flame retardants used as an additive

1. FLAME
RETARDANTS

2. Group Members:
■ Muhammad Inzamam
■ Rimsha Safdar
■ Umer Asif

3. Introduction:
Flame retardants:
 Are diverse group of chemicals
 Activated by the presence of ignition source
 Prevent or slow down the burning process
 Can be added as a copolymer or as an additive

4. How flame retardants work?
■ Ignition of burning
■ Pyrolysis(degradation of long chains)
■ Production of free radicals
■ Each flame retardant is specific to a particular polymer

5. Basic classification:
■ Added as an additive
■ All mineral based retardants
■ Some organo-halogens
■ Few organo-phosphorus
■ Inserted in the polymer chain during
polymerization
■ Mostly organo-halogens
■ Mostly organo-phosphorus
Active Reactive

6. Mechanisms of flame Retardants:
■ Endothermic Degradation
■ Gas Phase Radical Quenching
■ Thermal Shielding
■ Synergists

7. Endothermic
degradation:
Mineral compounds such as Aluminium
and Magnesium hydroxides
Breaks down endothermically
Limiting usage at high processing
temperatures
Usually are active flame retardants

8. Gas phase radical quenching:
Mostly are organo-
halogens
Retard the
oxidation reaction
of flame
Low in cost and
work in wide
variety
Toxic ,mostly are
banned for
consumption

9. Thermal shielding:
Mostly Are Organo-
phosphorus
Forms A Glassy
Layer Of Carbon
Prohibits
Pyrolysis
Acts On Solid
Phase

10. Synergists:
Combination Of
Retardants
To Obtain Better
Results
For Example, Halogenated
Combined With Antimony Trioxide

11. Brominated flame
retardants(BFR):
■ Commonly used in electrical and electrical equipments
■ Releases active bromine atoms before the ignition
temperature
■ Quench the chemical reactions, prevent fire cycle
■ De-hydrogenerate polymers by removing hydrogen
atoms

12. Phosphorus flame retardants:
■ Phosphoric acid is produced which forms glassy layer
of char
■ Char acts as two way barrier
■ Retards the availability of fuel and prevent pyrolysis
■ Used in engineering plastics, PU foams, textiles etc.

13. Halogen free flame
retardants:
■ Environment friendly, having low toxicity level
■ Mostly well suited for glass reinforced composites
■ Added as an additive and impart properties
■ Some impart color and other enhances mechanical properties

14. Thank You