Effects of Reorientation of Graphene Platelets (GPLs) on Young’s Modulus of Polymer Composites under Bi-Axial Stretching

Abstract

Effects of bi-axial stretching induced reorientation of graphene platelets (GPLs) on the Young’s modulus of GPL/polymer composites is studied by Mori-Tanaka micromechanics model. The dispersion state of the GPLs in polymer matrix is captured by an orientation distribution function (ODF), in which two Euler angles are used to identify the orientation of the GPLs. Compared to uni-axial stretching, the increase of the stretching strain in the second direction enhances the re-alignment of GPL fillers in this direction while it deteriorates the re-alignment of the fillers in the other two directions. Comprehensive parametric study on the effects of the out-of-plane Young’s modulus, stretching strain, strain ratio, Poisson’s ratio and weight fraction and GPL dimension on the effective Young’s moduli of the composites in the three directions are conducted. It is found that the out-of-plane Young’s modulus has limited effects on the overall Young’s modulus of the composites. The second stretching enhances the Young’s modulus in this direction while it decreases the Young’s modulus in the other two directions. The results demonstrate the increase of Poisson’s ratio is favorable in increasing the Young’s modulus of the composites. GPLs with larger diameter-to-thickness ratio have better reinforcing effect on the Young’s modulus of GPL/polymer nanocomposites.

Effects of Graphene Nanoplatelet Size and Surface Area on the AC Electrical Conductivity and Dielectric Constant of Epoxy Nanocomposites

“…Applications range from adding graphene into polymer matrices to develop high performance multifunctional composites to super capacitors [ 6 ]. Studies have demonstrated that a small amount of graphene added into polymers can improve the overall mechanical and physical properties without reducing the beneficial attributes of the polymers [ 7 , 8 , 9 , 10 , 11 , 12 , 13 , 14 , 15 , 16 ]. For example, Rafiee et al [ 17 ] demonstrated that the Young’s modulus of epoxy nanocomposites can be increased by 31% by adding 0.1 wt % graphene nanoplatelet (GNP).…”

“…Compared to pure polymer, an increase of up to 121% in thermal conductivity was observed by Kim et al for GNP-reinforced polymer composites [ 18 ]. More work on evidencing the reinforcing effects of graphene on mechanical, thermal performance, and functionality of composite materials and structures can also be found in [ 12 , 13 , 14 , 15 , 16 , 19 , 20 , 21 , 22 , 23 , 24 , 25 , 26 , 27 , 28 , 29 , 30 , 31 , 32 , 33 , 34 , 35 ].…”

Electromechanical Behaviors of Graphene Reinforced Polymer Composites: A Review

“…The molecular dynamics (MDs) simulation developed by Sun et al [24][25][26] and Rahman et al [27][28][29][30] exhibited significant increases in the mechanical properties of GRPCs. The micromechanics modeling work [31][32][33][34] also indicated graphene fillers' prominent enhancement on the mechanical properties of GRPCs. More work on mechanical properties can be found in [35][36][37][38][39][40].…”

Nonlinear free vibration of graphene platelets (GPLs)/polymer dielectric beam

“…Considerable work, including theoretical and experimental work [4][5][6], has demonstrated Polymer composites enhanced by graphene possess both excellent mechanical properties and impressive electrical and dielectric properties. For example, extensive theoretical and experimental work has demonstrated the mechanical performances of these composites can be remarkably enhanced by adding graphene fillers with low concentration [15][16][17][18][19][20][21]. At the same time, graphene can also substantially improve the dielectric properties of these composites.…”