The Chain Stretching Effect on the Morphology and Rheological Properties of Phase-Separating Polymer Blends Subjected to Simple Shear Flow

✍ Scribed by Kaifu Luo; Hongdong Zhang; Yuliang Yang

• Publisher: John Wiley and Sons
• Year: 2004
• Tongue: English
• Weight: 372 KB
• Volume: 13
• Category: Article
• ISSN: 1022-1344
• DOI: 10.1002/mats.200300032

✦ Synopsis

Abstract

Summary: The spinodal decomposition of a binary mixture subjected to simple shear flow is investigated in the framework of the modified time‐dependent Ginzburg‐Landau (TDGL) equation with an external velocity term. The domain growth and related rheological properties of a binary mixture under shear flow are simulated in three dimensions by means of the cell dynamics scheme (CDS). The simulation results show that the domain growth is anistropic and depends on the terminal relaxation time of the polymer chain. It is found that lamellae‐like domains with the normal parallel to the velocity gradient direction are observed when the terminal relaxation time is long enough. This result has also been confirmed by carefully checking the scattering functions in different incident light directions and the evolution of the domain size in different directions. In addition, when the chain stretching effect is strong, the transients of the excess shear viscosity are much higher than the case without the chain stretching effect. The terminal relaxation time of the chain also has an important effect on the first and second normal stress differences.

The time evolution of the morphology for the case with strong chain stretching effect.

imageThe time evolution of the morphology for the case with strong chain stretching effect.