Figure 4

Weathering induced release from nanocomposites. About one third of the nanorelease studies have examined release from nanocomposite due to weathering. The most frequently (94%) identified release debris were particles of matrix alone. Particles of matrix with embedded nanomaterial were reported in (65%) of the studies, while about a third (35%) identified dissociated nanomaterials among the released debris from weathered nanocomposites. Across study summaries are present in charts: (A) the added nanomaterial, (B) the matrix, (C) the released debris identified and (D) the number of experiments versus observational studies. (*) Authors report release only after a combination of weathering and machining; (-) authors report insignificant but detectable levels of dissociated nanomaterial; (?) data supporting this result are indirect or not presented, but described by the authors; (exp) rigorous experiments with replicate testing and negative controls (samples of matrix without added nanomaterial) examined; (obs) observational studies with no control samples and/or not replicate testing; (C) refers to any one of multiple forms of Carbonaceous nanomaterials, including: single and multi-walled carbon nanotubes, graphene oxide, carbon black and uncharacterized carbon nanotubes; (CSH) are calcium silicate hydrates; (%) a complex copper II with chlorinated phthalocyanine; (@) alumina based Cobalt Blue.