Amyloses tricarbanilates

The first is that the log M vs. elution volume data for both the molecular weight standards and the polymer in question must be linear over a sufficient range of molecular weights. Fortunately, this is not a serious concern since most commercially available high performance GPC columns have been designed with this feature. A second limitation of the method is that it can only be applied to linear homopolymers. In the case of amylose tricarbanilate (ATC) which contains a small amount ( 5%) of branched amylopectin tricarbanilate, the log vs. elution... 

Figure 7. Molecular weight—elution volume relationship determined by GPC/ LALLS for amylose tricarbanilate containing branched amylopectin tricarbanilate...

Chain conformations of a-and P-llnked glycan derivatives have been studied through CD. The studies suggested that a-llnked amylose tricarbanilate adopted a helical conformation, whereas the p-linked cellulose derivative did not. The CD spectra of these derivatives is shown in Figure 9.7. Frequent use of CD has been made to study not only the conformation of other polysaccharides but also their association in certain polysaccharide gels like alginate and pectin. 

Amylose tricarbanilate Amylopectin Benzyl amylose DS = 3 Starch... 

Fractional Precipitation of Amylose-lodine Solutions. Fairly concentrated amylose solutions containing a mixture of two to five components (DP 90-56CXJ) were precipitated by successive addition of KI2 solution. The purified fractions were converted into tricarbanilate derivatives and were then separated over a high performance GPC column. The ratio of the components was obtained from careful evaluation of the peak areas using the concentration dependence of the single components and various mixtures of known composition. Figure 9 shows the elution curves of fractions a-d obtained from a two component system (DP 90 and DP 1800, 1 1). 

Figure 11. Stepwise retrogradation of amyloses DP 100 and 2270 (1 1). HPLC-GPC of tricarbanilates in THF. (Amylose solution 200 mg DP 100 and 200 mg DP 2270 in 4 mL DMSO and diluted with water to 100 mL.)...

Glass-transition temperatures have been measured for cellulose tricarbanilate as a function of the chain-length the critical chain-length can be predicted if the D-glucopyranosyl residues are regarded as flexible. The data for cellulose tricarbanilate were compared with those for derivatives of amylose. 

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