About Sustainability in Ring-Opening Metathesis Polymerisation

Degradable polymers are macromolecules that can be broken down into their constituent unit or smaller by-products or oligomers under specific conditions. Degradable polymers obtainable via ring-opening metathesis polymerisation (ROMP) are rare. Poly(Dihydrofuran) (Poly(DHF) represents a recent example of a ROMP-obtained degradable polymer. 2,3-Dihydrofuran, the monomer leading to poly(DHF), is a cyclic enol ether. This furan derivative was previously synthesised following different synthetic routes described in the literature, such as cyclisation of alkynyl alcohol, or cycloaddition.[3] In this work, possible alternative pathways for the synthesis of 2,3- dihydrofuran are investigated to improve the sustainability of the synthetic process to poly(DHF). The dilution limit of the homopolymerisation of this monomer is investigated, and a copolymer with a norbornene derivative will be synthesised to modify the thermal proprieties of poly(DHF). In addition, the synthesis of five-membered rings heterocycles is also investigated, and ring-strain calculations on thiophene derivatives are performed. Sulfur-containing polymers are, in fact, of particular interest due to their unique optical and thermal properties. ... mehrIn this work, sulfur-containing norbornenes are synthesised as thioethers and sulfone and polymerised by ring-opening metathesis polymerisation (ROMP). Utilising the 3rd generation Grubbs catalyst, well-controlled reactions led to polymers with low dispersities and molecular weights up to 350 kg mol−1.
A diblock and a statistical copolymer bearing thioether and sulfone moieties were also successfully synthesised, while the thermal properties of all polymers were also evalu- ated, correlating them to the structural characteristics of the corresponding monomers. Lastly, the evaluation of Levoglucosenone-derivatives as building blocks for bio-based polymers is conducted. Bio-based polymers represent a sustainable alternative to the fossil fuel-based ones. Levoglucosenone is a suitable substrate for polymerisation reactions, as, for example, pairing this substrate with cyclopentadiene allows the formation of norbornene-like structures that can undergo ring-opening metathesis polymerisation. Such reactions, however, decrease the overall sustainability of the monomer. To obtain fully bio-based levoglucosenone-derived polymers, in this work, furan was implemented as a counterpart substrate for an electrophilic substitution reaction. Three aromatic moieties were synthesised based on the cellulose derivative levoglucosenone and bio-based furan or furan derivatives, such as methyl furan and ethyl furan. The resulting products were fully characterised and exposed to a combination of a ruthenium-based catalyst and ZnCl2 to investigate their polymerisation ability.