ISSN:
0098-1273
Keywords:
Physics
;
Polymer and Materials Science
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Chemistry and Pharmacology
,
Physics
Notes:
The non-Newtonian viscosity in steady flow was measured for solutions of polystyrene (M̄w/M̄n = 1.1) in diethyl phthalate at 30.0°C. In the moderately concentrated solutions, from 6.03 × 10-2 to 5.62 × 10-1g/cm3, the viscosity data modified by frictional parameters fit the Graessley theoretical curve for a narrow distribution polymer. The dilute solutions, from 3.26 × 10-3 to 1.57 × 10-2 g/cm3, were nonentangled systems whose non-Newtonian properties could be explained by the excluded volume effect as proposed by Fixman. On the basis of the non-Newtonian data, it was concluded that the solution of 3.30 × 10-2 g/cm3 was a lower critical entanglement concentration, which was distinguished from the usual higher critical concentration for entanglement. This lower critical concentration was also found in the concentration dependence of the activation energy of flow and the absorbance at 310 nm.
Additional Material:
8 Ill.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1002/pol.1978.180160414
