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1. EMA 6165 Polymer Physics AB Brennan 1 Dr. Anthony Brennan
University of Florida
Department of Materials Science & Engineering
2. EMA 6165 Polymer Physics AB Brennan 2 Agenda Glass Transition values
Organic
Inorganic
Thermodynamic Treatment of Tg
Kinetics of Tg
Physical Aging Behavior
3. EMA 6165 Polymer Physics AB Brennan 3
4. EMA 6165 Polymer Physics AB Brennan 4 Based in viscosity measurements of n-alkanes. Glass Transition Characteristics
5. EMA 6165 Polymer Physics AB Brennan 5
6. EMA 6165 Polymer Physics AB Brennan 6 = Fractional free volume @ Tg Glass Transition Characteristics
7. EMA 6165 Polymer Physics AB Brennan 7 What are the factors to consider now:
8. EMA 6165 Polymer Physics AB Brennan 8
9. EMA 6165 Polymer Physics AB Brennan 9 Start lecture on FRIDAY April 20Start lecture on FRIDAY April 20
10. EMA 6165 Polymer Physics AB Brennan 10 WLF
11. EMA 6165 Polymer Physics AB Brennan 11
12. EMA 6165 Polymer Physics AB Brennan 12 where Glass Transition Shift Factor
13. EMA 6165 Polymer Physics AB Brennan 13 Normally Glass Transition Shift Factor
14. EMA 6165 Polymer Physics AB Brennan 14 Thermodynamic Treatment
15. EMA 6165 Polymer Physics AB Brennan 15 Ehrenfest 1st Order Transition Glass Transition Ehrenfest
16. EMA 6165 Polymer Physics AB Brennan 16 2nd Order Glass Transition 2nd Order Transition
17. EMA 6165 Polymer Physics AB Brennan 17 Glass Transition Characteristics
18. EMA 6165 Polymer Physics AB Brennan 18 Consider Glass Transition Characteristics
19. EMA 6165 Polymer Physics AB Brennan 19 and
20. EMA 6165 Polymer Physics AB Brennan 20 Gibbs and Di Marzio
21. EMA 6165 Polymer Physics AB Brennan 21 OR Glass Transition Isothermal Compressibility
22. EMA 6165 Polymer Physics AB Brennan 22 Originally derived in terms of viscosity assuming:
23. EMA 6165 Polymer Physics AB Brennan 23 Thus..... Glass Transition Characteristics
24. EMA 6165 Polymer Physics AB Brennan 24 Time dependent quantity
25. EMA 6165 Polymer Physics AB Brennan 25 Typically, Glass Transition Characteristics
26. EMA 6165 Polymer Physics AB Brennan 26 Glass Transition Characteristics
27. EMA 6165 Polymer Physics AB Brennan 27 Glass Transition Characteristics
28. EMA 6165 Polymer Physics AB Brennan 28 Glass Transition Characteristics Kinetic Theory
29. EMA 6165 Polymer Physics AB Brennan 29 Vh = Molar volume of hole
Eh = Molar excess energy associated with hole
Ej = Molar energy for disappearance of a hole Nh* = Equilbrium # of holes
n = molar volume of segments
No = moles of repeat units Glass Transition Characteristics
30. EMA 6165 Polymer Physics AB Brennan 30 Relaxation time for the disappearance of a hole: Glass Transition Characteristics
31. EMA 6165 Polymer Physics AB Brennan 31
32. EMA 6165 Polymer Physics AB Brennan 32 Kovacs Apparent Activation Energy
33. EMA 6165 Polymer Physics AB Brennan 33 Glass Transition Thermodynamic Approach
34. EMA 6165 Polymer Physics AB Brennan 34 Partition function to define conformational states. Glass Transition Characteristics
35. EMA 6165 Polymer Physics AB Brennan 35 Glass Transition Characteristics
36. EMA 6165 Polymer Physics AB Brennan 36 Glass Transition Characteristics
37. EMA 6165 Polymer Physics AB Brennan 37 Summary Glass Transition is a second order thermodynamic transition.
Glass Transition is a fictive temperature dependent upon time, temperature, rate, pressure and thermal history.
WLF equation describes behavior from above Tg to Tg-50C.
Kinetics of Tg process appear Arrhenius.
