Dacron

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Dacron

• Sanaz Leilabadi and Linda Edwards

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Get to know Dacron

• Trade name for Polyethylene Terephthalate
• aka PET, PETE, PETP
• Polyethylene Terephthalate is a resin of the
  polyester family that is used to make beverage,
  food and other liquid containers, synthetic
  fibers
• Clear, tough plastic with good gas and moisture
  barrier properties

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Chemically Speaking

• Condensation Polymer
• Polyethylene terephthalate is synthesized
• by transesterification of two monomers
• Ethylene glycol and Dimethyl terephthalate

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• Transesterification is used in the synthesis of
  polyester, in which diesters undergo
  transesterification with diols to form
  macromolecules. In our case, dimethyl
  terephthalate and ethylene glycol react to form
  polyethylene terephthalate and methanol, which is
  evaporated to drive the reaction forward.

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Catalysts

• Transesterification reactions are often catalyzed
  by the addition of an acid or base.
• Acids can catalyse the reaction by donating a
  proton to the alkoxy group, thus making it more
  reactive, while bases can catalyse the reaction
  by removing a proton from the alcohol, thus
  making it more reactive.

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Polymer
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Mechanism of Polymerization
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History of Dacron

• PET originally patented by British chemists
• John Rex Whinfield and James Tennant Dickson in
  1941 after early research by Wallace Carothers
• Dupont used its nylon technology to improve the
  polyester fiber that was patented by the British
• Dacron was created in 1950 by Dupont

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What IS Dacron?

• A polyester fiber used in clothing.
• A yarn used in
• curtains
• dress fabrics
• high pressure fire hoses
• mens shirts
• threads.

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Dacron Products

• Boat sails
• Antenna rope
• Climbing ropes
• Foam covers
• Carpets and textiles
• Furniture
• Luggage

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Where can we find it?
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Dacron in Medicine

• Cardiothoracic and Vascular grafts and implants
• Aneurysm repair
• (Thoracic and Abdominal Aorta)
• Patch Angioplasty
• Vascular grafts
• Strong, flexible and treated
• with collagen to keep blood
• from soaking through
• Chemically inert and thus well
• tolerated inside the body

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Dacron- Then and Now

• Dacron has come a long way since 1950
• More commonly used today thanks to new technology
• Price range varies depending on the product it as
  been made into
• Intrinsic viscosity (thickness) of 0.60 (fibers)
  
• PET can range up to 0.85 for tire cord

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Recycling Dacron

• Methanolysis is an example
• of reverse transesterification
• and has been used to recycle
• polyesters into individual monomers
• Fully recyclable- when needed
• Its polymer chains can be recovered for reuse.

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Health Effects

• One study showed that after imbedding polymer
  films of Dacron in rodents there was evidence of
  some malignant tumor formation, study was later
  deemed inadequate
• Further research shows no short term or long term
  toxicity with use of Dacron
• However, strong evidence of nausea, vomiting,
  central nervous system paralysis and kidney
  damage with prolonged exposure to ethylene glycol

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Dacron Properties

• High tensile strength, high resistance to
  stretching, both wet and dry, and good resistance
  to degradation by chemical bleaches and to
  abrasion which is why it is preferred for
  surgical use
• High melting temperature of 496 degrees
  Fahrenheit (256 degrees Celsius), due to
  cross-linkage in synthesis of the fiber.

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For more information

• http//www.elmhurst.edu/chm/vchembook/402condense
  polymers.html
• http//www.bicuspidfoundation.com/Aortic_Aneurysm_
  and_Dissection.html
• http//www.bartleby.com/65/da/Dacron.html
• http//www.nlm.nih.gov/medlineplus/ency/article/00
  2345.htm
• http//md1.csa.com/partners/viewrecord.php?request
  ergscollectionTRDrecidCA6703713WC
• http//education.yahoo.com/reference/encyclopedia/
  entry/Dacron
• http//www.me.berkeley.edu/ME117/S05/finalproject/
  pdf/Vascular_Graft.pdf
• http//www.alibaba.com/productsearch/Adhesive_Pape
  r/10.html
• http//www.surgical-tutor.org.uk/default-home.htm?
  tutorials/graft.htmright
• http//www.texdev.com/sld007.html
• http//en.wikipedia.org/wiki/Dacron

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