Rheological Study of Vegetable Oil Based Hyperbranched Polyurethane/Multi-Walled Carbon Nanotube Nanocomposites

Abstract

Hyperbranched polyurethanes [HBPUs] and vegetable oil based polymer nanocomposites have been drawing an imperative attention for their plentiful advantages across a spectrum of potential applications. This study divulges the rheological behaviors of Mesua ferrea L. seed oil modified HBPU/multiwall carbon nanotube [MWCNT] nanocomposites prepared by in-situ technique. Rheological phase transition behavior was studied at 120°C in the steady shear and oscillation mode. The nanocomposites showed shear thinning behavior in both the modes. The rheological characteristics were dependent on the loading of the nanotube as confirmed from this study. The storage and loss moduli values were higher than the pure HBPU and they showed improved viscosity by nanocomposite formation. The nanocomposites revealed a pseudo–solid-like behavior at relatively low frequencies. The effects of temperature on storage and loss modulus have also been explored. The temperature dependence complex viscosity further described the ease of processibility. It has been tried to establish a structural property relationship of the systems from rheological study.

Keywords:

• Hyperbranched polyurethane
• MWCNT nanocomposite
• Rheology
• Shear thinning behavior

ACKNOWLEDGMENTS

The authors express their thanks to the financial assistance of DST, India through the Grant No. SR/S3/ME/13/2005-SERC-Engg, dated 9th April, 2007.