Rheo-Optical Study of Nonlinear Effects in an Immiscible Newtonian Polymer Blend Under Large Amplitude Oscillatory Shear Flow

作者：Deyrail Yves; Huneault Michel A; Bousmina Mosto^*

来源：Journal of Polymer Science Part B: Polymer Physics , 2009, 47(15): 1467-1480.

DOI：10.1002/polb.21747

• blends
• drop deformation
• emulsion
• immiscibility
• interfaces
• rheology
• of blends
• rheo-optcs

The morphology evolution of polydimethylsiloxane (PDMS) drops embedded in polyisobutylene (PIB) matrix blend was investigated under large amplitude oscillatory shear flow (LAOS) using rheo-optical techniques. The oscillatory shear experiments were carried out at various frequencies and deformation amplitudes up to 800%. The drop deformation was assessed by optical microscopy, small angle light scattering (SALS), and linear-dichroism. It was observed that when the flow is reversed, the drop returns back to its equilibrium spherical shape and then it deforms again symmetrically in the other direction, with exactly the same angle theta. However, when the deformation amplitude increases, various unusual behaviors have been observed and upon reversal of the flow in the opposite direction during oscillations, the drop does not reach the spherical equilibrium shape anymore at the flow reversal point but it rather adopts an ellipsoidal shape as was predicted by Yu et al. model.(3) Such a behavior was assessed by both optical microscopy observations and by optical techniques. When the deformation was further increased, the drops undergo break-up process and the break-up point was assessed by optical techniques.

• 出版日期2009-8-1