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Viscoelastic melt rheology and time-temperature superposition of polycarbonate – multi-walled carbon nanotube nanocomposites

Choong, Gabriel Y.H.; De Focatiis, Davide S.A.; Hassell, David G.

Authors

Gabriel Y.H. Choong Gabriel.Choong@nottingham.ac.uk

Davide S.A. De Focatiis davide.defocatiis@nottingham.ac.uk

David G. Hassell

Abstract

This work investigates the linear and non-linear viscoelastic melt rheology of four grades of polycarbonate melt-compounded with 3 wt% Nanocyl NC7000 multi-walled carbon nanotubes and of the matching matrix polymers. Amplitude sweeps reveal an earlier onset of non-linearity and a strain overshoot in the nanocomposites. Mastercurves are constructed from isothermal frequency sweeps using vertical and horizontal shifting. Although all nanocomposites exhibit a second plateau at ~105 Pa, the relaxation times estimated from the peak in loss tangent are not statistically different from those of pure melts estimated from cross-over frequencies: all relaxation times scale with molar mass in the same way, evidence that relaxation of the polymer network is the dominant mechanism in both filled and unfilled materials. Non-linear rheology is also measured in large amplitude oscillatory shear. A comparison of the responses from frequency and amplitude sweep experiments reveals the importance of strain and temperature history on the response of such nanocomposites.

Journal Article Type Article
Journal Rheologica Acta
Print ISSN 0035-4511
Electronic ISSN 0035-4511
Publisher Humana Press
Peer Reviewed Peer Reviewed
Volume 52
Issue 8
DOI https://doi.org/10.1007/s00397-013-0706-6
Keywords Polycarbonate, Multi-walled carbon nanotubes, Melt rheology, Linear viscoelasticity, Non-linear viscoelasticity, Time–temperature superposition
Publisher URL http://link.springer.com/article/10.1007%2Fs00397-013-0706-6
Copyright Statement Copyright information regarding this work can be found at the following address: http://creativecommons.org/licenses/by/4.0

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