Self-Ordered Silsesquioxane Cubic Powders from Alkyltrialkoxy Silane Monomers

초록

MTMS (Methyltrimethoxysilane) and ETMS (Ethyltrimethoxysilane) based silsesquioxane cubic powders were synthesized in basic alcohol solution. The cubic powders exhibited sublimation behavior between 180 and 250 degrees, which resulted no residue over 250 degrees. The analysis of a cross-polarization magic angle spinning (CP-MAS) 29Si NMR(VARIAN, Unity Inova, 200 MHz) indicated that they mainly consisted of T3 structure, which could be identified by the absorption peak at -67.7 ppm. The evidence for the presence of silsesquioxane structural features was also to be found in the Infrared and Raman spectra. We have investigated the crystal structure of methyl and ethyl silsesquioxane powders by the X-ray diffraction method (XRD, RAD-C with Cu Ka radiation). Applying Bragg`s Law, d=λ/2sin? with λ=1.5418A, gives d-spacing of 16.5 A, which is the distance between lamellar layers. From the above results, we conclude that the silsesquioxane cubic powders might have crystalline lamellar structure, which can provide the new structural feature. Physical and chemical properties of these cubic silsesquioxane powders are under investigation.