caa a22 4500 465814468 CHVBK 20180323112123.0 cr unu---uuuuu 170327e19900301xx s 000 0 eng 10.1007/BF01332377 doi (NATIONALLICENCE)springer-10.1007/BF01332377 Stress optical measurement of the third normal stress difference in polymer melts under oscillatory shear [Elektronische Daten] [J. Kornfield, G. Fuller, D. Pearson] Results are reported for the dynamic moduli,G′ andG″, measured mechanically, and the dynamic third normal stress difference, measured optically, of a series bidisperse linear polymer melts under oscillatory shear. Nearly monodisperse hydrogenated polyisoprenes of molecular weights 53000 and 370000 were used to prepare blends with a volume fraction of long polymer,Φ L, of 0.10, 0.20, 0.30, 0.50, and 0.75. The results demonstrate the applicability of birefringence measurements to solve the longstanding problem of measuring the third normal stress difference in oscillatory flow. The relationship between the third normal stress difference and the shear stress observed for these entangled polymer melts is in agreement with a widely predicted constitutive relationship: the relationship between the first normal stress difference and the shear stress is that of a simple fluid, and the second normal stress difference is proportional to the first. These results demonstrate the potential use of 1,3-birefringence to measure the third normal stress difference in oscillatory flow. Further, the general constitutive equation supported by the present results may be used to determine the dynamic moduli from the measured third normal stress difference in small amplitude oscillatory shear. Directions for future research, including the use of birefringence measurements to determineN 2/N 1 in oscillatory shear, are described. Steinkopff, 1990 P olyisoprenes nationallicence t hird normal s tress difference nationallicence o scillatory flow nationallicence s hear s tress nationallicence d ynamic m oduli nationallicence Kornfield J. Chemical Engineering Department, Stanford University, 94305-5025, Stanford, California, USA aut Fuller G. Chemical Engineering Department, Stanford University, 94305-5025, Stanford, California, USA aut Pearson D. Department of Chemical and Nuclear Engineering, and Materials Department, University of California, Santa Barbara, California, USA aut Rheologica Acta Steinkopff-Verlag 29/2(1990-03-01), 105-116 0035-4511 29:2<105 1990 29 397 https://doi.org/10.1007/BF01332377 text/html Onlinezugriff via DOI 1 research-article jats NATIONALLICENCE 856 40 https://doi.org/10.1007/BF01332377 text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Kornfield J. Chemical Engineering Department, Stanford University, 94305-5025, Stanford, California, USA aut NATIONALLICENCE 700 1- Fuller G. Chemical Engineering Department, Stanford University, 94305-5025, Stanford, California, USA aut NATIONALLICENCE 700 1- Pearson D. Department of Chemical and Nuclear Engineering, and Materials Department, University of California, Santa Barbara, California, USA aut NATIONALLICENCE 773 0- Rheologica Acta Steinkopff-Verlag 29/2(1990-03-01), 105-116 0035-4511 29:2<105 1990 29 397 Metadata rights reserved Springer special CC-BY-NC licence nationallicence BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-springer