Synthesis of physically cross-linked gum Arabic-based polymer hydrogels with enhanced mechanical, load bearing and shape memory behavior

Abstract

The TiO2 dispersed physically cross-linked polymer hydrogels were synthesized through a single step free radical addition polymerization mechanism based on acrylic acid and gum Arabic (GA) as polymer constituents, and ferric ions (Fe3+) as physical cross-linker. The effect of TiO2 powder was investigated on thermal and mechanical properties of the hydrogels by dispersion of 0.01, 0.02 and 0.03 g of TiO2 in hydrogels. The prepared hydrogels were successfully characterized through FTIR, XRD, SEM and thermogravimetric analysis (TGA). For the mechanical properties, dynamic mechanical analysis and universal testing machine (UTM) were used. The DMA results showed that the storage modulus was increased with the TiO2, while UTM results showed that 0.02 g of TiO2 powder significantly enhanced the fracture stress, elastic modulus, toughness and stretchability by 4514%, 4328%, 4124% and 20%, respectively, compared to the virgin hydrogels. Cole–Cole plot confirmed the homogeneity and viscoelastic behavior of the system, while manual load bearing and shape memory test showed that the hydrogels bear a load of 2.5 kg for a long time and it is recovered within 10 s to its original state. The materials can be applied for the synthesis of artificial body parts in the field of bio-engineering. The use of un-modified GA for the synthesis of hydrogels will open a new window for the researchers working in this field.