Release of nanomaterials from nanoproducts used in home building: lessons learnt from the EU NANOhouse project

B. Fiorentino, D. Boutry, A. Guiot, L. Golanski, J.F. Damlencourt
CEA, FR

Keywords: nano particle release, building materials

Summary:

Research and products developments in the area of nanotechnology have steadily increased especially due to new beneficial properties of nanomaterials (NM). The release of nanoparticles (NP) in the environment from products used and commercialized by the industry is actually not well known and may lead to health or environment effect during their whole life cycle. This concern has been identified early and was taken seriously by public bodies and the industry. The only way to guarantee a risk closed to zero is to verify that the materials containing nanoparticles do not release their nanoparticles. This implies in particular the control of the implementation of NP in consumer products through-out their life cycle during their manufacture, use and till the end of life Within the frame of the European-funded NanoHouse project, we investigate paints containing Engineered Nanoparticles (ENPs) and focus more precisely on the release potential during their cycle lifes. ENPs (i.e. Nano SiO2 and TiO2) are added in coatings in order to improve different properties (antimicrobial, rheological or mechanical properties) of the coating system or to produce multipurpose coatings with little cost difference. To represent the life cycle of that type of materials, panels covered with paints are inserted in a climatic chamber to simulate aging induced by sunlight and rain (called Q-UV). All these paints are characterized by Attenuated Total Reflectance Fourier Transform Infrared spectroscopy (ATR-FTIR) and by Scanning Electron Microscopy coupled with Energy Dispersive Spectrometry (SEM-EDS) to analyze the surface modifications before and after the aging (figure 1 and 2). Moreover, to reproduce accelerated mechanical aging, paints are abraded following norms commonly used in paint industry (figure 3). The emitted particles are characterized by an Electrical Low Pressure Impactor (ELPI) allowing the determination of the particle size distribution. The morphology and the chemical composition of the aerosolized particles are obtained by SEM-EDS analysis of the ELPI impaction membranes (figure 4). The parameter influencing the nanoparticles release is identified. Indeed, the chemical nature of the binder influences the release phenomenon; the acrylic copolymer shows a more important chemical degradation compare to the styrene-acrylic copolymer. When exposed to UV radiation, an oxidative removal of the polymer occurs at the surface of the paint samples and an increasing of the NPs concentration released during aging is observed (figure 5). TiO2 NPs added in paint formulation absorb the light and reflects it, preventing the photodegradation of the polymer. During this talk, the influence of formulation (i.e. binder, NPs, …) on the stability paint and the NPs released will be presented. Furthermore the degradation mechanism of the different binders during weathering will be presented and discussed.