ISSN:
0022-3832
Keywords:
Chemistry
;
Polymer and Materials Science
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Chemistry and Pharmacology
,
Physics
Notes:
The molecular weight of sugar beet araban fractions prepared by fractionation of the araban acetates on a charcoal column have been determined. Light-scattering measurements using 2 M NaCl and aqueous 1% N,N-dimethylformamide (DMF) as solvents gave, weight average molecular weights which did not agree, the values in the latter solvent being about half of those in the former. Other experimental observations, such as, number average and sedimentation-viscosity molecular weights favor the results in salt solution; the low results in 1% DMF are presumably due to the interaction between araban and DMF. Arabans exhibited appreciable fluorescence when incident light of wavelength 436 mμ was used, but none at λ = 546 mμ. Sample limitations prevented measurements at the higher wavelength, and an alternate procedure for correcting for fluorescence is presented. The weight average molecular weights in 2 M NaCI which ranged from 18,400 to 37,000 for this study are appreciably higher than the previously reported value of 10,000. Number-average molecular weights determined by the chlorous acid end-group method ranged from 8700 to 24,200 for the various fractions. No simple relationship between molecular weight and fraction number was observed, and most of the fractions showed appreciable molecular weight heterogeneity.
Additional Material:
2 Ill.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1002/pol.1959.1203613011
Permalink
