TY - JOUR
T1 - Effect of the addition of hydroxyl-terminated polydimethylsiloxane to TEOS-based stone consolidants
AU - Zárraga, Ramón
AU - Cervantes, Jorge
AU - Salazar-Hernandez, Carmen
AU - Wheeler, George
N1 - Funding Information:
The authors wish to thank SEP-CONACYT-Mexico Project 23597, CONCYTEG and the University of Guanajuato (Fondo UG) for financial support.
PY - 2010
Y1 - 2010
N2 - Hybrid stone consolidants prepared from tetraethoxysilane (TEOS) and α,ω-hydroxyl-terminated polydimethylsiloxane (PDMS-OH) have been considered as one of the most promising approaches to improve the effectiveness of traditional alkoxysilane-based formulations. They have emerged as response to the negative reports commonly found in the literature: the resulting silica gel phase (SiO2) tends to develop fractures and fissures inside the stone as the gel shrinks during the drying stage. In this work, we employed SEM, solid-state 29Si NMR spectroscopy and compressive tests to characterize SiO2-PDMS hybrid gels. We report the morphological characteristics exhibited by gels prepared in vitro and in situ. It was found an appreciable reduction of gel fracture for hybrids prepared from 5% w/w of PDMS. As TEOS polycondenses, PDMS-OH is chemically incorporated into the gel matrix via Si-O-Si bonds. The inclusion of these elastic chains provides the necessary flexibility to resist the stress imposed by capillary pressure. Additionally, an important hydrophobic character is imparted to the stone.
AB - Hybrid stone consolidants prepared from tetraethoxysilane (TEOS) and α,ω-hydroxyl-terminated polydimethylsiloxane (PDMS-OH) have been considered as one of the most promising approaches to improve the effectiveness of traditional alkoxysilane-based formulations. They have emerged as response to the negative reports commonly found in the literature: the resulting silica gel phase (SiO2) tends to develop fractures and fissures inside the stone as the gel shrinks during the drying stage. In this work, we employed SEM, solid-state 29Si NMR spectroscopy and compressive tests to characterize SiO2-PDMS hybrid gels. We report the morphological characteristics exhibited by gels prepared in vitro and in situ. It was found an appreciable reduction of gel fracture for hybrids prepared from 5% w/w of PDMS. As TEOS polycondenses, PDMS-OH is chemically incorporated into the gel matrix via Si-O-Si bonds. The inclusion of these elastic chains provides the necessary flexibility to resist the stress imposed by capillary pressure. Additionally, an important hydrophobic character is imparted to the stone.
KW - Ethyl silicate
KW - Hybrid gels
KW - PDMS-OH
KW - Stone consolidant
KW - TEOS
UR - http://www.scopus.com/inward/record.url?scp=77949838806&partnerID=8YFLogxK
U2 - 10.1016/j.culher.2009.07.002
DO - 10.1016/j.culher.2009.07.002
M3 - Artículo
SN - 1296-2074
VL - 11
SP - 138
EP - 144
JO - Journal of Cultural Heritage
JF - Journal of Cultural Heritage
IS - 2
ER -