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Starch derivatives of a high degree of functionalization. VI. Multistep carboxymethylation
Author(s) -
Lazik W.,
Heinze Th.,
Pfeiffer K.,
Albrecht G.,
Mischnick P.
Publication year - 2002
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.10983
Subject(s) - chemistry , sodium hydroxide , monomer , starch , capillary electrophoresis , methanol , surface modification , polymer , chemical modification , polymer chemistry , gel permeation chromatography , nuclear chemistry , chromatography , organic chemistry
For the first time, carboxymethyl starch (CMS) samples with a very high degree of substitution (DS CM = 2.1) were synthesized by multistep carboxymethylation under heterogeneous reaction conditions in methanol/water with sodium hydroxide and monochloroacetic acid as an etherifying agent. The stepwise increase in the total DS CM value gradually decreased with an increasing DS CM value of the starting polymer. The determination of the functionalization pattern of CMS by 1 H‐NMR spectroscopy after chain degradation indicated a high preference for 2‐O‐substitution. The distribution of the carboxymethyl functions was in the order O‐2 ≫ O‐6 > O‐3. A detailed analysis of the depolymerized sample by means of high‐performance liquid chromatography and capillary electrophoresis revealed a monomer composition that was in very good agreement with the statistical model of Spurlin. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 86: 743–752, 2002