Macro Molecules Exam Notes

Macro Molecules

• States of Macro Molecules:
  • Can exist in a disordered state.
  • Can undergo glass transition (vitrification).
  • Can exist in an aggregate state.
• Types based on reaction to heat:
  • Thermoplastic:
    • Cannot be returned to their original form after processing.
    • Can be further processed.
  • Thermosetting:
    • Undergo deformation and cannot be reprocessed.
    • Cannot be returned to their original shape.
  • Thermoelastic (Elastomers):
    • Deform under the influence of heat, but return to their original shape afterward.

Macro Molecules

• Definition:
  • Large molecules composed of many smaller, repeating molecular units (monomers).
  • Monomers are linked together, often numbering in the thousands.
• Polymerization:
  • The process of linking smaller molecules to form a macro molecule.
  • The resulting materials are called polymers.

Classification by Origin

• Natural:
  • Occur in nature, examples include cellulose and proteins.
• Synthetic:
  • Man-made, example: polyethylene.

Nomenclature

• Systematic Naming (IUPAC):
  • Based on standard chemical nomenclature.
  • A common method is to add the prefix "poly-" to the name of the monomer.
• Naming Based on Origin:
  • Mainly applies to natural polymers.
  • Name is derived from the monomer that constitutes the polymer.
• Traditional Names:
  • Common names that are widely used, generally for naturally occurring macro molecules.

Classification by Structure

• Chain Structure:
  • Monomers are linked in long chains, forming linear macro molecules.
• Network Structure:
  • Monomers connect and multiply, creating a cross-linked network.
• Coil structure :
  • Monomers are bound in long chains and build macro molecules.

Classification by Monomer Type

• Homo polymer:
  • Made from only one type of monomer.
  • Has the same composition throughout.
• Copolymer:
  • Composed of two or more different types of monomers.
  • These monomers repeat successively within the polymer structure.