Non-Linear Rheology of Entangled Linear and Branched Polymer Melts under Large Amplitude Oscillatory Shear

作者：Hyun K; Wilhelm M^*

来源：Kautschuk Gummi Kunststoffe, 2010, 63(4): 123-129.

• Non-linear rheology
• Polymer topology
• FT-Rheology
• Intrinsic nonlinearity
• LAOS

The nonlinear response of monodisperse linear and branched, specifically comb polymer melt has been investigated under large amplitude oscillatory shear (LAOS) with Fourier-Transform rheology (FT-Rheology). The relative intensity of the third harmonics (I(3/1)), which quantifies nonlinearity, was found to depend quadratically on the strain amplitude (gamma(0)) at small and medium strain amplitudes regardless of excitation frequency, temperature and polymer topology. From these results, we propose a new nonlinear parameter Q being the intrinsic nonlinearity, which is defined as Q equivalent to I(3/1)/gamma(2)(0) and we also defined an intrinsic zero-strain nonlinearity, Q(0). This parameter is constant at relatively small strain amplitude in analogy to e.g. the zero shear viscosity.

• 出版日期2010-4