Cardno ChemRisk; 130 Vantis Suite 170, Aliso Viejo, CA, 92656, USA.
ICF; Fairfax, VA, USA.
J Expo Sci Environ Epidemiol. 2018 May;28(3):203-215. doi: 10.1038/jes.2017.6. Epub 2017 May 31.
Composites made with engineered nanomaterials (nanocomposites) have a wide range of applications, from use in basic consumer goods to critical national defense technologies. Carbon nanotubes (CNTs) are a popular addition in nanocomposites because of their enhanced mechanical, thermal, and electrical properties. Concerns have been raised, though, regarding potential exposure and health risks from nanocomposites containing CNTs because of comparisons to other high aspect ratio fibers. Assessing the factors affecting CNT release from composites is therefore paramount for understanding potential exposure scenarios that may occur during product handling and manipulation. Standardized methods for detecting and quantifying released CNTs, however, have not yet been developed. We therefore evaluated experimental approaches deployed by various researchers, with an emphasis on characterizing free versus composite bound CNTs. From our analysis of published studies characterizing CNT releases from nanocomposites, we found that the qualitative and quantitative methods used across studies varied greatly, thus limiting the ability for objective comparison and evaluation of various release factors. Nonetheless, qualitative results indicated that factors such as composite type, CNT functionalization, and energy input during manipulation (i.e., grinding) may affect CNT release. Based on our findings, we offer several recommendations for future product testing and assessment of potential exposure and health risks associated with CNT nanocomposites.
用工程纳米材料制成的复合材料(纳米复合材料)具有广泛的应用,从用于基本消费品到关键的国防技术。由于其增强的机械、热和电性能,碳纳米管(CNT)是纳米复合材料中很受欢迎的添加物。然而,由于与其他高长径比纤维的比较,人们对含有 CNT 的纳米复合材料的潜在暴露和健康风险表示担忧。因此,评估影响 CNT 从复合材料中释放的因素对于了解在产品处理和操作过程中可能发生的潜在暴露情况至关重要。然而,尚未开发出用于检测和量化释放 CNT 的标准化方法。因此,我们评估了各种研究人员使用的实验方法,重点是表征游离 CNT 与复合结合 CNT。通过对已发表的研究中 CNT 从纳米复合材料中释放的研究进行分析,我们发现,研究中使用的定性和定量方法差异很大,从而限制了对各种释放因素进行客观比较和评估的能力。尽管如此,定性结果表明,复合材料类型、CNT 功能化以及操作过程中的能量输入(例如,研磨)等因素可能会影响 CNT 的释放。基于我们的发现,我们为未来与 CNT 纳米复合材料相关的产品测试和潜在暴露及健康风险评估提供了一些建议。