The global plastics production reached 335 million tons in 2016, absorbing about 6% of the fossil feedstock extraction. Nowadays, due to the depletion of the oil reserves and to the raising environmental concerns related with these raw materials and the end-of-life disposal (cf., “plastic soup”), many countries are now increasingly adopting strict legislation on the use of certain monomers and plastics to mitigate these effects. Therefore, the demand for more sustainable and renewable monomers and polymers is gaining huge momentum.
In this context, aliphatic polyesters (APEs) represent one of the most appealing types of plastic materials, because of their general biocompatibility and facile hydrolytic degradation. The ring opening polymerization (ROP) of cyclic esters and lactides (usually promoted by metal complexes) is one of the most effective ways toward APE production. This polymerization technique allows for excellent control over the molecular weights of the final polymer, and typically with narrow molecular weight distributions. Unfortunately, the reaction is often limited to six- and seven-membered cyclic monomers, reducing significantly the range of mechanical, thermal and post-synthetic properties of the APEs, and consequently a wider application of APEs in consumer products. The physical properties of poly(lactic acid) (PLA), a well-known commercial APE, can to some extent be modulated by copolymerization with other cyclic esters, and typically copolymerization with petrochemicals-derived ε-caprolactone (CL) is carried out to achieve this goal. However, current polymerization technologies greatly suffer from the availability of more functional monomers that can widen the scope (in particular the thermal resistance, cf. glass transitions (Tg) values) of APEs in current and new materials with an improved sustainability footprint. Therefore, the use of accessible, bio-sourced monomers for APE synthesis is highly attractive since these monomers are generally renewable, cheap and offer the structural and molecular diversity not present in the conventional monomers to explore novel and unexplored properties for APEs. A proper choice of the biobased monomer will greatly facilitate the design of new APEs with improved or unknown electronic, thermal and mechanical properties interesting from both an academic and industrial perspective.
The primary aim of the SUPREME project is the creation of new polyester formulations based on renewable and accessible terpene monomers to answer to the growing need for future generations of more functional and sustainable materials. The results of the action will have a strong impact on the society, giving the opportunity to assess circular economy concepts in industrial sector with high environmental impact, such as that of biopolymers. Therefore, this project is closely aligned with the H2020 priorities, especially within the societal challenge 5: Climate action, environment, resource efficiency and raw materials.
The specific objectives of the SUPREME project are the following:
SO1. ROP of 1,2-campholide (CAM) to afford the new APE poly(campholide), PCAM
SO2. Synthesis of new APEs through ROCOP of β-elemene monoxide (BEM) and camphoric
anhydride (CA) to produce various polyesters with tunable functionality and rigidity
SO3. Post-modification of a functional APE obtained under SO2, and the study of the thermal, chemical and mechanical properties
