JOURNAL OF APPLIED POLYMER SCIENCE
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2018
·Vol. 135
·期 21
·46312
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IF 1.901
Yangyang Zhao,Fuwei Nian,Hao Pang,Jianheng Huang,Hongwei Zhao,Kun Wang,Bing Liao
Star-shaped superplasticizers, which incorporated polyol ester with unsaturated bond at their cores and bore comb-type structures as their arms were synthesized via esterification-copolymerization in aqueous phase from pentaerythritol, acrylic acid (AA), and isopentenyl oxy poly(ethylene glycol ether) (TPEG). The monomer ratios of AA and TPEG were varied and comonomer sodium methallyl sulfonate (SMAS) bearing short side chains was added to regulate the arm structure of star-shaped polycarboxylate superplasticizers (SPCEs). The effects of the SPCEs on cement paste were investigated and the cement dispersion as well as early hydration mechanism were explored. As a main result, SPCEs with SMAS and certain molar ratios for anchoring groups and PEO side-chains in their arm structure exhibited good paste dispersion and fluidity retention, which also delayed the early hydration process and prolonged both the initial and the final setting time. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018 , 135 , 46312.
研究领域:
材料科学
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土木工程
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产品关联
DOI
高影响因子
Materials
·
2019
·Vol. 12
·期 7
·1132
·
IF 2.972
Kuangyi Hu,Zhenping Sun
Influence of polycarboxylate superplasticizers (PCs) with different functional units on the hydration heat and hydration products of C3A-gypsum was investigated. Three kinds of PCs with different monomers were discussed. It was seen that PCs mainly shortened the induction stage of C3A-gypsum hydration, and the amount of remaining gypsum was related to the duration of the induction stage. The second heat flow peak of the sample with PCs was higher than that of the blank. Moreover, PC intercalation occurred during the hydration.Keywords:polycarboxylate superplasticizers;C3A-gypsum;functional units;hydration
研究领域:
建筑材料学
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化学工程
✓ 已验证
产品关联
DOI
PubMed
高影响因子
JOURNAL OF APPLIED POLYMER SCIENCE
·
2018
·Vol. 135
·期 32
·46572
·
IF 1.901
Hongwei Zhao,Bing Liao,Fuwei Nian,Kun Wang,Ying Guo,Hao Pang
In this work, three kinds of HPEG-type polycarboxylate superplasticizers (PCs) were synthesized with three kinds of typical functional monomers: [diallyl dimethyl ammonium chloride (DMDAAC), 2-hydroxyethyl methacrylate (HEMA), and 2-(dimethylamino) ethyl methacrylate (DMAM), respectively. The effects of montmorillonite clay on the fluidity of cement/PC pastes were investigated. It was found that the fluidity was negatively affected by the clays in the order: DMAM-PC < HEMA-PC < conventional PC (CPC) < DMDAAC-PC. The DMAM-PC was found to disperse cement well even in presence of montmorillonite clay. The dispersion performance of DMDAAC-PC was much more effectively affected by clay due to the reaction between ammonium and montmorillonite. More study including mortar fluidity, adsorption behavior and morphology of the cement samples were investigated in details. Thermogravimetric analysis and X-ray diffraction experiments allowed us to observe the influence of PCs on the hydrated products. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018 , 135 , 46572.
研究领域:
材料科学
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化学工程
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产品关联
DOI
高影响因子
JOURNAL OF WUHAN UNIVERSITY OF TECHNOLOGY-MATERIALS SCIENCE EDITION
·
2021
·Vol. 36
·期 3
·446-455
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IF 0.957
Zhang Ying,Wang Pengshuo,Sun Guowen,Yang Jianming,Gao Rui
A low adsorption clay-resistant polycarboxylate superplasticizer (KN-PC) was synthesized using acrylic acid and isopentenol polyoxyethylene ether as the main reaction materials. The structural characterization and clay-resistant mechanism of the KN-PC were explored using Fourier transform infrared spectroscopy and X-ray diffraction, and the effect of the KN-PC on the performance of composite paste with various montmorillonite (MMT) contents was analyzed. Compared with ordinary polycarboxylate superplasticizer (PC), the KN-PC has a low sensitivity to the MMT. By the action of the MMT, the adsorption dosage of the KN-PC on the MMT is much smaller than that of the PC.
