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Branching measurement by analytical TREF: A fully quantitative technique
Author(s) -
Pigeon Michael G.,
Rudin Alfred
Publication year - 1994
Publication title -
journal of applied polymer science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.575
H-Index - 166
eISSN - 1097-4628
pISSN - 0021-8995
DOI - 10.1002/app.1994.070510213
Subject(s) - elution , branching (polymer chemistry) , polyethylene , fractionation , chromatography , chemistry , polymer , analytical chemistry (journal) , calibration , materials science , mathematics , organic chemistry , statistics
Conversion of analytical TREF data to accurate branching distributions of polyethylene requires a calibration of branching frequency as a function of elution temperature. It has been found that the elution temperature of a semicrystalline polymer such as polyethylene depends on molecular weight, branch content, branch length, and branch clustering. It stands to reason that every polymer will have its own unique relation of branch frequency and elution temperature. Ideally, the polymer would be fractionated by a preparative TREF technique and the fractions analyzed by NMR or IR to determine branch frequency with respect to elution temperature. This method is tedious and time‐consuming. An alternative method is described here to determine the relation between branch frequency and TREF elution temperature and to generate a calibration from analytical TREF data only. A twodetector system is used to simultaneously measure both concentration and branching frequency as a function of elution temperature. Each polymer is analyzed using analytical TREF data alone, eliminating the need for preparative TREF fractionation and NMR analysis of the fractions. © 1994 John Wiley & Sons, Inc.