Presentation of Lecture Problem 4'25

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Presentation of Lecture Problem 4.25

• By Chris Lee
• E106 Materials Engineering
• 1-31-2007

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Problem Statement

• Given density and unit cell volume parameters of
  nylon 6,6, determine number of mer units per
  unit cell

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Nylon 6,6

• Also known as hexamethylene adipamede
• Most common form of nylon polymers
• Uses condensation polymerization with diamine and
  hexamethylene.

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Visual representation
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Solving the problem

• Since we are given density and a method to find
  the volume of the unit cell, we can find the mass
  of a unit cell
• Volume of the triclinic cell is given as
• Insertion of parameters gives us a volume of
  0.309 nm3

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Continuing to solve

• We can now find the mass of a unit cell since we
  are given density
• Mass ?v
• Must use proper conversion from cm3 to nm3 which
  is 1x1021 nm3/cm3
• Mass is calculated to be 3.76x10-22 grams

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Still solving

• We must then acquire the molecular mass of a mer
  of nylon 6,6
• Formula is given as
• Calculated MW 226.322 g/mol

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And yet still solving

• To get number of moles per unit cell, we simply
  divide the unit cell mass by the molecular
  weight
• Calculated moles 1.66x10-24 moles
• Then use NA to find out how many mers
• Get 1 mer per unit cell

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What can we learn?

• Understand the layout of the unit cell of nylon
  and in turn more about the structure of the nylon
  polymer.
• Questions?