Polymers chemistry

• Why do polyalkenes have a high melting and boiling point?

  Van de walls intermolecular forces, large number of them. Lots of energy required to overcome them.
• Why are polyalkenes not degradable or biodegradable?

  • .non polar
  • nothing for nucleophiles or electrophiles to attack
  • carbon bonds are very strong
• Unplasticised PVC?

  • Rigid
  • dipole dipole forces are in a regular arrangement
  • used for doors and window frames
• Plasticised PVC?

  • flexible
  • interrupts many dipole dipole forces
  • used in shoes and clothing
• Polyesters?

  • formed from dicarboxylic acids and diols
  • or between hydroxy-carboxylic acids
• Polyesters contain dipole dipole forces
• Polyamides?

  • formed from dicarboxylic acid and diamine
  • or formed by many amino carboxylic acids
• Polyamides contain hydrogen bonding
• Why is Kevlar stronger than nylon?

  The molecules line up better so there are more hydrogen bonds than in nylon
• Acid hydrolysis of polyamines?

  • produces carboxylic acid and amine salt
  • positive hydrogen attacks the negative nitrogen
• Base hydrolysis if polyamines?

  • produces carboxylate salt and an amine
  • OH- attacks the positive Carbon
• Acid hydrolysis of polyesters?

  • form carboxylic acid and alcohol
  • Hydrogen attacks negative oxygen
• Why is base hydrolysis faster than acid?

  • acid hydrolysis is a reversible reaction, but base hydrolysis goes to completion