Synthesis of biobased monomers and polymers

As fossil sources depletion and pollution are posing severe drawbacks to the polymer industry, the need for new pathways for the production of materials by renewable and sustainable means arises. The aim of the project is producing bio-based monomers and, subsequently, the corresponding bio-based polymers. The focus is on polyolefins and epoxy resins. The substrates come from the upgrading of agricultural and forestry industries waste streams. Those are mainly vanillin, guaiacol, furfural and glycerol, which are all potentially renewable and for which it is expected an increase in production in the near-term future1-3. In the case of olefins, their production is aimed towards Atom Transfer Radical Polymerization (ATRP). The technique allows precise tailoring of chain length and molecular weight distribution by means of a reversible deactivation equilibrium mediated by a transition metal salt complex. The technique is to be considered environmentally benign as it operates in mild conditions and is able to achieve control even at catalyst loadings as low as ppm levels4. 4-Vinyl Guaiacol Acetate (4‑VG‑Ac), Vanillin MethAcrylate (VMA) and Vanillin Ethylene MethAcrylate (VEMA) were successfully produced from vanillin and polymerized in a controlled fashion by SARA ATRP. Studies on their metal-free ATRP are being performed to increase process sustainability. As BPA was banned by the European Union due to its endocrine disrupting activity, there is need for sustainable alternatives. Guaiacol is the ideal substrate to upgrade, as it was demonstrated that the higher degree of substitution of the aromatic ring results in a decrease in toxicity by various orders of magnitude5. Various reaction pathways were tested on laboratory scale. Production of 2‑Methoxy Hydroquinone (MHQ) was performed by Dakin oxidation of vanillin, affording minimal waste production. Guaiacol condensation by oxidative coupling into the corresponding triphenylene was performed, albeit at non-satisfactory conversion values. Condensation studies performed on furfural and furfural derivatives have been unsuccessful. Studies on guaiacol dimerization into bisguaiacols by electrophilic aromatic substitution reactions are ongoing. Upscaling is planned to afford the quantities required for mechanical testing. The corresponding bi-component resins will be tested as binders in mortars for the construction sector and in epoxy/graphite composites in bipolar plates for fuel cells, aimed towards sustainable hydrogen production.