Slipping in Stress Relaxation in Shear Estimated by Damping and Stress- Strain Behavior of Polyisobutylene

抄録

In this article the slipping of less entangled polyisobutylene (PIB) melts and solutions in shear is investigated by the damping as well as the stress growth behavior. The obtained data are also compared with those of the moderately and highly entangled PIB systems. The concentrated solutions do not show the slipping at the sample-fixture interface probably because the stress level on the stress-strain curves is very low even at large preset strains. The less entangled melts do not show strong damping, although they show a stress peak whose value amounts to the critical stress of the moderately and highly entangled PIB samples. It is suggested that little slipping occurs for the melts of the less entangled PIB due to the existence of the fast stress relaxation processes.