ANALYSIS AND TOXICITY TESTING OF COMBUSTION GASES .2. CHARACTERIZATION OF COMBUSTION PRODUCTS FROM HALOGEN-FREE FLAME-RETARDANT DUROPLASTIC POLYMERS FOR ELECTRONICS

Gaseous combustion products from two new halogen-free flame-retardant polymers for electronic engineering were characterised using analytical and toxicological methods. These duroplastic materials, developed by Siemens, are based on novolak-glycidyl-ether and bisphenol-A-diglycidyl-ether. They contain oxazolidinone and isocyanurate structures as well as phosphonate elements in the polymeric backbone which are responsible for their flame-retardancy. The polymeric materials were combusted in a VCI oven at 200, 400, 600 and 800 degrees C. The combustion gases were sampled on two cartridges containing Tenax and a third, containing a molecular sieve connected in series. The ethanolic eluates of the Tenax were analysed by gas chromatography/mass spectrometry (GC/MSD) and gas chromatography/infrared spectroscopy. This solution was also used for toxicity testing with the Microtox Test(R) after appropriate dilution. The fraction of highest volatility was desorbed from the molecular sieve and analysed directly via headspace GC/MSD. The thermal reactions of the two new polymers are discussed and compared with literature data. Reaction pathways of the nitrogen containing structure elements to N-heterocyclic compounds during combustion were proposed. Some factors regarding the fate of the phosphorus during combustion were discovered. The results of the Microtox Test(R) were compared with data from the combustion of polystyrene and beech-wood.