Polymer Characterization ppt

3.  Molar Mass And Molar Mass Distribution
• 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

14. 14
Product
Concept Design
Properties
Fundamentals
Synthesis

15. 15
Synthesis
Structure
Properties
Characterization

17. 17
Mechanical
Property
Strength,
Modulus,
etc
Degree of Polymerization
DP Critical
Limiting Value
General Relationship
sB = A - (BMn)

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

19. 19
Mechanical
Property*
Degree of Polymerization
Viscosity
Useful Range

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

21.  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.  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. Mn =
2 x 1000 x sample wt
meq COOH + meq OH
C.
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
Measurement of Number Average Molecular Weight

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. *
A
A
A P
X
P 
A
X
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,
A
A P
P
P 

 *
P

A
A
A X
P
P *
*


*
)
1
( A
A P
X


*
A
B P
X
P 

where: B
X = mole fraction of solute

31. 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. B
vap
X
H
RT
T











2
*
B
m
A
B
B
A
B
B M
m
m
M
m
X 


/
1
(for dilute solutions)
where A
M is the molar mass of the solvent and
the molality of the solute in mol/kg

36. B
vap
A
b
m
H
M
RT
T











2
*
m
K
T b
b 











H
M
RT
K
vap
A
b
b
2
*
where
Kb= boiling point constant or
ebullioscopic constant of the solvent
for dilute solutions

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
(
C HvMn
Tb
)C=0 =
RT2
+ A2C

40. m
K
T f
f 











H
M
RT
K
A
f
f
fus
2
*
where
(for dilute solutions)
Kf= molal freezing point depression
constant or cryoscopic constant

42. 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