Research on the performances of VPEG macromonomer grafted different functional groups to prepare polycarboxylate superplasticizers

The advent of novel polyether macromonomer has garnered significant attention within the industrial domain. In this study, a range of polycarboxylate superplasticizers (PCEs) was produced via free radical polymerization, employing a new polyether monomer, 4-hydroxybutyl vinyl polyethylene glycol ether (VPEG). This monomer served as the predominant component and was grafted with various functional monomers on its main chain. The molecular configuration of the resultant PCEs was discerned through Fourier infrared spectroscopy and gel permeation chromatography, while the surface tension underwent assessment via a surface tension meter. Both the initial and subsequent fluidity of cement paste and mortar were leveraged to ascertain the dispersion and retention efficacy of the synthetic PCEs. The ramifications of diverse functional group grafts of the new polyether monomer on the cement hydration procedure and strength attributes were elucidated via setting time, hydration heat assays of cement paste, SEM analysis, and compressive strength evaluations of mortar. Observations reveal that the carboxylic acid group significantly reduces surface tension, whereas the sulfonic acid group's effect remains minimal. The incorporation of both the amide and sulfonic acid groups marginally impacts the preliminary dispersion efficacy of PCEs but notably affects dispersion retention. Furthermore, these functional groups facilitate cement hydration, expedite the primary setting time of the cement paste, and bolster the initial compressive strength of the mortar. Specifically, the grafted of sodium methacrylsulfonate (SMAS) yields the most noticeable results. Finally, the working mechanism of PCEs with varying molecular structures has been explained in light both theoretical and experimental results. This research offers valuable insights for subsequent investigations into the fabrication of polycarboxylate superplasticizers using the VPEG macromonomer.     

含气量对全尾砂膏体胶结充填料浆性能的影响

在掺入由聚羧酸系超塑化剂和引气剂复合而成的泵送剂的情况下,通过改变复合泵送剂中引气剂的用量来调整全尾砂膏体胶体充填料浆中含气量,研究了含气量对全尾砂膏体胶体充填料浆各项性能（坍落度、分层度、泌水率,硬化后的抗压强度等）的影响。结果表明：料浆中含气量的增加,可以明显改善料浆的分层度和泌水性,并提高料浆的坍落度;但同时引气含量过高则会导致料浆硬化后的抗压强度的急剧下降。因此,可以得出以下结论：采用本文的原材料和泵送剂,全尾砂膏体胶体充填料浆最佳含气量为7.5%~9.5%。。     

含偏高岭土水泥与高效减水剂相容性研究

研究了含偏高岭土水泥与高效减水剂的相容性,结果表明,在硅酸盐水泥中单独加入偏高岭土时,水泥与减水剂的相容性有所降低,但若将偏高岭土与矿渣适当配合后再加入硅酸盐水泥之中,则可以改善水泥与减水剂的相容性;研究了偏高岭土单掺及其与矿渣复掺对水泥物理、力学性能的影响,并用DTA,SEM分析了水泥的水化产物。     

RCC超缓凝复合外加剂的试验研究

结合岚河蔺河口水电站碾压混凝土的配合比设计及施工,研究了RCC超缓凝复合外加剂的配方设计及混凝土拌合物性能,并按选定配方以最佳掺量掺入RCC混凝土中进行力学、热学和耐久性试验,测试结果满足设计和施工要求。     

硅烷偶联剂改性聚羧酸保坍剂的制备与应用

以改性聚醚(TPEG)、丙烯酸(AA)、丙烯酸羟丙酯(HPA)、3-缩水甘油醚氧基丙基三甲氧基硅烷(KH560)为原料,以过硫酸铵为引发剂,在反应温度50℃下合成一种硅烷偶联剂改性聚羧酸保坍剂。混凝土试验结果表明,该保坍剂能有效改善混凝土的和易性能,延长混凝土的凝结时间,并能提高混凝土的3、7、28 d抗压强度。     

聚羧酸盐在棉织物X型活性轧染中的应用研究

纯棉织物X型活性染料轧染时，使用聚丙烯酸盐（PA）和聚马来酸盐（PM）代替Na2SO4作促染剂。通过比较染色织物的表观色深（K／S值）、各项牢度和强力指标，探讨了聚羧酸盐作为促染剂应用于纯棉织物X型活性染料轧染工艺的可行性，并得出了最佳染色工艺条件。试验结果表明，当聚羧酸盐用量为50g／L时，染色织物的K／S值、各项牢度指标和强力均与用Na2SO4作促染剂时相当。     

一种两性聚羧酸减水剂对水泥净浆及混凝土早期性能的影响

通过引入2-丙烯酰胺-2-甲基丙磺酸(AMPS)和甲基丙烯酰氧乙基三甲基氯化铵(DMC)两种小单体,并采用相对分子量较大的甲基烯丙基聚氧乙烯醚(HPEG)大单体,合成了一种两性聚羧酸减水剂ZQ-3,使用红外光谱对其结构进行了确证.将该减水剂与另外三种聚羧酸减水剂进行了性能对比研究.水泥净浆实验结果表明:减水剂ZQ-3具有良好的分散性及分散性经时保持性能,对净浆的凝结时间影响不大;混凝土实验及XRD分析表明:减水剂ZQ-3能够促进水泥的早期水化,明显提高混凝土蒸养脱模强度和早期强度.     

沉淀法制备的固体聚羧酸减水剂性能研究

采用沉淀法制备了固体聚羧酸减水剂,依据国标方法对该聚羧酸减水剂的宏观性能进行测试,采用IR、GPC分析技术对其结构进行表征,并将其性能与传统方法制备的液体聚羧酸减水剂和外购固体聚羧酸减水剂进行比较研究.结果表明:采用沉淀法制备的固体聚羧酸减水剂减水率可达28%,初始坍落度为160 mm,经时坍损小;固化过程对聚羧酸减水剂官能团、分子量及多分散系数、水泥的吸附性均无明显影响;宏观性能方面虽然对水泥的分散作用、坍落度、硬化水泥砂浆抗压强度虽略低于液体聚羧酸减水剂,但各项指标均能达到国标要求,说明沉淀法制备固体聚羧酸减水剂是一条可行的途径.     

混合材对水泥与减水剂适应性的影响研究

通过对掺高效减水剂水泥净浆流动性及流动性损失的测定试验，研究了3种混合材(粉煤灰、水淬高炉矿渣和沸石)在不同替代率情况下对减水剂作用效果的影响。结果表明：水淬高炉矿渣有利于改善减水剂与水泥的适应性，而掺粉煤灰和沸石(尤其是沸石)则会导致减水剂塑化作用的降低，而且浆体流动性损失也有增大趋势。     

水性高分子材料在混凝土外加剂中的应用研究进展

综述了水性高分子材料在混凝土外加剂中的研究及应用情况,其中包括减水剂、引气剂、减缩剂、水下不分散剂及阻锈剂等。并着重介绍三聚氰胺系、脂肪族、氨基磺酸系和聚羧酸系等几类高效减水剂的合成及应用现状。