APPLICATION Shimadzu News 1/2005 Identification of brominated flame- r FTIR-Spectroscopy – Method for compliance with the RoHS directive

Figure 1: Structural formulae of brominated biphenyls

he RoHS* directive trations of 5 % up to 10 %. RoHS other brominated BDE’s), the GCMS is highly suitable as all (Restriction of the use of restricts the use of compounds PBDE content will exceed the brominated compounds can be Tcertain Hazardous Sub- such as tetrabrominated biphenyl RoHS threshold value of 1,000 ppm. separated and detected down to the stances in electrical and electronic A (TBBA), brominated poly- trace level. GCMS, on the other equipment) regulates the restric- styrene and brominated aromatic FTIR spectroscopy – hand, is more time consuming with tion of the use of brominated triazine. fast, non-destructive, simple respect to sample preparation and flame-retardants in electrical and data analysis. electronic devices as of July 2006. Figure 1 presents the structural In order to comply with the requi- Consequently, polybrominated formulae of brominated biphenyls. rements of the RoHS directive, In general, it is recommended to biphenyls (PBB) and polybromi- first the total bromine content of carry out an overall pre-screening nated diphenylethers (PBDE) can According to RoHS, the following a sample is determined. If this via energy-dispersive X-ray no longer be used as flame-retar- compounds are considered haz- exceeds 5 % after the preliminary fluorescence (EDX). Using this dants in polymers unless their con- ardous: pentabrominated diphenyl examination using the EDX sys- analytical method the total concen- centrations are lower than 1,000 ether (PentaBDE) and octabromi- tems, infrared spectroscopy is tration of elemental bromine in the ppm. The objective of the RoHS nated (OctaBDE). recommended as this will enable sample is detected, although it is directive is the protection of hu- OctaBDE has been used in poly- identification of compounds. not possible to distinguish which man health and the environment mers such as ABS and PS. Current- This simple and non-destructive compound actually contains from hazardous effects. During ly, decaBDE is largely being used method quickly leads to useful bromine. When more than 5 % of recycling of electronics waste, as a flame retardant in PS, PE, ABS results. Compound identification total bromine is detected, FTIR contamination by brominated and polyester. DecaBDE has not is possible as the flame-retardants, can be used for further identifica- compounds should therefore be yet been included in the RoHS di- were present up to now in poly- tion of bromine compounds. When reduced. rective. Commercial decaBDE mers in concentrations of higher less than 5 % bromine is detected, however consists of a mixture of than 5 %. This level is still detect- GCMS analysis can be implement- Polybrominated biphenyls are approximately 97 % - 98 % able in polymer mixtures using ed for separation and identifica- classified as health hazards. PBB decaBDE and 0.3 % up to 3 % of FTIR. Concentrations that appro- tion. and PBDE are chemicals that have, other BDE’s. Therefore, when a ach the detection limit, however, in the past, been used as flame- polymer contains 10 % decaBDE must be measured using other ana- Fast and straightforward IR-analy- retardants in polymers in concen- (containing 1 % contamination of lytical methods. In this case, sis of polymers is possible since

Thermoplastic Polymers Brominated Flame Retardants ABS PS PP PE PC PC/ABS Poly amide Polyester PVC S-PS S-PU ȜȜ Ȝ ȜȜȜȜ ȜȜȜ ȜȜȜȜ Octabromodiphenyl Ether ȜȜȜȜ Brominated Aromatic Triazine ȜȜȜȜ ȜȜ Ȝ Brominated ȜȜȜȜȜȜȜ Ȝ

Thermoplastic Polymers Others Brominated Flame Retardants Epoxy Unsaturated Polyester Phenol Elastomer Adhesive · Paint Fiber Woody Tetrabromobisphenol A ȜȜȜ Ȝ Decabromodiphenyl Ether ȜȜȜȜȜ Ȝ Octabromodiphenyl Ether ȜȜ Brominated Aromatic Triazine Brominated Polystyrene

Table 1**: Typical polymers and their flame-retardants. Listing of brominated flame-retardants and their use in polymers. (ABS = acrylonitrile-butadiene-styrene, PS = polystyrene, PP = polypropylene, PE = polyethylene, PC = polycarbonate, PVC = polyvinylchloride, PU = polyurethane)

10 Shimadzu News 1/2005 APPLICATION ominated flame- retardants in polymers

1.0 DBDPE (Decabromodiphenyl ether)

Polystyrene with TBBPA 0.8 (Tetrabromobisphenol A)

