石墨烯改性水泥材料的制備及其機(jī)理研究
發(fā)布時(shí)間：2018-10-11 09:03
【摘要】：水泥混凝土作為世界上使用最廣泛的建筑工程材料,研究其性能改善具有十分重要的現(xiàn)實(shí)意義。隨著納米科技的發(fā)展,很多研究者將納米材料引入到水泥中來(lái)改善水泥的諸多性能,且取得了可觀的效果。石墨烯作為新型的二維納米材料,由于其優(yōu)異的性能而受到人們的廣泛關(guān)注。本文研究了石墨烯和氧化石墨烯對(duì)水泥水化歷程及水化程度的影響,在此基礎(chǔ)上分析了氧化石墨烯在水泥堿性環(huán)境中的絮凝現(xiàn)象,同時(shí)試圖通過(guò)球磨法將石墨烯分散在水泥基體中,從而制備出具有良好性能的改性水泥材料。首先采用改性Hummers法制備氧化石墨烯分散液,氧化石墨烯表面呈現(xiàn)褶皺狀且含有大量的-OH、-O-和-COOH官能團(tuán)。借助水化熱、TG-DSC等分析方法,研究了石墨烯/氧化石墨烯對(duì)水泥水化歷程及水化程度的影響:石墨烯/氧化石墨烯的加入對(duì)水泥的水化放熱速率及總放熱量基本沒(méi)有影響,且氫氧化鈣(CH)和化學(xué)結(jié)合水的含量也沒(méi)有顯著變化。結(jié)合SEM分析,可以得出:石墨烯/氧化石墨烯只是物理性的分散在水泥中。對(duì)氧化石墨烯在水泥漿體中的絮凝現(xiàn)象進(jìn)行了研究,采用CH溶液模擬水泥水化后的堿性環(huán)境,通過(guò)紫外分光光度計(jì)和ζ-電位等方法,系統(tǒng)分析了氧化石墨烯發(fā)生絮凝現(xiàn)象的過(guò)程及解決辦法。結(jié)果表明:少量的CH(30 mg/L)即可導(dǎo)致氧化石墨烯的絮凝現(xiàn)象,聚羧酸減水劑(PC)能夠有效抑制氧化石墨烯的絮凝過(guò)程,且氧化石墨烯與PC之間沒(méi)有化學(xué)鍵的作用。從官能團(tuán)的角度探究了PC分散氧化石墨烯的機(jī)理:相比于-OH,-COOH官能團(tuán)能有效抑制氧化石墨烯的絮凝過(guò)程,同時(shí)PC特殊的分子結(jié)構(gòu)對(duì)分散氧化石墨烯也有一定的空間位阻作用。通過(guò)球磨法將石墨烯均勻分散在水泥中,研究了石墨烯對(duì)水泥材料的增強(qiáng)效果。實(shí)驗(yàn)結(jié)果表明:石墨烯的加入提高了水泥凈漿的抗壓強(qiáng)度,其最佳摻量為0.03 wt%,此時(shí)的強(qiáng)度增長(zhǎng)率在9%左右。石墨烯在球磨后其形態(tài)基本沒(méi)有變化,且石墨烯的加入沒(méi)有誘導(dǎo)水泥礦物生成新的水化產(chǎn)物。
[Abstract]:Cement concrete is the most widely used building material in the world. It is of great practical significance to study its performance improvement. With the development of nanotechnology, many researchers have introduced nanomaterials into cement to improve many properties of cement, and achieved considerable results. Graphene, as a new two-dimensional nanometer material, has been paid more and more attention because of its excellent properties. In this paper, the effects of graphene and graphene oxide on the hydration process and hydration degree of cement were studied, and the flocculation of graphene oxide in alkaline cement environment was analyzed. At the same time, the graphene was dispersed in the cement matrix by ball milling method, so that the modified cement material with good properties was prepared. Firstly, graphene oxide dispersions were prepared by modified Hummers method. Graphene oxide surfaces were ruffled and contained a large number of-OH,-O- and-COOH functional groups. The effects of graphene / graphene oxide on the hydration process and the degree of hydration of cement were studied by means of hydration heat, TG-DSC and other analytical methods: the addition of graphene / graphene oxide had little effect on the hydration heat release rate and total heat release of cement. The content of calcium hydroxide (CH) and chemically bound water did not change significantly. Combined with SEM analysis, it can be concluded that graphene / graphene oxide is only physically dispersed in cement. The flocculation of graphene oxide in cement paste was studied. CH solution was used to simulate the alkaline environment of cement hydration, and ultraviolet spectrophotometer and 味-potential were used to study the flocculation of graphene oxide in cement paste. The process and solution of flocculation of graphene oxide are analyzed systematically. The results show that a small amount of CH (30 mg/L) can lead to the flocculation of graphene oxide. The polycarboxylic acid superplasticizer (PC) can effectively inhibit the flocculation process of graphene oxide, and there is no chemical bond between graphene oxide and PC. The mechanism of PC dispersed graphene oxide was studied from the point of view of functional groups. Compared with-OH,-COOH functional group, the flocculation process of graphene oxide can be effectively inhibited by the functional group. At the same time, the special molecular structure of PC also has a certain steric effect on the dispersion of graphene oxide. Graphene was uniformly dispersed in cement by ball milling, and the reinforcing effect of graphene on cement was studied. The experimental results show that the compressive strength of cement paste is increased with the addition of graphene, and the strength growth rate of the cement paste is about 9% when the optimum addition amount is 0.03 wt%,. The morphology of graphene did not change after ball milling, and the addition of graphene did not induce cement minerals to form new hydration products.