研究领域:
材料科学
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化学工程
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF WUHAN UNIVERSITY OF TECHNOLOGY-MATERIALS SCIENCE EDITION
·
2018
·Vol. 33
·期 1
·226-232
·
IF 0.524
Chen Gang,Lei Jiaheng,Du Yong,Chen Xuebing
The dispersion ability of polycarboxylate superplasticizer (PCE) in fresh concrete was much impeded by clay impurities. To improve the dispersion of PCE in the clay-contained concrete, a novel PCE with carboxyl as a specific branched chain terminal group was synthesized, using modified polyether as the raw material which was prepared through esterification between hexahydrophthalic anhydride (HHPA) and isobutenyl polyoxyethylene ether (IPEG) with hydroxy as the terminal group. The esterification product and PCE molecular structure were characterized by infrared spectroscopy and 1HNMR resonance. The results confirmed that the product molecular structure was a comb-type copolymer with long-chain terminal carboxyl group and PEO attached directly to the backbone chain. The as-synthesized PCEs had favorable dispersibility in cement than conventional PCE in the presence of montmorillonite (Mmt) clay. This can be attributed to the introduction of electronegative carboxyl to PCE long-chain terminal group, which reduces the adsorption of PCE on Mmt, and thus improves the tolerance of PCE to the Mmt.
研究领域:
材料科学
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化学工程
✓ 已验证
产品关联
DOI
高影响因子
CONSTRUCTION AND BUILDING MATERIALS
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2019
·
IF 4.046
Baoguo Ma,Chunbao Li,Yang Lv,Hongbo Tan,Hui Wang,Huahui Qi,Xiaohai Liu,Qi Yang,Pian Chen
The problem of bleeding and segregation in high fluidity concrete can be eliminated by the addition of viscosity-enhancing agents (VEA). However, the dispersion capacity of PCE would be perturbed by the addition of VEA. In most cases, this negative impact was due to competitive adsorption between VEA and PCE. In order to mitigate the negative impact, ester groups were introduced to reduce the adsorption capacity, and one new kind of viscosity-enhancing agents was designed; the polymers were copolymerized of acrylic acid (AA) and 2-hydroxyethyl acrylate (HEA), with 1:1 and 1:8 M ratios of AA and HEA. And then, the effect of these two VEAs on rheology of cement paste plasticized by PCE at 5 min and 30 min were studied. Adsorption behavior was analyzed by total organic carbon (TOC), and the zeta potential was also measured. The conformation of the polymers in liquid phase were analyzed by dynamic light scattering (DLS). And the decomposition of ester group under alkaline condition was verified by FTIR and 1 HNMR. The results indicated that the synthesized VEA could plasticize cement paste, and the reason was that VEA could be adsorbed by cement grains and act as the same role as the first-generation superplasticizer. The plasticizing capacity was increased over time, because the adsorption capacity was enhanced due to the released carboxyl groups from the decomposition of ester groups. Furthermore, from 5 min to 30 min, the decomposition of ester group could increase the conformation size of VEA by producing crosslinking in the presence of Ca 2+ , and the crosslinking act as positive role in increasing viscosity and resist the bleeding and segregation. Moreover, it was observed that VEA had negative impact on dispersion capacity of PCE, and the higher density of ester group resulted in lower negative impact at the beginning; one reason for this was because the higher density of ester group showed lower competitive adsorption capacity. Such results offered one new type of VEA available for superplasticizer system.
