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Artikkel9. juuni 2017

Are multi-walled carbon nanotubes suitable synergists to improve performance of flame retardants?

© EU, 2017

JRC scientists carried out an assessment of chemical alternatives of different flame retardants. The aim was to suggest safer and more environmental friendly alternatives to halogenated flame retardants of concern.

Flame retardants (FRs) are a diverse group of chemicals used as additives in a wide range of products to inhibit, suppress or delay ignition to prevent the spread of fire. Halogenated FRs are widely used, however health and environmental concerns have driven research for safer alternatives.
JRC scientists therefore carried out a chemical alternatives assessment. The assessed FRs to be applied in five industrial and consumer products included also multi-walled carbon nanotubes (MWCNT). The addition of MWCNT can improve the performance and thus reduce the loading of other FRs by forming a char layer covering the polymer surface and acting as insulating barrier.

For this study a review was made on human and environmental hazards as well as environmental fate data of one halogenated and four potential halogen-free substitutes (nitrogen- or phosphorous based FRs, minerals). The FRs were ranked by following the REACH guidance, the criteria of U.S.-EPA Design for Environment and the GreenScreen® assessment. The most decisive property for substances of concern is bioaccumulation; persistence is an inherent property of many inorganic compounds, as they are recalcitrant to biodegradation. The major concern for MWCNT is inhalation exposure to pristine nanotubes, as due to their fibre-like shape and persistency they have the potential to induce lung cancer; long and rigid CNTs have been suspected to induce mesothelioma.

The conclusions from the chemical alternatives assessment (CAA) are:
1) REACH dossiers are a comprehensive source of hazard and fate data, but their quality is variable
2) Correct identification of chemicals is sometimes challenging but crucial to consult the appropriate data
3) Assessment criteria of CAA need to be further developed to consider the particularities of inorganics and specifically nanomaterials.

The study was carried out as part of the FP7 project DEROCA (Development of safer and more Eco-friendly flame Retardant materials based on CNT cO-additives for Commodity Applications), grant agreement n° 308391.

© EU, 2017

Read more in: K. Aschberger et al. "Chemical alternatives assessment of different flame retardants – A case study including multi-walled carbon nanotubes as synergist", Environment International 101 (2017) 27-45, doi:10.1016/j.envint.2016.12.017

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Chemical alternatives assessment of different flame retardants – A case study including multi-walled carbon nanotubes as synergist


9. juuni 2017