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1、解解读读聚聚羧羧酸酸盐盐高性能减水高性能减水剂剂的作用机理的作用机理Interpretation of poly carboxylic acid salt, the mechanism of the high performance water reducing agent 聚羧酸盐高性能减水剂是由带有磺酸基、羧基、氨基以及含有聚氧乙烯侧链等的大分子化合物，在水溶液中，经过自在基共聚原理合成的具有梳型构造的高分子外表活性剂。Poly carboxylic acid salt of high performance water reducing agent is made with a sulf
2、onic group, carboxyl, amino, and containing polyoxyethylene side chain of macromolecular compounds, such as in aqueous solution, after a comfortable base copolymerization principle of synthetic polymer surface active agent with the comb type structure. 合成聚羧酸盐高性能减水剂所需的主要原料有：甲基丙烯酸、丙烯酸、丙烯酸乙酯、丙烯酸羟乙酯、烯丙基
3、磺酸钠、甲基丙烯酸甲酯、2-丙烯酰胺基-2-甲基丙烯酸、甲氧基聚氧乙烯甲基丙烯酸酯、乙氧基聚乙二醇丙烯酸酯、烯丙基醚等，在聚合过程中可采用的引发剂为：过硫酸盐水性引发剂、过氧化苯甲酰、偶氮二异丁氰；链http:/ http:/ http:/ http:/ of poly (carboxylic acid salt of main raw material for high performance water reducing agent are: methyl acrylate, ethyl acrylate, acrylic acid, hydroxy ethyl acrylate, sod
4、ium allyl sulfonic acid, methyl methacrylate, 2 - acrylamide - 2 - methyl acrylate, methoxy polyoxyethylene methyl acrylate and ethoxy polyethylene glycol acrylate, allyl ether, etc., can be used in the process of polymerization initiator for: water-based persulfate initiator, benzoyl peroxide, azo
5、diisobutyl cyanogen; Chain transfer agent has: 3 - hydrophobic thin base of propionic acid, acetic acid, ethanol and isopropyl alcohol. 聚羧酸盐高性能减水剂是一种新型减水剂，具有许多突出的优点，但其作用机理目前尚未完整分明，以下是其中的一些观念：Poly carboxylic acid salt of high performance water reducing agent is a new type of water reducing agent, has
6、 many prominent advantages, but its mechanism has not yet complete and clear, here are some ideas: http:/ http:/ http:/ http:/ Ca2+离子作用构成络合物，降低溶液中的 Ca2+离子浓度，延缓 Ca(OH)2 构成结晶，减少 C-H-S 凝胶的构成，延缓了水泥水化。Poly carboxylic acid polymers of cement have relatively significant retarding effect, mainly because of
7、the carboxyl filled retarded components, R - COO and Ca2 + ions constitutes a complex, reduce the Ca2 + ion concentration in the solution, to delay the Ca (OH) 2 crystal, reduce C -h -s gel formation and delay the cement hydration. 羧基(-COOH)，羟基(-OH)，胺基(-NH2)，聚氧烷基(-O-R)n 等与水亲和力强的极性集团主要经过吸附、分散、潮湿、光滑等外
8、表活性作用，对水泥颗粒提供分散和活动性能，并经过减少水泥颗粒间摩擦阻力，降低水泥颗粒与水界面的自在能来增加新拌混凝土的和易性。同时聚羧酸类物质吸附在水泥颗粒外表，羧酸根离子使水泥颗粒带上负电荷，从而使水泥颗粒之间产生静电排挤作用并使水泥颗粒分散，招致抑止水泥浆体的凝聚倾向(DLVO 理论)，增大水泥颗粒与水的接触面积，使水泥充沛水化。在扩散水泥颗粒的过程中，http:/ http:/ http:/ http:/ (-cooh) group, hydroxyl (OH), amino group (-nh2) group, gather oxygen alkyl (-o - R) n and w
9、ater such as the polarity of the strong affinity group mainly through adsorption activity, dispersion, moist, smooth appearance, performance of cement particle dispersion and activity, and reduce the frictional resistance between cement particles, can reduce cement particles and water boundary surfa
10、ce free to increase the workability of fresh concrete. And poly carboxylic acid class material in cement particle adsorption appearance, carboxylic acid ions cement particles with negative charge, so that the electrostatic exclusion effect between cement particles and cement particles dispersed, by
11、dampening water slurry agglomeration tendencies (DLVO theory), increase the contact area of the cement particles and water, and make full hydration of cement. In the process of diffusion of the cement particles, surrounded by condensed matter lock is released free water, improved the workability, re
12、duce the mixed with water. http:/ http:/ http:/ http:/ ，在凝胶资料的外表构成吸附层，聚合物分子吸附层互相接近穿插时，聚合物分子链之间产生物理的空间障碍作用，避免水泥颗粒的凝聚，这是羧酸类减水剂具有比其他体系更强的分散才能的一个重要缘由。Space barrier effect of poly carboxylic acid molecular chain (i.e., plane). Poly carboxylic acid is a class member in cement particle adsorption appearanc
13、e shows “comb“, constitute the adsorption layer of gel materials, polymer molecules adsorbed layer near with each other, between polymer molecular chain to produce physical space barrier, avoid the cement particles condensed, the carboxylic acid type water reducer is stronger than other system sprea
14、d can be an important reason. 聚羧酸类高效减水剂的坚持分散机理能够从水泥浆拌和后的经过时间和 Zeta 电位的关系来理解。普通来说，运用萘系及三聚氰胺系高效减水剂的混凝土经 60min 后坍落度损失明显高于含聚羧酸系高性能减水剂的混凝土水处理药剂。这主要是后者与水泥粒子的吸附模型不同，水泥粒子间高分子吸附层的作用力是平面静电斥力，Zeta 电位变化小。http:/ http:/ http:/ http:/ to the dispersion mechanism of poly (carboxylic acid type of high efficient water reducing agent can pass after cement slurry mixing time and Zeta potential relationship to understand. General speaking, using naphthalene and melamine series high efficient water reducing agent after 60 min the slump loss of concrete is significantly