研究领域:
材料科学
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化学工程
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产品关联
DOI
高影响因子
JOURNAL OF APPLIED POLYMER SCIENCE
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2020
·Vol. 138
·期 11
·50012
·
IF 2.52
Xiuju Lin,Bing Liao,Jialin Li,Jianheng Huang,Mangeng Lu,Hao Pang
In order to investigate the effect of double bond content in the crosslinkers on the performance of superplasticizers, three different crosslinked polycarboxylate superplasticizers were synthesized herein with various respective crosslinkers. Their impacts on the fluidity, absorption, and hydration behavior of cement systems were studied. The results showed that the polymer, which was synthesized using a crosslinker with four double bonds and five/six double bonds, had higher fluidity and the highest fluidity reached up to 395 mm at W/C of 0.35. Additionally, thermogravimetric analysis and hydration heat tests showed that the crosslinked polycarboxylate superplasticizers could prolong the hydration process of cement slurries. Among these three kinds of crosslinked polycarboxylate superplasticizers, the induction period of cement slurry containing the polymer with crosslinker of four double bonds was significantly extended to facilitate the processing of the concrete. The purpose of this study is to provide strategies for studying high-performance polycarboxylate superplasticizers with novel topological structure.
研究领域:
建筑材料
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化学工程
✓ 已验证
产品关联
DOI
高影响因子
Advances in Materials Science and Engineering
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2016
·
IF 1.01
Jingzhi Wu,Min Qiao,Zhifeng Lyu,Qianping Ran
Using maltodextrin (MD) of different dextrose equivalent (DE) values, 1,3-propanesultone, and maleic anhydride as raw materials, a novel binary modified maltodextrin (BMMD) was synthesized and further applied as a water-reducing agent. Its structure was characterized by Fourier transform infrared (FT-IR) and UV. The rheological behavior of the sample solution and strengths for concrete were also determined and the adsorption was tested by TOC. The influence of the process parameters to degree of substitution (DS) and the dosage on the fluidity of cement paste were investigated. The results show that the optimal conditions of sulfonation were the MD of DE 15, (sulfonated agent)/ (MD) of 1.4, the catalyst amount of 1% by mass MD, and the reaction time of 12 h; the optimal conditions of esterification were (esterified agent)/ (SMD) of 0.6, the reaction temperature of 90°C, and the reaction time of 4 h. The optimal dosages of sulfonated maltodextrin (SMD) and BMMD were 0.475% and 0.45%, respectively. In this dosage, the main dispersion capacity of BMMD attributes to two kinds of anchoring groups () and the appropriate molecular weight of MD.
研究领域:
材料科学
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化学工程
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF DISPERSION SCIENCE AND TECHNOLOGY
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2023
·
IF 2.2
Bin Li,Ling Wang
In this study, β-Cyclodextrin (β-CD) as the terminal group was grafted on polyoxyethylene (PEO) via click reaction for preparing monovinyl β-Cyclodextrin monomer (β-P). Then β-P was employed to synthesize a polycarboxylate superplasticizer with β-CD grafted on the side chain [PAA-g-(β-P)nHPEG]. The functional groups, molecular weights, and molecular weight distributions of synthesized copolymers PAA-g-(β-P)nHPEG were characterized by Fourier transform infrared spectra (FT-IR), 1H nuclear magnetic resonance spectroscopy (1H NMR), and gel permeation chromatography (GPC). The dispersion performance of PAA-g-(β-P)nHPEG in cement paste containing montmorillonite (MMT) clay was tested. Sorption measurement and X-ray diffraction (XRD) analysis revealed that the PAA-g-(β-P)nHPEG intercalated less into the interlayer space of MMT than PAA-g-HPEG only with PEO as the side chain. β-CD as the terminal group grafted on the end of the side chain of PCE effectively hindered PCE sorption on MMT and enhanced the clay-tolerance property of PAA-g-(β-P)nHPEG. This study offered a new idea in designing polycarboxylate superplasticizers to lower their clay sensitivity.
