Polyurethanes

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Polyurethanes
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History of Polyurethanes Polyurethane Chemists

• Dr. Otto Von Bayer (1937)
• IG Farben Industries
• Rigid and flexible foams
• TDI and polyols
• Attempts to reduce natural rubber use

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History of PolyurethanesPolyurethane Chemists

• Adolf Wurtz (1848)
• Karl-Heinz Hentschel (1884)
• Phosgenation of amines

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Isocyanate Monomer Synthesis

• Dr. Otto Bayer (1937)
• First diisocyante synthesis
• Toluene Diisocyanate Synthesis (TDI)
• Reaction creates 80/20 mixture of 2,4-TDI and
  2,6-TDI

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Isocyanate Monomer Synthesis

• Diphenylmethane Diisocyanate (MDI) Synthesis
• Attempt to find less toxic monomer for PU
  reactions
• MDI chemistry is more complex
• Allows for more specific applications

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Imperial Chemical Industries

• ICI and WWII applications of isocyanates
• Barrage balloons
• Used MDI as cross-linking agent
• Resistant to hydrogen
• Applications also included rigid foams in planes
• War applications soon faded
• Isocyanates and water
• Carbon dioxide is side product
• Initially a defect it was turned into an
  application as foam
• ICI takes notes from Bayer AG
• Designs a machine outside of the Germans patented
  machine

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Imperial Chemical Industries

• Toxicity of TDI (1950s)
• Led to design of MDI/polyester systems
• Portable refrigerators, domestic chambers of
  ships, chemical plan insulation
• Further improvements with CFCs
• CFC blowing agents created superior insulating
  foams
• Thin walled refrigerators create interest rigid
  PU foams around the world

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Polyurethanes

• Polyurethanes are much more than just foam
• PUs can be
• Elastomers
• Paints
• Adhesives
• Fibers
• Spandex

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Breakdown of the PU Industry
Figure from Essentials Chemical Industry on
University of York website
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Economics

• The PU industry was estimated to produce 13.65
  million tons of plastic in 2010 and is expected
  to grow to 17.95 million tons by 2016
• The PU industry is expected to grow from 33
  billion in 2010 to 55.5 billion in 2016
• North America, Asia-Pacific, and Europe account
  for 95 of the PU market

Numbers found from source 6
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Polyurethane Structure
Carbamate bonds created by isocyanates reacting
with hydroxy groups of a polyol
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Polyurethane Reactions

• Tertiary amines catalyze the reactions
• Isocyanate groups react with polyols

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Polyurethane Monomers

• Polyurethanes consist of different block
  co-polymers
• MDI- 4 4'-diphenylmethane diisocyanate
• TDI- Toluene-2,4-diisocyanate

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Polyurethane Monomers

• Polyols- hydroxy terminated polyether, polyester,
  polyolefins, and glycols

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Polyurethane Block Copolymers

• Soft block/hard block microphases

-Poly(1,4-butylene adipate) is part of the soft
block microphase -Soft blocks have 600-3000 MW
and Tg below room temperature
-The soft block cross-link interaction with the
hard block gives rise to the rubbery nature of
these elastomers
-The hard block consists of TDI or MDI -Higher
density of phenyl rings and urethane links cause
hardness
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Soft/Hard Block H-Bonding Interactions
Figures from source 7
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Importance of Polyol choice
Figures from source 7
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Polyurethane Reactions

• Multiple types of reactions make up different end
  products of polyurethanes
• Polyurea reactions are important for spandex
  production

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Which sometimes can be a bad thing!

• Someone needs to introduce this guy to pants and
  suspenders!
• Suspenders are made of polyesters
• Dr. Tisko should tell this guy how awesome
  suspenders are

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Bibliography

• http//www.pslc.ws/macrog/urethane.htm
• http//www.8linx.com/cnc/polyurethane_foam.htm
• http//www.essentialchemicalindustry.org/polymers
  /polyurethane.html
• http//sunilbhangale.tripod.com/pu.html
• http//www.poliuretanos.com.br/Ingles/Chapter1/132
  comercial.htm
• http//www.plastemart.com/Plastic-Technical-Articl
  e.asp?LiteratureID1674Paperglobal-polyurethane-
  market-PU-foams-thermoplastic-elastomers
• J.M. Buist. Developments In Polyurethane-1
  Applied Science Publishers LTD, UK, 1978.