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Title: A mechanistic study explaining the synergistic viscosity increase obtained from polyethylene oxide (PEO) and {beta}-naphthalene sulfonate (BNS) in shotcrete

Abstract

In shotcrete, a combination of polyethylene oxide (PEO) and {beta}-naphthalene sulfonate (BNS) is commonly applied to reduce rebound. Here, the mechanism for the synergistic viscosity increase resulting from this admixture combination was investigated via x-ray diffraction (XRD), infrared and nuclear magnetic resonance (NMR) spectroscopy. It was found that the electron-rich aromatic rings present in BNS donate electrons to the alkyl protons of PEO and thus increase the electron density there. This rare interaction is known as CH-{pi} interaction and leads to the formation of a supramolecular structure whereby PEO chains bind weakly to BNS molecules. Through this mechanism a polymer network exhibiting exceptionally high molecular weight and thus viscosity is formed. Among polycondensates, sulfanilic acid-phenol-formaldehyde (SPF) provides even higher synergy with PEO than BNS while melamine (PMS), acetone (AFS) or polycarboxylate (PCE) based superplasticizers do not work at all. Effectiveness of lignosulfonates is dependent on their degree of sulfonation.

Authors:
;
Publication Date:
OSTI Identifier:
22149353
Resource Type:
Journal Article
Journal Name:
Cement and Concrete Research
Additional Journal Information:
Journal Volume: 42; Journal Issue: 11; Other Information: Copyright (c) 2012 Elsevier Science B.V., Amsterdam, The Netherlands, All rights reserved.; Country of input: International Atomic Energy Agency (IAEA); Journal ID: ISSN 0008-8846
Country of Publication:
United States
Language:
English
Subject:
37 INORGANIC, ORGANIC, PHYSICAL AND ANALYTICAL CHEMISTRY; 36 MATERIALS SCIENCE; ACETONE; ELECTRON DENSITY; INTERACTIONS; MELAMINE; NAPHTHALENE; NMR SPECTRA; NUCLEAR MAGNETIC RESONANCE; PLASTICIZERS; POLYETHYLENE GLYCOLS; PROTONS; RHEOLOGY; SULFONATION; VISCOSITY; X-RAY DIFFRACTION

Citation Formats

Pickelmann, J., and Plank, J., E-mail: sekretariat@bauchemie.ch.tum.de. A mechanistic study explaining the synergistic viscosity increase obtained from polyethylene oxide (PEO) and {beta}-naphthalene sulfonate (BNS) in shotcrete. United States: N. p., 2012. Web. doi:10.1016/J.CEMCONRES.2012.08.003.
Pickelmann, J., & Plank, J., E-mail: sekretariat@bauchemie.ch.tum.de. A mechanistic study explaining the synergistic viscosity increase obtained from polyethylene oxide (PEO) and {beta}-naphthalene sulfonate (BNS) in shotcrete. United States. doi:10.1016/J.CEMCONRES.2012.08.003.
Pickelmann, J., and Plank, J., E-mail: sekretariat@bauchemie.ch.tum.de. Thu . "A mechanistic study explaining the synergistic viscosity increase obtained from polyethylene oxide (PEO) and {beta}-naphthalene sulfonate (BNS) in shotcrete". United States. doi:10.1016/J.CEMCONRES.2012.08.003.
@article{osti_22149353,
title = {A mechanistic study explaining the synergistic viscosity increase obtained from polyethylene oxide (PEO) and {beta}-naphthalene sulfonate (BNS) in shotcrete},
author = {Pickelmann, J. and Plank, J., E-mail: sekretariat@bauchemie.ch.tum.de},
abstractNote = {In shotcrete, a combination of polyethylene oxide (PEO) and {beta}-naphthalene sulfonate (BNS) is commonly applied to reduce rebound. Here, the mechanism for the synergistic viscosity increase resulting from this admixture combination was investigated via x-ray diffraction (XRD), infrared and nuclear magnetic resonance (NMR) spectroscopy. It was found that the electron-rich aromatic rings present in BNS donate electrons to the alkyl protons of PEO and thus increase the electron density there. This rare interaction is known as CH-{pi} interaction and leads to the formation of a supramolecular structure whereby PEO chains bind weakly to BNS molecules. Through this mechanism a polymer network exhibiting exceptionally high molecular weight and thus viscosity is formed. Among polycondensates, sulfanilic acid-phenol-formaldehyde (SPF) provides even higher synergy with PEO than BNS while melamine (PMS), acetone (AFS) or polycarboxylate (PCE) based superplasticizers do not work at all. Effectiveness of lignosulfonates is dependent on their degree of sulfonation.},
doi = {10.1016/J.CEMCONRES.2012.08.003},
journal = {Cement and Concrete Research},
issn = {0008-8846},
number = 11,
volume = 42,
place = {United States},
year = {2012},
month = {11}
}