Quantitative Evaluation of Released Nanomaterials from Carbon Nanotube Epoxy Nanocomposites during Environmental Exposure and Mechanical Treatment

Published

September 29, 2023

Author(s)

Yue Zhao, David Goodwin, Lipiin Sung, Girish Ramakrishnan, Qiyuan Wu, Jiajie Cen, Elijah Petersen, Alexander Orlov

Abstract

Carbon nanotubes (CNTs) are promising nanomaterials exhibiting high thermal and electrical conductivities, significant stiffness, high tensile strength, and light weight. 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 effect of environmental weathering and mechanical stresses on degradation of CNT epoxy nanocomposites. The weathering experiments included nanocomposites exposure to both UV and a water spray, 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. Nanocomposite degradation was confirmed by attenuated total reflectance-Fourier transform infrared spectroscopy (ATR-FTIR), scanning electron microscopy (SEM), and light microscopy. In contrast to the existing literature, 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 collected during the total 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), uncovering a previously underestimated pathway for nanomaterial release in the environment.

Citation

NanoImpact

Pub Type

Journals

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Citation

Zhao, Y. , Goodwin, D. , Sung, L. , Ramakrishnan, G. , Wu, Q. , Cen, J. , Petersen, E. and Orlov, A. (2023), Quantitative Evaluation of Released Nanomaterials from Carbon Nanotube Epoxy Nanocomposites during Environmental Exposure and Mechanical Treatment, NanoImpact, [online], https://tsapps.nist.gov/publication/get_pdf.cfm?pub_id=936338 (Accessed April 27, 2024)