Development of sustainable polysaccharide matrices whit hidrophobic modifications

Résumé

The feasibility of producing several types of green sorbent matrices has been explored in this investigation. These matrices were based on three polysaccharides: xanthan gum, locust bean gum and chitosan, and mainly on one crosslinker, citric acid, and one adjuvant, β-cyclodextrin. The most suitable reaction conditions (temperature, time, catalyst) in a solventless crosslinking process were studied. The influence of the proportion of each reagent has also been studied by using a mixture design in order to understand the effect of the ingredients on the swellability in water and the sorption properties of the crosslinked matrices. By mixing the different polysaccharides and incorporating two types of cyclodextrins (α or β), the possibility of tailoring the matrices to selectively absorb a compound of interest from a phenolic mixture has also been explored. In addition, to enhance their sorption properties, another natural hydrophobic modifier, lignin, was also added to the crosslinked networks. Its particular affinity towards phenolic compounds resulted in higher sorption capacities. Because the sorption properties are also impacted by the specific area of the materials, the use of saponin, a natural detergent, was incorporated into the matrices, using different reaction paths, to produce crosslinked foams, whose performance was compared to that of the previous samples. With the aim of ascertaining the possibilities of preparing films by photocrosslinking reactions, an experimental design was carried out. The variables selected were the type of crosslinker (citric or itaconic acid), its amount, the catalyst type, and the presence of a photoinitiator (curcumin). A preliminary study, using different illumination conditions, was carried out to propose the best possible method to apply these natural-based mixtures to 3D-bioprinting in future works. Finally, the formation of nanofibers by electrospinning was also studied. Experimental conditions, such as polysaccharide concentration, voltage or flow, were changed to select the most appropriate to prepare good quality nanofibers. Once those were found, thermal crosslinking was carried out to obtain an insoluble crosslinked material, and the release of triclosan was studied to investigate their possible application for medical purposes.