Sustainable production of monomers, polymers and composites using click chemistry and renewable raw materials

Polymers drastically changed the society within the last century, and the maintenance of modern life, as we know it, is not possible without synthetic polymers. However, their indiscriminate use and disposal have led to a growing accumulation of waste in the environment, which implies a great threat to ecosystems, biodiversity, and human beings. Additionally, the non-renewable origin of most polymeric materials implies the emission of greenhouse gases, which must be drastically reduced to guarantee the stabilization of Earth’s average temperature. In this context, efforts have been directed to the development of alternative materials, mainly of vegetable origin, that can be obtained through chemical processes that are aligned with the concepts of green and sustainable chemistry. Thus, the production of waste must be avoided, and the design of synthetic methodologies that can maximize the incorporation of all starting materials into the products, as well as the use of renewable sources of raw material, shall be prioritized. "Click" chemistry provides important guidelines and techniques to produce new molecules of reduced environmental impacts with respect to their conventional counterparts. Herein, we intend to build a fully renewable platform for the synthesis of monomers and copolymers by (i) synthesizing monomers from methyl alpha-eleostearate (the major fatty acid methyl ester produced via the transesterification reaction of tung oil) and itaconic acid (industrially produced by fermentation of carbohydrates), using two "click" reactions, i.e., the Diels-Alder reaction and the thiol-Michael reaction; (ii) synthesizing polymer networks via step-growth and chain-growth polymerization reactions, considering that they will most likely exhibit increased polarity with respect to vegetable oil-based homopolymers; and (iii) using the synthesized polymer networks as continuous phases for the production of composites with varying disperse phases, such as lignocellulosic fibers, algae biomass with high silica content, and sands of different granulometries, in a strategy that eliminates the use of compatibilization agents so that superior thermal and mechanical properties are achieved, which is consistent with the concept of green chemistry. The project will be carried out in collaboration with Prof. Dr. Rafael L. Quirino (Georgia Southern University, United States), who has extensive experience in the synthesis and characterization of polymers from unsaturated vegetable oils. The results to be gathered here are considered very relevant at a time when it becomes increasingly necessary to consolidate processes and materials that are ecologically benign for the maintenance of the environment and the quality of life of a society totally dependent on polymeric materials. (AU)