分散剂对石墨烯水泥基复合材料压敏性能的影响研究

Influence of Dispersant on Pressure-Sensitive Properties of Graphene Cement-Based Composites

石墨烯能显著改善水泥基复合材料的压敏性能,而分散剂是影响石墨烯分散以及复合材料性能的关键因素。本文通过紫外分光光度仪、超景深显微镜、激光粒度仪及Zeta电位测试,研究了聚羧酸减水剂(PCE)、聚氧乙烯(20)山梨醇酐单月桂酸酯(TW-20)、十二烷基磺酸钠(SDS)、十二烷基苯磺酸钠(SDBS)4种分散剂对石墨烯分散性能的影响,并通过直流二电极、直流四电极和交流二电极测试研究了4种分散剂对石墨烯水泥基复合材料导电性能和压敏性能的影响。结果表明:在去离子水和水泥孔溶液中,PCE由于静电斥力和空间位阻的协同作用,对石墨烯具有良好的分散性;而在水泥孔溶液中,TW-20、SDS、SDBS与Ca^(2+)之间的络合作用导致分散效率显著下降。石墨烯水泥基复合材料的导电和压敏性能与石墨烯在水泥基体中的分散性密切相关,掺PCE的石墨烯水泥基复合材料的电阻率最小,压敏性能最优。另外,SDS、SDBS的引气作用也会影响水泥基体的孔结构,导致电阻率增大,压敏性变差。

Graphene can significantly improve the smart performance of cement-based composites,and dispersants are a key factor affecting the dispersion of graphene and the performance of composites.In this paper,through ultraviolet(UV)spectrophotometer,ultra-depth-of-field microscope,laser particle size analyzer and Zeta potential test,the polycarboxylate water reducing agent(PCE),polyoxyethylene(20)sorbitan monolaurate(TW-20),sodium dodecyl sulfonate(SDS)and sodium dodecyl benzene sulfonate(SDBS)on the dispersion properties of graphene were studied.The effects of four dispersants on the conductivity and pressure-sensitive properties of graphene cement-based composites were studied through DC two-electrode,DC four-electrode and AC two-electrode tests.The results show that in deionized water and cement pore solution,PCE has good dispersibility for graphene due to the synergistic effect of electrostatic repulsion and steric hindrance.In the cement pore solution,the complexation between TW-20,SDS,SDBS and Ca^(2+) leads to a significant decrease in dispersion efficiency.The conductivity and pressure-sensitive properties of graphene cement-based composites are closely related to the dispersion of graphene in the cement matrix.Graphene cement-based composites doped with PCE have the smallest resistivity and the best pressure-sensitive properties.In addition,the air-entraining effects of SDS and SDBS also affect the pore structure of the cement matrix,resulting in increased resistivity and poor pressure sensitivity.