Synthesis of phosphonated comb-like copolymers and evaluation of their dispersion efficiency on CaCO3 suspensions. Part I: Effect of an increasing phosphonic acid content

Abstract

Superplasticizers are admixtures widely used in the building industry for reducing the water content of concrete with a high fluidity and workability at short term, and for increasing concrete mechanical properties at long term. Polycarboxylates, which are synthetic comb-like copolymers, are the most used superplasticizer admixtures. In order to improve polycarboxylate efficiency and compatibility with use of mineral additives, high-sulfate concretes etc., various authors tried to change macromolecular architectures, including nature of anionic function. This paper is the first part of a study which presents synthesis of several macromolecular architectures of comb-like copolymers with phosphonic acid functions instead of classical carboxylic acid. Adsorption, dispersion and fluidification efficiency of these admixtures are evaluated on calcite suspensions in order to simulate earlyage cement behavior. Moreover, settling behaviors are studied in order to characterize dispersion ability of synthetized polymers.

Synthesis of phosphonated comb-like copolymers and evaluation of their dispersion efficiency on CaCO3 suspensions part II: Effect of macromolecular structure and ionic strength

“…This dosage is chosen for different reasons. As described in our previous work [21], there is no marked adsorption difference between superplasticizers for dosages lower than 0.5%. Moreover, limited amounts of polymers have been synthesized.…”

“…Sodium nitrate and calcium hydroxide were provided by Panreax AppliChem, and sodium sulfate was purchased from Prolabo. The granular and physicochemical characteristics of calcite powder were determined in a previous work [21]. Measured density was of about 2.75 g/cm 3 and specific surface area was 1.25 m 2 /g.…”

“…(Methacryloyloxy)methyl phosphonic acid (MAPC1(OH)) was obtained from MAPC1(OMe) hydrolysis; corresponding procedure is detailed in [21].…”

“…Syntheses of three statistical copolymers (Stat PCE, Stat PCE-15P and Stat-PCE-30P) have been detailed in the previous work [21]. We present hereafter the synthesis of Stat PCE-30P DPn10.…”

“…In our previous work [21], the synthesis of several comb-like copolymers with phosphonic acid moieties and PEG side chains was described. These copolymers were tested on calcite suspensions in alkaline conditions through adsorption measurement, stability with Turbiscan MA2000, and rheology.…”