Abstract Our study aims at a better understanding of the release process of graphene-related materials (GRMs) from epoxy composites during an abrasion process and the quantification of the released GRM fraction in the abraded particles. We investigated the GRM dispersion in epoxy-based composites using terahertz spectroscopy and determined the released exposed (freestanding and protruding) fraction of GRMs in the abraded powders. First, GRMs were labeled with lead and immersed into epoxy resin. Composites were produced by adding hardener and curing. Results from EDX-SEM (energy-dispersive X-ray-scanning electron microscopy) mapping and Raman spectroscopy mapping showed exposed GRMs on the surface of the abraded powders. In the first approach, we identified the released exposed GRM fraction by measuring the amount of detached lead ions from lead-labeled GRMs using inductively coupled plasma-optical emission spectrometry (ICP-OES). In the second approach, we employed Raman spectroscopy mapping as a semi quantitative method to assess the released exposed GRM fraction via determining the GRM surface coverage in the abraded powders. The results from the Raman intensity ratio maps are similar to those of the ICP-OES technique. The fractions of released exposed GRMs ranged from 18% to 92% depending on the type of GNP. Our study combines multiple qualitative, semi quantitative and quantitative methods to determine the released exposed GRM fraction and thereby facilitates exposure and risk assessment of GRM containing composites.

中文翻译：

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环氧石墨烯相关材料复合材料：纳米结构表征和释放量化

摘要 我们的研究旨在更好地了解石墨烯相关材料 (GRM) 在磨损过程中从环氧复合材料中的释放过程，以及对磨损颗粒中释放的 GRM 分数的量化。我们使用太赫兹光谱研究了环氧基复合材料中的 GRM 分散，并确定了磨损粉末中 GRM 的释放暴露（独立和突出）部分。首先，GRM 用铅标记并浸入环氧树脂中。通过添加硬化剂和固化来生产复合材料。EDX-SEM（能量色散 X 射线扫描电子显微镜）测绘和拉曼光谱测绘的结果表明，研磨粉末表面有暴露的 GRM。在第一种方法中，我们通过使用电感耦合等离子体光发射光谱法 (ICP-OES) 测量从铅标记的 GRM 中分离的铅离子的量来确定释放的暴露 GRM 部分。在第二种方法中，我们采用拉曼光谱映射作为一种半定量方法，通过确定研磨粉末中的 GRM 表面覆盖率来评估释放的暴露 GRM 分数。拉曼强度比图的结果与 ICP-OES 技术的结果相似。根据 GNP 的类型，释放的暴露 GRM 的比例从 18% 到 92% 不等。我们的研究结合了多种定性、半定量和定量方法来确定释放的暴露 GRM 分数，从而促进含 GRM 复合材料的暴露和风险评估。