Physicochemical Characterization and Network Modeling of Cross-Linked Inulin Based Hydrogels

Inulin (In)-based hydrogels were produced using 1,3-diepoxybutane (BDE) as a crosslinker under basic conditions. The amount of BDE influences the network properties of In/BDE gels. FTIR spectroscopy revealed the formation of ether bridges, indicating successful synthesis of gels, and thermal characterization confirmed that higher cross-linking density increased polymeric matrix stability. In PBS medium, the equilibrium swelling capacity decreased from 3.32 g/g to 1.44 g/g with increasing BDE content. Flory–Rehner thermodynamic analysis indicated that restricted swelling was driven by an 18-fold increase in effective crosslink density (𝜈𝑒) and reduction in the molecular weight between crosslinks (𝑀𝑐̅̅̅̅) 1023.89 to 57.14 gmol-1. Kinetic data followed Fickian diffusion with exponent (n) values between 0.126 and 0.305, fitting the Pseudo-Second Order (PSO) model well. Overall structural evidence indicates that the developed In/BDE hydrogel matrices possess finely adjustable configurations. This architectural control makes them excellent candidates for both controlled-release therapeutics and wastewater purification applications.