硅酸盐学报

聚羧酸减水剂分子结构中丙烯酸酯单元的缓释机理及其温度敏感性

作者：王芳1 张力冉2 孔祥明2 王栋民1 郝挺宇3

单位：1. 中国矿业大学(北京)化学与环境工程学院北京 100083 2. 清华大学土木工程系北京 100084 3. 中冶集团建筑研究总院北京 100056

分类号：TU528

出版年,卷(期):页码：2018,46(2):173-180

DOI：

摘要：

以丙烯酸羟乙酯(HEA)或丙烯酸羟丙酯(HPA)为功能单体，与丙烯酸(AA)、甲基烯丙醇聚氧乙烯醚(HPEG)通过自由基共聚制备两类丙烯酸酯改性的聚羧酸减水剂PCHEA和PCHPA。通过测试PCE、PCHEA、PCHPA在25 ℃与60 ℃对水泥的分散性能，发现丙烯酸酯改性的PCE可用于提高水泥混凝土流动性的经时保持能力。同时，高温下酯基的加速水解可有效缓解高温下水泥混凝土流动性损失过快的问题。测试在25 ℃与60 ℃碱性溶液水解后的电荷密度与吸附量，研究其缓释工作机理及温度敏感性表明，在水泥浆体中，PCHEA、PCHPA链段中酯基不断水解生成羧基，导致聚合物分子中电荷密度逐渐增加，PCHEA的水解速率比PCHPA快。由于酯基在水泥浆体溶液碱性作用下不断水解而导致其在水泥颗粒表面的吸附量逐渐增加，表现出缓释行为。

Two types of acrylate containing polycarboxylate (PC) superplasticizers, (i.e., PCHEA, and PCHPA) were synthesized via radical polymerization of acrylic acid (AA) and α-methallyl-ω-methoxy poly (ethylene glycol) ether (HPEG) with hydroxyethyl acrylate (HEA) or hydroxypropy (HPA) as functional monomers. The dispersive property of the obtained polymers was investigated by a mini-cone fluidity test of fresh cement pastes at 25 ℃ and 60 ℃. The results show that acrylate-modified PCE can be used to improve the time retention ability of cement concrete fluidity. Also, the accelerated hydrolysis of ester groups at high temperatures can effectively alleviate the excessive loss of cement concrete fluidity at high temperatures. According to measurements of the specific charge density of polymer samples treated under alkaline condition at 25 ℃ and 60 ℃, the ester groups of PCHEA and PCHPA gradually hydrolyze to produce additional carboxyl groups, leading to the increase of the charge density of the polymer molecules. The measurement of the polymers adsorbtion on the surface of cement grains reveals that the hydrolysis of ester groups of the releasing behavior of such acrylate contacting PCEs can eliminate the fluidity loss due to cement hydration，showing a slow releasing behavior with time.

基金项目：

天津市科技计划课题(16YFXTSF00050)；中国京冶工程技术有限公司国家认定企业技术中心开放基金课题(2016JZAKj01)资助项目。

作者简介：

王芳(1991—)，女，博士研究生。

参考文献：

[1] SAKAI E, KASUGA T, SUGIYAMA T, et al. Influence of superpla sticizers on the hydration of cement and the pore structure of hardened cement[J]. Cem Concr Res, 2006(36): 2049–2053.

[2] NOCU?-WCZELIK W, CZAPIK P. Use of calorimetry and other methods in the studies of water reducers and set retarders interaction with hydrating cement paste[J]. Constr Build Mater, 2013(38): 980–986.

[3] SAKIR E, CANER A. Influence of fly ash and silica fume on the consistency retention and compressive strength of concrete subjected to prolonged agitating[J]. Constr Build Mater, 2011(25): 1277–1281.

[4] 李国新, 何廷树, 伍勇华, 等. 葡萄糖酸钠对萘系高效减水剂塑化水泥浆体流动性的影响[J]. 硅酸盐学报, 2010, 38(4): 768–773.

Li Guoxin, HE Tingshu, WU Yonghua, et al. J Chin Ceram Soc, 2010, 38(4): 768–773.

[5] NICHOLAS C C, NEIL B M, KARL P T, et al. The effect of organic retarders on grout thickening and setting during deep borehole disposal of high-level radioactive waste[J]. Prog Nucl Energy, 2016(90): 19–26.

[6] ISMAIL A. Influence of time addition of superplasticizers on the rheological properties of fresh cement pastes[J]. Cem Concr Res, 2003(33): 1229–1234.

[7] LIU Xiao, WANG Ziming, ZHU Jie, et al. Synthesis, characterization and performance of a polycarboxylate superplasticizer with amide structure[J]. Colloids and Surfaces A: Physicochem Eng Aspects, 2014(448): 119–129.

[8] PENG Tao, XIANG Hongjun. A synthesis method of the slump retaining polycarboxylate superplasticizers[P]. C.N. Patent 103183793 B. 2015.05.20.

[9] WANG Jianjun, WANG Shangpin. A room temperature synthesis method of the high slump retaining polycarboxylate superplasticizers[P]. C.N. Patent 103897119 A. 2017.07.02.

[10] KONG Fanrong, PAN Lisha, WANG Chenman, et al. Effects of polycarboxylate superplasticizers with different molecular structure on the hydration behavior of cement paste[J]. Constr Build Mater, 2016(105): 545–553.

[11] LEI L, PLANK J. A concept for a polycarboxylate superplasticizer possessing enhanced clay tolerance[J]. Cem Concr Res, 2012 (42): 1299–1306

[12] BRADLEY G, HOWARTH I. Water soluble polymers: the relationship between structure, dispersing action, and rate of cement hydration[J]. Cem Concr Aggr, 1986(8): 68–75.

[13] EL?BIETA Janowska-Renkas. The influence of the chemical structure of polycarboxylic superplasticizers on their effectiveness in cement pastes[J]. Proc Eng, 2015(108): 575–583.

[14] 李崇智, 马健, 挺林, 等. 缓释型聚羧酸系减水剂TP2000的试验研究[J]. 混凝土, 2013(6): 50–53.

LI Congzhi, MA Jian, TING Lin, et al. Con Creto, 2013(6): 50–53.

[15] DUAN J P, LV S H, GAO R J, et al. Spectrophotometric determination of polycarboxylate superplasticizer and its application[J]. Modern Chemical Industry, 2011, 31(10): 89–91.

[16] BURAK F, HASAN S. Effect of chemical structure of polycarboxylate-based superplasticizers on workability retention of self-compacting concrete[J]. Constr Build Mater, 2008, 22: 1972–1980.

[17] JANSEN D, NEUBAUER J, GOETZ-NEUNHOEFFER F, et al. Change in reaction kinetics of a Portland cement caused by a superplasticizer-calculation of heat flow curves from XRD data[J]. Cem Concr Res, 2012(42): 327–332.

[18] 刘晓, 王子明, 朱洁, 等. 新型酰胺结构聚羧酸高性能减水剂的制备与表征[J]. 硅酸盐学报, 2013, 41(8): 1079–1086.

LIU Xiao, WANG Ziming, ZHU Jie, et al. J Chin Ceram Soc, 2013, 41(8): 1079–1086.

[19] PLANK J, SACHSENHAUSER B.Experimental determination of the effective anioniccharge density of polycarboxylate superplasticizers in cement pore solution[J]. Cem Concr Res, 2009(39): 1–5.

[20] FLATT R J, HOUST Y F. A simplified view on chemical effects perturbing the action of superplasticizers[J]. Cem Concr Res, 2001(31): 1169–1176.

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