Papers by Author: Sea Fue Wang

Abstract: This paper is an investigation of the properties of covalently bonded magadiite/polyimide nanocomposites synthesized with magadiite and polyimide（PI）. Synthesized magadiite was organically modified by n-hexadecyl trimethyl-ammonium bromide (CTAB) and then grafted by γ-aminopropyltriethoxysilane (APTS) γ-glycidoxypropyltrimethoxysilane( GPS ) or γ-methacryloxy-propyltrimethoxysilane ( MPS ). XRD confirmed the formation of the CTAB-magadiite and showed that the basal spacing increased from 1.54 to 2.46 nm. Three silylating reagents, APTS ,GPS and MPS, were reacted with the CTAB- exchanged magadiite. The subsequent formation of the organic derivatives was confirmed by XRD (X-ray diffractometer), FTIR (Fourier transform infrared spectrometer), and 29Si CP-MAS NMR (Solid-state nuclear magnetic resonance ) spectra. The copolymerization of the APTS- GPS- and MPS- modified magadiite produced new layered silicate-organic compounds and each one contained covalent bonds between the interlayer spaces. This structure is dissimilar to that produced using conventional clay polymer systems in which the ionic interactions between silicates and organic modifiers are dominant.

Abstract: In this study, the feasibility for use of multiphase BaTiO3 ceramics as microwave dielectric resonators was evaluated through the substitution of metal ions in B sites, such as ions of Mn, Co, Mg, In, Fe, Zn, and Ni. The effects of metal ions substitution and sintering conditions on the densification, microstructural evolution and microwave properties of the BaTiO3 ceramics containing cubic and hexagonal phase were examined.