Scheduled maintenance tonight at 9:00 PM (HKT). The site may be temporarily unavailable.
Resources

Condensation Polymerization

Learn how polyesters and polyamides are formed with the loss of small molecules
HOCOCOOH
HOCH₂CH₂OH

Polymer (Repeat Unit)

Terylene / PET

Chemical Equation

HKDSE Tip

  • Addition vs condensation:
    Condensation polymerization requires two functional groups per monomer. A small molecule (usually water) is released during the reaction.
  • Linkage types:
    Polyesters form -COO- linkages; polyamides form -CONH- linkages.
  • Intermolecular forces & properties:
    Physical properties depend on the strength of intermolecular forces between polymer chains. Polyamides (e.g. nylon) have -CONH- linkages that form hydrogen bonds between chains, giving high melting points and high tensile strength. Polyesters (e.g. PET) have polar -COO- linkages with strong van der Waals' forces, also making them tough and suitable for fibres.

Select Polymer Type

Monomers

  • Benzene-1,4-dicarboxylic acid
    HOCOCOOH
  • Ethane-1,2-diol
    HOCH₂CH₂OH

Common Uses

  • Clothing and fabrics
  • Plastic bottles
  • Food packaging

Environmental Issues

  • Non-biodegradable: Do not break down easily, causing long-term pollution.
  • PET bottles and packaging: Can persist for hundreds of years in landfills and oceans.
  • Synthetic fibres (e.g. polyester, nylon): Washing releases microplastic fibres into waterways.