New strategies for the preparation of high-perfomance bio-based polymers

Abstract

Nowadays there is a great interest to substitute petroleum-derived polymers with more sustainable materials. In this thesis the preparation of monomers, polymers and copolymers from renewable resources was carried out, following two strategies. The first one consisted in developing new routes to obtain the traditional polymers from biomass instead that from petroleum. Then, the synthesis of p-toluic acid (the terephthalic acid (TPA) precursor, and monomer for polyethylene terephthalate (PET)) from natural molecules (acrylic and sorbic acids) was set up by exploiting a Diels-Alder (DA) reaction. The developed strategy contributed to a more sustainable production of TPA, and, therefore, of a 100% bio-PET. The second strategy was based on exploiting monomers deriving from biomass to get new polymeric structures. Starting from vanillic acid, a monomer from natural resources, the synthesis of polyethylene vanillate, an homopolymer whose melting and glass transition temperatures are close to those of PET, was set up. To reduce its brittleness, random copolymers with ϵ-polycaprolactone or polyricinoleic acid were prepared; new possible antibacterial functionalities were introduced by ricinoleic acid functionalities. The preparation of copolymers was furthermore studied by considering DA reactions between furans (obtainable from natural resources) and maleimides: a copolymer was prepared by exploiting the tendency by DA adducts located within monomers structures to break over 100°C and to recombine at lower temperatures: the ability to associate and dissociate in a reversible manner can be used to produce innovative self-mending materials. Finally, a compound deriving from vegetal oil biorefinery (dihydroxyacetone) was exploited for obtaining innovative and bio-based polycarbonates and polyesters. In conclusion, strategies to get a 100% bio-PET, new bio-polymers that can substitute PET even with advanced functionalities, innovative bio-copolymers for self-mending materials and new polyesters and polycarbonates making the most of oil biorefinery byproducts were studied.