Synthesis And Characterization Of Metal-coordinated Natural Polymeric Gels

Metal-coordinated natural polymeric gels(MCNPGs)can be described as a subset of physically cross-linked natural polymers that with three-dimensional networks,and where linkages between natural polymer backbones or functional groups of natural polymers are provided by pediocratic metal-ligand coordination interactions.MCNPGs are biocompatible,biodegradable,safe and non-toxic like natural polymeric materials anddisplay particular the optical,electrical,magnetic properties compared to synthetic polymeric gels by chemical crosslinking.And MCNPGs have received considerable attention from scientists due to their potential applications in fields of ploymer materials.Metal coordination interaction,especially coordination between multivalent metal ions and carboxyl groups,as a kind of most common method has demonstrated some of peculiar advantages in synthesis of gel networks,like strong coordination ability and fast reaction rates.Conventional synthesismethods of synthetic polymeric gels require multiple reactions and post-processing operations,which are very complicated.Initiator,crosslinking agent,catalysis used in reaction are toxic,researches have consideratetrouble removing drastically them in post-processing operations.Then a novel strategy to synthesize MCNPGs is using natural polymers and metal coordination,which can avoid effectively above-mentioned shortages and synthetic MCNPGs with certain strength and functionalities.In this study,the coordination reaction of carboxyl groups and Neodymium ions or trivalent iron ions were investigated to prepare Alginate and carboxylic graphene oxide composite gels via Neodymium ions coordination(Nd-SA/GO-COOH gels)and trivalent iron ions coordinated xanthan gum gels(Fe-XG gels)with high strength,respectively.Chemical structures of the gels were characterized by FT-IR,UV-Vis and XPS.The properties of the MCNPGs were characterized by SEM,TGA,swelling ratio and mechanical testing and so on.