Abstract

DIAZ, CARLOS; VALENZUELA, MARÍA LUISA; YUTRONIC, NICOLAS  and  AGUIRRE, PEDRO. GELATION OF N₃P₃[NH(CH₂)₃Si(OEt)₃]_6-n [X]_n X = NH(CH₂)₃Si(OEt)₃, NCH₃(CH₂)₃CN AND OC₆H₄(CH₂)CN, n = 0 or 3 at the LIQUID/AIR/INTERFACE. J. Chil. Chem. Soc. [online]. 2010, vol.55, n.3, pp. 415-418. ISSN 0717-9707.  doi: 10.4067/S0717-97072010000300031.

The compounds N₃P₃[NH(CH₂)₃Si(OEt)₃]₆ (1), N₃P₃[NH(CH₂)₃Si(OEt)₃]₃[NCH₃(CH₂)₃CN]₃ (2) and N₃P₃[NH(CH₂)₃Si(OEt)₃]₃ [HOC₆H₄(CH₂)CN]₃ (3) undergo slow gelation at the interface oil/air at low temperatures to give perfect gels G₁, G₂ and G₃ respective ly. TEM analysis reveals nanoparticles of silica with mean size of about 10 nm. Pyrolysis under air at 800 °C of these gels affords a mixture of mainly Si₅(PO₄)₆O, SiP₂O₇ and SiO₂. Gelation and pyrolysis products were characterized by IR, solid-state NMR, TEM, SEM-EDAX microscopy and X-ray diffraction. The sol-gel process in the interface liquid /air is discussed in comparison with the usual sol-gel solution process.

Keywords : Sol-gel; cyclotriphosphazenes; nanostructure materials; silica nanoparticles; Phosphazenes.