Handbook of Size Exclusion Chromatography and Related ...

(AM/AA), and acrylamide/dimethyldiallylammonium chloride (AM/DMDAAC)
copolymers by Micropak TSK Gel PW and PWXL columns with an RI/LALLS
dual detecting system. Also, the authors determined the molecular weight
reduction and mass loss of degraded AM/AA copolymer in a boiler by SEC with
RI detector. Lesec and Volet (47) applied RI/LALLS/on-line viscometer triple
detectors to determine the absolute MW and MWD of PAM.
A Calgon in-house computer simulation program developed by Min and
Cha (48) has been applied to construct a conventional calibration curve. This
program is written in Fortran. It needs two standards for a linear fit and four
standards for a third-order fit. The required parameters are the M w and M n
(number-average molecular weight) of each standard. The different weighted
factor (0 to 1) can be entered into the program to specify the degree of importance
of the given M w or M n value.
Rand and Mukherji (49) reported a MW calibration technique with the
assistance of a computer program to handle the routine analysis of a specific
polymer with a special set of columns, identical mobile phase, and identical SEC
experiment. This method deals with modifying the previous calibration curve by
shifting the retention times of the upper and/or lower limits to obtain a new
calibration curve for the current experiment.
A list of the SEC conditions used in the above references will be compiled in
the Appendix of this chapter.
The methodology and applications of SEC for characterizing acrylamide
polymers will be discussed in this chapter from a practical point of view.
2 EXPERIMENTAL
2.1 Column and Mobile Phase
The selections of columns and mobile phase depend on the chemistry and
molecular weight of the polymer to be analyzed. Important factors (31,32) such as
chemistry, pore size, particle size, ionic group, and adsorptive properties of
the stationary phase, the resolving power, molecular weight separation range,
solvent compatibility, lifetime, sample loading capacity, and temperature stability
should be considered before selecting a column. When a high-molecular-weight
(.10 6 g/mole) polymer is analyzed, the shear degradation of the polymer in the
columns is an important factor, which influences the accuracy of the MW and
MWD determinations. Giddings (31) reported the reduction in intrinsic viscosity
of polyacrylamide solution (M w ¼ 6:25 10 6 g=mole) after passing through a
CPG-10 column (3000 A ˚ pore size and 39–75 mm particle size) at a flow velocity
as low as 0.025 cm/s.
© 2004 by Marcel Dekker, Inc.