ISSN:
0449-2951
Keywords:
Chemistry
;
Polymer and Materials Science
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Chemistry and Pharmacology
,
Physics
Notes:
The depolarization ratios of unpolarized light, vertically polarized light, and horizontally polarized light at 90° have been measured for polyvinyl acetate solutions at high dilutions with the help of a specially designed differential amplifier. Over the concentration range (0.01-0.25%) studied, the values of ρu and ρv decrease sharply with increasing concentrations up to a concentration of about 0.1% and then the curves flatten out. Depending upon the nature of the solvent, there exists for each polymer - solvent system a critical concentration range above which the anisotropy of the molecules does not later further. This behavior is the same both in the good solvent (methyl ethyl ketone) and the relatively poor solvent (ethyl acetate). The experimentally determined ρh values generally are in agreement with the values calculated from the reciprocity theorem, except where ρh values are greater than one. In the case of ρh values which are greater than unity the difference between the experimentally determined and the calculated values is as high as 70%.
Additional Material:
3 Ill.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1002/pol.1963.100010145
