水中可分散型石墨烯对水泥净浆导电、发热及热电性能的影响

Effects of dispersible graphene in water on the electrical conductivity,heat generation and thermoelectric properties of cement slurry

为解决石墨烯(G)在水泥浆中均匀分散及其功能化水泥基材料时掺量过高的难题,选择一种兼顾高导电性与水溶性的石墨烯(G-SD)作为导电填料,研究了聚羧酸减水剂(PCE)存在时,木质素磺酸钠(MN)对G-SD在模拟水泥水化孔隙液的饱和氢氧化钙溶液(CH)中分散能力的影响及其对水泥净浆的导电性能、电热性能、融雪化冰和热电性能的影响。吸光度测试表明,当MN与G-SD质量比为3∶1时,G-SD的分散性最佳。电学性能测试发现,石墨烯水泥基材料的渗滤阀值为0.4%,阀值下试件的电热性能良好,在外加30 V电压下通电20 min,试件温度可达320℃,40 min内可将4 cm厚冰层完全融化,具有优异的融雪化冰潜力。热电性能研究表明,当G-SD掺量为0.1%时,试件的Seebeck系数为154.4μV/K。以上研究表明,G-SD能在极低掺量下赋予水泥基材料优异的电、热及热电等功能特性。

In order to solve the problem that graphene(G)is uniformly dispersed in cement slurry and its dosage is too high when it is functionalized into cement-based materials,a graphene(G-SD)with both high conductivity and water solubility was selected as a conductive filler.The effect of sodium lignosulfonate(MN)on the dispersion ability of G-SD in saturated calcium hydroxide solution(CH)used for simulated cement pore solution in the presence of polycarboxylate superplasticizer(PCE)and the effects of G-SD on the resistivity,electrothermal properties,snow melting and deciding,and thermoelectric properties of cement paste were investigated.The absorbance test shows that when the mass ratio of MN to G-SD is 3∶1,the dispersion of G-SD reaches the best.The electrical performance test shows that percolation threshold of graphene cement-based materials is 0.4%.What's more,good electrothermal performance are shown under the threshold,the temperature of cement paste specimen can be increased by 320℃ for 20 min with 30 V voltage,and 4 cm thick ice layer can be basically melted within 25 min,so it possesses good potential for deicing and snow-melting.The thermoelectric properties shows that Seebeck coefficient of cement paste specimen is 154.4μV/K when the content of G-SD is 0.1% by the cement mass.The above studies show that G-SD can endow cement-based materials with excellent electrical,thermal and thermoelectric functional properties at very low dosage.