Thixotropic composite hydrogels based on agarose and inorganic hybrid gellants

Water can be used as oxidant in conjunction with metal particles to form metal–water propellant to increase the energy of propellant. For this application, water needs to be stored in form of solid and capable of becoming liquid when use. Stable and thixotropic hydrogel has good potential as water-retaining material and oxidant of metal-based propellant. In this study, we prepared organic/inorganic composite hydrogels by combining inorganic gellants hectorite and fumed silica with organic gellant agarose, respectively. The total content of the gellants can be reduced to less than 2% by adding agarose. The influence of agarose on water content, phase transition temperature, centrifugal stability and other basic physical properties of composite hydrogels were discussed. The results show that the composite hydrogels have better thixotropy and stability than pure inorganic hydrogels, and the gel–sol transformation can be realized by applying shear force or heating to the phase transition temperature. The composite hydrogels have good shear thinning ability and improved mechanical stability. Fumed silica/agarose hydrogels have better physical stability, while the thixotropy and shear thinning ability of hectorite/agarose hydrogels are better.