0.6

Polystyrene with DBDPE

ABS DBDPE 0.4 ABS Polystyrene with brominated PS with 5 % DBDPE DBDPE Bands aromatic Triazine 0.2

pure PS pure Polystyrene 0.0

400 350 300 250 200 175 150 125 100 75 50 4000 3500 3000 2500 2000 1750 1500 1250 1000 750 DBDPE measured with the single-reflection ATR method (diamond/KRS-5) 1/cm 1/cm

Figure 2: Polystyrene spectra with and without flame-retardant as well as the Figure 3: IR spectra of polystyrene with several flame-retardants IR spectrum of the flame-retardant decabrominated diphenyl ether.

brominated biphenyls exhibit their identification of brominated flame- state. The diamond sample surface (approximately 1 min.) and is eval- own very characteristic infrared retardants, where clear differences enables the application of high uated automatically according to spectra. The polystyrene example between the spectra can be seen. pressures to ensure that the sample RoHS guidelines. exhibits three spectra: DBDPE, Based on this information, an ana- is positioned tightly on the crystal PS with DBDPE and pure PS. The lytical method for fast identifica- so that optimum penetration of the To validate analysis results, the range in the IR fingerprint, where tion of brominated flame-retar- sample by the IR beam is guaran- spectrum is compared subsequently DBDPE in PS identification is pos- dants and polymers has been teed. The beam penetrates the sam- with a library of polymer spectra. sible, is clearly discernible (Figure developed using Shimadzu’s ple surface to a depth of approxi- For polymer identification, a 2). Figure 3 shows polystyrene FTIR-8400S in combination with mately 2 µm. database already containing 41 with other brominated flame- a single-reflection accessory. polymers (see table 2) is used. This retardant additives. As RoHS specifies a homogeneous database contains logical associa- In the present example, a diamond sample material, this depth of tions and the Distinction Software Fast identification of ATR unit with KRS-5 crystal was penetration is sufficient in order to tests for plausibility, for instance brominated flame-retardants used as single-reflection accessory. completely characterise the sample. by evaluation of signal ratios. A diamond as sample surface is Using this measuring configura- The fingerprint region of 1500 cm-1 recommended as the polymer can tion, the spectrum is acquired The decision criterion includes - 1000 cm-1 is important for the be present in a flexible or solid within a very short time interval warning messages that range from “Identification of the polymer not Abbreviation Polymer Abbreviation Polymer possible” to “Applied pressure not ABS Acrylonitrile-butadiene-styrene PI Polyimide sufficient” and finally to the con- ABS+PBDE ABS containing PBDE PMMA Polymethyl methacrylate clusion “O.K.” or “Not O.K.”. EVA Ethylene-vinylacetate copolymer PMMA+PBDE PMMA containing PBDE These FTIR analysis results can be NYLON Nylon POM Polyoxymethylene (acetal) considered as unambiguous when NYLON+PBDE Nylon containing PBDE POM+PBDE POM containing PBDE combined with the pre-analysis PBT Poly(butylene terephthalate) PP Polypropylene from the EDX System. PBT+PBDE PBT containing PBDE PP+PBDE PP containing PBDE PC Polycarbonate PPS Poly(phenylen sulfide) Infrared spectrometry can there- ȜȜȜȜ PC+PBDE PC containing PBDF PPS+PBDE PPS containing PBDE fore be regarded as a fast and sim- PC+TBBPA PC containing TBBPA (Tetrabromobisphenol A) PS Polystyrene ple alternative solution to the pre- PCTFE Polychlorotrifluoroethylene PS+PBDE PS containing PBDE selection of polymers. Minimal PCTFE+PBDE PCTFE containing PBDE PS+TBBPA PSPS containing TBBPA sample pretreatment is necessary PE Polyethylene PS+Triazine PS (containing brominated aromatic triazine) and fast results are obtained via PE+PBDE Polyethylene containing PBDE PU Polyurethane predefined methods. PEEK Polyether-ether-ketone PVA Poly(vinyl alcohol)

PEEK+PBDE PEEK containing PBDE PVC Poly(vinyl chloride) * Directive 2002/95/EC of the European PEI Polyetherimide PVDF Poly(vinylidene fluoride) Parliament and of the council of 27 January PES Polyester PVDF+PBDE PVDF containing PBDE 2003 on the restriction of the use of certain PES+PBDE PES containing PBDE SBS Styrene-butadiene-styrene copolymer hazardous substances in electrical and PET Poly(ethylene terephthalate) SBS+PBDE SBS containing PBDE electronic equipment PET+PBDE PET containing PBDE ** Flame retardants chemicals association Table 2: Overview of 41 polymers and polymer mixtures in an expandable database of Japan (FRCJ)

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