caa a22 4500 46581395X CHVBK 20180323112122.0 cr unu---uuuuu 170327e19901101xx s 000 0 eng 10.1007/BF01329306 doi (NATIONALLICENCE)springer-10.1007/BF01329306 Wagner M. Institut für Kunststofftechnologie, Universität Stuttgart, Böblingerstr. 20, 7000, Stuttgart 1, FRG aut The nonlinear strain measure of polyisobutylene melt in general biaxial flow and its comparison to the Doi-Edwards model [Elektronische Daten] [M. Wagner] The nonlinear strain measure of a polyisobutylene (PIB) melt as determined by analysis of uniaxial, planar, ellipsoidal, and equibiaxial extensions is compared to the predictions of the molecular model of Doi and Edwards. It is found that the universal strain function of the Doi-Edwards model is unable to predict the nonlinear behavior of this polymer melt in general extensional flow. The qualitative agreement between predictions and experimental data for the strain dependence of shear stress and first normal stress difference in shear flow that was considered as powerful evidence for the correctness of the Doi-Edwards model seems to be accidental. The exaggerated strain dependence of the model suggests a need to reconsider the assumptions concerning the chain retraction process. Steinkopff, 1990 Doi-Edwards theory nationallicence nonlinear viscoelasticity nationallicence general extensional flow nationallicence polyisobutylene (PIB) nationallicence Rheologica Acta Steinkopff-Verlag 29/6(1990-11-01), 594-603 0035-4511 29:6<594 1990 29 397 https://doi.org/10.1007/BF01329306 text/html Onlinezugriff via DOI 1 research-article jats NATIONALLICENCE 856 40 https://doi.org/10.1007/BF01329306 text/html Onlinezugriff via DOI NATIONALLICENCE 100 1- Wagner M. Institut für Kunststofftechnologie, Universität Stuttgart, Böblingerstr. 20, 7000, Stuttgart 1, FRG aut NATIONALLICENCE 773 0- Rheologica Acta Steinkopff-Verlag 29/6(1990-11-01), 594-603 0035-4511 29:6<594 1990 29 397 Metadata rights reserved Springer special CC-BY-NC licence nationallicence BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-springer