The influence of fire retardant additives on the properties of HIPS and PBT

Halogen compounds and antimony-based synergists are used at low loading levels in many polymers systems to impart high levels of flame retardancy. This study used a range of brominated flame retardants (BFR) and the most commonly used synergist for halogen-based flame retardance, antimony trioxide (Sb2O3), to investigate the effects on mechanical and physical properties of flame retardants in HIPS and PBT. The polymers used were High Impact Polystyrene (HIPS) and Polybutylene Terephthalate (PBT). Initially each of the additives was used individually, before being combined to study the effect of the complete package. This was achieved by producing a series of compounds using a twin-screw extruder, and then an injection moulder to produce impact, tensile and fracture toughness specimens. The compounds were also analysed using rheological testing and thermal analysis. Also the effects of Stereon impact modifier and Fyrebloc masterbatches were determined in HIPS. [Continues.]