Graziela Solferini Baccarin

Textile waste from clothing production poses growing environmental and economic challenges with global fabric disposal expected to reach 148 million tons by 2030. Polyamide 6 (PA6), commonly used in fabrics, degrades during recycling due to hydrolysis, lowering its molar mass and limiting its reuse. This study presents a method to recycle PA6 fabrics using a carbodiimide (CDI) additive, which acts as an antihydrolysis agent and chain extender, aiming for cradle-to-cradle recycling. Controlling physicochemical properties, especially molar mass, is crucial; yet, the mechanisms of molar mass recovery are not well-understood and can be affected by humidity. This work showed that CDI reduced degradation in both dry and wet PA6, increasing molar mass by 40% and 75%, respectively, as confirmed by rheological analysis. Molecular investigation through ¹³C NMR showed no tertiary carbon signals, and Time Domain NMR indicated a higher glass transition temperature with CDI. These findings, supported by Density Functional Theory (DFT) calculations, suggest that CDI promotes linear chain extension over branching. This approach supports closed-loop recycling of PA6 fabrics, enhancing textile circularity and minimizing environmental impact.

Edible films were produced by combining a pectin (PEC) matrix with chitosan nanopar-ticle (CSNP), polysorbate 80 (T80), and garlic essential oil (GEO) as an antimicrobial agent. CSNPs were analyzed for their size and stability, and the films, throughout their contact angle, scanning electron microscopy (SEM), mechanical and thermal properties, water vapor transmission rate, and antimicrobial activity. Four filming-forming suspensions were investigated: PGEO (control); PGEO@T80; PGEO@CSNP; PGEO@T80@CSNP. The compositions are included in the methodology. The average particle size was 317 nm, with the zeta potential reaching +21.4 mV, which indicated colloidal stability. The contact angle of the films exhibited values of 65°, 43°, 78°, and 64°, respec-tively. These values showed films with variations in hydrophilicity. In antimicrobial tests, the films containing GEO showed inhibition only by contact for S. aureus. For E. coli, the inhibition occurred in films containing CSNP and by direct contact in the culture. The results indicate a promising al-ternative for designing stable antimicrobial nanoparticles for application in novel food packaging. Although, it still shows some deficiencies in the mechanical properties, as demonstrated in the elongation data.

Edible films were produced combining pectin (P) matrix with chitosan nanoparticle (CSNP), polysorbate 80 (T80), and garlic essential oil (GEO) as an antimicrobial agent. The CSNP were analyzed for their size and stability, and the films, throughout their contact angle, scanning electron microscopy (SEM), mechanical and thermal properties, WVP and antimicrobial activity. Four filming-forming suspension were investigated: PGEO (control); PGEO@T80; PGEO@CSNP; PGEO@T80@CSNP. The average particle size was 317nm with zeta potential reaching +21.4 mV, which indicated colloidal stability. The wettability of the films exhibited values of 65°, 43°, 78°, 64° respectively. In antimicrobial tests, the films containing GEO showed inhibition only by contact for S.aureus. For E. coli, the inhibition occurred only in films containing CSNP and by direct contact in the culture. The results indicate a promising alternative for designing stable antimicrobial nanoparticles for application in novel food active packaging.