Inhibitive Role and Mechanism of Water-Soluble Polymer PVP on the Surface-Exfoliation Problem of Ceramic Green Bodies Prepared byGelcasting
水溶性高分子PVP对陶瓷凝胶注模成型坯体表面起皮的抑制作用与机理

The inhibition of oxygen, which occurred in gelcasting during the formation of polymer networks by in-situ polymerization of monomers in air, was successfully prevented by adding a proper amount of polyvinylpyrrolidone (PVP) to the aqueous acrylamide solution. Thus, the surface-exfoliation problem of green bodies was eliminated and the aim of precisely controlling the size of the formed green bodies was achieved by gelcasting in air. The influence of PVP on the dispersion of alumina, the static and dynamic rheological properties of alumina slurry and the strength and microstructure of green bodies was investigated. Furthermore, the mechanism of PVP in eliminating the surface-exfoliation problem of green bodies gelcast in air, namely the role of PVP in thickening and the hydrogen bonding between the molecules of PVP, which serve as a ceramic binder for the particles on the sample surface, was analyzed via the infrared spectra.