研究领域:
材料科学
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土木工程
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产品关联
DOI
高影响因子
DESIGNED MONOMERS AND POLYMERS
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2024
·
IF 1.8
Guide Liu,Xin Zheng,Guoliang Xie,Gongliang Liu
To explore the effect of polycarboxylate superplasticizers on the strength and hydration performance of alkali slag building materials, this study prepared cross-linked polycarboxylate superplasticizers with different ratios of hydrogen peroxide, methyl allyl alcohol polyoxyethylene ether, acrylic acid, polyethylene glycol diacrylate, monomer aqueous solution, reducing agent, chain transfer agent, etc. according to certain ratios, and tested their effects on the hydration performance and strength of alkali slag building materials. Through experimental analysis, it was found that the higher the proportion of cross-linked polycarboxylate based high-efficiency water-reducing agents, the lower the initial flowability of building material slurry; The addition of cross-linked polycarboxylate water-reducing agent will prolong the initial and final setting time of alkali slag building materials, delaying the hydration time of building materials; Cross linked polycarboxylate superplasticizers can reduce the electrical conductivity of alkali slag building material slurry, delaying its hydration rate; Different ratios of water-reducing agents have a significant impact on the water reduction rate of alkali slag building materials, with V2 water-reducing agent having the highest water-reduction rate of 28.6%; Cross linked polycarboxylate superplasticizers can increase the flexural and compressive strength of alkali slag building materials. Therefore, cross-linked polycarboxylate water-reducing agents have shown great potential in regulating the properties of alkali slag building materials.
研究领域:
材料科学
·
建筑工程
✓ 已验证
DOI
PubMed
高影响因子
LANGMUIR
·
2024
·
IF 3.7
Haotian Duan,Tianfeng Zhou,Beibei Li,Yuxia Pang,Hongming Lou,Dongjie Yang,Xueqing Qiu
Polycarboxylate superplasticizers (PCEs) achieve dispersion mainly via steric hindrance from poly(ether) side chains. However, long side chains may cause structural collapse. This study mitigates this issue by introducing sulfonic acid terminations to the long side chains, synthesizing sulfonic-terminated polycarboxylates (PCEPS). Electrostatic repulsion between sulfonic and carboxyl groups on the main chain reduces the level of collapse, enhancing PCE dispersion in cement. PCEPS-4000 showed the strongest dispersion compared with conventional PCEs (PCEC). PCEPS-4000 formed an adsorption layer thickness (ALT) of 11.65 nm, showing a significant improvement over the 7.93 nm observed in the carboxyl-terminated long side chain polycarboxylate (PCETA). Stronger negative charge and lower complexation of sulfonic acid groups enhance the side chain extension. PCEPS also shows good clay tolerance and slump retention, proving its versatility as a concrete admixture.
研究领域:
材料科学
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化学工程
✓ 已验证
产品关联
DOI
PubMed
高影响因子
COLLOIDS AND SURFACES A-PHYSICOCHEMICAL AND ENGINEERING ASPECTS
·
2020
·
IF 3.99
Shengli Chen,Shenmei Sun,Xiaolong Chen,Kaihong Zhong,Qiang Shao,Haijun Xu,Jiangxiong Wei
Polycarboxylate superplasticizer nanomicelles (nano-PCEs) with a core-shell structure were prepared via aqueous emulsion copolymerization in one pot. The shells are constructed with hydrophilic segments of poly(acrylic acid)- co -poly(isobutenyl polyethenoxy ether) (PAA- co -PHPEG), offering the water-reducing performance and stability for nano-PCEs. The cores are self-assembled with hydrophobic segments of polystyrene- co -poly(hydroxyethyl acrylate) (PS- co -PHEA), endowing nano-PCEs with good loss resistant of fluidity for cement pastes . The chemical structure of nano-PCEs was verified by the nuclear magnetic resonance spectrum ( 1 H NMR) and fourier transform infrared spectroscopy (FTIR), and the 16−48 nm diameter of nano-PCE nanomicelles was determined by dynamic laser scattering (DLS) and transmission electron microscopy (TEM). Compared with comb PCEs, the cement paste containing nano-PCEs exhibited better fluidity retention of three hours by mini-slump measurements, lower hydration heat and more delayed hydration heat evolution by isothermal calorimetry tests. Furthermore, the hydrolysis and adsorption behavior of nano-PCEs in alkaline cement pastes were deduced, and a working mechanism of nano-PCEs was theoretically explained. This new type of superplasticizer nanomicelles can be used as a long time rheology modifying agent in fresh cementitious systems.
研究领域:
建筑材料学
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化学工程
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材料科学
✓ 已验证
DOI
高影响因子
危险品化学品经营许可证（带存储）