Polymerization Kinetics: Summary

The answers to the ConcepTests are given below and will open in a separate window. 
Key points from this module:
  1. In addition polymerization, one monomer is added at a time to a growing chain.
  2. Addition polymerization is also called chain-growth polymerization.
  3. The three steps in addition polymerization are initiation, chain-growth, and termination.
  4. The polydispersity is an indication of how broad the molecular weight distribution is.
  5. The degree of polymerization is the average number of monomers in a polymer.
  6. The weight-averaged molecular weight is greater than the number-averaged molecular weight.
  7. The lifetime of reactive species is long for step-growth polymerization compared to addition polymerization.
From studying this module, you should now be able to:
  • Explain the difference between number-averaged and weight-averaged molecular weights.
  • Explain the steps in addition and step-growth polymerization.
  • Be able to apply the steady-state approximation to a polymerization reaction.
  • Calculate number-averaged and weight-averaged molecular weight of a polymer.
  • Calculate polydispersity and degree of polymerization and be able to explain what they represent.
Prepared by John L. Falconer, Department of Chemical and Biological Engineering, University of Colorado Boulder