Sustainable synthetic pathways towards the formation of bio-based polymeric materials

Sammanfattning: Increasing environmental and social awareness arising from the use of oil as main source of raw materials, has awaken the interest of many scientists to explore new synthetic pathways for polymer production. These new approaches embrace the use of alternative feedstock and sustainable synthetic routes aiming for enhancing biodegradability and recyclability. This shift towards more benign strategies is considered positive from different perspectives. Through the exploitation of bio-based feedstock it is possible to minimize the carbon foot print at the same time as new tools for material formation are provided. The use of selective catalysts reduces the formation of side-products, minimizes or avoids the use of solvents and diminish energy consumption. At the same time, new polymeric structures can be formed in terms of functionality and architectures.  The work herein presented have focused on the development of sustainable synthetic routes for the formation of bio-based polymeric materials with targeted properties. In order to afford this, two bio-sources have been explored for the retrieval of different epoxy-fatty acids, i.e. outer birch bark and vegetable oils. In order to be able to tailor the final material properties and thus be able to target specific applications, we have relied on the selectivity of lipases to preserve the epoxy-functionalities during synthesis. Through the design of specific polymer architectures, e.g. telechelic oligomers, and branched or linear macromers, different degrees of functionality could be prepared. By covalently reacting the epoxy groups through different polymerization techniques, polymer networks were achieved. The proposed synthetic approach resulted in polymeric materials with wide variety of properties ranging from functional networks, to high Tg materials and adhesives, prepared all from renewable sources. This also proved the benefits of the use of lipases in synthesis of polymers for material applications.