Study of the biopolymers chitin and chitosan chemically modified for metal chelation and for carbon dioxide capture and fixation.

Abstract

The project aims to study the structural modifications that can be made in the side groups of the polymers chitin and chitosan. These modifications occur in the synthesis of various polymeric materials through the N-alkylation reaction of chitin-chitosan with an aromatic aldehyde and coupling reactions between the product and different diazonium salts. The coupling reaction forms the poly-azo-compounds which are composed by two phenyl rings connected by the group -N=N-. These azo-polymers may be promising materials for technological applications, such as optical storage. Besides the chemical modification of side groups of the polymer chitin-chitosan, the aim of the project is also to study the capacity of these products to form complexes with transition metals. Another objective of the project is the study of capture and fixation of CO2 molecule in the form of carbonates. The proposed work may lead to materials with potential application in the solution of environmental problems such as the treatment of industrial effluent and carbon dioxide recycling, which may contribute to reducing the emission of the gas into the atmosphere. To confirm the synthesis of the polymeric compounds, it will be used spectrometry and spectroscopic techniques such as, FTIR, NMR in solution, solid state NMR and mass spectrometry using electrospray ionization. The UV-Visible technique will be used in this study to investigate the effect of the substituents present in the structure of poly-azo-compounds in the absorption in the ultraviolet-visible region. It will be also studied the thermal stability of these compounds by the techniques TG/FT-IR and DSC. The polymeric complexes and polycarbonates will be also studied by the techniques mentioned above.