MATERIALS AND STRUCTURES
·
2023
·Vol. 57
·期 1
·1-17
·
IF 3.8
Chen Xingren,Liu Zuguang,Fu Xiyao,Xie Xiongmin,Wang Ting,Rong Zhijuan,Nong Youchao,Lu Zhenren
A series of polycarboxylate superplasticizers (PCEs) with varying carboxyl densities were synthesized at room temperature using the molecular design principle. The PCEs molecular structure was determined using 1 H NMR and MALDI-TOF. The paste fluidity, foam stability as well as other performance of PCEs obtained was also tested. The investigations reveal that the PCEs with high carboxyl density cause the extended main chain conformation due to the strong electrostatic repulsion, resulting in the increase of hydrodynamic radius (Rh), which is beneficial to increase the ‘accessible carboxyl’ in the main chain, and improves its adsorption capacity; In addition, the PCEs with high carboxyl density also have high hydrophilicity, which will form micro bubbles to better disperse cement particles, and improve the fluidity of cement pastes. This study is aimed to provide a comprehensive understand for the mechanism of maleic anhydride-modified TPEG-type PCEs from the viewpoint of molecular architecture and conformation, and improve the workable performance of concrete mixture with the PCEs.
研究领域:
材料科学
·
高分子化学
·
土木工程
·
表面化学
✓ 已验证
DOI
高影响因子
RSC Advances
·
2015
·Vol. 5
·期 55
·44435-44446
·
IF 3.84
Yangyang Chen,Funian Mo,Shaojun Chen,Yan Yang,Shiguo Chen,Haitao Zhuo,Jianhong Liu
This study reports a novel shape memory copolymer synthesized with 2-(dimethylamino)-ethyl-methacrylate (DMAEMA) and methyl-allyl-polyethenoxy-ether (TPEG) for potential biological applications. In the DMAEMA–TPEG copolymers, TPEG segments form a semi-crystalline phase that serves as the reversible phase, while DMAEMA segments form an amorphous phase containing physical interactive networks that serve as the hard phase. As the TPEG content increases, the crystallinity and the rate of crystallization increase, and the TPEG phase changes from dispersed small spherical crystals to a continuous crystalline phase. Additionally, good crystallinity of the TPEG phase endows the copolymers with good shape fixity, whereas the shape recovery decreases as the TPEG content decreases. DMAEMA–TPEG copolymers also exhibit the multi-shape memory effect with a good triple-shape memory effect. Finally, the investigation of the water contact angle illustrates that all DMAEMA–TPEG copolymers have good hydrophilicity. Thus, it is proposed that DMAEMA–TPEG copolymers might have great potential for biological applications.
研究领域:
材料科学
·
生物医学工程
·
高分子化学
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF DISPERSION SCIENCE AND TECHNOLOGY
·
2025
·
IF 1.9
Nana Shi,Zhensheng Yang,Che Yu,Jingwei Wang,Zhongchao Fu,Lu Li
The shrinkage cracking of concrete will reduce the durability and bearing capacity of the structure, accelerate the corrosion of steel bars, and affect the safety and service life of buildings. Meanwhile, traditional polyether shrinkage reducers, while reducing drying shrinkage, will have adverse effects on mechanical properties and durability. To simultaneously improve the shrinkage capacity, mechanical properties and durability of concrete, In this paper, a polyether reducing agent (SRA1) was prepared by free radical polymerization using isopentenol polyoxyethylene ether (TPEG-2400) as the large monomer of polyether and diethylene glycol monobutyl ether maleic anhydride ester (MABE), acrylic acid (AA), and sodium methylallenesulfate (SMAS) as the small monomers. Based on SRA1, the number of ether bonds was increased and hydrophilic amide groups were introduced. Polyether shrinking agent (SRA2) was prepared by the same method using polyethylene glycol methacrylate (PEGMA), N-hydroxymethylacrylamide (HAM), and sodium methylallenesulfate (SMAS) as small monomers. Based on SRA2, a hydrophobic benzene ring was introduced, and polyether shrinking agent (SRA3) was prepared by the same method using polyethylene glycol methacrylate (PEGMA), N-hydroxyethyl acrylamide (HEAA), and sodium p-styrene sulfonate (SSS) as small monomers. The molecular structures, thermal stability, and microscopic morphologies of three SRAs were characterized by FTIR, 1HNMR, GPC, XRD, TG-DTG, and SEM. The effects of the three SRAs on the properties of cement-based materials were compared and evaluated through the performance test experiments of cement materials. The experimental results of the performance of cement-based materials show that the addition of the three kinds of SRAs effectively improves the shrinkage rate, fluidity, mechanical properties and durability of the mortar. When the dosage of SRAs is 2.0% of the mass of the base material, the performance of the cement-based material with SRA3 added is the best: Compared with the blank group, the drying shrinkage rate decreased by 41.2% at 30 days, the fluidity of the clean slurry reached 230 mm, the compressive strength and flexural strength increased by 33.3% and 7.9%, respectively, at 28 days, the non-steady-state migration coefficient decreased by 52.6%, and there were better retarding and water reduction effects.
