Title: Influence of Molecular Structure of Comb-Type Superplasticizers and Inorganic Electrolytes on the Dispersion Mechanisms of Limestone Powder

Author(s): E. Sakai, D. Atarashi, A. Kawakami, and M. Daimon

Publication: Symposium Paper

Volume: 217

Issue:

Appears on pages(s): 381-392

Keywords: adsorption; comb-type superplasticizers; dispersion mechanisms; inorganic electrolytes; limestone powder; molecular structure

DOI: 10.14359/12926

Date: 9/1/2003

Abstract:
Polymers with a shorter graft length or longer intervals of graft chains are adsorbed more easily even though the adsorption sites are decreased. The content of carboxyl groups in polymer increased with the decrease in graft chain length. The intervals between graft chains are prolonged, with changed composition of the copolymer where methoxypolyethylene is replaced by styrene or allyl sulfonates. When a larger amount of carboxyl groups was introduced on the main chain or when the distance between the graft chains was extended, the influence of inorganic electrolytes on the fluidity of the suspension with the superplasticizer was decreased. These superplasticizers can be adsorbed on limestone powder even though the adsorption sites were decreased when inorganic electrolytes were added. In contrast to the case of C032-, the addition of S042may possibly cause shrinking of the polymer chain as well as hindering the adsorption of the superplasticizer. Superplasticizers containing graft chains with longer chain length are effective for preventing the fluidity decrease when S042- is added.