PLMSE 410: MECHANICAL AND ELECTRICAL PROPERTIES OF POLYMERS AND COMPOSITES

Textbook (optional): Mechanical Properties of Polymers and Composites, L. E. Nielsen & R. F. Landel

Faculty: J. Runt

Description

This course is an introduction to the mechanical and electrical properties of polymers and polymer-based composites: focusing on the importance of molecular structure, rubber elasticity, mechanisms of yielding, viscoelasticity and manifestation thereof, static and ac dielectric properties, and conduction.

Course Topics

1. Basic mechanical testing and terminology: e.g. simple force - elongation experiments, impact testing
2. Relationship of modulus and stress-strain characteristics to molecular structure (e.g. crystallinity, crosslinking, polymer architecture) and selected external variables
3. Rubber elasticity: thermodynamic and statistical treatments.
4. Introduction to fracture mechanics; fracture toughness
5. Relationship between polymer structure and impact properties; rubber-toughened polymers.
6. Plastic deformation in polymer glasses and crystalline polymers; environmental stress 'cracking'.
7. Viscoelasticity: general concepts; mechanical models; time-temperature superposition; master curves; structural factors influencing creep and stress relaxation.
8. Dynamic mechanical properties: segmental and local motions; influence of molecular structure.
9. Mechanical properties of particle- and fiber-filled polymer composites: general features; models for predicting modulus; viscoelastic behavior.
10. Introduction to dielectric properties: polarization. Piezoelectricity.
11. Dielectric relaxation: influence of frequency; Debye model
12. Conduction in polymers and composites: ionic and electronic conduction; synthetic metals, PTC composites
13. Dielectric breakdown: general features, mechanisms

Course Objectives

1. To provide students with a comprehensive understanding of the relationship between polymer structure (chain chemistry and architecture, crystallinity, and crosslinking) and their mechanical properties, so that they can make predictions about mechanical performance from knowledge of polymer structure and organization.
2. To teach students the basic concepts of rubber elasticity (using two models) and to emphasize the differences in behavior compared to that of non-polymeric materials.
3. To provide students with a basic understanding of yielding in polymeric materials, particularly crazing in polymer glasses (and rubber toughened blends) and deformation of crystalline polymers.
4. To teach students basic concepts of viscoelasticity, particularly time-temperature superposition, dynamic mechanical properties and the influence of polymer structure on time or frequency response.
5. To give students an overview of mechanical properties of polymer-based composites, including modulus behavior and viscoelasticity.
6. To teach students the basics of dielectric properties of polymers, including polarization, dielectric relaxation and breakdown.
7. To provide students with a basic understanding of conduction in polymers, both ionic and electronic. Also, to introduce synthetic metals.

Course Outcomes

1. Given a polymer structure/architecture (and information about its ability to crystallize, whether it is crosslinked, etc.) the student should be able to predict mechanical performance and how to alter that performance to meet a desired outcome.
2. The student should be able to understand how elastomers behavior mechanically and the origins of that behavior.
3. The student should understand the concept of fracture toughness and how that of typical polymers compares to those of other materials.
4. The student should be able to recognize the importance of polymer yielding, both as a precursor to failure and as a toughening mechanism.
5. The student should be able to use basic mechanical models to illustrate viscoelastic behavior.
6. The student should be able to construct master curves, given time or frequency dependent viscoelastic data at several temperatures.
7. The student should be able to predict how the mechanical properties of a polymer will be altered when filled with a particulate, rigid filler (or fiber)
8. The student should understand the origin of a polymer's dielectric constant, and its frequency and temperature dependence.
9. The student should be able to understand the origin of electrical conductivity in polymer dielectrics, as well as in highly conducting conjugated polymers.

Assessment Tools

1. In-class closed book exams
2. Problem sets and homework that promote a measure of student collaboration
3. A written paper (10 pgs.) on a selected topic in mechanical or electrical properties that was not covered (or only touched on) elsewhere in the course. This provides the student with in depth knowledge of an additional, topical area.