Linear and nonlinear viscoelasticity of self-associative hydrogen-bonded polymers

Abstract

We conducted a nonequilibrium dissipative particle dynamics simulation on the linear and nonlinear viscoelastic behaviors of polymer melt associated with hydrogen bonds. The effects of the number of hydrogen bonding groups and the strength of hydrogen bonding on viscoelasticity were examined. The simulation results show that the polymers with strongly associating hydrogen bonds exhibit supramolecular networks, and their motion displays some similarities to that of polymer melts following the Reptation model. The strain hardening is due to the strain-induced stretching of polymer chains in the supramolecular networks. The number and lifetime of hydrogen bonding have a combined impact on the dynamic and linear viscoelastic behaviors of self-associative polymers. The storage moduli increase linearly with increasing the numbers of hydrogen bonding groups as the lifetime of hydrogen bonds is comparable to or larger than the relaxation time of polymer chains. In contrast, hydrogen bonding has a less pronounced influence on the dynamics and viscoelasticity as the lifetime of hydrogen bonds is minimal. The results are closely aligned with the experimental findings and provide a deep insight into the viscoelasticity of self-associative polymers via hydrogen bonds.