Nanotech 2011

Comprehensive Study of Release from Nanocomposites: Normal-Use vs. Do-It-Yourself vs. Weathering (invited presentation)

W. Wohlleben, S. Brill, M.W. Meier, M. Mertler, G. Cox, S. Hirth, B. von Vacano, L. Ma-Hock, R. Landsiedel
BASF SE, DE

Keywords: nanocomposites, aluminosilicates, carbon nanotubes, toxicity, biophysics

Abstract:

Nanocomposites are the dominating class of nanomaterials to come into consumer contact. For the first time, our comprehensive study compares 3 release mechanisms and assesses in-vivo the hazard potential on a systematic series of 4 thermoplastic and cementitious nanocomposite materials. We confirm earlier reports that ‘chalking’ does occur also for weathered nanocomposites. In contrast, mechanical forces by normal consumer use or do-it-yourself sanding do not disrupt nanofillers (SiO2, CSH, CNTs) from their matrix. We provide detailed evidence (from SEM, AUC, XPS, SIMS, diffraction) on the nature of the degradation products: We detected no free nanofillers up to the detection threshold of 100 ppm. And yet, is there a hazard from aerosols generated by sanding of nanocomposites up to the nuisance dust limit? We perform in vivo instillation in rats and quantify physiological effects a) on degradation products from abraded nanocomposites, in double comparison to b) the abraded matrix without nanofiller and c) to the pure nanofiller. In this first evaluation, the hazard potential does not distinguish with or without nanofiller. A summarizing risk assessment substantiates the assumption that nanocomposites are indeed safe in consumer settings.
 

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