Preparation and characterization of porous titanium dioxide sulfonated polystyrene composite microspheres with amphiphilicity

Abstract

Porous particles with amphiphilicity were prepared by a nonpolymeric pore-formation process with the sulfonation of polystyrene microspheres. Nano titanium dioxide (TiO 2 ) particles were then grafted onto the surface via a sol-gel method to finally form the composite particles. The effects of the mass ratio of ethanol (EtOH) to water, temperature, and solubility parameter on the pore-formation process is discussed in detail. The morphology, porous structure, and wetting properties of the particles were studied by scanning electron microscopy, transmission electron microscopy, Fourier transform infrared (FTIR) spectroscopy, and contact angle measurement. The results show that porous sulfonated polystyrene (SP) microspheres could be fabricated at 60 C with a 1 : 1 mass ratio of EtOH-water and a solubility parameter of 29.69 MPa 1/2 . The TiO 2 particles were determined to be grafted onto the SP microspheres by physical-bond interaction on the basis of FTIR analysis. The contact angles for both water (aqueous-phase) and various organic solvent (oil-phase) droplets with different polarities on the surface of compressed tablets of TiO 2 -SP powder were all lower than 30 ; this indicated excellent amphiphilicity in the composite particles.

Synthesis of Low-Density Heat-Resisting Polystyrene/Graphite Composite Microspheres Used as Water Carrying Fracturing Proppants

“…It was obviously found that due to the appearance of slightly creased layered graphite, the morphology of microspheres looked like fish-scale pieces. The morphologies and properties of microspheres had been changed before and after modification, which provided direct visual evidence for the presence of graphite and the graphite that was successfully doped into the PS microsphere during polymerization [22,23] . By comparison, the SEM images of quartz sand and resin-coated sand were presented (Figs.…”

Preparation of heat resisting poly(methyl methacrylate)/graphite composite microspheres used as ultra‐lightweight proppants

“…It could be explained that since the density of graphite powder is higher than that of pure PMMA, when they were blended the density of composite particles is between both components, and increased with increasing graphite content. 28 What's more, the density of traditional ULW proppant, such as resin coated and impregnated ground walnut hull and porous ceramic particle coated (not impregnated) by resins, 32,33 were 1.25 and 1.75 g/cm 3 , respectively. Thickening agents, such as guar gum were needed in the fracturing fluid by using conventional high-density hydraulic fracturing proppants, 34 which are contaminative and hard to be degraded.…”

“…This provided direct visual evidence that the graphite was successfully doped into the PMMA microsphere during polymerization. 27,28 For comparison, the SEM images of ceramics under different magnification were presented in Figure 5(m,n,o), which showed a rough surface and a bad sphericity to the composite microspheres.…”