Síntese de xerogel para fins de conforto térmico em placas cerâmicas

Abstract

The production of the xerogel material was made through the sol-gel synthesis method by the hydrolysis and condensation reactions using the tetraethylortosilicate (TEOS) and trimethylchlorosilane as the precursors materials in a hydroalcoholic solution containing ethanol and bi-distilled water. Hexamethyl-bis-siloxane, trimethylmethoxy- siloxane and Triethoxy-trimethyl-bis-siloxane were identified as main components presents in the mixture of synthetized xerogel material. These materials when inserted at 8% (w/w) in a red clay extracted near to west-south region of Rio Grande do Sul state from Brazil provides an increase in thermal resistance on ceramic plates in reduced scale. Measurements of thermal conductivity was made by parallel hot wire method (DIN-EN-993-15) shows a reduction by around half of thermal conductivity from 0,5354 W/mK (ceramic plates in reduced scale containing only red clay) for 0,2850 W/mK (ceramic plates in reduced scale containing 8% of mixture of xerogel). This feature was attributed to increases on voids number on ceramic plates structure by presence of 8% (w/w) of the mixture of xerogels synthetized according revel the decreases of density from 1,75±0,02 g/cm³ to 1,72±0,02 g/cm³.