Desenvolvimento de filmes biopoliméricos reforçados com material híbrido a base de haloysita e pontos poliméricos de carbono

Abstract

Carbon polymer dots (CPDs) are a novel type of carbon-based fluorescent (0D) nanomaterial with a size smaller than 20 nm. Due to their unique properties, CPDs hold potential applications in various fields of interest, such as optics, electronics, sensors and biomedicine. On the other hand, inorganic solids, such as clay minerals have the potential for integration with various species and form composites with low toxicity, increased biocompatibility and enhance mechanical stability. Within this perspective, clay minerals can be combined with polymers, being processed into films. In this study, a mixture of alginate and carboxymethylcellulose polysaccharides was incorporated with different concentrations of a hybrid material developed from the union of the clay mineral halloysite and CPD (HC) obtained by dry and wet processes (HC-VS and HC-VU), to form reinforced biodegradable films (ACHC-VS and ACHC-VU). The materials were characterized by various physicochemical techniques (FTIR, UV-Vis, XRD, DSC, BET, SEM, EDS, PL), and their barrier, optical, textural and mechanical properties were investigated. Through UV-Vis spectroscopy, XRD, FTIR, and BET analyses, it was observed that the HC-VS material exhibited a higher CPD content in its final composition compared

to the HC-VU material. Thus, the structural and morphological properties of ACHC-VS and ACHC- VU films showed significant differences. The FTIR spectra of the ACHC-VS films indicated strong

hydrogen bonds between the material components, while the introduction of the HC-VS hybrids into the biopolymeric matrix significantly blocked a substantial part of the ultraviolet radiation due to the ability of the CPDs to absorb ultraviolet radiation and blue photons. In addition to the good mechanical properties, the water vapor transmission rate of the resulting films showed an almost 2-fold decrease in the composite films compared to the pure polymer film, indicating that the addition of the HC-VS hybrid improved the barrier properties against water vapor. These results were corroborated when the 0.06 ACHC-VS film demonstrated excellent perfomance when applied as a UV blocker on bananas and as packaging for strawberries.