【學(xué)位授予單位】：濟(jì)南大學(xué)
【學(xué)位級(jí)別】：碩士
【學(xué)位授予年份】：2017
【分類號(hào)】：TQ172.1
本文編號(hào)：2263619
[Abstract]:Cement concrete is the most widely used building material in the world. It is of great practical significance to study its performance improvement. With the development of nanotechnology, many researchers have introduced nanomaterials into cement to improve many properties of cement, and achieved considerable results. Graphene, as a new two-dimensional nanometer material, has been paid more and more attention because of its excellent properties. In this paper, the effects of graphene and graphene oxide on the hydration process and hydration degree of cement were studied, and the flocculation of graphene oxide in alkaline cement environment was analyzed. At the same time, the graphene was dispersed in the cement matrix by ball milling method, so that the modified cement material with good properties was prepared. Firstly, graphene oxide dispersions were prepared by modified Hummers method. Graphene oxide surfaces were ruffled and contained a large number of-OH,-O- and-COOH functional groups. The effects of graphene / graphene oxide on the hydration process and the degree of hydration of cement were studied by means of hydration heat, TG-DSC and other analytical methods: the addition of graphene / graphene oxide had little effect on the hydration heat release rate and total heat release of cement. The content of calcium hydroxide (CH) and chemically bound water did not change significantly. Combined with SEM analysis, it can be concluded that graphene / graphene oxide is only physically dispersed in cement. The flocculation of graphene oxide in cement paste was studied. CH solution was used to simulate the alkaline environment of cement hydration, and ultraviolet spectrophotometer and 味-potential were used to study the flocculation of graphene oxide in cement paste. The process and solution of flocculation of graphene oxide are analyzed systematically. The results show that a small amount of CH (30 mg/L) can lead to the flocculation of graphene oxide. The polycarboxylic acid superplasticizer (PC) can effectively inhibit the flocculation process of graphene oxide, and there is no chemical bond between graphene oxide and PC. The mechanism of PC dispersed graphene oxide was studied from the point of view of functional groups. Compared with-OH,-COOH functional group, the flocculation process of graphene oxide can be effectively inhibited by the functional group. At the same time, the special molecular structure of PC also has a certain steric effect on the dispersion of graphene oxide. Graphene was uniformly dispersed in cement by ball milling, and the reinforcing effect of graphene on cement was studied. The experimental results show that the compressive strength of cement paste is increased with the addition of graphene, and the strength growth rate of the cement paste is about 9% when the optimum addition amount is 0.03 wt%,. The morphology of graphene did not change after ball milling, and the addition of graphene did not induce cement minerals to form new hydration products.
【學(xué)位授予單位】：濟(jì)南大學(xué)
【學(xué)位級(jí)別】：碩士
【學(xué)位授予年份】：2017
【分類號(hào)】：TQ172.1
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