ISSN:
0022-3832
Keywords:
Chemistry
;
Polymer and Materials Science
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Chemistry and Pharmacology
,
Physics
Notes:
It is shown that ηsp/c for a polystyrene fraction (M̄v = 250,000) in toluene decreases approximately linearly as the concentration is lowered from 1.0 to 0.1 g./100 ml. and then increases to a maximum at 0.001 g./100 ml. as the concentration is lowered still further. This increase in ηsp/c with dilution is a new effect which we ascribe to the expansion of polymer coils as well as to the disentangling of entire polymer molecules once the concentration is lowered to where there is ample room in the solution for each polymer molecule. The new techniques employ a viscometer with a flow time of 3893 seconds for toluene, special filtering of the solutions, and prolonged agitation of the solutions after each dilution. We present data to show that ηsp/c is time dependent at concentrations below 0.1 g./100 ml.
Additional Material:
3 Ill.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1002/pol.1954.120147302
