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Determination of the polydispersity of poly(tetramethylene ether) glycol by means of high‐performance liquid chromatography and curve fitting
Author(s) -
Graf Hermann,
Schulz Günter,
Plitzko KlausDieter
Publication year - 1997
Publication title -
macromolecular chemistry and physics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.57
H-Index - 112
eISSN - 1521-3935
pISSN - 1022-1352
DOI - 10.1002/macp.1997.021980719
Subject(s) - molar mass distribution , dispersity , gel permeation chromatography , chemistry , ether , polymer , chromatography , analytical chemistry (journal) , degree of polymerization , polymer chemistry , polymerization , organic chemistry
A modified high‐performance liquid chromatographic method for the analysis of the molecular weight distribution of poly(tetramethylene ether) glycol (PTMEG) is described. The weight percentage of the polymer homologues, up to a degree of polymerization X of 79, can be determined. This covers about 93 wt.‐% of the material with number‐average molecular weight M̄ n = 1000, but only 65 wt.‐% of that with M̄ n = 2000. Direct calculation of the means M̄ n , M̄ w , and M̄ z from these percentages leads to erroneous results because of the neglect of the summands with X > 79. Therefore, a curve fit is performed and M̄ n , M̄ w , and M̄ z are calculated from the fitting parameters. From the known molecular weight distribution functions, Wesslau's and Kubin's function yielded the best fit. The results of this method are compared with those of gel permeation chromatography, viscosimetric measurements, supercritical fluid chromatography, matrix‐assisted laser desorption/ionization time‐of‐flight mass spectrometry, and evaporative light scattering detector methods. The scope and the limitations of this method are discussed.