STUDY OF PHASE-TRANSFER-CATALYST INFLUENCE IN CAO-SIO2 GEL PREPARATION

Gels in a CaO-SiO2 (20:80 wt%) system were prepared in a heterogeneous phase. The following phase-transfer catalysts were tested: 1 8-Crown- 6, 1 5-Crown-5 and tetrabutylammonium hydrogenosulphate. The influence s of the polarity of two non-classical solvents (toluene and dichlorom ethane) were also studied. The degrees of polymerization and of oxide contents were analysed by infrared spectroscopy and thermal analysis. Finally, the morphology and structure of the dry and fired gels were s tudied by scanning electron microscopy (SEM) and X-ray diffraction (XR D).