Starch derivatives of a high degree of functionalization. VI. Multistep carboxymethylation

✍ Scribed by W. Lazik; Th. Heinze; K. Pfeiffer; G. Albrecht; P. Mischnick

• Publisher: John Wiley and Sons
• Year: 2002
• Tongue: English
• Weight: 161 KB
• Volume: 86
• Category: Article
• ISSN: 0021-8995
• DOI: 10.1002/app.10983

✦ Synopsis

Abstract

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