CHE 596 612 Viscoelasticity and Time-Dependent Mechanics of Polymers and Soft Matter

Prerequisites

Graduate Standing

Course Objectives

Some expected student outcomes are:

• Be able to use linear viscoelasticity (Boltzmann superposition) to calculate simple loading histories.
• Understand the linear viscoelastic functions and how they are used to interprte behavior soft materials.
• Understand the physics of time-temperature and time-concentration superposition principles.
• Understand concepts of structural recovery and physical aging in glasses, including colloids and how these relate to material performance.
• Be familiar with the ideas of polymer mechanical durability.

Textbook

Required:

M. Findley, J.S. Lai, and K. Onaran, Creep and Relaxation of Nonlinear Viscoelastic Materials (with and Introduction to Linear Viscoelasticity), Dover Publications, 1976.

References

• G B. McKenna, “Viscoelasticity,” in Encyclopedia of Polymer Science and Technology, J. Wiley, New York.
• G B. McKenna, “Glass Formation and Glassy Behavior,” in Comprehensive Polymer Science: Vol. 2. Polymer Properties, ed. By C. Booth and C. Price, Pergamon, Oxford, 311-363 (1989).
• G B. McKenna, “Physical Aging in Glasses and Composites,” Chapter 7 in Long-Term Durability of Polymeric Matrix Composites, ed. by Kishore V. Pochiraju, Gyaneshwar P. Tandon and Gregory A. Schoeppner, Springer, New York, 2011. pp. 237- 309.
• J-L. Halary, F. Laupretre, L. Monnerie, Polymer Materials: Macroscopic Properties and Molecular Interpretations, Wiley, Hoboken, NJ, 2011.
• John D. Ferry, Viscoelastic Properties of Polymers, 3^rd ed. J. Wiley, New York, 1980

Grading

5 %   – Class participation

 0 %  –   Homeworks (But lack of submission and completion of homeworks results   in negative points of 20% per homework)

45 % –  Projects (15% minor project, 30% major project)

 50 % –  Exams (15% exam 1, 15% exam 2, 20% Final Exam)

Tentative Course Outline:

Mondays and Wednesdays 8:30 AM – 9:45 AM Room:  EB 3-02232

Lessons 1-3 “Introduction to the Nature of Soft Materials and of Viscoelasticity”

(1/8, 10, 17) {1/15 is MLK holiday}

• What is a ‘Soft Material’
• What is Viscoelasticity?
• General ideas about material mechanics and response functions needed for constitutive modeling.

Lessons 4-6 “General Viscoelastic Response Functions for Polymers and Other Soft Matter”

(1/22, 24, 29)

• Linear viscoelastic material functions
• Interrelations between viscoelastic functions
• Boltzmann superposition principle

Lessons 7-8 “Experimental Methods: How do we determine the Response Functions?”

(1/31, 2/5)

• Commercial Instruments
  • Controlled stress and controlled strain instruments
  • Servo-hydraulic instruments
• ‘Self-built’ methods
  • Creep
  • Torsion pendulum
  • Membrane inflation
  • Piezo-electric systems

 Lessons 9-10 “Temperature and Concentration Effects on Viscoelastic Properties. 1”

(2/7, 12)

• Ideas of the glass transition
  • Glass transition temperature
  • Glass transition concentration
  • Importance for measurements: How good does my temperature control have to be?

Lessons 11-12 “Temperature and Concentration Effects on Viscoelastic Properties. 2”

(2/14, 19)

• Time-temperature superposition (reduced time)
• Time-concentration superposition (reduced time)
• Ranges of validity and power of the methods

EXAM 1.  (February 21, 2024)

Lessons 13-15 “Glassy Kinetics:  The Fading Memory Models or Reduced Time Space

(2/26, 28, 3/4)     Boltzmann Superposition”

• A discussion of the Kovacs, Aklonis, Hutchinson, Ramos (KAHR) and Tool-Narayanaswamy-Moynihan (TNM) models of structural recovery.
• Challenges for the future?
• Review of Exam 1

 Lessons 16-17 “Time-Dependent Failure of Polymers and Time-Dependence of Other

(3/6, 18)             Engineering Properties”

• Static Fatigue
• Dynamic Fatigue
  • Miner’s rule
  • Baily criterion
• Lifetime predictions-Can we use the above information to set experimental protocols?

 Lessons 18-20 “Non-Linear Behavior of Polymers”

(3/20, 4/1, 3)

• Nonlinear response of solid polymers
  • Rubber
  • Glass
• Nonlinear response of entangled polymers
  • Melts
  • Solutions

March 25, no class

 EXAM 2.  March 27, 2024

Lessons 21-24 “Dynamics of Colloids and Other Glass-forming Systems”

(4/8, 10, 15)

• The colloidal glass
  • Concentration effects and jamming
  • Yield behavior
  • Structural recovery: the Kovacs signatures
• Viscoelasticity of small molecule glass-formers
  • Linear response
  • Aging behavior

Project Presentations and review of course:  April 17 and April 22

 April 23 is the last day of classes.

 FINAL EXAM:  Friday April 26. 8:30 AM – 11:00 AM.

Updated: 11/09/2022