ISSN:
0022-3832
Keywords:
Chemistry
;
Polymer and Materials Science
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Chemistry and Pharmacology
,
Physics
Notes:
The flow and retarded-elastic behavior of four polyisobutylene specimens (M̄w 1.09 × 104 to 8.54 × 104), measured in a concentric cylinder rotational viscometer, are reported. Under the conditions investigated the non-Newtonian flow behavior can be represented by Ferry's equation. The logarithm of the viscosity η varied linearly with the reciprocal of the square of the absolute temperature. The time-scale for retarded elasticity was found to vary with temperature in the same way as the viscosity. The normalized retarded elasticity functions at temperatures corresponding to unit viscosity are substantially identical. The time corresponding to a normalized retarded elastic compliance of 0.5 is about 10-5 η second when η is in poises. The reciprocal steady state shear compliances 1/J and internal shear moduli Gi in Ferry's equation are of the same order of magnitude for each polymer. The retardation time function L(ln τ) is calculated for one of the polymers, and then the dynamic response; these results are in good agreement with dynamic measurements on this material. From a consideration of the stress relaxation behavior of high molecular polymers, it is pointed out that there must exist another retarded elasticity mechanism, the time-scale of which depends only on temperature and not on molecular weight. This second mechanism is masked in the reported experiments on low molecular polymers.
Additional Material:
24 Ill.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1002/pol.1954.120147306
