It also emphasized that release results first in occupational (or consumer) exposure selleck compound and then also in environmental exposure. The highest likelihood for release of ENM is during the synthesis and handling of ENM, particularly during the handling of powders prior to the fabrication of the composite (Tsai et al., 2009 and Yeganeh et al., 2008). In fabrication activities, post-material generation, or master batch formation, release might occur when creating applications from the composite product. For a polymer composite, mechanical processes such as drilling, cutting and sanding could generate the release of nanomaterials.
Thermal and high-energy processes, that, for example, might be used to shape a composite, could destabilize the composite resulting in a release of nanomaterials. If the composite material is flexible, for example a fabric, all of the above activities and additional ones, including rolling, folding or other handling might release nanomaterials. In summary, at the fabrication phase a release of nanomaterial is possible if there are steps in which the polymer structure is modified. Kuhlbusch et al. (2011) summarized and reviewed all publications
which include investigations of ENM release at workplace or simulated scenarios for use and end of life up to the year 2011 and gave a good overview of possible release scenarios, not only for polymer compounds. During the use phases, RO4929097 research buy both environmental sources of stress and human activities that stress the composite may result in releases. The media in which
the composite is used affect the environmental factors: weathering is affected by moisture, salinity, pressure, temperature and light radiation (especially UV), and will vary in marine or fresh water, or with altitude and biogeochemical conditions of exposure. Specific applications — represented by a limited number of standardized processes, are useful to limit the number for of possible release scenarios. Human activities at the use phase include mechanical, thermal and biochemical interactions, but conditions may differ in the environment. For example, CNT/polymer composite building materials will normally be subjected to weathering stress, and less to mechanical stress. On the other hand, a CNT/polymer composite used in a laptop computer housing will mainly be subject to mechanical stress (e.g. by scratching or cracking). Generally speaking, the likelihood that only the nanostructured material is released is small, because of the high-energy input needed. Most likely, lumps of composite material containing CNTs or nanostructured material or vaporized nanostructured materials will be released. Post-use releases could result from waste treatment — landfilling, recycling or incineration. Otherwise, they are more likely to occur from environmental rather than human impacts such as weathering effects after waste treatment.