1. Polymer Characterization

2. Topics

3. Topics Molar Mass And Molar Mass Distribution Structure And Morphology
Molecular Weight Determination
Laser Light Scattering
Chromatography Size Exclusion (GPC)
Mass Spectroscopy
Structure And Morphology
Infrared Spectroscopy
Nuclear Magnetic Resonance
X-ray Microscopy
Scanning Electron Microscopy
Atomic Force Microscopy
Dynamic Properties
Thermal Analysis

4. References

5. References

6. References

7. References

8. References

9. References

10. References

11. References

12. Find them Collectively on one CD

13. Development of Polymers

14. Development of Polymers
Product
Synthesis
Concept
Design
Properties
Fundamentals

15. Role of Polymer Characterization
Structure
Synthesis
Properties
Characterization

16. Molecular Weight

17. Molecular Weight Effect on Properties
Limiting Value
Mechanical
Property
Strength,
Modulus,
etc
General Relationship
sB = A - (B\Mn)
DP Critical
Degree of Polymerization

18. Molecular Weight Effect on Flow
General Relationship
[h] = K Ma K and a are constants
Viscosity
Mark-Houwink-Sakurada Relation
Degree of Polymerization

19. Optimization of Molecular Weight
Mechanical
Property*
Useful Range
Viscosity
Degree of Polymerization

20. Molecular Weight Distribution
Low molecular weight molecules
Single Value
# of Molecules
Molecular Weight
Synthetic Polymers
# of Molecules
Broad Range of Values
Molecular Weight
Biological Polymers
Single Value
# of Molecules
Molecular Weight

21. Methods of Molecular Weight Determination
Number Average Molecular Weight
End-group analysis
determine the number of end-groups in a sample of known mass
Colligative Properties
most commonly osmotic pressure, but includes boiling point elevation and freezing point depression
Weight Average Molecular Weight
Light scattering
translate the distribution of scattered light intensity created by a dissolved polymer sample into an absolute measure of weight-average MW

22. Methods of Molecular Weight Determination
Viscosity Average Molecular Weight
Viscometry
The viscosity of an infinitely dilute polymer solution relative to the solvent relates to molecular dimension and weight.
Molecular Weight Distribution
Gel permeation chromatography
fractionation on the basis of chain aggregate dimension in solution.

23. Measurement of Number Average Molecular Weight
2.3.1 End-group Analysis
A. Molecular weight limitation up to 50,000
B. End-group must have detectable species
   
a. vinyl polymer : -CH=CH2
   b. ester polymer : -COOH, -OH
   c. amide and urethane polymer : -NH2, -NCO
   d. radioactive isotopes or UV, IR, NMR detectable functional group

24. Measurement of Number Average Molecular Weight
2 x 1000 x sample wt
Mn = C.
meq COOH + meq OH
D. Requirement for end group analysis   
1. The method cannot be applied to branched polymers.
2. In a linear polymer there are twice as many end of the chain
and groups as polymer molecules.
3. If having different end group, the number of detected end group
      is average molecular weight.
4. End group analysis could be applied for
polymerization mechanism identified
E. High solution viscosity and low solubility : Mn = 5,000 ～ 10,000

25. ? 1: Find a procedure for End group Analysis for one kind of Polymer

26. Colligative properties
Properties determined by the number of particles in solution rather than the type of particles.
Vapour pressure lowering
Freezing point depression
Boiling point elevation
Osmotic pressure

27. How Vapor Pressure Lowering Occurs
Solute particles take up space in a solution.
Solute particles on surface decrease number of solvent particles on the surface.
Less solvent particles can evaporate which lowers the vapor pressure of a liquid.

28. Vapor Pressures of Pure Water and a Water Solution
The vapor pressure of water over pure water is greater than the vapor pressure of water over an aqueous solution containing a nonvolatile solute.
Solute particles take up surface area and lower the vapor pressure

29. Vapor Pressure Lowering
Let component A be the solvent and B the solute.
solute B is nonvolatile
Applying Raoult’s Law:
where:
PA= vapor pressure of the solvent in solution
= vapor pressure of the solution
PA*= vapor pressure of the pure solvent
XA= mole fraction of the solvent

30. The lowering in vapor pressure,
where:
= mole fraction of solute

31. Boiling Point Elevation
When a non volatile solute is added to solvent:
• Vapor pressure of solvent is lowered
• solution formed must be heated to higher temperature than boiling point of pure solvent to reach a vapor pressure of 1 atm.
• This means that non volatile solute elevates the boiling point of the solvent which we call boiling point elevation

35. Boiling Point Elevation
(for dilute solutions)
where
is the molar mass of the solvent and
the molality of the solute in mol/kg

36. Boiling Point Elevation
for dilute solutions
where
Kb= boiling point constant or ebullioscopic constant of the solvent

38. Boiling-point elevation (Ebulliometry)
      
     Tb   : boiling point elevation
     H v  : the latent heats of vaporization
   
We use thermistor to major temperature. (1×10-4℃)
    limitation of Mn : below 20,000
HvMn
Tb
)C=0 =
RT2
+ A2C ( C

39. Freezing Point Depression
Addition of a nonvolatile solute to a solution lowers the freezing point of the solution relative to the pure solvent.

40. Freezing Point Depression
(for dilute solutions)
Kf= molal freezing point depression constant or cryoscopic constant

42. Freezing-point depression (Cryoscopy)
Freezing-point depression (Cryoscopy)
      
      Tf  : freezing-point depression,
        C :  the concentration in grams per cubic centimeter
        R :  gas constant
        T : freezing point
      Hf: the latent heats of fusion
        A2 : second virial coefficient ( C
Tf
)C=0 =
Hf Mn
RT2
+ A2C