TY - JOUR

T1 - A comparative study of the properties of different distribution curves

AU - Schnöll-Bitai, Irene

N1 - Coden: MCHPE
Affiliations: Institut fur Physikalische Chemie, Universität Wien, Währinger Str. 42, A-1090 Vienna, Austria
Adressen: Schnöll-Bitai, I.; Institut fur Physikalische Chemie; Universität Wien; Währinger Str. 42 A-1090 Vienna, Austria; email: [email protected]
Source-File: PhysChemieScopus.csv
Import aus Scopus: 2-s2.0-0037200557
Importdatum: 21.12.2006 12:10:31
09.02.2010: Datenanforderung UNIVIS-DATEN-DAT.RA-2 (Import Sachbearbeiter)

PY - 2002

Y1 - 2002

N2 - The maximum, points of inflection and the derived peak width are enumerated for a Poisson, a Gauss and a Schulz-Flory distribution. Starting with a (not necessarily normalized) number distribution the respective molar mass and hyper distributions are derived and the extrema and the peak width are determined as well. It turned out, that Poisson and (narrow, D <1.1) Gauss distributions can be characterized by the fact that the peak width is an invariant quantity with respect to the number, molar mass and hyper distribution, whereas the peak width changes considerably for a Schulz-Flory distribution. In order to demonstrate the theoretical results commercial polymer standards (prepared by anionic polymerization) were measured by size exclusion chromatography and the constancy of the peak width is demonstrated but the peak widths exceeded by far the theoretically expected values. The influence of axial broadening in size exclusion chromatography is discussed in this context and a simple correction procedure is presented for an ideal Poisson distribution. On the other hand, polymers prepared by stationary radical polymerization displayed a very marked deviation from an invariant peak width, as derived theoretically. It is demonstrated that the location of the peak maximum in the molar mass and the hyper distribution is identical with Mn and Mw, respectively.

AB - The maximum, points of inflection and the derived peak width are enumerated for a Poisson, a Gauss and a Schulz-Flory distribution. Starting with a (not necessarily normalized) number distribution the respective molar mass and hyper distributions are derived and the extrema and the peak width are determined as well. It turned out, that Poisson and (narrow, D <1.1) Gauss distributions can be characterized by the fact that the peak width is an invariant quantity with respect to the number, molar mass and hyper distribution, whereas the peak width changes considerably for a Schulz-Flory distribution. In order to demonstrate the theoretical results commercial polymer standards (prepared by anionic polymerization) were measured by size exclusion chromatography and the constancy of the peak width is demonstrated but the peak widths exceeded by far the theoretically expected values. The influence of axial broadening in size exclusion chromatography is discussed in this context and a simple correction procedure is presented for an ideal Poisson distribution. On the other hand, polymers prepared by stationary radical polymerization displayed a very marked deviation from an invariant peak width, as derived theoretically. It is demonstrated that the location of the peak maximum in the molar mass and the hyper distribution is identical with Mn and Mw, respectively.

M3 - Article

VL - 203

SP - 1754

EP - 1762

JO - Macromolecular Chemistry and Physics

JF - Macromolecular Chemistry and Physics

SN - 1022-1352

IS - 12

ER -