Synergistic action of fluorine-containing additives in bromine/antimony fire retardant ABS

1
Synergistic action of fluorine-containing
additives in bromine/antimony fire retardant ABS

• Ali DURAN
• POLYMER TECHNOLOGY
• SEMINER

2
RESULTS AND DISCUSSION

• The effect of PTFE is quite evident at oxygen
  concentrations 23-26, where the slope of the
  curve is large, whereas it tends to vanish if
  combustion is carried out in any oxygen excess
  above 27,
• The effect of SbF3 on combustion rate is similar
  to that of PTFE and does not seem to depend on
  its concentration,

3
RESULTS AND DISCUSSION

• As far as the combustion times are concerned, the
  results presented in fig. 2 again show the
  similarity between the effect of PTFE and that of
  SbF3 at relatively high concentration vs. the
  combustion time (SQT) of FR ABS,
• In both cases the initial instability of the
  flame in FR ABS shown by the low increase of SQT
  with O2 increase (22-25),
• However, FR ABS exceeds the limiting combustion
  rate already at O2 concentration of 23.5, shown
  in fig. 1,

4
RESULTS AND DISCUSSION

• FR ABS with very low concentration of SbF3 shows
  a trend qualitatively similar to that of PTFE or
  0.2 phr SbF3 containing FR ABS,
• Moreover, in tis case, the intermediate unstable
  flame regime is reached at larger SQT (gt 180 S.),
• Because of the parallel behaviour of PTFE and
  SbF3 might be one of the truly active fire
  retardant agents,
• In its presence the combustion proceeds at a very
  low rate but the extinguishment of the flame is
  rather delayed,
• In forced combustion conditions the additional
  effect of the fluorine containing compound is no
  longer sagnificiant and the fire retardance is
  restricted to that of the synergic Br/Sb system,

5
RESULTS AND DISCUSSION

• In fig. 3 the TG of ABS, FR ABS and
  PTFE-containing FR ABS are reported together with
  the calculated TG for the FR ABS system assuming
  no interaction occuring amongst the components,
• By comparing the experimental and calculated TG
  of FR ABS, the role played by the polymer in the
  thermal behaviour can be deduced because the
  experimental curve shows a weight loss larger
  than the calculated one in the BTBPE degredation
  temperature range (370-390 0C),

6
RESULTS AND DISCUSSION

• Moreover, the amount of char stable at 700 0C is
  larger than expected for a simple additive
  behaviour,
• Interaction is supposed to take place between the
  polymer and the FR system and not between the FR
  components because it has already been reported
  that BTBPE and Sb2O3 do not react at relatively
  low heating rate,

7
CONCLUSION

• It has been shown that the effect of SbF3 on
  combustion of FR ABS is parallel to that of PTFE
  reducing the rate of combustion of ABS in mild
  combustion conditions,
• Furthermore, both compounds induce crosslinking
  in ABS on heating,
• Thus, it is likely that SbF3 or (SbF5) created in
  situ could be responsible for the effect of PTFE
  on the combustion of ABS fire retarded with the
  Br/Sb system,
• However further work is necessary to understand
  the mechanism of the fire retardant action.