Pyrolysis and debromination of flame retarded polymers of electronic scrap studied by analytical pyrolysis

摘要

Two typical components of electronic scrap have been investigated by analytical pyrolysis: an electronic junction (phthalic polyester filled with ceramic fibres, flame retarded with brominated polystyrene) and a printed circuit board (epoxy resin on woven glass fibre support, flame retarded with brominated epoxy resin). Copyrolysis of these plastic materials has been carried out with inorganic solids of basic character. The volatile thermal decomposition products were analysed on line using pyrolysis-gas chromatography-mass spectrome-try. The product analysis revealed that the decomposition reactions of the polymer constituents are significantly altered in the presence of the strong inorganic bases. Due to debromination of the dibromo- and tribromophenyl groups of brominated polystyrene, copyrolysis with sodium hydroxide and with basic zeolites resulted in a considerably reduced yield of dibromo- and tribromostyrenes. From brominated epoxy resins pyrolysed with sodium hydroxide an enhanced bromomethane evolution, while a depressed brominated phenol formation was observed. A diminished production of bromophenols takes place in pyrolysis with sodium-containing silicates as well.