Influence of flame retardant additives on the processing characteristics and physical properties of ABS

Antimony trioxide (Sb₂O₃) is a common additive in flame retardant formulations and a study has been made to determine the effects of adding different grades into ABS polymer either alone or with commercial brominated materials bis(Tribromophenoxy)ethane (BTBPE) or Tetrabromobisphenol A (TBBA). The results consider mechanical, microscopical and flame retardant properties, and the effects of different Sb₂O₃ grades with average particle sizes of 0.1 μm, 0.52 μm and 1.31 μm. The Sb₂O₃ was added at 4wt% loadings and the bromines at 20wt% loadings. Additions of different grades of antimony trioxide showed that standard grades (0.52 and 1.31 μm) had a detrimental effect on impact and flexural properties when added at a 4wt% loading. The use of a new sub-micron particle size product (0.1 μm) had little effect on impact properties and only a slight detrimental effect on the flexural modulus and flexural strength when added to the ABS. Additions of either of the two brominated materials also caused a large drop in impact properties when added at 20wt% loadings. The addition of TBBA BA-59P into ABS caused an increase in both flexural modulus and flexural strength which was contrary to expectations. When formulated with 4wt% 1.31 μm Sb₂O₃ these bromine containing compounds suffered a further reduction in impact energies. Using the 0.1 μm material improved both impact and flexural properties but impact values were still below those of unfilled ABS. The addition of the 0.1 μm grade resulted in improvements in fire resistance as measured by the UL-94 properties.