A systematic study on polymer modified alkali-activated slag – Part I: Stability analysis of colloidal polymer dispersion in sodium water glass. (10th October 2019)

• Record Type: Journal Article
• Authors: Lu, Zichen; Merkl, Jan-Philip; Schmidtke, Christian; Pulkin, Maxim; Deschner, Florian; Wache, Steffen; Jin, Yu; Stephan, Dietmar
• Is Part Of: Construction & building materials. Volume 221(2019)
• Page Start: 40
• Page End: 49
• Publication Date: 2019-10-10
• Subjects: Polymer dispersion -- Colloidal stability -- Alkali activated material -- Sodium water glass; Building materials -- Periodicals; 624.18
• DOI: 10.1016/j.conbuildmat.2019.05.164
• Languages: English
• ISSNs: 0950-0618

Abstract

Highlights: Stability of classical cement-stable polymers in sodium silicate was investigated. Styrene acrylate (SA) polymer is more stable than ethylene-vinyl acetate (EVA) polymer. Highest colloidal stability of SA was observed with the lowest modulus (M < 1.81). Sodium sulfate alone or with hydroxide ions doesn't affect the colloidal stability of SA. Sodium sulphate greatly decreases the colloidal stability of SA with sodium silicate. Abstract: Colloidal stability of polymer particles in activator is the pre-condition for the application of polymer dispersion in alkali activated materials (AAM). In this study, investigation of the stability of classical cement-stable polymers (styrene acrylate (SA) and ethylene-vinyl acetate (EVA)) in the presence of sodium silicate with different moduli at varied dosages and storing times was conducted through combined techniques including laser particle analysis and ultraviolet-visible spectrophotometry (UV–Vis). It is found that SA is significantly more stable than EVA dispersions. Dosage of sodium silicate and storing time are the main factors for loss of colloidal stability of the polymer particles. The highest colloidal stability of the latexes was observed with the lowest investigated modulus (M < 1.81). Sodium sulphate alone or a combination of sodium sulphate and hydroxide ions have no effect on the colloidal stability of polymer particles. However, in the presence of sodium silicate, sodium sulphate greatly decreases the colloidal stability.