低温合成聚羧酸减水剂的研究

发布时间：2018-01-21 04:18

本文关键词： 聚羧酸减水剂低温合成综合性能对比测试　出处：《武汉科技大学》2014年硕士论文　论文类型：学位论文

【摘要】：随着国内大兴建设，聚羧酸高效减水剂在混凝土结构中的应用越来越多，其优越的减水性能给混凝土的施工技术带来了很大的提升，但是，其综合性能、生产工艺和经济效益依然值得我们探索。目前，普通聚羧酸高效减水剂合成温度较高，普遍在70-90℃甚至更高，由于较高的反应温度给合成工艺的控制加大了难度，所以如何降低反应温度，更合理的控制大单体的聚会反应，提高大规模生产的经济效益是本课题研究的重点，另外现代混凝土的原材料差异变化，也给混凝土拌和物的质量控制增加了不少难度。难以使混凝土拌和物在较短的时间内保持良好的和易性以及坍落度保持性。而低温合成的聚羧酸高效减水剂能有效降低混凝土拌和物的坍落度的损失，使混凝土拌和物在长时间内具备良好的工作性能，同时亦具有较好的力学性能和良好的耐久性。本论文研究了聚羧酸减水剂的低温合成，通过单因素的试验方法确定了最佳的合成工艺以及最佳原材料反应配比。以甲基烯丙基聚氧乙烯醚（TPEG）、丙烯酸（AA）和衣康酸等为主要的原材料，在引发剂的作用下，低温合成聚羧酸高效减水剂，最佳合成工艺为n(AA)：n(衣康酸)：n(巯基乙酸)：n(TPEG)=1.7：0.23：0.005：1，m(引发剂)：m(TPEG)=0.25%；反应温度为44℃，滴加反应时间为4h。在该条件下合成的缓释型聚羧酸高效减水剂，，控制水灰比为0.29，减水剂掺量为0.4%，其中水泥净浆流动度试验所采用的水泥为适应性较差的昌阁水泥，水泥初始净浆流动度可以达到280mm，1h后的水泥净浆流动度为260mm，具有较好的分散性和分散保持性。为了进一步对低温合成的聚羧酸高效减水剂的性能进行研究，同时选取了不同厂家的水泥进行了适应性对比试验。对于不同的水泥样品4#、13#均表现出了较好的水泥适应性，可使水泥具有较好的初始分散性和分散保持性，其作用效果优于市售格瑞林减水剂和台界减水剂。而混凝土对比试验表明4#、13#具有相对较好的减水效果及综合性能优于市售格瑞林、台界混凝土的减水剂。四种聚羧酸高效减水剂配置的混凝土的力学性能相当。由红外光谱图可知，4#、13#减水剂的官能团结构与格瑞林减水剂、台界减水剂相似。4#、13#、格瑞林、台界减水剂的羟基吸收振动峰相当，说明合成的2种减水剂都具有较高的综合性能。4#的C-H的吸收振动峰最强，说明该聚羧酸高效减水剂的单体转换率最高；4#的—COOH的伸缩振动峰最强，13#的—COOH的伸缩振动峰的强度仅次于4#，格瑞林、台界减水剂的—COOH的伸缩振动峰稍弱，说明4#的减水效果最好；4#的C-O-C的吸收振动峰最强，说明单体的转化率最好，其支链密度最高，支链密度越高，其空间位阻效应越好，分散保持性越好；两种聚羧酸高效减水剂的分子结构上带有减水、缓凝和保坍作用的羧基、磺酸基和羟基等官能团，从分子结构上进一步验证，所合成的减水剂具有综合功能。
[Abstract]:With the domestic construction of Daxing, polycarboxylate superplasticizer is more and more used in concrete structure, its excellent water reducing performance improved, but to the concrete construction technology, its comprehensive performance, production process and economic benefit is still worth exploring. At present, the common polycarboxylate superplasticizer synthesis high temperature generally at 70-90 DEG C or higher, due to the higher temperature to increase the difficulty of controlling the synthesis process, so how to reduce the reaction temperature, the reaction control macromer party more reasonable, improve economies of scale in production is the focus of this research, in addition to raw material differences of modern concrete changes, but also to the quality control concrete mixture increased a lot of difficulty. It is difficult to make the concrete mixture to maintain good workability and slump retention in a relatively short time and low temperature. The synthesized polycarboxylate superplasticizer can effectively reduce the slump loss of concrete mixture, make the concrete mixture good working performance in a long time, and also has good mechanical properties and good durability.
This paper studied the low temperature synthesis of poly carboxylic acid water reducing agent, to determine the best synthesis and the best raw material reaction ratio by single factor test method. By polyoxyethylene allyl methyl ether (TPEG), acrylic acid (AA) and itaconic acid as main raw material, under the action of initiator, low temperature synthesis polycarboxylate superplasticizer, the optimum synthesis process for n (AA):n (itaconic acid):n (thioglycolic acid):n (TPEG) =1.7:0.23:0.005:1, m (initiator):m (TPEG) =0.25%; reaction temperature is 44 DEG C, adding the reaction time is 4h. in the condition of synthesis of slow-release poly carboxylic acid superplasticizer, control the water cement ratio is 0.29, water reducing agent dosage is 0.4%, of which the fluidity of cement paste test for cement adaptability Chang Ge cement, cement initial fluidity can reach 280mm, the fluidity of cement paste was 260mm 1H, with a Good dispersivity and dispersivity.
To improve the performance of polycarboxylate superplasticizer synthesized at low temperature was studied, and the selection of different manufacturers of cement adaptability. The comparative test for different cement samples 4#, 13# showed good adaptability to cement, the cement has good initial dispersibility and holding dispersibility, water reducing agent and Taiwan superplasticizer grelling sold its effect is better than the city. But the concrete comparative test showed that 4# and 13# have relatively good water reducing effect and the comprehensive performance of grelling was better than commercial, Taiwan water reducer of concrete. Mechanical properties of four types of polycarboxylate based superplasticizer concrete is considerable.
The infrared spectra showed that 4#, 13# and grelling reduced functional group structure water reducing agent, water reducing agent and Taiwan similar to.4#, 13#, grelling, Taiwan Jianshuiji hydroxyl vibration absorption peaks, indicating that the absorption peak of the vibration performance of.4# high 2 superplasticizer synthesized by C-H, that the polycarboxylate superplasticizer with monomer conversion rate; stretching vibration peak of 4# was the strongest COOH, the stretching vibration peak of 13# - COOH strength after 4#, grelling, Taiwan has weaker stretching vibration peak water reducer COOH, 4# water reducing effect is best; vibration absorption peak 4# C-O-C, shows that the monomer conversion was the best, the highest density of branched chain branched chain, the higher the density, the steric effect is better, and better dispersion retention; two kinds of molecular structure of polycarboxylate superplasticizer with water reducing retarder, and slump effect of carboxyl, The functional groups such as sulfonyl groups and hydroxyl groups are further verified from the molecular structure that the synthesized water reducing agents have comprehensive functions.

【学位授予单位】：武汉科技大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TU528.042.2

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