当前位置: X-MOL 学术New Carbon Mater. › 论文详情
Our official English website, www.x-mol.net, welcomes your feedback! (Note: you will need to create a separate account there.)
Impact of the microstructure of polycarboxylate superplasticizers on the dispersion of graphene
New Carbon Materials ( IF 6.5 ) Pub Date : 2020-11-13 , DOI: 10.1016/s1872-5805(20)60508-x
Qin Wang , Da-fu Zhan , Guo-dong Qi , Yue Wang , Hai-yu Zheng

Graphene can not only toughen cement-based materials, but also give them sensing ability. However, the uniform dispersion of graphene in a cement matrix is the major problem in the fabrication process. Four polycarboxylate superplasticizers (PCEs) with different charge densities and side-chain lengths were synthesized and the effects of their microstructures on the dispersibility of graphene in deionized water and in solution in cement pores were examined by UV-Vis spectroscopy, dynamic light scattering and optical microscopy with a large depth of field. A mechanism for the dispersion of graphene in the two media was also proposed. In deionized water, PCEs with a higher charge density showed more electrostatic repulsion, which improved the graphene dispersion efficiency. Conversely,PCEs with a lower charge density and longer side-chains gave a lower graphene dispersion. In solution in the cement pores, however, a PCE with a high charge-density produced a low graphene dispersibility, due to a cross-linking Ca2+-bridging effect. This effect was insignificant in cement pores for a solution containing low charge-density PCEs. Moreover, it was found that PCEs with the longer side-chains produced the worst graphene dispersion efficiency in both media. Overall, PCEs with a low charge density and relatively short side chains are more suitable for the preparation of graphene-composited cement pastes.



中文翻译:

聚羧酸类高效减水剂的微观结构对石墨烯分散性的影响

石墨烯不仅可以使水泥基材料增韧,还可以赋予它们感应能力。然而,石墨烯在水泥基体中的均匀分散是制造过程中的主要问题。合成了四种具有不同电荷密度和侧链长度的聚羧酸类高效减水剂(PCE),并通过紫外-可见光谱,动态光散射和光学方法研究了它们的微观结构对石墨烯在去离子水和溶液中在水泥孔隙中的分散性的影响。显微镜具有大景深。还提出了石墨烯在两种介质中的分散机理。在去离子水中,电荷密度较高的PCE表现出更大的静电排斥力,从而改善了石墨烯的分散效率。反过来,具有较低电荷密度和较长侧链的PCE产生较低的石墨烯分散体。但是,在水泥孔隙中的溶液中,由于钙的交联,具有高电荷密度的PCE产生了较低的石墨烯分散性。2+-桥接效果。对于含低电荷密度PCE的溶液,这种影响在水泥孔隙中微不足道。而且,发现具有较长侧链的PCE在两种介质中产生最差的石墨烯分散效率。总体而言,具有低电荷密度和相对短侧链的PCE更适合于制备石墨烯复合水泥浆。

更新日期:2020-11-13
down
wechat
bug