聚羧酸减水剂的合成、表征及其在水泥和陶瓷中的应用研究

发布时间：2018-05-28 03:13

  本文选题：自由基聚合 + 聚羧酸减水剂　； 参考：《湖南大学》2015年硕士论文

【摘要】：聚羧酸减水剂具有掺量低、减水率高、分子结构变化自由度大、适用性范围广等特点。它可以显著提高混凝土的和易性,减少拌合水的用量,改变混凝土的凝结时间,克服混凝土坍落度损失过快的问题,增强混凝土的抗压强度等,具有较好的应用前景。本文采用水溶液中的自由基聚合法,以异戊烯醇聚氧乙烯醚和其他可聚合单体合成聚羧酸减水剂。利用傅里叶红外光谱仪对合成产物的结构进行了表征,Zeta电位仪对掺入聚羧酸减水剂的水泥粒子表面ζ电位的变化进行了探讨,凝胶渗透色谱对聚羧酸分散剂的分子量进行表征;利用数显粘度计、流变仪和透射电镜对加入聚羧酸分散剂的悬浮液的粘度、流变性及分散性能进行研究。研究结果表明:(1)酸醚比、引发剂的用量、甲基烯丙基磺酸钠的用量、温度对产物性能有较大的影响。当在丙烯酸和异戊烯醇聚氧乙烯醚的摩尔比是4:1,异戊烯醇聚氧乙烯醚与甲基烯丙基磺酸钠的摩尔比是1:0.6,引发剂的用量是单体总质量的6%,温度在80℃的条件下合成的产物能使水泥泥浆有最高的净浆流动度,可达285mm。(2)酸醚比、链转移剂巯基丙酸的用量、还原剂VC的用量和滴加时间对产物性能有较大的影响。当在丙烯酸和异戊烯醇聚氧乙烯醚的摩尔比是4.16:1,异戊烯醇聚氧乙烯醚与巯基丙酸的摩尔比是1:0.18,异戊烯醇聚氧乙烯醚与还原剂VC的摩尔比是1:0.01,滴加时间为1 h的条件下合成的产物能使水泥泥浆有最高的净浆流动度,可达235 mm。通过与水泥的相容性试验和混凝土的适配实验可知,自制的常温聚羧酸减水剂的性能已基本达到国外某品牌减水剂的效果。(3)利用低分子量的异戊烯醇聚氧乙烯醚和可聚合单体聚合而成的聚羧酸分散剂也能应用于陶瓷领域。这种聚羧酸分散剂能使表观粘度从1088 m Pa·s降低到258 m Pa·s。
[Abstract]:Polycarboxylic acid superplasticizer has the characteristics of low content, high water reducing rate, wide degree of freedom of molecular structure change and wide applicability. It can significantly improve the easiness of concrete, reduce the amount of mixing water, change the setting time of concrete, overcome the problem of excessive slump loss of concrete, and enhance the compressive strength of concrete. It has a good application prospect. In this paper, polycarboxylic acid water reducer was synthesized from isopentenol polyoxyethylene ether and other polymerizable monomers by free radical polymerization in aqueous solution. The structure of the synthesized product was characterized by Fourier transform infrared spectroscopy (FTIR). The Zeta potentiometer was used to study the change of Zeta potential on the surface of cement particles mixed with polycarboxylic acid superplasticizer. The molecular weight of polycarboxylic acid dispersant was characterized by gel permeation chromatography. The viscosity, rheology and dispersibility of suspension with polycarboxylic acid dispersant were studied by means of digital display viscometer, rheometer and transmission electron microscope. The results show that the ratio of acid ether, the amount of initiator, the amount of sodium methylallyl sulfonate and temperature have great influence on the properties of the product. When the molar ratio of acrylic acid and isopentenol polyoxyethylene ether is 4: 1, the molar ratio of isopentenol polyoxyethylene ether to sodium methylallyl sulfonate is 1: 0.6, the amount of initiator is 6% of the total mass of monomer, and the temperature is 80 鈩，

本文编号：1945010