Preparazione e studio di film compositi basati su biopolimeri e nanofillers caricati con sostanze con specifiche funzioni.

This Ph.D. thesis entitled “Preparation and study of composites films based on biopolymers and nanofillers charged by substances with specific properties” was initiated in November 2015 and finalized in October 2019. The study has almost carried out at the University of Palermo (Physics and Chemistry Department) and some experiments have been done at the Institute of Physics of Santiago De Compostela University during a training of about four months. The thesis is a contribution to the possibility to replace the traditional plastic materials with bioplastics, composite materials based on environmental friendly resources, such as biopolymers and nanoclays. In detail, the thesis includes six chapters. The first is an introduction to the green materials world, the properties and the current and most important applications of biopolymers, nanoclays and their composites. Chapter 2 reports studies on HNTs stability in aqueous polymer dispersions, considering the structural and the thermodynamic features that influence the interactions between the two components. Chapters 3 is dedicated to the physicochemical characterization of nanocomposite based on biopolymer/ nanofiller, considering the effect of biopolymer charge and the nanoclay morphology on materials obtained. A thermal study on multilayer nanocomposites based on an alternation of layers of hydroxypropyl cellulose and halloysite nanotubes combined to chitosan and the preparation and a thorough physic-chemical investigation on novel biocomposite characterized by halloysite nanotubes sandwiched in two chitosan layers are reported in chapter 4. The work done during my training at Santiago de Compostela can be divided into two-part. One part focuses on the possibility of designing and characterizing layer-by-layer systems such as drug delivery. Chapter 5 is an in-depth explanation. The second part, that is reported in chapter 6, focuses on the possibility to verify the cytotoxicity of nanocomposites based on chitosan and halloysite nanotubes at different concentrations of components. The possibility of degradation of materials during the first 72 hours in incubation with DMEM is investigated and the possibility of release of toxic substances to cells is verified too.