✓ 已验证
产品关联
DOI
高影响因子
Materials Research Express
·
2024
·Vol. 11
·期 8
·085310
·
IF 1.8
Yunhai Shi,Kai Lu,Zejian He,Yulong Chen,Mi Zhou
Water reducing agent as an important admixture. It is used to decrease the initial water content in cement paste, improving its fluidity. Polycarboxylic acid water reducing agent (PCE) is a high-performance type with advantages such as low dosage, high water reduction rate, environmental friendliness, and a simple synthesis process. In this study, the third monomer (TPEG-SAA-SHES) was synthesized by modifying isopentenol polyoxyethylene ether (TPEG) with sodium hydroxyethyl sulfonate (SHES). Subsequently, a modified ether polycarboxylic acid-based water reducing agent (PCE-S) was synthesized with TPEG and acrylic acid (AA). The experimental conditions for the synthesis of PCE-S were optimized through orthogonal tests. The synthesized PCE-S showed a certain degree of improvement in the initial net slurry flow compared to PCE, with a maximum enhancement of 19.64%. The adsorption increased by 18.25% when the TSS dosage was 5%. PCE-S enhances the hydration products of cement, increasing the compactness of the structure. The product is environmentally friendly, safe, and durable, effectively reducing the dosage of additives and helping to cut costs. It lays the foundation for the next industrialized mass production.
研究领域:
建筑材料化学
·
高分子材料合成
✓ 已验证
产品关联
DOI
高影响因子
CONSTRUCTION AND BUILDING MATERIALS
·
2020
·
IF 4.419
Hang Zhang,Miaomiao Hu,Yang Xu,Xiujian Xia,Chi Zhang,Yongjin Yu,Yakai Feng,Jintang Guo
Aberrant thickening of cement slurry caused by polycarboxylate retarders mainly refers to abnormal gelation and thickening time reversal (TTR) when temperature reaches above 120 °C. These phenomena would directly jeopardize cementing operation and hinder the application of polycarboxylate retarders in oil and gas exploitation. Herein, two functionalized polycarboxylate retarders were synthesized to overcome the challenges in complex conditions. The incorporation of isoprenyl oxy poly(ethyleneglycol) ether (TPEG) and [3-(methacryloylamino) propyl] trimethyl ammonium chloride (MAPTAC) was capable of preventing unfavorable “crosslinking and chelation” reaction between cement grains and polymer, thereby avoiding abnormal gelation. It was also found that the hydrophobic association behavior of long side chain in TPEG could cause the gradual release of carboxyl groups at elevated temperature, which was unfavorable for TTR inhibition. When the TPEG was replaced by N-Vinyl-2-Pyrrolidinone (NVP), its retarding effect gradually weakened when temperature rose from 130 °C to 150 °C, and excellent inhibition of TTR was achieved.
研究领域:
石油工程
·
材料科学
·
化学工程
✓ 已验证
产品关联
DOI
高影响因子
危险品化学品经营许可证（带存储）