3.3.12 Polymers

• Polymers are very large molecules made when lots of monomers add togther
• Polyalkenes have only Van der Waals forces between chains. Since the polymer chains are often very long, the Van Der Waals forces between the chains are often strong and so the polymers have relatively Hugh melting and boiling points. As the chains are not rigidly held in place by each other, polymers tend to be soft
• Benzene-1,4-dicarboxylic and ethane-1,2-diol react together to form a polyester

  Type of reaction: Condensation

  Polyester formed: Terylene

  Use: Clothing
• Hexanedioic acid and Hexane-1,6-diamine react together to form a polyamide.

  Type of reaction: Condensation

  Name: Nylon

  Use: clothes, carpets and ropes
• Benzene-1,4-dicarboxylic acid and benzene-1,4-diamine reacts to form a polyamide.

  Type of reaction: Condensation

  Use: Bulletproof vest (very strong and low density)

  Name: Kevlar
• Polyamides contain hydrogen bonding between chains in addition to the Van der Waals forces
• Polyesters have dipole-dipole forces between the C=O groups in the different chains in addition to the Van der Waals forces between the chains
• Highest to lowest melting point:

  Highest: Polyamides

  Polyesters

  Lowest: Polyalkene
• Addition polymers are not biodegradable and the polymers persist in the environment.

  This is because they are unreactive because they do not have polar bonds and contain strong C-C single bonds and so are difficult to break down
• Condensation polymers such as polyesters and polyamides can be hydrolysed by acids, alkalis and enzymes due to the polar bonds and so can be broken down and attacked by nucleophiles.
• Terylene -> Polyester

  A) Benzene-1,4-dioic acid

  B) Ethane-1,2-diol

  C) Terylene

  D) Clothing

  
• Nylon-6,6 -> Polyamide

  A) Hexanedioic acid

  B) Hexane-1,6-diamine

  C) Nylon 6,6

  
• Kevlar -> Polyamide

  A) Benzene-1,4-dicarboxylic acid

  B) Benzene-1,4-diamine

  C) Kevlar