The SURE-Poly project aims to develop sustainable thermoset materials through an integrated approach. Renewable precursors derived from agro-alimentary and biomass waste were utilized and functionalized using green chemistry. These precursors were then processed to form crosslinked polymeric networks. By introducing dynamic covalent bonds into these networks, recyclability and reduced waste generation was therefore achieved throughout the thermoset lifecycle. Overall, the activities have been performed according to the following steps:
Waste Recovery and Valorization
The project began with recovering and valorizing waste from agro-food industries. Plant and woody biomass serve as an attractive and abundant source of bio-based precursors for thermoset synthesis. Plant biomass, as the Earth's most abundant renewable feedstock, provides significant opportunities. For instance, the pulp and paper manufacturing industry is identified as a promising sector for bio-based plastics, leveraging its wood-based lignocellulose availability. Lignin, the second most abundant biopolymer globally and an industrial by-product of the pulp and paper industry, is produced at approximately 50 million tons annually. However, less than 2% of lignin is currently used for producing chemicals or lignin-based products, with the rest predominantly utilized for energy generation. Recognizing lignin’s potential, it was selected as a feedstock for this project. Various bio-derived building blocks were developed (WP1) and subsequently functionalized (WP2).
Functionalization of Bio-Based Polymers
In WP2, recovered bio-based polymers were functionalized through methacrylation, acrylation, allylation, and oxidation reactions to introduce epoxy functional groups. These functionalized monomers were then employed to produce bio-based polymer networks using environmentally friendly UV-curing processes, which emit low levels of volatile organic compounds (VOCs) and consume minimal energy. Traditional thermal curing methods were also applied (WP3). The resulting polymer networks were designed to exhibit dynamic covalent bonds properties, enabling network rearrangement under thermal stimuli. Stress-relaxation measurements confirmed these properties, as applied forces led to significant stress relaxation, absent in permanently crosslinked networks.
Application in 3D Printing
In the final phase (WP4), the previous investigated bio-based formulations were employed in 3D printing technologies. This approach enabled the creation of complex 3D structures with dynamic topology properties. These structures demonstrated reprocessability and recyclability, advancing the potential for sustainable applications of bio-based polymers.
Through its innovative integration of waste valorization, green chemistry, and advanced processing techniques, the SURE-Poly project underscores the viability of sustainable thermoset materials for a circular economy.
