Agglomeration effects of carbon nanotube on residual stresses in polymer nano composite using experimental and analytical method

Abstract

Since, mechanical properties of carbon nanotubes (CNTs) reinforced polymers and their composites are affected by poor dispersion of CNTs, the present study has been done to investigate the effect of CNT agglomerates on the residual stresses in a fiber reinforced Nano composite using experimental measurements and analytical method. CNTs are incorporated into an epoxy matrix with two weight fractions of 0.1% and 0.5% and are reinforced by unidirectional carbon fibers (CFs) to fabricate laminated composites with [02/902]s layup. The hole-drilling method is employed to measure the residual stresses in cross-ply CNT/CF/epoxy composite laminates. The CNT/epoxy sample is produced where the degree of agglomeration is changed from perfectly dispersed state up to fully agglomerated one. Based on the classical laminate theory, analytical solution is used to calculate the residual stress caused by thermal treatment. The residual stresses measured by incremental hole-drilling method are in good agreement with the theoretical residual stresses calculated by each layer of the laminates. The results show that dispersed samples perfectly are produced lower residual stresses compared to poor dispersed samples and this phenomenon is more significant in case of Nano composite with higher weight fractions of CNTs.