Authors: C.R. Locker, J. Bergstrom, X. Liu, A.H. Tsou, V.B. Buchholz, A.K. Mehta
Affilation: ExxonMobil Research and Engineering, United States
Pages: 606 - 609
Keywords: micromechanical model, nanocomposite
Nanofiber-reinforced polymer-based compounds have the potential to be the next generation light-weight structural plastic materials. In this work, micromechanical models of polymer-nanofiber and polymer-rubber-nanofiber systems have been developed to compute the thermal, mechanical, and thermo-mechanical properties of these composites using a commercial non-linear finite element code. A stochastic method to generate 3D representative volume elements (RVEs) has been developed to produce unit cells that are representative of real polymer-nanofiber composites. Linear fibers were planarly placed inside the RVE according to a prescribed statistical distribution (random, uniform or Gaussian) without overlap allowing fiber loadings that exceed the theoretical upper limit derived from a 2D random planar fiber orientation. Tensile modulus, heat distortion temperature, and thermal expansion coefficients were computed as a function of nanofiber concentration and compared to experimental results and the Cox-Krenchel model for discontinuous fiber composites. Simulation results agree well with experimental findings, validating the simulation protocol. An extension of the stochastic RVE algorithm will also be discussed. The extension has been developed to model polymer nanofiber compounds containing elastomers, where the elastomer dispersion diameters are significantly greater than the diameters of nanofibers studied.