhibited a considerable improvement in hydrophobicity, with an increase of up to 38.52%. The mechanical properties, especially elongation, were significantly enhanced, with an increase of up to 82.38% compared to films without KLNPs. Although other mechanical properties, such as Young's modulus (YM) and Tensile Strength (TS), as well as thermal properties, did not show significant changes, this can be attributed to the low concentration of KLNPs used. The potential application of these films in packaging, especially for products sensitive to UV radiation, represents a relevant contribution to sustainability and the valorization of industrial waste.