Preparation of TiO2-P(AM-AA) organic-inorganic composite water-retaining agent based on photocatalytic surface-initiated polymerization

The organic-inorganic composite water-retaining agent has been widely concerned because of its advantages such as strong salt tolerance, high strength and good thermal stability. However, there are still problems with non-uniform dispersion of inorganic particles and organic-inorganic interface is not tightly integrated. It causes the three-dimensional network structure formed is unstable, affecting the mechanical strength and water absorption properties of the water-retaining agent. To solve the above problems, this paper proposes a new method for preparing the double network structure organic-inorganic composite water-retaining agent by photocatalytic surface-initiated polymerization technology. Subsequently, the photocatalytic surface-initiated polymerization mechanism was studied by IR, and the distribution of TiO2 nanoparticles in polymers as well as their interface with organic phase were observed by TEM. Additionally, the water absorption performance and the kinetic process of absorption of water-retaining agent were researched. The results show that the free radicals produced by TiO2 with UV irradiation stimulate the copolymerization of acrylamide (AM) and acrylic acid (AA) monomers on its surface. The inorganic particles of TiO2 are dispersed evenly in the polymer and the organic and inorganic two-phase interfaces are tightly integrated. Meanwhile, the organic-inorganic composite water-retaining agent has water absorption performance and the water absorbency in deionized water reaches 942 g/g (1 g TiO2-P(AM-AA) organic-inorganic composite water-retaining agent (TiO2 / AM-AA = 5:1000) can absorb 942 g water). Therefore, this work provides a reference for the research and development of new organic-inorganic composite water-retaining agent.