本文選題：自由基聚合 + 聚羧酸減水劑��； 參考：《湖南大學》2015年碩士論文

【摘要】：聚羧酸減水劑具有摻量低、減水率高、分子結(jié)構(gòu)變化自由度大、適用性范圍廣等特點。它可以顯著提高混凝土的和易性,減少拌合水的用量,改變混凝土的凝結(jié)時間,克服混凝土坍落度損失過快的問題,增強混凝土的抗壓強度等,具有較好的應(yīng)用前景。本文采用水溶液中的自由基聚合法,以異戊烯醇聚氧乙烯醚和其他可聚合單體合成聚羧酸減水劑。利用傅里葉紅外光譜儀對合成產(chǎn)物的結(jié)構(gòu)進行了表征,Zeta電位儀對摻入聚羧酸減水劑的水泥粒子表面ζ電位的變化進行了探討,凝膠滲透色譜對聚羧酸分散劑的分子量進行表征;利用數(shù)顯粘度計、流變儀和透射電鏡對加入聚羧酸分散劑的懸浮液的粘度、流變性及分散性能進行研究。研究結(jié)果表明:(1)酸醚比、引發(fā)劑的用量、甲基烯丙基磺酸鈉的用量、溫度對產(chǎn)物性能有較大的影響。當在丙烯酸和異戊烯醇聚氧乙烯醚的摩爾比是4:1,異戊烯醇聚氧乙烯醚與甲基烯丙基磺酸鈉的摩爾比是1:0.6,引發(fā)劑的用量是單體總質(zhì)量的6%,溫度在80℃的條件下合成的產(chǎn)物能使水泥泥漿有最高的凈漿流動度,可達285mm。(2)酸醚比、鏈轉(zhuǎn)移劑巰基丙酸的用量、還原劑VC的用量和滴加時間對產(chǎn)物性能有較大的影響。當在丙烯酸和異戊烯醇聚氧乙烯醚的摩爾比是4.16:1,異戊烯醇聚氧乙烯醚與巰基丙酸的摩爾比是1:0.18,異戊烯醇聚氧乙烯醚與還原劑VC的摩爾比是1:0.01,滴加時間為1 h的條件下合成的產(chǎn)物能使水泥泥漿有最高的凈漿流動度,可達235 mm。通過與水泥的相容性試驗和混凝土的適配實驗可知,自制的常溫聚羧酸減水劑的性能已基本達到國外某品牌減水劑的效果。(3)利用低分子量的異戊烯醇聚氧乙烯醚和可聚合單體聚合而成的聚羧酸分散劑也能應(yīng)用于陶瓷領(lǐng)域。這種聚羧酸分散劑能使表觀粘度從1088 m Pa·s降低到258 m Pa·s。
[Abstract]:Polycarboxylic acid superplasticizer has the characteristics of low content, high water reducing rate, wide degree of freedom of molecular structure change and wide applicability. It can significantly improve the easiness of concrete, reduce the amount of mixing water, change the setting time of concrete, overcome the problem of excessive slump loss of concrete, and enhance the compressive strength of concrete. It has a good application prospect. In this paper, polycarboxylic acid water reducer was synthesized from isopentenol polyoxyethylene ether and other polymerizable monomers by free radical polymerization in aqueous solution. The structure of the synthesized product was characterized by Fourier transform infrared spectroscopy (FTIR). The Zeta potentiometer was used to study the change of Zeta potential on the surface of cement particles mixed with polycarboxylic acid superplasticizer. The molecular weight of polycarboxylic acid dispersant was characterized by gel permeation chromatography. The viscosity, rheology and dispersibility of suspension with polycarboxylic acid dispersant were studied by means of digital display viscometer, rheometer and transmission electron microscope. The results show that the ratio of acid ether, the amount of initiator, the amount of sodium methylallyl sulfonate and temperature have great influence on the properties of the product. When the molar ratio of acrylic acid and isopentenol polyoxyethylene ether is 4: 1, the molar ratio of isopentenol polyoxyethylene ether to sodium methylallyl sulfonate is 1: 0.6, the amount of initiator is 6% of the total mass of monomer, and the temperature is 80 鈩，

本文編號：1945010