A feasible method to determine the critical DS for modified polysaccharide derivatives' gelation by gel point, t(g)

Autor(en): Xing, H
Nierling, W
Lechner, MD
Stichwörter: carboxyl methylation; Chemistry; Chemistry, Applied; Chemistry, Organic; degree of substitution; gel point; gelation; guar gum; hydrogel; locust bean gum; POLYMER; Polymer Science; polysaccharide; super water absorber
Erscheinungsdatum: 2004
Volumen: 56
Ausgabe: 4
Startseite: 397
Seitenende: 402
The process of determining a critical DS to a polymer's gelation is a key link in identifying degradable polymers' cross-linking behaviors. A feasible method was developed from the theological technique. In principle, it was a new application of gel point, t(g), in an overlapping field of polymers' modification and characterization, by which the gelling properties of carboxyl methylated guar gum (CMGG) and locust bean gum (CMLBG) were dynamically investigated by identifying their t(g). Differing from the routine research in theology or synthesis chemistry, the present study focused on neither pure t(g) nor pure DS but on their interrelation. The results demonstrated that CMGG/CMLBG's gel points could be observed only when their DS were 0.2. However, it was not guaranteed to yield the tested polymers' gel points unless the investigation was performed on a plateau region. Two preconditions, DSless than or equal to0.2 and omega=3-60 rad s(-1), must be satisfied simultaneously besides gamma of 0.5% was maintained in order to obtain the expected gel point. Since DS was regarded as a contradictory focus related to the polymers' hydrophilicity and cross-linking behavior, the value DS=0.2 was exactly the upper limit of CMGG/CMLBG's gelation. The significance of the present study rests not only in the first successful attempt in determining galactomannan-based derivatives' DScritical but also in its universal application for other polysaccharide-based derivatives because of a similarity in structure. (C) 2004 Elsevier Ltd. All rights reserved.
ISSN: 01448617
DOI: 10.1016/j.carbpol.2004.03.020

Show full item record

Google ScholarTM