Z. Kabatek et al., GEL-PERMEATION CHROMATOGRAPHY OF POLYMERS DEGRADING RANDOMLY IN THE COLUMN - THEORETICAL TREATMENT AND PRACTICAL ASPECTS, Journal of chromatography, 786(2), 1997, pp. 209-218
Citations number
36
Categorie Soggetti
Chemistry Analytical","Biochemical Research Methods
Gel permeation chromatography (GPC) separation accompanied with the ra
ndom degradation of polymer in the column is modelled by a set of cont
inuity equations. Numerical solution of the equations yields: (i) time
evolution of the axial concentration profiles of all X-mers that visu
alize a course of the processes running in the column; and (ii) the nu
mber-distribution function of degrees of polymerization (DP) of each p
olymer fraction passing through the detector (i.e., of each GPC-slice)
. These data are evaluated by the exact approach way and by convention
al methods based on DP values taken from the calibration curve or meas
ured by a light-scattering (LS) detector. Thus obtained DP averages ar
e compared with each other, with those predicted by the theory of poly
mer random degradation and with those of the non-degraded original pol
ymer. The procedure of determination of the degradation rate constant
and original values of DP averages of the degrading polymer with a hel
p of the kinetic equation of random degradation has been also simulate
d and the following conclusions have been reached: the degradation rat
e constant is available from GPC measurements performed with the use o
f both a single concentration detector and its combination with the LS
detector. In contrast, the values of DP averages of original non-degr
aded polymer are not available except for the original weight-average
DP provided that values of weight-average DP of degraded polymer are m
easured with an LS detector. Extrapolation to zero degradation time of
the DP values obtained by the calibration curve method yields overest
imated DP values of non-degraded polymer. (C) 1997 Elsevier Science B.
V.