Rapid analysis of flame retardants in polymers: Fid-Bau Portal

Rapid analysis of flame retardants in polymers

Baird, P. / Finberg, I. / Georlette, P. / Herman, H. / Mortimore, W. / Stevens, G.C.

The rapid analysis of fire retardants (FRs) in polymers is a requirement not only for primary production of FRs and compounded polymers but also to meet the increasing need to recycle and reuse FR containing polymers in a variety of markets. Although there are elemental methods for examining halogens in polymers, such as X-ray fluorescence (XRF), these will not provide a molecular identification of the FR. This is necessary because there are particular FRs in the supply chain that are now proscribed by RoHS (reduction of hazardous substances) and which in the future may come under actions arising from REACH. We have investigated a variety of molecular and optical emission spectroscopies to provide both elemental and molecular descriptions of a number of engineering thermoplastics containing new and conventional brominated FRs. We have also produced a set of gravimetrically calibrated specimens in a variety of polymers as a training set for the development of predictive models to enable rapid and accurate determination of the FRs in question. Discrimination of polymers in the recyclates stream is done using a number of techniques, with near infrared (NIR) methods being favoured for non-black samples. This same method is capable of identifying many brominated FRs, if they contain a significant organic component, and we will demonstrate the utility of this method for obtaining identified FR concentrations down to 0.1 % wt/wt. The NIR method is not applicable to heavily halogenated such as Decabromodiphenylether or completely inorganic systems, in which case Raman spectroscopy is more applicable. We will show that both spectroscopic methods are capable of discriminating between halogenated organic and inorganic FRs, with Raman spectroscopy being particularly well suited because of its capability of capturing low frequency spectral information. Ironically, the less sensitive Raman method, because it is laser-based, can be used in a somewhat dirtier environment than conventional NIR methods and this opens new possibilities.