(733a) Improving Sustainability of CNT/Polymer Composites: Tracking CNTs Release

Carbon nanotubes (CNTs) exhibit high thermal and electrical conductivity, stiffness, tensile strength and light weight and as a result, CNTs have been employed as additives/nanofillers to enhance the properties of polymeric materials. CNTs containing polymer composites have been used in many industries including energy, environment, personal care, health care and life sciences, etc. Several studies have shown that the polymer matrix degradation can occur as a result of environmental factors such as ultraviolet (UV) radiation, moisture, mechanical stress, and/or a combination thereof. Such degradation can lead to surface accumulation, protrusion and potential release of CNTs thus it is essential to develop method and study CNTs release from composite. In this study, we investigated the effect of environmental factors on the degradation of MWCNTs/epoxy nanocomposites. Chemical changes resulting from epoxy matrix degradation were investigated by attenuated total reflectance infrared spectroscopy (ATR-FTIR) and morphological changes of the samples were assessed by scanning electron microscopy (SEM). In order to determine the rate of CNT release, we incorporated ¹⁴C-labelled MWCNTs into the nanocomposites and measured their release with liquid scintillation counting (LSC) after weathering treatment. Degradation of epoxy resulted in matrix removal, exposure of CNT network, and release of a detectable amount of CNTs to the environment.