Authors: C. Motzkus, C. Chivas-Joly, E. Guillaume, S. Ducourtieux, L. Saragoza, D. Lesenechal, T. Macé
Affilation: Laboratoire National de Metrologie et d’Essais, France
Pages: 491 - 494
Day after day, new applications using nanoparticles appear in industry, increasing the probability to find these particles in workplaces as well as in ambient air. As epidemiological studies have shown an association between increased particulate air pollution and adverse health effects in susceptible members of the population, it is particularly important to characterize aerosols emitted by different sources of emission, during the combustion of composites charged with nanoparticles for example. The present study is led within the framework of the NANOFEU project, supported by the French Research Agency (ANR, Agence Nationale de la Recherche), in order to characterize the fire behaviour of polymers charged with suitable nanoparticles and make an alternative to retardant systems usually employed. To determine the impact of these composites on the emission of airborne particles produced during their combustion, an experimental setup has been developed  to measure the mass distribution in the range of 30 nm – 10 μm and the number concentration of submicrometric particles of the aerosol produced. The morphology of the particles collected by the impactor has been studied using Atomic Force Microscopy (AFM) and Scanning Electron Microscopy (SEM). A comparison  has been performed on the aerosol emitted during the combustion of several polymers alone (PMMA, PA-6), polymers containing nanofillers (silica, alumina, and carbon nanotubes) with or without surface treatment based on silane and polymers containing both nanofillers and a conventional flame retardant system (ammonium polyphosphate). In the case of all formulations of PMMA or PA-6 modified or not with and without nanofillers of SiO2, NTC, or Al2O3, the results illustrate that the mass fraction for the submicrometric particles (< 1 μm) is high (close of 80 %). One comparison of mass distributions is presented in figure 1. This figure illustrates the average mass distribution on the results of three replicates of combustion of a Polyamide-6 (PA-6) and PA-6 filled with 1% Multi Wall Carbon Nanotubes (MWNT). The results of PA-6 with or without nanofillers seem to show mono-modal distributions with mode diameter between 0.1 μm and 0.4 μm with regard to uncertainties. In a next step, we will perform, with a Differential Mobility Analysing System (DMAS), the measurement of the count size distribution of the emitted aerosol produced during the combustion of different formulations of polymers containing nanocomposites. These measurements will allow to provide the kinetics of the aerosol size distribution according to the kinds of polymers burned in different tests.