Effective Young's modulus of carbon nanotube/epoxy composites

A formulation based on shear-lag model and global force equilibrium is proposed to identify the effective Young's modulus of single and multi-walled carbon nanotube (CNT)/epoxy composites. The effective Young's modulus from the model is validated by available experimental results and good agreements are identified. The results show that an increase in CNT length, CNT layer number, interspace shear modulus between adjacent CNT layers and CNT volume percentage leads to an increase in the effective Young's modulus. It is found that the effective Young's modulus of a ten-walled CNT/epoxy composite is as high as 152 GPa with the CNT half-length of and CNT volume percentage being 8200 nm and 14.5%, respectively. It also reveals that although a single-walled carbon nanotube (SWCNT) composites have a superior load transfer, the SWCNTs demonstrate a weaker reinforcing capability than its counterparts, multi-walled CNTs.