• layered double hydroxides
• glycyrrhetinic acid
• bio-based polymers
• antimicrobial activity
• active packaging
• rosmarinic acid

This thesis is divided into two parts. In the non-experimental part, an extensive study of the literature was carried out about: synthetic/natural polymers with antimicrobial character for applications in food packaging; preparation and characterization of host-guest systems by intercalation of active molecules into 2D nanofillers; use of molecules with antimicrobial/antiviral properties from natural sources.
In the experimental research, modified layered double hydroxides (LDHs) were prepared by anion exchange and calcination-rehydration methods with the aim of obtaining host-guest hybrid systems through the intercalation between the lamellae of two organic anions deriving from rosmarinic acid (RA) and glycyrrhetinic acid (GA), chosen for their antibacterial and antioxidant properties and their natural origin. The hybrid systems were characterized by XRD, FT-IR, UV-Vis and TGA. Antioxidant properties of LDH-RA were also tested by DPPH method.
The hybrid fillers were dispersed into bio-base polymers like PLA, PBS and PLA/PBS blend to prepare composite materials for potential use in the active packaging industry. The degree of the dispersion of the LDH into the polymer matrices and the structure of the nanocomposites were evaluated by XRD, FT-IR and SEM analysis; the MW of polymers was determined by SEC and the thermal properties of materials were studied by TGA and DSC. Antimicrobial tests were carried out on PLA/LDH-RA and PLA/LDH-GA films against E. coli and S. aureus.