解读聚羧酸盐高性能减水剂的作用机理.doc

/ / / /解读聚羧酸盐高性能减水剂的作用机理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 sulfonic 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；链转移剂有：3-疏基丙酸、疏基乙酸、疏基乙醇以及异丙醇等。Synthesis 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, sodium 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 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 many prominent advantages, but its mechanism has not yet complete and clear, here are some ideas: 聚羧酸类聚合物对水泥有较为显著的缓凝作用，主要由于羧基充任了缓凝成分，R-COO与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 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，放出凝聚体锁包围的游离水，改善了和易性，减少了拌水量。Carboxyl (-cooh) group, hydroxyl (OH), amino group (-nh2) group, gather oxygen alkyl (-o - R) n and water 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 surface 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 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, reduce the mixed with water. 聚羧酸分子链的空间障碍作用(即平面排挤)。聚羧酸类物质份子吸附在水泥颗粒外表呈“梳型”，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 appearance 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 spread 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。Adhere 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 higher than concrete containing poly (carboxylic acid is a high performance water reducing agent. This is mainly the latter and cement particle adsorption model is different, the cement layer polymer adsorption force between particles is planar electrostatic repulsion, Zeta potential changes little. 在研讨其对水泥分散作用机理时发现，仅用DLVO理论解释为离子间斥力常与实验结果有很大出入泰山奇石。Uchikawa和Tanaka等人的实验结果阐明，空间位阻效应可胜利地解释聚羧酸型减水剂对水泥的分散作用机理，即高分子吸附于水泥颗粒外表，其伸展进人溶液的支链产生了空间位阻使粒子不能彼此靠近，从而使水泥颗粒分散并稳定。目前该机理得到普遍承受。Kihoshita等人在研讨了分子质量相近、支链长度不同的聚合物对水泥等温吸附后指出，具有长支链的聚合物有低的电位和高的空间斥力，因此吸附后对水泥分散性能很好，但对粒子分散稳定性却不佳起重机。笔者以为，支链过长可能招致已分散粒子间外表支链的互相缠绕，反而形成粒子的凝聚。In the discussion on the cement dispersing mechanism, only with DLVO theory explanation for the repulsive force between ions often have big discrepancy with the experimental results. Uchikawa and Tanaka et al. The experimental results illustrate that the space steric effect can successfully explain the poly carboxylic acid type water-reducer of cement dispersion mechanism of the polymer adsorption on the cement granular appearance, its stretch into to the branched chain of solution space steric hindrance which particles cannot be close t