HOMOGENIZATION METHOD FOR 2-D NANO-STRUCTURE REINFORCED POLYMER MATRIX
Paper in proceedings, 2018
Graphene flakes are used as additives in polymer matrices to improve the material properties. Critical aspects of obtaining graphene enhanced functional properties in polymer nanocomposites include the composition and morphological optimization. The concentrations of flakes must be optimized to create components’ material properties which achieve the target design and cost. Via processing, the microstructure can be tailored to attain the desired material properties by de-agglomerating the particles, improving dispersion and, ensuring the desired orientation of the nano-structures in the matrix. A predictive model is needed to understand the increased stiffness of the reinforced matrix of these composite materials. Using a 2D image and FE representation of micrographs of polyethylene (PE) embedded with (2-D) graphite nanoplatelets obtained via melt extrusion, the mechanical properties are assessed based on computational homogenization. A representative volume element (RVE) of the nano-structure reinforced polymer matrix is established, where the PE bulk and 2-D flakes are modeled based on their elastic properties. The 2-D flakes are considered as internal interfaces that store energy for membrane actions. From the homogenization analysis, macroscopic stiffness properties are simulated and compared to the experimental of Gaska et al.  with respect to increasing volume concentrations, orientation and distribution of the graphene. References:  Gaska et al., (2017) Gas Barrier, Thermal, Mechanical and Rheological Properties of Highly Aligned Graphene-LDPE Nanocomposites, Polymers 9, 294.