Effect of polymer latexes with varied glass transition temperature on cement hydration

Lu, Zichen; Kong, Xiangming; Zhang, Chaoyang; Cai, Yi; Zhang, Qing; Zhang, Yanrong

doi:10.1002/app.45264

Cited by 12 publications

(3 citation statements)

References 30 publications

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“…The effect of polymer dispersions on the hydration of Portland cement has been well disclosed from previous studies [13][14][15][16][17][18][19][20]. Generally, the addition of polymer dispersions would retard the hydration of ordinary Portland cement (OPC) [20][21][22][23][24][25][26][27][28][29][30], and this retardation effect becomes much more significant when the bigger polymer content was dosed [31,32].…”

Section: Introductionmentioning

confidence: 98%

Rejuvenation, embryonic shear bands and improved tensile plasticity of metallic glasses by nanosecond laser shock wave

Yan

Zhang

et al. 2019

Journal of Non-Crystalline Solids

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The influence of three polymer dispersions [styrene-butadiene copolymer (SB), styrene-acrylic ester copolymer (SA) and polyacrylic ester (PA)] on the hydration of calcium sulfoaluminate (CSA) cement within 72 h was investigated by using isothermal conduction calorimetry, X-ray diffraction analysis and thermal gravimetric analysis. The results indicate that these three polymer dispersions perform different influences on the hydration heat flow of CSA cement during different periods, they all postpone the occurrence time of the maxima peaks, and its extent is mainly dependent on the addition amount. Polymer dispersions manifest great retardation on the initial hydration of CSA cement, and the effect is much more significant within 1 h. In this stage, the generation of ettringite is strongly delayed; however, the formation of ettringite is accelerated by these polymer dispersions at and after 2 h. Among these three polymer dispersions, PA demonstrates the highest acceleration effect on the hydration degree.

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Section: Introductionmentioning

confidence: 98%

Rejuvenation, embryonic shear bands and improved tensile plasticity of metallic glasses by nanosecond laser shock wave

Yan

Zhang

et al. 2019

Journal of Non-Crystalline Solids

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“…Following the adsorption and chelation processes, SISBR-5 latex with the most -COOH groups induced the longest induction period. Moreover, not merely the amount of -COOH groups but the separation distance of the anionic groups also greatly affected its chelation with Ca 2+ [ 32 ]. As a result, the retardation effect of the cement hydraulic reaction was stronger with increasing dosage of IA, on account of the higher density of -COOH groups along the polymer backbone.…”

Section: Resultsmentioning

confidence: 99%

Dispersion Mechanism of Styrene–Butadiene Rubber Powder Modified by Itaconic Acid and Its Toughening Effect on Oil Well Cement

Xing

Cao

et al. 2022

Materials

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Styrene–butadiene rubber (SBR) has been extensively applied to enhance the toughness of hardened cement. The instability of existing liquid latex leads to difficulties in storage and transportation, and even performance regression. Thus, the well-dispersed carboxylated butylbenzene (SISBR) latex powders were fabricated through the seed emulsion polymerization of liquid polybutadiene (LPB), styrene (St), itaconic acid (IA), and sodium p-styrenesulfonate (SSS) to overcome the difficulties. The dispersion performance of latex powders with various IA amounts was quantitatively evaluated using particle size distribution, zeta potential, and ultraviolet–visible spectrophotometry. Results showed that the carboxylic ionic (COO-) from IA enhanced the dispersing abilities of SISBR latex powders, which ensured the uniform distribution in water. Based on this, the influence of latex powder on cement was assessed mainly by fluidity, isothermal heat flow calorimetry, X-ray diffraction (XRD), and triaxial mechanical testing. Results showed the fluidity and dispersion performance of cement were improved with more IA in latex, while the hydration of cement was retarded due to excessive adsorption of carboxyl (-COOH) groups in IA. Triaxial mechanical testing showed that cement with SISBR-3 (latex containing 3% IA) exhibited the minimal elastic modulus of 3.16 GPa, which was lower than that of plain cement (8.34 GPa).

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“…Approximately −25 ∘C was estimated in all cases, which is in agreement with the estimated value for a copolymer with composition STY/2-EHA 25/75 wt% using the Fox equation [41,42]:1Tg=ω1Tg,1+ω2Tg,2+...+ωnTg,n where ωk and Tg,k are the weight ratio and the glass transition temperature of the generic monomer k , respectively. This property needs to be closely controlled in the application considered in this work since the polymer Tg is known to affect film formation, film shape and cement hydration in mortars [43]. Note that the reported Tg values refer to the core only, as it was not possible to observe the characteristic S-shape at higher temperatures corresponding to the shell composition, because the core-shell transition is quite smooth and, therefore, there is a very gradual change in the composition towards the harder shell.…”

Section: Resultsmentioning

confidence: 99%

Core-Shell Morphology of Redispersible Powders in Polymer-Cement Waterproof Mortars

et al. 2018

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Redispersible powders based on soft core-hard shell polymer particles can be used as additives in polymer-cement mortars. The role of this morphology on the spray-drying production of these powders and on the crack-bridging properties of the corresponding cement-based membranes is investigated. Different polymer latexes at high solid content with varied core-shell ratio, shell thickness and chemical composition (hardness) were prepared from styrene and 2-ethylhexyl acrylate monomers via semi-batch emulsion polymerization. The latexes were characterized in terms of size, composition, and glass transition temperature (T g ), and spray-dried to obtain redispersible polymer powders (RPPs) using poly (vinyl alcohol) and limestone powder as anti-caking agents. The polymer powders were mixed with a mortar mixture and redispersed in water to produce cement-based membranes, which were tested for crack-bridging properties at different temperatures. The results showed that it was not possible to spray-dry a dispersion of homogeneous polymer particles with T g of −25 ∘ C, unless these particles are protected by much harder (high T g ) shell. In particular, it was observed that a thicker shell improved the spray-ability, but lowered the crack-bridging properties of the produced membrane. A trade-off between these two was revealed to be the key for the optimal design of the polymer nanoparticles, as proven by the systematic study of the core-shell morphology reported in this work. The best compromise was shown to consist of particles larger than 300 nm, shell thickness of about 5 nm, and core-shell ratio of 97%, with styrene content in the shell not larger than 80% to avoid excessive hydrophobicity.

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Effect of polymer latexes with varied glass transition temperature on cement hydration

Cited by 12 publications

References 30 publications

Rejuvenation, embryonic shear bands and improved tensile plasticity of metallic glasses by nanosecond laser shock wave

Rejuvenation, embryonic shear bands and improved tensile plasticity of metallic glasses by nanosecond laser shock wave

Dispersion Mechanism of Styrene–Butadiene Rubber Powder Modified by Itaconic Acid and Its Toughening Effect on Oil Well Cement

Core-Shell Morphology of Redispersible Powders in Polymer-Cement Waterproof Mortars

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