Effect of interphase on elastic behavior of multiwalled carbon nanotube reinforced composite

In this work, elastic response of multiwalled carbon nanotube (MWCNT) reinforced composite is reported for different interphase property between matrix and multiwalled carbon nanotube. Continuum modeling is performed using three phase representative volume element (RVE), which incorporates, multiwalled carbon nanotube, interphase and matrix. Interphase is assumed as a layer developed around the multiwalled carbon nanotube embedded in a matrix, accommodating smoothly the differences in properties of two phases. Variation in interphase stiffness is taken in a range from soft interphase to stiff interphase in a form of Ei/Ematrix from 0.55 to 5.5 based on the available literature. Effect of interphase thickness, interphase stiffness, MWCNT length, matrix material and volume fraction of MWCNT on mechanical behavior of nanocomposite is estimated. Thick interphase (≈ CNT thickness = 0.34) with higher stiffness strongly influences the stiffness of composite. With the increase in volume fraction of multiwalled carbon nanotube in the matrix, a significant enhancement in composite stiffness is observed. MWCNT in a soft matrix have strong influence of interphase thickness in the mechanical reinforcement. The finite element results are compared with the modified rule of mixture results which incorporates the effect of interphase also. The results are found to be in close proximity with the modified rule of mixture results which validates the present model.