ISSN:
0025-116X
Keywords:
Chemistry
;
Polymer and Materials Science
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Chemistry and Pharmacology
,
Physics
Notes:
The structure of a partially formalized poly(vinyl alcohol) (PFV)-iodine color complex was investigated at a series of iodine concentrations by using small-angle X-ray scattering and resonance Raman Methods. Scattering experiments show that the increase of iodine concentration induces a structural change of the PFV polymer chains from an expanded coil to a Gaussian coil. On the process of complexation of PFV with iodine, the number of iodine atoms occluded by a PFV molecule with degree of polymerization (D.P.) 560 was evaluated to be less than 25 (0,044/D.P.) in the amorphous state or 31 (0,056/D.P.) in the crystal state, a value being much smaller than those deduced for amylose and cyclodextrin. The resonance Raman Spectrum of the PFV-iodine complex clearly indicates the presence of polyiodine chains in the polymers. Therefore, it can be assumed that the hetrogeneous occlusion of iodine in polymer chains occurs cooperatively, and that the formation of polyiodine chains changes the local structure of the polymer chains breaking the long-range interactions between the polymer segments for exhibiting an excluded volume effect.
Additional Material:
4 Ill.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1002/macp.1993.021941021
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