Adsorption and Dispersion Mechanisms of Comb-Type Superplasticizer Containing Grafted Polyethylene Oxide Chains.

Abstract

This paper discusses the influence of molecular structure and composition of copolymer for comb-type polymers on the fluidity of CaCO₃suspension with various types of inorganic electrolytes. When a larger amount of functional groups(-SO^3-/-COO^-) was introduced on the main chain or when the distance between the grafted chains was extended, the influence of inorganic electrolytes on the fluidity of CaCO₃ suspension with comb-type polymer was decreased. These comb-type polymers can be adsorbed on limestone powder even though the adsorption sites were decreased when inorganic electrolytes were added. In contrast to the case of CO₃^2- or PO₄^3-, the addition of SO₄^2- may possibly cause shrinking of the polymer chains as well as hindering the adsorption of the comb-type polymer. Comb-type polymers containing graft chains with some extent of chain length are effective for preventing the fluidity decrease when SO₄ ^2- is added.