3DBIOBASED

Research on synthesis of biobased polymers and fabrication of biobased materials recently intensified. The separation and characterization methods for these polymers remain however mostly the same as for fossil-based polymers. Methods to accurately determine the distributions of sizes, molar masses, of chemical compositions or the branching of biobased polymers are needed to enable the synthesis of biobased polymeric materials with optimal properties. A new platform for the routine separation and characterization of biobased polymers will be established. Advanced (two-dimensional) separation and characterization methods will be developed in parallel. Selected polymers will thus be characterized in-depth at the molecular level. These advanced methods will also enable us to benchmark the routine (simple, fast and robust) methods of the platform to characterize the size or molar mass, chemical composition and purity of biobased (co)polymers as well as their heterogeneities. Capillary electrophoresis (CE) in the critical conditions will for example be used for the fast characterisation of branching and chemical composition. The CE methods will be complementary to and less tedious than current size-exclusion chromatography (SEC) methods. Taylor dispersion analysis (TDA) and multiple detection SEC together with CE will provide an assessment of the current SEC methods to determine distributions of molar masses but also hydrodynamic volumes, as well as the related averages (e.g., Mn, Mw) and dispersities (e.g., Ð). This characterization platform will be developed using two very relevant families of biobased polymers researched in the Polymer Chemistry team (ECP) at Sorbonne University: polyamides and polyesteramides synthesized from non-purified biobased monomers (dimer acids), as well as graft copolymers obtained from the artificial polymer chitosan. With dimer acids, the aim is to take advantage of their complexity to produce polyesteramides and polyamides with molecular structures designed and predicted through structure-property relations. Dimer acids contain diacids to be polymerized with diamines or ethanolamine, as well as monoacids (residual fatty acids which have not dimerized) and triacids in various proportions. Monoacids stop the chain extension and limit the macromolecular chains size; triacids give rise to branched structures, changing the chain topology while increasing the molar mass and possibly causing gel formation. CE will enable monitoring the conversion of the different acids during polymerization, and thus predicting average molar masses and the average degree of branching. This will thus also allow establishing structure-property relations. Chitosan, an artificial polymer produced from chitin, will be used for graft copolymers. Chitin is a waste from the food industry. CE will allow determining the distributions of chemical compositions of chitosan, a composition better known as degree of acetylation. The knowledge of these distributions will enable a more accurate characterisation of chitosan and of chitosan-based copolymers. Acrylamide and N-vinylpyrrolidone, two monomers that can be biobased, will both be used to separately synthesize graft copolymers from chitosan backbones. These two families of biobased polymers with different and complex structures will allow the design, development and validation of the separation and characterization platform. This platform will then be open to the French and European, academic and industrial, biobased polymer community.