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Extensional Rheological Investigation of Biodegradable Polylactide‐Nanographite Platelet Composites via Constitutive Equation Modeling
Author(s) -
Narimissa Esmaeil,
Gupta Rahul K.,
Kao Nhol,
Nguyen Duc A.,
Bhattacharya Sati N.
Publication year - 2014
Publication title -
macromolecular materials and engineering
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.913
H-Index - 96
eISSN - 1439-2054
pISSN - 1438-7492
DOI - 10.1002/mame.201300382
Subject(s) - materials science , rheology , viscoelasticity , composite material , extensional viscosity , constitutive equation , strain hardening exponent , extensional definition , shear (geology) , hardening (computing) , rheometry , shear viscosity , thermodynamics , physics , paleontology , tectonics , finite element method , biology , layer (electronics)
The focus of this research is on linear and nonlinear melt rheological investigations of polylactide (PLA) and nanographite platelet (NGP) based bionanocomposites. The linear steady and dynamic shear viscoelastic behaviors of the samples is analyzed to study the effects of NGP filler contents on the rheological properties of the composites at terminal and zero‐shear viscosity regions whilst the nonlinear shear behaviors are investigated to predict and validate the extensional rheological properties of neat PLA and PLA/NGP composites. Uniaxial extensional measurements are performed to probe the impacts of nanofiller contents along with extensional strain rates on linear viscoelastic envelope (LVE) and nonlinear elongational strain hardening behaviors of the samples. The modeling of strain‐hardening behavior of neat PLA and its composites is accomplished by means of analyzing their dynamic moduli, steady shear viscosity, relaxation spectrum and damping function based on Papanastasiou–Scriven–Macosko–Luo–Tanner (PSMLT) form of Kaye–Bernstein–Kearsley–Zapas (K‐BKZ) constitutive equation.