Synthesis and study of a novel bio-based unsaturated polyester resin based on succinic acid Dimitra Patsiaoura1, Lazaros Papadopoulos2, Charles Markessini3, Electra Papadopoulou3, Eleni Pavlidou1, Georgios Vourlias1, Dimitrios Bikiaris2, Konstantinos Chrissafis1 1Physics Department, Aristotle University of Thessaloniki, Thessaloniki, Greece 2Department of Chemistry, Aristotle University of Thessaloniki, Thessaloniki, Greece 3CHIMAR HELLAS SA, 15 km National road Thessaloniki – Polygyros, GR-57001, Thermi, Thessaloniki, Greece Unsaturated polyester resins (UPRs) are one of the most eminent types of thermoset polymers in the industrial sector, having found applications in diverse sectors such as in the marine and the automotive industry. However, the growing levels of environmental awareness, as well as the urgency to develop non-petroleum based monomers, have led to a phenomenal interest in the development of bio-based UPRs (BioUPRs). In the current study, bio-based UPRs were synthesized based on succinic acid. The synthesis was conducted both via one-step and two-step polymerization. The structure of the materials was studied by means of Fourier-transform infrared spectroscopy and nuclear magnetic resonance spectroscopy, while thermal properties of the obtained materials were studied both by means of differential scanning calorimetry and thermogravimetric analysis. The materials which were prepared by the one-step polymerization procedure were miscible with the reactive diluents and were successfully crosslinked. On the contrary, the materials which were prepared by the two-step polymerization procedure were not miscible with the reactive diluent. Acknowledgments This research has been co-financed by the European Union and Greek national funds through the Operational Program Competitiveness, Entrepreneurship and Innovation, under the call RESEARCH – CREATE – INNOVATE (project code:T1EDK-01413).