One of the most important projected commercial applications of carbon nanotubes (CNTs) involves their incorporation into polymer matrices to improve thermal, mechanical, and electrical properties. The loading of CNTs into polymer nanocomposites varies considerably and strongly influences polymer nanocomposite properties. Most engineered nanomaterials, such as carbon nanotubes (CNTs) will enter the environment within nanoproducts, such as polymer nanocomposites. As a result of exposure to environmental conditions polymer nanocomposites can be degraded and cause the unintended release CNTs into the environment. From a life cycle perspective, determining CNT release rates is important in terms of risk assessment, because release is the precursor to exposure. In this presentation I will discuss how the CNT loading in polymer nanocomposites influences: 1) Biodegradation: Polymer nanocomposites will often be exposed to microorganisms when they enter the environment post-consumer. The effect of embedded CNTs on microbial interactions and polymer biodegradation rates will be discussed including scenarios which are likely to facilitate CNT release. 2) Photodegradation: One of the principle routes of polymer degradation in the environment is through exposure to sunlight and the resulting photodegradation. A major challenge is the need to accurately detect and quantify released CNTs under environmentally relevant conditions where CNT concentrations are expected to be at part-per-trillion levels. As part of our studies on polymer photodegradation, I will discuss the use of single particle – inductively coupled plasma – mass spectrometry to detect trace catalytic metal nanoparticles intercalated in the CNT structure as proxies for the nanotubes. Collectively, information from these studies has important consequences in assessing the environmental risks posed by polymer-CNT nanocomposites, in developing better risk assessment models and in the design of nano-enabled products that retain their intended function without posing any unwanted long-term environmental liability.

Influence of loading on the degradation and release of carbon nanotubes from polymer nanocomposites

249th National Meeting (2015)

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