Addition Polymerization Lecture Notes

Introduction to Addition Polymers

• Addition Polymerization: Process of forming a polymer by bonding monomers with double bonds.
• Monomers: Small molecules with double bonds that can react to form polymers.

Mechanism of Addition Polymerization

• Breaking the Double Bond:
  • Double bond in a monomer (e.g., propene) is broken.
  • The electrons from the double bond form new single bonds.
• Formation of Carbon Chain:
  • The resulting single bonds allow the chain to lengthen by bonding with other monomers.
  • This process continues, creating a long carbon backbone.

Structure of Addition Polymers

• Backbone of the Polymer:
  • Made up of the original carbons from the double bonds.
• Side Chains:
  • Other groups attached to the carbons in the monomer become side chains of the polymer.
• Example with Propene:
  • Carbons from double bonds form the backbone.
  • Attached groups (e.g., hydrogen, ethyl, methyl) become side chains.

Examples and Applications

• Polymerization Example:
  • 2-pentene Polymerization: Double bond carbons form the main chain, side groups attach accordingly.
• Other Monomers:
  • Example given: 2,5,5-trimethylheptene.
  • Practice identifying backbone and side chains.

Important Rules and Tips

• Direction of Attachment:
  • Monomers can add in any orientation as long as the carbons align correctly.
  • Example: a-b or b-a pattern along the chain.
• Open Ends in Polymers:
  • Polymers often illustrated with open ends to show continuation.
  • Repeating units: Sequence of monomers repeated in the polymer chain; demonstrated with 3 repeating units.

Practice and Review

• Practice drawing and identifying the backbone and side chains for different monomers.
• Understand the concept of open ends and repeating units in polymer structures.

Summary

• Key Concept: Breaking of double bonds in monomers followed by formation of a long carbon backbone with side chains.
• Applications: Practice identifying polymers and drawing structures with open ends and repeating units.