Quantitative evaluation of released nanomaterials from carbon nanotube epoxy nanocomposites during environmental exposure and mechanical treatment

Yue Zhao; David G Goodwin Jr; Lipiin Sung; Girish Ramakrishnan; Qiyuan Wu; Jiajie Cen; Elijah J Petersen; Alexander Orlov

doi:10.1016/j.impact.2023.100486

Quantitative evaluation of released nanomaterials from carbon nanotube epoxy nanocomposites during environmental exposure and mechanical treatment

NanoImpact. 2023 Oct:32:100486. doi: 10.1016/j.impact.2023.100486. Epub 2023 Sep 29.

Authors

Yue Zhao¹, David G Goodwin Jr², Lipiin Sung², Girish Ramakrishnan³, Qiyuan Wu³, Jiajie Cen³, Elijah J Petersen⁴, Alexander Orlov⁵

Affiliations

¹ Department of Chemistry, Stony Brook University, Stony Brook, NY 11794, USA.
² Engineering Laboratory, National Institute of Standards and Technology (NIST), Gaithersburg, MD 20899, USA.
³ Department of Materials Science and Chemical Engineering, Stony Brook University, Stony Brook, NY 11794, USA.
⁴ Material Measurement Laboratory, National Institute of Standards and Technology (NIST), Gaithersburg, MD 20899, USA. Electronic address: elijah.petersen@nist.gov.
⁵ Department of Materials Science and Chemical Engineering, Stony Brook University, Stony Brook, NY 11794, USA. Electronic address: alexander.orlov@stonybrook.edu.

PMID: 37777181
DOI: 10.1016/j.impact.2023.100486

Abstract

Carbon nanotubes (CNTs) are promising nanomaterials exhibiting high thermal and electrical conductivities, significant stiffness, and high tensile strength. As a result, CNTs have been utilized as additives to enhance properties of various polymeric materials in a broad range of fields. In this study, we investigated the release of CNTs from CNT epoxy nanocomposites exposed to environmental weathering and mechanical stresses. The presence and amount of CNTs released from degraded polymer nanocomposites is important because CNTs can impact physiological systems in humans and environmental organisms. The weathering experiments in this study included nanocomposite exposure to both UV and a water spray, to simulate sunlight and rain exposure, whereas mechanical stresses were induced by shaking and ultrasonication. CNT release from epoxy nanocomposites was quantified by a ¹⁴C-labeling method that enabled measurement of the CNT release rates after different weathering and mechanical treatments. In this study, a sample oxidizer was used prior to liquid scintillation counting, because it was shown to reduce interferences from the presence of polymeric materials and achieve a high recovery (95%). Polymer nanocomposite degradation was confirmed by attenuated total reflectance-Fourier transform infrared spectroscopy (ATR-FTIR), scanning electron microscopy (SEM), and light microscopy. A continuous release of ¹⁴C-labeled nanomaterials was observed after each UV and simulated rain exposure period, with 0.23% (mass/mass) of the total embedded mass of CNTs being released from the CNT nanocomposite during the full weathering process, suggesting that the water spray induced sufficient mechanical stress to eliminate the protective effect of the surface agglomerated CNT network. Importantly, additional mechanical stresses imposed on the weathered nanocomposites by shaking and ultrasonication resulted in further release of approximately 0.27% (mass /mass).

Keywords: Accelerated weathering; Carbon nanotubes; Isotope labeling; Nanocomposite; Nanomaterial quantification; Nanomaterial release.

Published by Elsevier B.V.

MeSH terms

Environmental Exposure
Humans
Nanocomposites* / chemistry
Nanotubes, Carbon* / chemistry
Polymers / chemistry
Water

Substances

Nanotubes, Carbon
Polymers
Water