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Fractionation of Methyl Cellulose According to Polarity – a Tool to Differentiate First and Second Order Heterogeneity of the Substituent Distribution
Author(s) -
Adden Roland,
Müller Romy,
Mischnick Petra
Publication year - 2006
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.200600048
Subject(s) - substituent , chemistry , fractionation , monomer , residue (chemistry) , hydrolysis , polymer , cellulose , stereochemistry , analytical chemistry (journal) , polymer chemistry , crystallography , chromatography , organic chemistry
Summary: A set of four MCs (DS 1.80–1.95) has been analyzed with regard to their substituent pattern in the glucosyl units and along the polymer chain. The average heterogeneity of methylation observed for the entire material was analyzed in more detail after fractionation according to polarity. All fractions obtained were analyzed with respect to their DS, monomer composition and deviation from a random distribution of these monomers in the polymer chains. By this approach, heterogeneity of first and second order could be differentiated. While for three of the MCs only a minor DS‐gradient over the material was observed, a more pronounced heterogeneity of first order was obtained for MC 4.ESI mass spectrum of the undissolved residue of MC 2 after deuteromethylation and partial hydrolysis; DP 2 and 3 are shown in detail. Signals are assigned according to the number of CH 3 ‐groups.