Sol-gel polymeric coatings produced from TEOS and γ-MPS

Y. CASTRO; A. DURÁN; S. PELLICE; P. GALLIANO

Foz do Iguaçu, Brazil.

Simposio; First International Symposium on Non Crystalline Solids in Brazil - Fifth Brazilian Symposium on Glass and Related Materials.; 2001

Instituto de Física de Sao Carlos – USP Sao Carlos. ICG – International Commission on Glass.

Fragility is one of the most important problems of glass materials due to the presence of superficial defects and microcracks. The mechanical strength could be increased by applying protective coatings. Organic-inorganic hybrid coatings produced by sol-gel process is an interesting alternative. The aim of this work was to prepare coatings onto glass slides from polymeric sols. Hybrids sols from tetraetoxysilane (TEOS) and 3-(metacryloxypropil)trimethoxysilane (g-MPS) were prepared in acid medium for different TEOS/g-MPS ratios. These sols were modified by the addition of a colloidal silica suspension and/or titanium alcoxyde stabilised with acetilacetone in order increase the hardness. Stability of the different sols was evaluated by viscosity measurements. Coatings were obtained dipping at different withdrawal rates between 10 and 50 cm/min. Several thermal treatments (100 – 300°C) were performed to select the best sintering thickness and hardness measurements. Thickness higher than 4 mm was reached for most of the studied compositions with hardness enough high to protect glass products.