Hydrophobizing of gypsum by silanes (Part 2)

The effectiveness of silanes as known water repellents for gypsum building materials had been the topic of the experimental studies on the example of propyltriethoxysilane in Part 1 of this article (ZKG 7-8/2013, pp. 72-78). Part 2 considers the involved processes on a molecular level, using molecular dynamic simulations. The results are interpreted together with the findings of Part 1 to obtain an understanding of the working mechanism of the hydrophobizing effect of silanes, especially alkyltriethoxysilanes, using the example of propyltriethoxysilane.

2.4 Molecular dynamic (MD) simulations
The MD simulations were carried out using the GROMACS-software package [22, 23] together with the GROMOS96 force field [24]. Force field parameters for calcium ions were taken from Åquist [25]. For silanes the parameters were derived from the GROMOS96 force field parameters. GROMOS96 is a united atom force field, thus different CHn-groups are treated as one atom, for example.

The simulations were based on the assumption that the silane molecules adsorb on the gypsum surface to achieve the hydrophobizing effect. The adsorption/desorption processes were...

Related articles:

Issue 2013-7-8

Hydrophobizing of gypsum by silanes (Part 1)

1 Introduction Gypsum products are used in a wide range of applications, primarily in the building material sector. The most important are gypsum and gypsum-lime plasters, plaster boards, gypsum fiber...

more
Issue 2022-3 US 2022/0064069 A1

Gypsum building material with improved high-temperature resistance

(22) 20.12.2018 (43) 03.03.2022 (57) A gypsum building material, characterised in that the gypsum building material comprises at least gypsum, H-siloxane and/or amorphous silicon dioxide and...

more
Issue 2019-5 KAZAN STATE UNIVERSITY OF ARCHITECTURE AND ENGINEERING

The influence of water-repellent admixtures on the water resistance of hardened gypsum-cement-puzzolan paste based on low-grade gypsum

1 Introduction The widespread use of gypsum-cement-puzzolan binder (GCPB) is a result of its low cost, environmental friendliness and the high performance properties of the products based on it. GCPB...

more
Issue Drymix 2015 DOW CORNING/NUBIOLA

New silicone resin-based hydrophobic powder for the drymix market

1 Introduction The porous structure of construction materials based on ordinary Portland cement leads to their high sensitivity to capillary water absorption. Control of water absorption is therefore...

more
Issue 2016-12 WO 2016/136485 A1

Apparatus and method for calcination of gypsum

(22) 12.02.2016 (43) 01.09.2016 (57) [Problem] To improve the flowability of a material gypsum deposit layer in a furnace to thereby prevent the development of “unevenness” in calcined gypsum, while...

more