Teachers and Employees

Weber, Johannes ao. Univ.-Prof. Dr.phil.

title
Efficiency & Compatibility of Selected Alkoxysilanes on Porous Carb. & Silicate
type
article in journal with citation index
keywords
Chemistry, Conservation and Restoration
texts
description
The study compares the consolidation efficiency and compatibility of three selected alkoxysilanes on two porous carbonate and silicate substrates. Emphasis was given to artificially induced microstructural defects and subsequent restoration of mechanical and physical properties. Two newly engineered formulations (1) a TiO2 modified tetraethyl-orthosilicate in isopropanol with 70% active content and (2) a TiO2 modified alkyl- trialkoxysilane in isopropanol with 75% active content were compared to a commercial product (3), a solvent free tetraethyl-orthosilicate with 99% active content. Treatments were evaluated by scanning electron microscopy, mercury intrusion porosimetry, colour impact and their effect on dynamic modulus of elasticity, splitting tensile- and flexural strengths, capillary water absorption and water vapour permeability. A key outcome was that mechanical strength gain induced by treatments is primarily governed by a stone’s texture and microstructure, and secondarily by the gel deposition rate of consolidants. Likewise, the kinetics of the gel-forming reaction during curing is dependent not only on the product but also on the substrate. Therefore, the moisture related properties and the visual impact develop during time. There is no general trend on how it evolves in time, which can lead to incorrect interpretations of treatment compatibility. The results prove that wide-ranging treatment performance is obtained when applying the same products on different substrates.
authors
Johannes Weber, M. Ban, E. Mascha, A. Rohatsch, J. Delgado Rodrigues
editors
MDPI
publishers
MDPI
date
2019
location
Basel (Schweiz)
URL
published in
title
Materials 2019, 12, 156; doi:10.3390/ma12010156
volume/issue
2019,12,156
pages
1-28