Characterization of Dialdehyde Carboxymethyl Cross-Linked Sesbania Gum and its Application in Solid Electrolyte Membranes

Sesbania gum (SG), as an environmentally friendly natural polymer, was chemically modified in heterogeneoususing systems using a combination of cross-linking, carboxymethylation and oxidation to broaden its applications. The experimental results showed that the cross-linking was chiefly conducted on the smaller particles of SG, while the carboxymethylation and oxidation were primarily carried out on the larger particles. The carboxymethylation and oxidation obviously increased the average size of SG. The dialdehyde oxidation destroyed the crystalline structure of SG more severely than cross-linking and carboxymethylation. The cross-linking, carboxymethylation and oxidation increased the thermal stability of SG, but decreased its enthalpy change. The pasting properties of tapioca starch were influenced by the addition of SG and modified SG. The crystalline structure of polyethylene oxide (PEO) was influenced by addition of SG and modified SG. The reduction in crystallinity degree and introduction of dialdehyde carboxymethyl cross-linked sesbania gum (DCCLSG) with aldehyde groups were beneficial for ameliorating the ion migration through the solid electrolyte membrane.