Polymers

• polyamide link:

  A) amide link

  B) water

  
• polyester link:

  A) dicarboxylic acid

  B) diol

  C) ester link

  D) water

  
• condensation polymers:

  • polypeptides
  • polyamides
  • polyesters
• polyamides:

  • made by reacting dicarboxylic acids with diamines
  • amide links form
• polyesters:

  • made by reacting dicarboxylic acids with diols
  • ester links are formed
• polypeptides:

  • found in proteins
  • peptide links formed
• polyamide examples:

  • Kevlar
  • Nylon
• Kevlar:

  • used in bulletproof vests, car tyres and some sports equipment
  • lightweight but strong
  • benzene-1,4-dicarboxylic acid + 1,4-diaminobenzene
• Nylon:

  • used in rope, carpets and clothing
  • hexanedioic acid + 1,6-diaminobenzene
• polyesters:

  • terylene (PET) - used in plastic drinks bottles
  • benzene-1,4-dicarboxylic acid + ethane-1,2-diol
• condensation polymers can be hydrolysed back to their original monomers
• condensation polymers have polar bonds caused by C=O and C-N
• • condensation polymers have Hydrogen bonds between the polymer chains along with van der waals and dipole-dipole forces
  • this makes them stronger and more rigid than addition polymers
• • condensation polymers are polar so they are susceptible to attack by nucleophiles
  • this makes them biodegradable
  • they are broken down slowly by hydrolysis
• • addition polymers such as polyalkanes are saturated and non-polar
  • this makes them unreactive and non-biodegradable
• nylon - 6,6 structure:

  A) (CH2)4

  B) (CH2)6

  
• Terylene structure:

  A) C=O

  B) C=O

  
• kevlar structure:

  A) C=O

  B) C=O

  C) N-H

  D) N-H