The Entanglement-disentanglement Transition (EDT) During Creep with Either Constant Or Oscillatory Stress in Highly-entangled Polybutadiene Solution

Download or read book The Entanglement-disentanglement Transition (EDT) During Creep with Either Constant Or Oscillatory Stress in Highly-entangled Polybutadiene Solution written by Sirui Ge and published by . This book was released on 2016 with total page 50 pages. Available in PDF, EPUB and Kindle. Book excerpt: Nonlinear rheological behavior of entangled polymer systems has been investigated for decades, most of which were carried out in strain-controlled mode. In 2004, the yield-like Entanglement-Disentanglement Transition (EDT) was observed in entangled polymer solutions during creep at constant stress. The 2004 study attracted further investigations that attributed the EDT to edge instability. In this work, it is shown that the EDT can take place in absence of any edge instability in the highly entangled 1,4-polybutadiene solutions. In addition, the behavior of EDT was also studied using oscillatory stress-controlled mode (LAOStress) to minimize edge effect. In the LAOStress, EDT takes place when the responding strain grows in amplitude over time. The distortion of the strain response was observed upon the EDT. In order to reflect the nonlinear viscoelasticity, the harmonic analysis and strain decomposition was conducted. Apparent higher harmonics was found in the strain response. In addition, different disentanglement mechanisms are founded in two samples.