Synthesis And Properties Of Silica Or Artificial Sand Composites

In view of the better heat resistance and resistant crushed property of SiO2 cores, they are more suitable for application in construction, such as railway, highway and bridge. Unfortunately, SiO2 cores intend to aggregate into larger clusters, losing the specific properties associated with their nanometer dimensions. So, in this paper, we synthesized amphiphilic silica nanocomposites contained quaternary ammonium group based on SiO2 nanoparticles.The silicate based cement composite has been widely used in housing, railways, highways, and bridges. The artificial sand is an ideal fine aggregate however, it is coarser which will weaken the fluidity of the cement-based composites and increase water demand. Here in, the silicate based cement composite was modified with hydrophilic polymer, to weaken the influence of the silicate based cement composite on fluidity and improve the dispersibility of the artificial sand. The main tasks are as follows:(1) A new kind artificial sand particles modified by poly (acrylic acid) and poly (methoxy poly (ethylene glycols) methacrylate) are successfully prepared. After reacted with 3-methacryloxypropyltrimethoxysilane and grafted with poly (acrylic acid) and poly (methoxy poly (ethylene glycols) methacrylate), artificial sand turn into the new artificial sand particles. Structure properties of the modified artificial sand particles are investigated by scanning electron microscopy (SEM), fourier transform infrared spectra (FI-IR), X-ray diffraction (XRD) and thermogravimetric analysis (TGA). The fluidity and stability of the surface-modified artificial sand microfines/cement paste are better than those of pristine artificial sand microfines/cement paste. The results revealed that the surface-modified artificial sand microfines can significantly improve the workability and the durability of concrete.(2) Ultrafine silicon dioxide has attracted a great interest in the field of lubricating additives because of its excellent tribology performance. In this paper, the surface structure characteristic, the mechanism of surface modification and the general modification methods of ultrafme silicon dioxide were introduced, especially for alcohol/ester method, silane coupling agents method and surface grafting modification, and the more promising modification approach was indicated. In addition, the application of ultrafine silicon dioxide in lubricating oil was reviewed briefly. The future development trend of its application in lubrication oil was finally expected.