Correlation of Morphology and Rheological Response of TPUPCL diol /PCL Blends

Morphology and rheology of thermoplastic Polyurethane based on Polycaprolactone diol (TPU-PCL- diol) and Poly(ε-caprolactone) (PCL) blends examined and theoretically analyzed using Coran model. PCL was melt blended in a mixer with TPU-PCL diol with different ratio of two polymers. The viscoelastic dynamic moduli of the blends in the molten state have been measured in a two parallel plate rheometer as a function of frequency. Coran model pridicts the viscoelastic dynamic moduli of TPU-PCL diol / PCL blends, but the model shows some discrepancies from the experimental data in the low frequency region. Coran model predicts moduli of hetrogeneous polymer based on phenomenological adjustment between parallel and series models, which relate to upper and lower bound moduli of polymer mixtures. This model produced the parameter of f for each blend that correlates to phase morphology and here gives a measure for the continuity of the TPU matrix. This value shows decrease with increase of PCL content in the blends. Morphological observations were in good agreement with the results of Coran model.

Keywords:

Rheology , Modeling , Morphology