• bionanocompositi
• cellulosa
• nanowhiskers di cellulosa
• PCL
• PLLA

In the present work, innovative polysaccharide-based materials were designed by exploiting synthetic or mechanical procedures for the controlled modification of the original structure and thus allowing to obtain defined macromolecular architectures. In this context, cellulose nanowhiskers (CNWs) modification, through covalent bond and/or secondary interactions, was investigated as an efficient and versatile tool for the synthesis of complex structures with biocompatible and biodegradable polymers. In addition, Ring Opening Polymerization (ROP) of cyclic polyester, such as L-Lactide and ε-Caprolactone, was exploited as a “key” process for the preparation of macromolecules with well defined composition and functionalities, characterized by high versatility. The selection of both the type of interaction, between polymer matrix and bionanofiller, and the reactive strategy to combine them into the final products was carried out by considering the peculiar feature of both the polymers and the nanowhiskers in terms of structure, molecular mass, functionality and main potential application. Two system were developed: poly-( ε-Caprolactone -b- L-Lactide) block copolymers functionalized with CNWs and poly-( ε-Caprolactone -r- L-Lactide) statistical copolymers filled with CNWs.
In particular, in the first part of the research the surface grafting “onto” approach of copolymer was applied to nanowhiskers, by urethane bond formation between 2,4- Toluenediisocyanate and both them, in order to study an innovative route to functionalize CNWs with biocompatible polymers. The following part of the research interested the dispersion of cellulose nanowhiskers into statistical copolymer, based on the same comonomer, in order to study the influence of the bionanofiller on thermal, mechanical and hydrolytic degradation properties of polymer matrix. This last approach was exploited for further processing development.
All the experiments that are described and discussed in the present thesis have been carried out aiming to establish various procedures for the efficient and versatile modification/dispersion of polysaccharides nanofillers in order to obtain, even in perspective, well-defined, fully biocompatible and biodegradable, composite with predictable structures and specific target properties.