Study on the performance of polycarboxylate-based superplasticizers synthesized by reversible addition–fragmentation chain transfer (RAFT) polymerization

Yu, Bin; Zeng, Zhong; Ren, Qinyu; Yang, Chen; Liang, Mei; Zou, Huawei

doi:10.1016/j.molstruc.2016.05.035

Cited by 33 publications

(23 citation statements)

References 18 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…For this one, chain extremity is assumed to be derived from CIDB, the RAFT agent required for this diblock structure. To our knowledge, only one paper deals with the synthesis of block copolymers for superplasticizer study [33].…”

Section: Macromolecular Synthesis and Characterizationsmentioning

confidence: 99%

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

Tramaux¹,

Azéma²,

David

et al. 2018

Powder Technology

View full text Add to dashboard Cite

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.

show abstract

Section: Macromolecular Synthesis and Characterizationsmentioning

confidence: 99%

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

Tramaux¹,

Azéma²,

David

et al. 2018

Powder Technology

View full text Add to dashboard Cite

show abstract

“…Adopting the Arrhenius equation (Equation )) and results from Figure 2, the apparent adsorption activation energy ( k 0 ) of the adsorption process could be calculated as follows: 24

k = k_{0} \exp ((), - E_{a} / italicRT),

where k 0 was the pre‐exponential factor (min −1 ), E a was the apparent activation energy (kJ·mol −1 ), R = 8.3145 × 10 −3 kJ·mol −1 ·K −1 was the molar gas constant and T was the adsorption temperature (K). k 0 and E a could be obtained as the straight line intercept and slope, respectively.…”

Section: Resultsmentioning

confidence: 99%

Synthesis and characteristics of pectiniform polyurethane‐modified polycarboxylate and its effects on behavior of cement paste

Xiang

Gao

2020

J of Applied Polymer Sci

View full text Add to dashboard Cite

In this research, two kinds of polycarboxylate (M-PCE and O-PCE) with the same degree of polymerization in side chains but different main chains were synthesized via a radical polymerization reaction at room temperature. Along with two commercial polycarboxylates (C-PCE-1 and C-PCE-2), their properties on adsorption, hydration, zeta potential, liquid surface tension, and flowability of cement pastes were investigated. The results showed that the adsorption of M-PCE on the surface of cement particles increased 14.1% and the adsorption rate increased 24% compared with C-PCEs. Furthermore, three polycarboxylates (O-PCE, C-PCE-1, and C-PCE-2) exhibited a delayed effect on the hydration of cement due to the shielding effect of their chain alkyl groups, meanwhile the hydration of the cementitious materials by the M-PCE was not delayed but promoted because of its incomplete hydrolysis of the siloxane. As a result of the higher adsorption amount, M-PCE with siloxane groups exhibited favorable effects in terms of zeta potential, liquid surface tension, and flowability of cement pastes.

show abstract

“…It has been revealed that adsorption of PCE onto the surface of cement particles is the precondition for exerting high dispersion efficiency of PCE [ 3 , 20 ]. Carboxyl groups exist in the side chain of PAA, and these active groups can adsorb on the surface of cement particles by means of chemical combination and electrostatic force [ 21 , 22 , 23 ].…”

Section: Resultsmentioning

confidence: 99%

Effect of Polyacrylic Acid on Rheology of Cement Paste Plasticized by Polycarboxylate Superplasticizer

Peng

Tan

et al. 2018

Materials

View full text Add to dashboard Cite

Viscosity-enhancing agents (VEA) have been widely employed in high flowability cement-based materials, so as to ensure that no bleeding and segregation would occur. However, in most cases, interaction between VEA and superplasticizer would be unavoidable. In this study, the effect of polyacrylic acid (PAA), known as one of the most commonly used VEAs, on rheology performance of cement paste containing polycarboxylate superplasticizer (PCE), was studied. The initial fluidity was assessed with mini slump, and rheological behavior of cement paste was evaluated with rotor rheometer. Adsorption amount was examined with total organic carbon (TOC) analyzer, and the zeta potential was also tested. The interaction between PAA and PCE in the presence of calcium ion (Ca2+) was analyzed with conductivity, X-ray photoelectron spectroscope (XPS), and dynamic light scattering (DLS). The results illustrate that PAA can adsorb onto the surface of cement particles to plasticize cement paste, being similar to PCE. In the presence of Ca2+, PAA can be curled and crosslinked, as a result of the combination between carboxyl groups (COO−) and Ca2+, thereby affecting the adsorption performance and conformation behavior. It is interesting that negative impact of PAA on dispersion efficiency of PCE can be demonstrated; one reason is the reduced adsorption amount of PCE by PAA competitively adsorbing onto the cement surface, and another possible reason is the invalided PCE by adsorption of PAA. Additionally, molecular weight of PAA should be considered if being used as VEA in PCE system.

show abstract

Study on the performance of polycarboxylate-based superplasticizers synthesized by reversible addition–fragmentation chain transfer (RAFT) polymerization

Cited by 33 publications

References 18 publications

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

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

Synthesis and characteristics of pectiniform polyurethane‐modified polycarboxylate and its effects on behavior of cement paste

Effect of Polyacrylic Acid on Rheology of Cement Paste Plasticized by Polycarboxylate Superplasticizer

Contact Info

Product

Resources

About