水性环氧树脂对聚合物水泥混凝土材料电气性能的影响

Effect of Waterborne Epoxy Resin on Electrical Properties of Polymer Cement Concrete Material

以硫铝酸盐水泥(S)为基料,通过掺杂水性环氧树脂(E),采用浇注成型方式制备了SE系列新型聚合物水泥混凝土输电管道用绝缘材料。通过对该材料进行局部放电、扫描电子显微镜、电导率及热学性能测试,研究了微观形貌和电气性能的关联性,并计算了试样的电导活化能。结果表明:掺杂水性环氧树脂对聚合物混凝土材料的电气性能具有显著影响,局部放电起始电压随掺杂含量的增加先增大后减小,其中SE-7.5(水性环氧树脂的含量为0.075%)试样的局部放电起始电压最大。分析SEM的结果发现,SE-7.5试样的表面更为致密,孔隙率低,使得放电通道难以形成,导致其具有较大的局部放电起始电压。随着掺杂含量的增加,试样的电导率减小,电导活化能先增加后减小,SE-7.5试样的电导活化能最大,且具有更稳定的热性能。这是因为具有强粘接性的水性环氧树脂能够使水泥化合物粘接更紧密,适量的掺杂可以减小材料的孔隙率,改善材料的界面特性。当水性环氧树脂的掺杂含量为0.075%时,聚合物混凝土试样具有最佳的综合电气性能。

A series of polymer cement concrete insulating materials （series SE） used for transmission pipe were prepared by pouring forming after adding waterborne epoxy resin （E） to sulpho-aluminate cement （S） matrix. The relationship between the microstructure and the electric properties of the materials was studied by scanning electron microscopy （SEM） and testing their partial discharge, conductivity, and thermal performance. The conductivity activation energy of the samples was also calculated. The results show that the introduction of waterborne epoxy resin has significant effects on the＇ electrical properties of the polymer concrete materials. With the increase of waterborne epoxy resin content, the partial discharge inception voltage of the materials increases at first and then decreases, reaches the maximum value when the content of waterborne epoxy resin is 0.075% （sample SE-7.5）. According to SEM test, the surface of sample SE-7.5 is denser and has a lower porosity than other samples, it makes the discharge channels difficult to form, resulting in a higher partial discharge inception voltage. With the increase of waterborne epoxy resin content, the conductivity of the samples increases, while the conductivity activation energy increases at first and then decreases, sample SE-7.5 has the maximum conductivity activation energy value and a stable thermal performance. It is indicated that the waterborne epoxy resin with strong adhesion makes the cement hydrate bond closer, and a proper doping rate can reduce the porosity and improve the interfacial properties of the materials. When the content of waterborne epoxy resin is 0.075%, the overall electrical properties of the polymer concrete are the best.