Polymers

Understanding Polymers

  • Polymers are large macromolecules formed by the repetition of smaller units, known as monomers.
  • Polymerization, the process through which polymers are synthesised, involves two methods: Addition polymerization and condensation polymerization.

Types of Polymers

  • Thermosetting polymers permanently retain their shape once cooled and solidified. Example: Urea-formaldehyde resins.
  • Thermoplastics polymers can be reheated and reshaped multiple times. Examples include polyethylene and polyvinyl chloride (PVC).
  • Elastomers can stretch significantly and then return to their original shape. Examples include natural rubber.

Properties of Polymers

  • Polymers display a range of physical properties, from rubber-like flexibility to rigid plastic.
  • The specific properties can be influenced by the type and proportion of monomers used, as well as the structure and processing methods.
  • Many polymers are resistant to chemicals, heat, impact, and other wear and tear.
  • They can be transparent or opaque, and in various colours.
  • They have low electrical and thermal conductivity.

Applications of Polymers

  • Polymers have diverse applications ranging from packaging, clothing, home products, and other sectors.
  • Thermosetting polymers have applications in electronic components and construction materials.
  • Thermoplastics are used for packaging, insulation in wires, pipes, and other applications.
  • Elastomers find use automotive industry, including tyres, and in sportswear.

Environmental Impact of Polymers

  • Many polymers are non-biodegradable and persist in the environment for prolonged periods.
  • Increasingly, biodegradable and compostable polymers are being developed.
  • Recycling is a crucial strategy for managing polymer waste, although it presents challenges such as sorting and cleaning.
  • Life cycle assessment can be used to assess the environmental impact of different polymers and their applications.

Manufacturing Techniques

  • Some commonly used techniques for shaping polymers include extrusion, injection moulding, blow moulding, and rotational moulding.
  • Cutting, drilling, and other subtractive manufacturing processes can also be used with polymers.
  • Joining techniques for polymers include adhesive bonding, ultrasonic welding, and mechanical fastening.