Characterization of polyamides 6, 11, and 12. Determination of molecular
weight by size exclusion chromatography (IUPAC Technical Report)
E. C. Robert,*
R. Bruessau, J. Dubois, B. Jacques, N. Meijerink, T. Q. Nguyen, D. E.
Niehaus, and W. A. Tobisch
Abstract: This report presents the results from IUPAC Working
Party IV.2.2 of the global trial within the framework of IUPAC Commission
IV.2, Characterization of Commercial Polymers. The results
were compared on the basis of molecular weight obtained by size exclusion
chromatography (SEC)using different techniques practiced in participating
laboratories, the majority of which were materials suppliers. The practical
methodologies used different solvents for the polymers, in particular,
benzyl alcohol, 1,1,1,3,3,3 hexafluoropropan-2-ol and tetrahydrofuran;
the latter solvent was used after chemical modification of the polyamides,
in general with trifluoroacetic anhydride. Eight laboratories participated
in the trial. The repeatability for molecular weight in each laboratory
was good, whatever technique was used, the relative standard deviation
averaged over all laboratories being around 3%. The deviations in distribution
of molecular weights with different experimental methodologies were
broader, but were reasonably good despite the diversity of methods.
The differences in the distribution correspond to a confidence interval
of about 30% in molecular weight.
* Corresponding author.
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