This document provides information about polymers and techniques for analyzing their properties. It discusses solvent selection for dissolving polymers and determining intrinsic viscosity and molecular weight from the Mark-Houwink equation. The document also mentions calibration curves, molecular weight distributions, and hydrodynamic volume as it relates to polymer size in solution. Additional resources are provided on SEC, MMD interpretation, detector types, and developing an analytical method for polymer analysis. The homework involves when to use SEC, non-SEC applications, SEC detector types and uses, and developing an example polymer analysis method.

2. HARDNESS OF
WATER
28-OCTOBER-2013
S.T. POPOVICI

3. HARRIS 25-7
• Why and when SEC
• Limitations of SEC

4. POLYMERS SKELETAL
STRUCTURES
- Are related to mechanical propertjes/product/ lifetime etc…..

5. POLYMERS SKELETAL
STRUCTURES
- Are related to mechanical propertjes/product/ lifetime etc…..

6. DISTRIBUTIONS OF POLYMERS

7. DISSOLUTION OF POLYMERS
- Which solvent to use ??? To dissolve your sample?

8. DISSOLUTION OF POLYMERS
The Mark–Houwink equation gives a relation between intrinsic
viscosity and molecular weight :
From this equation the molecular weight of a polymer can be
determined from data on the intrinsic viscosity and vice versa.
The values of the Mark–Houwink parameters, and , depend on
the particular polymer-solvent system. For solvents, a = 0,5
value of is indicative of a theta solvent - then the solvent
starts to precipitate !!!! (not wanted)
a and K are empirically determined constants (to be found in

9. BEST SOLVENT?
- You want a sort of ideal shape of a polymer in solution (see
Flory - Nobel Price in Chemistry in 1974) – page 160
- http://www.nobelprize.org/nobel_prizes/chemistry/laureat
es/1974/flory-lecture.pdf
- Leading to a Univarsal Calibration curve (example article
below)
- http://www.nist.gov/data/PDFfiles/jpcrd273.pdf

10. HYDRODYNAMIC VOLUME
- The apparent size of the polymer in solution
- Reflects both the polymer chain itself and the solvating
molecules in inner and outer spheres
-Hydrodynamic Volume is related to an Expansion Factor, α
α = 1 is the value for the “non-expanded” polymer in the
“ideal” statistical coil having the smallest possible size
as α increases, so does the Hydrodynamic Volume of the
sample

11. SOME EXTRA INFO
http://www.shimadzu.com/an/hplc/support/lib/lctalk/55/55int
ro.html

12. INTERPRETATION OF MMD
http://www.ias.ac.in/initiat/sci_ed/resources/chemistry/MolW
eight.pdf

13. CALIBRATION CURVE OF 14
STANDARDS

14. Molecular weight and dispersion an example:
Here are:
10 chains of 100 molecular weight
20 chains of 500 molecular weight
40 chains of 1000 molecular weight
5 chains of 10000 molecular weight
Mn
Mw
Polydispersity
(10 100) (20 500) (40 1000) (5 10000)
1347
10 20 40 5
(10 100 2 ) (20 500 2 ) (40 1000 2 ) (5 10000 2 )
(10 100 ) (20 500 ) (40 1000 ) (5 10000 )
Mw
Mn
4
5390

15. EXTRA INFO (FOR THE ONES
WANTING MORE)
http://www.shodex.net/?lang=2&applic=1483
http://www.separations.us.tosohbioscience.com/ServiceSuppo
rt/TechSupport/ResourceCenter/FAQs/HPLCColumns/SizeExclu
sion/
http://www.chem.agilent.com/Library/brochures/5990-7995GPCaqueous-Apr11-9lo.pdf
15

16. HOMEWORK (IN DUO) – NOTE
NEXT SLIDE TOO
1) When would you use SEC ?
2) When wouldn’t you use SEC ?
• Make a list of examples immagine from practice!
3) Which type of detectors can you use for SEC. Which
information give these detectors? How can you kwantitate
4) Make a scheme of the method development of a procedure
for the analysis of a polymer. Choose yoursef a easy example
and describe the procedure with existing equipment !!!! .
You will discuss it during next CHR lesson. SEE NEXT SLIDE!!!!!

17. HOMEWORK (2)
5) Explain in your own words what happends if the polymer
you are injecting has a high viscosity ?? (which negative aspect
can occur, why ?)