Modeling of viscoelastic behavior of a shape memory polymer blend

Shape memory effect (SME) of polymers is a property that concerns both, macroscopic and microscopic changes. The variation of internal polymer properties such, as molecular weight (M-w), rigidity, and viscoelasticity could alter its SME. In this study, a bi-parabolic model with six parameters is used to describe the viscoelastic behavior of a shape memory polymer (SMP) blend (40% poly(caprolactone), PCL/60% Styrene-Butadiene-Styrene) with different PCL M-w. These parameters are determined using the Cole-Cole method. Modeling curves (E '' = f (E ')) will be then compared to experimental data from dynamical mechanical analysis (DMA) tests. It is shown that the bi-parabolic model predicts well the behavior of the SMP mixture for different M-w of PCL. Afterwards, the evolution of the model parameters with the M-w of PCL is investigated. It is revealed that, when M-w of PCL drops, the relaxation modulus E-0 increases. This result proves that the rigidity of the SMP blend rises with M-w declines.

Automated summary

The study successfully described the viscoelastic behavior of shape memory polymer blends using a bi-parabolic model, showing that the model accurately predicts the behavior of SMP mixtures with different PCL M-w, and the rigidity of the blends increases with the decline of PCL M-w.