水泥浆体中石墨烯纳米片团聚的X射线计算机断层扫描解析

X-ray computed tomography analysis of graphene nanoplatelets agglomeration in cement paste

为了实现纳米颗粒在水泥基材料中的均匀分散以及探究如何无损地检验纳米颗粒的分散程度,利用石墨烯纳米片(GNPs)作为代表性的碳纳米添加剂,设置3种不同的超声分散方式(VSD)-直接、间接和直接-间接结合分散,得到具有不同GNPs分散状态的水泥浆体.利用X射线计算机断层扫描技术(XCT)对孔隙和石墨烯团聚体进行无损表征;基于两者的形状特征差异(球形度和紧密度)筛分出GNPs团聚体,解析其分布、数量和粒径等;利用扫描电子显微镜(SEM)对GNPs团聚体形貌进行观察;进行抗压强度测试以验证GNPs分散情况对宏观性能的影响.XCT结果表明基于形状特征能够无损地区分出GNPs团聚体,直接分散作用下GNPs团聚体数量和累计体积均最小;SEM观测结果表明GNPs团聚体具有复杂多样的形貌;力学测试结果表明抗压强度与分散质量呈正相关关系.

Graphene nanoplatelets(GNPs)were used as a representative carbon nano-additive,to achieve uniform dispersion of nanoparticles in cement-based materials and investigate non-destructive methods for assessing the degree of dispersion.And three different ultrasonic dispersion(USD)methods were set up:direct,indirect and direct-indirect combined USD.These methods were utilized to produce cement pastes with varying degrees of GNPs dispersion.X-ray computed tomography(XCT)was employed to characterize pores and GNPs agglomerates nondestructively.Based on differences in morphology features(sphericity and compactness),GNPs agglomerates were identified and their distribution,quantity and size were analyzed.Scanning electron microscopy(SEM)was used to observe the morphology of GNPs agglomerates.Compressive strength testing was conducted to demonstrate the influence of GNPs dispersion on macroscopic properties.The XCT results show that GNPs agglomerates can be distinguished non-destructively based on shape features.The results also indicate that the number and cumulative volume of GNPs agglomerates are the smallest under direct USD.SEM observation results show that GNPs agglomerates have complex and diverse morphologies.Mechanical results indicate the positive correlation between compressive strength and dispersion quality.