聚羧酸系减水剂结构与性能关系的研究

发布时间：2018-03-18 08:32

本文选题：聚羧酸减水剂　切入点：结构与性能　出处：《北京工业大学》2013年硕士论文　论文类型：学位论文

【摘要】：聚羧酸减水剂（PCE）具有结构可设计性的优点，研究PCE结构与性能的关系，具有通过理论设计PCE分子结构，获得不同性能的重大意义。为系统探索PCE结构与性能的关系，本文采用不同分子量异丁烯聚氧乙烯醚大单体（HPEG，分子量分别为M500, M1000, M1500, M2000, M2400与M2700）制备侧链密度与主链长度逐步变化的PCE样品。结构表征上，开发凝胶渗透色谱仪（GPC）在PCE结构表征方面的应用；结构控制上，比较了四种不同反应工艺对结构的影响；在性能表征上，比较了不同水泥净浆方法对性能评价的准确性，进而探索不同结构因素对PCE性能的影响。研究发现，引发剂与活性单体分别滴加工艺更有利于控制PCE结构；GPC可以准确判定PCE结构变化，有效聚合物等质量添加更能准确评价PCE性能。在侧链密度的影响上，随着侧链密度的降低，初始流动度逐步增加，达到一定值后变化不明显，保持能力随侧链密度的降低而显著下降，并且分析了侧链密度对PCE性能的影响机理；在主链长度的影响上，链转移剂与大单体摩尔比例[T/E]值不宜高于0.30，根据主链长度不同把PCE分为过短、较短、较长与过长四种结构且分析了每种结构的作用机理；另外通过水化热实验看出，主链越长，对水泥水化抑制作用越强。在侧链长度的影响上，随着侧链长度增加，达到较高转化率所需侧链密度越低；侧链长度越长，为达到优良性能PCE所需侧链密度越低，主链长度越短；通过分子量测试发现，，PCE重均分子量在35,000至50,000之间时性能最优，且侧链长度越长，越有利于提升PCE性能，这为PCE性能优化提供了方向。
[Abstract]:Polycarboxylic acid superplasticizer (PCE) has the advantages of structural designability. It is of great significance to study the relationship between the structure and properties of PCE and to obtain different properties by theoretically designing the molecular structure of PCE. In order to explore the relationship between structure and properties of PCE, PCE samples with different molecular weight of isobutene polyoxyethylene ether macromonomer (M500, M1000, M1500, M2000, M2400 and M2700) were prepared. The application of gel permeation chromatograph (GPC) in PCE structure characterization, the influence of four different reaction processes on the structure, and the accuracy of performance evaluation by different cement paste methods were compared in structure control. Furthermore, the influence of different structure factors on the performance of PCE was explored. It is found that the process of adding initiator and active monomer separately is more beneficial to the determination of PCE structure change by controlling PCE structure, and the addition of effective polymer can evaluate the performance of PCE more accurately. With the decrease of the side chain density, the initial fluidity increases gradually, but the retention capacity decreases significantly with the decrease of the side chain density, and the mechanism of the influence of the side chain density on the performance of PCE is analyzed. On the influence of main chain length, the molar ratio of chain transfer agent to macromonomer [T / E] should not be higher than 0.30. According to the difference of main chain length, PCE is divided into four kinds of structures: too short, shorter, longer and longer, and the mechanism of each structure is analyzed. In addition, the hydration heat experiment shows that the longer the main chain is, the stronger the hydration inhibition of cement is. In the influence of side chain length, with the increase of side chain length, the lower the side chain density required to achieve higher conversion rate, and the longer the side chain length, the lower the side chain density required to achieve good performance PCE, and the shorter the main chain length. The results of molecular weight test show that the optimum performance of PCE is between 35,000 and 50,000, and the longer the length of the side chain, the more favorable the performance of PCE is, which provides a direction for the optimization of PCE performance.
【学位授予单位】：北京工业大学
【学位级别】：硕士
【学位授予年份】：2013
【分类号】：TU528.042.2

【相似文献】