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1、碩l:論文聚羧酸系高效減水劑的制備與性能研究摘要聚羧酸系減水劑具有高減水率和控制坍落度損失的優(yōu)點,但不同結(jié)構(gòu)的聚羧酸減水劑其減水性能和坍落度保持性有很大差別,因此研究和開發(fā)具有特定結(jié)構(gòu)的新型聚羧酸減水劑及結(jié)構(gòu)與性能的關(guān)系受到國內(nèi)外的廣泛關(guān)注。本文從聚羧酸減水劑的結(jié)構(gòu)入手,通過分子設(shè)計,以兩步合成法制得了聚羧酸系減水劑。試驗分別采用三種不同分子量的甲氧基聚7,--醇與甲基丙烯酸,通過直接酯化合成制備出不同結(jié)構(gòu)的甲氧基聚乙二醇甲基丙烯酸酯(大分子單體),然后將這些不同結(jié)構(gòu)的甲氧基聚7,--醇甲基丙烯酸酯與甲基丙烯酸、甲基丙烯磺酸鈉等單體在水
2、溶液中經(jīng)過自由基聚合,得到了不同結(jié)構(gòu)的聚羧酸減水劑。結(jié)果表明:同時具有長側(cè)鏈與短側(cè)鏈相間結(jié)構(gòu)的聚羧酸減水劑比單--t奧ll鏈長度的減水劑有更好的水泥分散性和分散保持性;利用紅外光譜和核磁共振譜對特定結(jié)構(gòu)的聚羧酸系高效減水劑官能團和分子結(jié)構(gòu)進行了表征。此外還研究了聚合反應(yīng)原料配比、工藝參數(shù)、控制條件對聚羧酸減水劑水泥分散性和分散保持性的影響規(guī)律,進而確定了聚羧酸系高效減水劑的最佳配比和工藝條件。應(yīng)用制備的減水劑按混凝土相關(guān)標準對其性能進行了測試,結(jié)果表明所制備的減水劑具有摻量小、減水率較高以及坍落度保持性好的特點,對新拌和硬化混凝土的性能
3、有顯著改善。關(guān)鍵詞:聚羧酸系高效減水劑,分子設(shè)計,斷齒形結(jié)構(gòu),水泥漿體流動性,結(jié)構(gòu)表征Abstract碩十論文Polycarboxylicwater-reducerexhibitsallexcellentabilityofwater-reducingandcontrollingslumplosses.However,polycarboxylicacidtypewater-reducerwithdifferentstructureshasdifferentwater-reducingperformanceandslump&eepingca
4、pability.Researchonthestructureofpolycarboxylicacidwater-reducerandtheconnectionbetweenthestructureandthepropertieshavegottenwide-spreadattentionathomeandabroad.Inthisthesis,polycarboxylictypewater-reducerWassynthesizedbythemethodoftwosteps,andthemoleculeframeofthechemic
5、alstructureofhighperformancewater-reducerswasdesigned.Usingmethylacrylicacidandthreekindsofmethoxypolyethyleneglycolwithdifferentmolecularweightseriesesterswithmacromoleculewerepreparedbydirectesterificationreaction.Andthenpolycarboxylicwater-reducerswithdifferentstructu
6、reweresynthesizedbyradicalpolymerizationinaqueoussystemwhicharethemixtureofmethoxypolyethyleneglycolacrylate,methac眄licacid,andsodiummethallylsulfonate.Theresultsshowedthatthedispersiveanddispersiveretentivityofpolycarboxylicwater-reducerwithinterphasestructureoflongside
7、-chainandshortside—chainwerebetterthanpolycarboxylicacidtypewater-reducerwithsingleside-chain.Itshowedcharacteristicsofthesuperplasticizerfunctionalgroupsthroughtheresearchofinfraredspectrumandnuclearmagneticresonance.Thereactantratio,processparametersandcontrolcondition
8、sofpolymerizationreactionwerestudiedbecausetheyhadinfluenceonthedispersivepropertyanddispersingretentio