Defence Mattia Lenti: "Sustainable routes for sustainable products: advanced materials from lignin and starch"

Promotors: Prof P. Raffa, Prof F. Picchioni and Prof K. Barta

Abstract: The environmental impact of fossil fuel-based polymers has driven the scientific community to seek sustainable alternatives, with lignocellulosic biomass and starch emerging as promising natural feedstocks. Lignin, one of the major components of lignocellulose, has potential to replace toxic bisphenol A in epoxy resins. However, lignin’s complex structure poses extraction challenges, usually resulting in a low value- added use of lignin as fuel in traditional biorefineries. Deep Eutectic Solvents (DES), a novel class of solvents with outstanding properties, can increase the efficiency of lignin recovery from lignocellulosic biomass, allowing for an effective valorization of this natural polymer in the preparation of bio-based epoxy resins. In the first part of this thesis, we explore the use of DES for the extraction of oligomeric lignin in high yield to be used as starting material for the production of green epoxy resins adhesives. We then tested those materials for bonding wood samples and revealed outstanding mechanical properties, comparable to commercially available fossil-based glues. Starch is another natural, biodegradable polymer with vast potential for the synthesis of advanced materials, but its poor native properties require modification for most applications. In particular, the low hydrophobicity of starch limits its use in many fields. In the second half of this thesis, we explore the use of supercritical CO2 for the chemical modification of potato starch to increase its hydrophobicity via a sustainable and scalable process using different, benign compounds. The improvements in starch properties along with its high biodegradability, make hydrophobized starch a promising candidate for various industrial applications, including coatings, adhesives, and packaging, where it could replace traditional products obtained from non-renewable feedstocks.

Dissertation