低溫合成聚羧酸減水劑的研究
本文關(guān)鍵詞: 聚羧酸減水劑 低溫合成 綜合性能 對比測試 出處:《武漢科技大學(xué)》2014年碩士論文 論文類型:學(xué)位論文
【摘要】:隨著國內(nèi)大興建設(shè),聚羧酸高效減水劑在混凝土結(jié)構(gòu)中的應(yīng)用越來越多,其優(yōu)越的減水性能給混凝土的施工技術(shù)帶來了很大的提升,但是,其綜合性能、生產(chǎn)工藝和經(jīng)濟(jì)效益依然值得我們探索。目前,普通聚羧酸高效減水劑合成溫度較高,普遍在70-90℃甚至更高,由于較高的反應(yīng)溫度給合成工藝的控制加大了難度,所以如何降低反應(yīng)溫度,更合理的控制大單體的聚會(huì)反應(yīng),提高大規(guī)模生產(chǎn)的經(jīng)濟(jì)效益是本課題研究的重點(diǎn),另外現(xiàn)代混凝土的原材料差異變化,也給混凝土拌和物的質(zhì)量控制增加了不少難度。難以使混凝土拌和物在較短的時(shí)間內(nèi)保持良好的和易性以及坍落度保持性。而低溫合成的聚羧酸高效減水劑能有效降低混凝土拌和物的坍落度的損失,使混凝土拌和物在長時(shí)間內(nèi)具備良好的工作性能,同時(shí)亦具有較好的力學(xué)性能和良好的耐久性。 本論文研究了聚羧酸減水劑的低溫合成,通過單因素的試驗(yàn)方法確定了最佳的合成工藝以及最佳原材料反應(yīng)配比。以甲基烯丙基聚氧乙烯醚(TPEG)、丙烯酸(AA)和衣康酸等為主要的原材料,在引發(fā)劑的作用下,低溫合成聚羧酸高效減水劑,最佳合成工藝為n(AA):n(衣康酸):n(巰基乙酸):n(TPEG)=1.7:0.23:0.005:1,m(引發(fā)劑):m(TPEG)=0.25%;反應(yīng)溫度為44℃,滴加反應(yīng)時(shí)間為4h。在該條件下合成的緩釋型聚羧酸高效減水劑,,控制水灰比為0.29,減水劑摻量為0.4%,其中水泥凈漿流動(dòng)度試驗(yàn)所采用的水泥為適應(yīng)性較差的昌閣水泥,水泥初始凈漿流動(dòng)度可以達(dá)到280mm,1h后的水泥凈漿流動(dòng)度為260mm,具有較好的分散性和分散保持性。 為了進(jìn)一步對低溫合成的聚羧酸高效減水劑的性能進(jìn)行研究,同時(shí)選取了不同廠家的水泥進(jìn)行了適應(yīng)性對比試驗(yàn)。對于不同的水泥樣品4#、13#均表現(xiàn)出了較好的水泥適應(yīng)性,可使水泥具有較好的初始分散性和分散保持性,其作用效果優(yōu)于市售格瑞林減水劑和臺(tái)界減水劑。而混凝土對比試驗(yàn)表明4#、13#具有相對較好的減水效果及綜合性能優(yōu)于市售格瑞林、臺(tái)界混凝土的減水劑。四種聚羧酸高效減水劑配置的混凝土的力學(xué)性能相當(dāng)。 由紅外光譜圖可知,4#、13#減水劑的官能團(tuán)結(jié)構(gòu)與格瑞林減水劑、臺(tái)界減水劑相似。4#、13#、格瑞林、臺(tái)界減水劑的羥基吸收振動(dòng)峰相當(dāng),說明合成的2種減水劑都具有較高的綜合性能。4#的C-H的吸收振動(dòng)峰最強(qiáng),說明該聚羧酸高效減水劑的單體轉(zhuǎn)換率最高;4#的—COOH的伸縮振動(dòng)峰最強(qiáng),13#的—COOH的伸縮振動(dòng)峰的強(qiáng)度僅次于4#,格瑞林、臺(tái)界減水劑的—COOH的伸縮振動(dòng)峰稍弱,說明4#的減水效果最好;4#的C-O-C的吸收振動(dòng)峰最強(qiáng),說明單體的轉(zhuǎn)化率最好,其支鏈密度最高,支鏈密度越高,其空間位阻效應(yīng)越好,分散保持性越好;兩種聚羧酸高效減水劑的分子結(jié)構(gòu)上帶有減水、緩凝和保坍作用的羧基、磺酸基和羥基等官能團(tuán),從分子結(jié)構(gòu)上進(jìn)一步驗(yàn)證,所合成的減水劑具有綜合功能。
[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.
【學(xué)位授予單位】:武漢科技大學(xué)
【學(xué)位級別】:碩士
【學(xué)位授予年份】:2014
【分類號】:TU528.042.2
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