Optimize epoxy matrix with RSM/CCD method and influence of multi-wall carbon nanotube on mechanical properties of epoxy/polyurethane

In this research, the effect of three factors amounts of polyurethane, post-curing temperature and time on the mechanical properties of epoxy/polyurethane (EP/PU) composite have been studied. Response surface methodology (RSM) coupled with central composite design was used to optimize the mechanical properties of these composites. The optimization results also show that yield strength and Young's modulus at optimum value improved up to 23.3% and 10% compared to neat epoxy matrix. The chemical structure of the EP/PU composites were characterized by FT-Infrared (FT-IR), X-ray diffraction (XRD), scanning electron microscope (SEM), UV–vis diffuse reflection (DRS) and Thermogravimetric analysis (TGA), also the mechanical properties were obtained by Dynamic Mechanical Thermal Analysis (DMTA) and tensile test measurements. The FT-IR spectra indicate a very weak interaction between EP and PU. Also, the influence of multi-wall carbon nanotube (MWCNT) with different concentrations (0–0.25 wt.%) on mechanical and physical properties of EP/PU matrix was investigated. The interaction behavior of the MWCNT with EP/PU as a matrix was investigated using XRD, FT-IR and molecular dynamic (MD) simulations. Dispersion of MWCNT in the EP/PU composite was also observed using SEM. The yield strength of EP/PU/MWCNT nanocomposites increased about 59.7% with the addition of 0.15 wt.% MWCNT nanofiller.