Percolation Effects

Polymer Nanocomposites: Percolation Effects

Based on a variety of experimental data, we hypothesize that well dispersed nanotubes within a polymer matrix induce a significant interphase zone of altered polymer mobility surrounding each nanoparticle, which leads to a percolating network inside of the composite. Fully understanding the percolation effects is important not only to accurately predict the overall material properties but also to provide guidelines for new material design. To investigate this concept, a finite element model (Figure 1) is developed to study the impact of interphase zones on the overall properties of composite. The loss moduli, shown in Figure 2, are clearly broadened or shifted corresponding to the increase of interphase volume fraction. This simulation result correlates well with experimental data showing broadening of loss peaks for unfunctionalized composites and a large shift of the loss modulus for functionalized nanotube polymer composites.

Percolation Effect
Figure 2

Researcher on the project:


Hua Deng

Publications:

T. Ramanathan, H. Liu and L. C. Brinson, Functionalized SWNT polymer nanocomposites for dramatic property improvement, Journal of Polymer Sciences Part B: Polymer Physics, Vol. 43, 000–000 (2005).

H. Liu, L.C. Brinson, A Hybrid Numerical-Analytical Method for Modeling the Viscoelastic Properties of the Polymeric Nanocomposites, Journal of Applied Mechanics, Vol. 73, 758 (2006).

R. Qiao, L.C. Brinson, A Numerical Study of Percolation Effects in the Polymeric Nanocomposites, Manuscript in preparation (2007)


Advanced Materials Laboratory, Department of Mechanical Engineering
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