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New results concerning the behavior of cellulose acetate in solutions and films by means of CD measurements

✍ Scribed by D. Meißner; J. Einfeldt; T. Schareina


Publisher
Wiley (John Wiley & Sons)
Year
1999
Tongue
English
Weight
73 KB
Volume
50
Category
Article
ISSN
0006-3525

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✦ Synopsis


Cellulose acetate (DS ϭ 2.45) was extensively investigated by Circular Dichroism (CD) in acetonitrile and dioxane. We found great differences between the CD spectra of a 1 wt % acetonitrile solution and the corresponding dioxane solution of cellulose acetate (CA) indicating that the macromolecules exist in those solutions in different molecular arrangements (e.g., persistence length, solvatation shell). The resulting morphologies could be transformed reversibly into each other, as we found by measuring the CA in mixtures of both solvents. Solid CA films show discernible CD spectra depending on the solvent they were evaporated from. In this way, we prepared solid films of the same polysaccharide owning different chiral properties. Furthermore, changes in the spectra occurred with increasing CA concentration. Basing upon our findings, some general statements concerning the polymer behavior of CA are possible.