Sanding and analysis of dust from nano-silica filled composite resins for stereolithography

The aim of this work was to assess whether with high amounts of nano-silica filled cured resins release nano-particles upon their abrasion, as this could form an occupational health risk and require specific safety measures. A standardised abrasion stress method involving a Taber linear abrasion apparatus (Model 5750) has been applied to the filled polymer samples. This linear abrasion apparatus simulates the mechanical solicitation, i.e. abrasion. Various particle size measurement techniques were applied to assess the size distribution and the quantity of particles released. Observations of airborne particle from abrasion tests are consistent with TEM characterization of the nanomaterials before any tests. Abrasions of both samples (called here '1' and '2') gave rise to emissions. For sample 1, a few 'dust' particles and micronic particles are observed. For sample 2, despite a track on the sample, no detectable micronic particles and very few 'dust', particles are detected. As a result, we can state there were effective abrasions which gave rise to a low emission (sample 1) and a very low emission (sample 2) under the detection limits of particle sizing and counting, for the last case. The emission of particles upon Taber test abrasion is extremely low (less than 8 particles per cm(3)) and for one of the samples at the level of the detection limit. Moreover, the size of these particles is generally larger than 100 nm. (C) 2020 INERIS. Published by Elsevier B.V. on behalf of Institution of Chemical Engineers.