Chapter 2: Study Guide and Self-Assessment
Synthetic polymer materials, the things we call plastics, fibers, elastomers, glues, and so on, are made up of small molecules linked together to form chains and networks. The length of these chains (molecular weight) and how the units are arranged in a chain, what we call microstructure, ultimately determines structure at a larger scale (e.g., whether or not the material crystallizes) and hence physical properties and how the polymer can be processed. A thorough understanding of polymer microstructure thus lays the foundation for a proper understanding of the whole subject and in this section we will work our way systematically through the principal chain architectures that are found in plastics and other polymeric materials.
Objectives
Upon successfully completing this chapter you should be able to:
- Understand the difference between linear and branched chains and how this affects their ability to align in a regular manner and hence crystallize.
- Describe the ways network structures are formed in polymers.
- Understand the different isomeric forms found in macromolecular chains (sequence, stereo and structural isomerism).
- Explain the difference between the arrangement of units in “random”, block, alternating and graft copolymers.
- Have a broad “feel” for how microstructure affects the ability to crystallize and hence affects properties like strength, toughness and stiffness.
- Understand that synthetic polymers have a distribution of chain lengths (molecular weight) and this distribution can be described by various averages, the most important being number average and weight average.
Self-Assessment Questions
When you click on the button the test will open in a new tab. The questions are multiple choice and you just have to click on the appropriate button to answer the question. The test is interactive and you will get feedback immediately.