Transcript Fire Retardant Polymers

Synergistic action of fluorine-containing
additives in bromine/antimony fire retardant
ABS
Ali DURAN
POLYMER TECHNOLOGY
SEMINER
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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,
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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,
3
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 (> 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
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synergic Br/Sb system,
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
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(370-390 0C),
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,
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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.
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