不同拓扑结构聚羧酸减水剂的制备及其应用研究

发布时间：2018-04-05 13:15

本文选题：减水剂　切入点：梳型　出处：《合肥工业大学》2017年硕士论文

【摘要】：随着混凝土行业迅速发展,减水剂的应用也越来越广泛。聚羧酸减水剂因具备小掺量,高减水率,环保等优势应用最为广泛。在混凝土中,较其他类减水剂而言,添加聚羧酸减水剂后水灰比可显著降低,且在较低的水灰比下仍然有比较高的流动度,故而提高混凝土强度。聚羧酸减水剂能通过静电斥力和空间位阻效应提供水泥颗粒优良的分散性能,并且不同的拓扑结构产生的空间位阻的大小不同,对减水剂应用性能会有不同的影响。本文采用不同的聚合方法调控分子结构,合成有不同拓扑结构聚羧酸减水剂,探究结构对性能的影响。1、采用含三羟基的三乙醇胺(TEA),与2溴-异丁酰溴反应(BIBB)制备星型引发剂(TEA-Br(3),后采用原子转移自由基聚合法,澳化亚铜/2,2-联吡啶为催化体系,聚合甲基丙烯酸羟乙酯(HEMA),丙烯酸(AA)制备星型聚羧酸减水剂(TEA-Br(3)-PHEMA-AA)。采用同样的方法用乙二醇(EG)替代TEA合成梳型聚羧酸减水剂(EG-Br(2)-PHEMA-AA)。测试表明:成功合成星型引发剂(TEA-Br(3))和星型聚羧酸减水剂,引发剂(EG-Br(2))和梳型聚羧酸减水剂,通过净浆流动度确定了最佳聚合度和反应时间;与梳型减水剂相比,星型减水剂有更高净浆流动度,并且7d星型减水剂混凝土抗压强度提高9-10%。2、选取含四羟基的季戊四醇(PER),与2溴-异丁酰溴反应(BIBB)合成四臂引发剂(PER-Br(4),再利用原子自由基聚合法,以溴化亚铜/2,2-联吡啶为催化体系,与甲基丙烯酸羟乙酯(HEMA),丙烯酸(AA)聚合制备四臂聚羧酸减水剂(PER-Br(4)-PHEMA-AA)。测试表明:四臂聚羧酸减水剂成功合成,通过净浆流动度确定了最佳反应时间和聚合度,与星型聚羧酸减水剂相比,其浆体体系有更好的分散性,且7d四臂聚羧酸减水剂混凝土抗压强度提高3-4%。3、木糖醇(MTC)和丙烯酰氯进行反应,N-N二甲基甲酰胺(DMF)为溶剂,制备单体木糖醇丙烯酸酯(AMTC),在过硫酸铵引发剂作用下,与甲基丙烯酸羟乙酯(HEMA),丙烯酸(AA),甲基烯丙基聚氧乙烯醚(TPEG)自由基聚合制备木糖醇改性聚羧酸减水剂。测试表明:成功制备木糖醇丙烯酸酯(AMTC)和木糖醇改性聚羧酸减水剂,从木糖醇丙烯酸酯用量,反应温度,反应时间,引发剂用量探究最佳合成条件,较普通聚羧酸减水剂而言,浆体体系有更好净浆流动度,7d混凝土抗压强度提高11-12%。
[Abstract]:With the rapid development of concrete industry, the application of water reducing agent is more and more extensive.Polycarboxylic acid water reducing agent is widely used because of its advantages of low content, high water reducing rate and environmental protection.Compared with other water-reducing agents, the water-cement ratio of concrete with polycarboxylic acid water reducing agent can be decreased significantly, and the flow degree is still higher at lower water-cement ratio, so the strength of concrete is improved.Polycarboxylic acid superplasticizer can provide excellent dispersion properties of cement particles through electrostatic repulsion and steric resistance effect, and different topological structures have different spatial steric resistance, which will have different effects on the application performance of water reducer.In this paper, polycarboxylic acid superplasticizer with different topological structure is synthesized by using different polymerization methods to regulate molecular structure.The star polycarboxylic acid superplasticizer (TEA-Br3PHEMA-AA) was prepared by polymerization of hydroxyethyl methacrylate (Hema) and acrylic acid (AAA).The combed polycarboxylic acid superplasticizer was synthesized by using ethylene glycol (EGG) instead of TEA in the same way.The results showed that star initiator TEA-Br3), star-like polycarboxylic acid superplasticizer, initiator EG-Br2) and comb-type polycarboxylic acid water reducer were successfully synthesized. The optimum polymerization degree and reaction time were determined by the net slurry mobility, and compared with comb-type water reducer.A four-arm polycarboxylic acid superplasticizer, PER-Br-4- PHEMA-AAN, was prepared by polymerization of cuprous bromide / 2o 2-bipyridine with hydroxyethyl methacrylate (Hema) and acrylic acid (AAA).The results showed that the four-arm polycarboxylic acid superplasticizer was successfully synthesized, and the optimum reaction time and polymerization degree were determined by the flow degree of the slurry. Compared with the star-shaped polycarboxylic acid superplasticizer, the slurry system had better dispersion.The compressive strength of 4-arm polycarboxylic acid superplasticizer concrete was increased by 3-40.3.The monomer xylitol acrylates (AMTCU) was prepared in the presence of ammonium persulfate initiator in the presence of N-N dimethylformamide (DMF) as solvent.Xylitol modified polycarboxylic acid water reducer was prepared by free radical polymerization with hydroxyethyl methacrylate (Hema), acrylic acid (AA) and methyl allyl polyoxyethylene ether (TPEG).The results showed that xylitol acrylates (AMTC) and xylitol modified polycarboxylic acid water reducers were successfully prepared. The optimum synthetic conditions were explored from the amount of xylitol acrylate, reaction temperature, reaction time and initiator dosage, compared with common polycarboxylic acid water reducers.The concrete compressive strength of the slurry system is increased by 11-12 when the flow degree of the slurry is 7 days.
【学位授予单位】：合肥工业大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TU528.042.2

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