PBDEs

1
PBDEs YOU

• A Presentation and Study
• By,
• Mark Willis, Nora Calder Jackie Vachon

2
PBDEs

• Polybrominated diphenyl ethers are brominated
  compounds widely used as flame-retardants.
• PBDEs have two basic benzene ring structures with
  different amounts of bromine on them in different
  places.
• All 209 different kinds of related PBDEs are
  called congeners. They are like chemical
  cousins with the same basic backbone, with the
  only thing different being the number and
  location of the bromines.

3
PBDEs
4
PBDEs

• PBDEs are used as flame-retardants. They are
  added to plastics, foams and fibers to inhibit
  the spread of flames in the event of fire.
• The carbon-bromine bond is much weaker than the
  carbon chlorine bond, making bromine what we
  call a good leaving group, meaning it leaves
  the benzene with ease, much more easily than
  chlorine does.
• The bromine ions scavenge for the free radicals
  of oxygen that are necessary to fuel the spread
  of a fire.

5
PBDEs

• When you heat the plastic product to which you
  added the PBDE chemical, the bromine is displaced
  and intercepts the free radical chain reaction
  that is fire.

6
PBDEs

• There are about 75 million pounds used every year
  in the United States.
• PBDEs are commonly used in high impact
  polystyrene plastics, such as that used in TV and
  computer casings.
• Between 5 and 30 by weight of the plastic
  casing can be PBDEs. If true, this means that up
  to a third of the weight of the plastic in your
  TV or computer console is a bromine-releasing
  flame retardant

7
Major Industrial Products

• Deca-BDE
• Polymers for textile backing, electrical
  electronic equipment
• More pure 95 Deca-
• Octa-BDE
• Plastic housings esp. office equipment
• More complex mixture of penta, octa, hexaPBDEs
• PentaBDE
• Flexible polyurethane foam (up to 30)
• Cushions mattresses carpet padding

8
PBDE Effects on Humans

• They are neurotoxic.
• They are toxic to the liver
• Endocrine Disruptors
• Negative impacts on thyroid and estrogen.
• May cause brain damage during child development.

9
What we did?Day 1

• Purpose To find the wavelength of a sample of
  deca-PBDE so that it can be run through the HPLC
  (high performance liquid chromatography)
• Method
• -Add PBDE(powder form) to a volume of THF.
• - Fill cuvette with mixed solution to the fill
  line.
• - Run sample through the UV spectrophotometer.

10
What we found.Day 1

• Results
• - Sample was overly saturated with PBDE.
• - Accurate readings were not seen.

11
UV Spec. ReadingsDay 1
12
What we learned.Day 1

• The THF was exposed to the ambient air for too
  long leading to inaccurate readings.
• Too much PBDE was used (oops.)

13
What we did.Day 2

• Purpose To find the wavelength of a sample of
  mono and deca-PBDE.
• Methods Same as previous but using both powder
  and liquid form solute.

14
What did we find?Day 2

• Results
• - Liquid PBDE disolves better than powder
  form.
• - New THF was used, however, results were
  still inconclusive.

15
UV Spec. ReadingsDay 2
16
What we learnedDay 2

• Conclusion
• - Different solvent was needed for solution.
• ( maybe Heptane???)

17
What we did.Day 3

• Purpose To find the wavelength of a sample of
  mono and deca-PBDE.
• Methods Dilute samples of combined powder and
  liquid PBDE with a volume of Heptane.
• - This was done to see two different spikes
  when run through the HPLC.

18
What we foundDay 3

• Once the wavelength of a sample was found, we ran
  this sample through the HPLC.
• The first time through the machine did not give
  us conclusive data, and we didnt know how to
  print the graphs.
• Professor Ford ran samples on his own time of
  mono, deca, and a mixture of the two. He also
  figured out how to print the HPLC trace.

19
UV Spec. ReadingsDay 3
20
ConclusionDay 3

• The HPLC separated the peaks of the mono and deca
  compounds.
• -Deca peaked at 2.5 minutes.
• -Mono peaked at 0.9 minutes.
• The detection limits were unknown because we did
  not measure volumes of solutions, but we now know
  that the HPLC column is capable of separating the
  components.

21
MONO-PBDE
22
DECA-PBDE
23
MONO DECAPBDE