Effect of Multi-Walled Carbon Nanotubes Addition on Mechanical Properties of Polymer Composites Laminate

Carbon nanotubes (CNTs) have high potential for the modification of glass-fiber reinforced polymer (GFRP) composite laminates. This paper reports the fabrication of CNTs/GFRP composite laminates using ultrasonication and the hand lay-up method. The aim of this study is to investigate the interlaminar shear strength (ILSS) and flexural strength of composites consisting of several different proportions of CNTs. When CNT content is 0.75 percent hundred resin (phr), the mechanical properties are the best. The ILSS was significantly improved 15.7% and flexural strength improved 9.2%. The effects of addition of CNTs on the mechanical performances were evaluated with respect to retention of high-temperature properties up to 200 °C. It was found that ILSS, flexural strength and bending modulus were significantly enhanced by CNTs at different temperatures. Dynamic mechanical analysis (DMA) was employed to measure the storage modulus of composite laminates. To consider the effect of temperature on GFRP and CNTs/GFRP composite laminates, the results showed the trends in the temperature-dependence and were nearly identical to the ILSS, flexural strength, bending modulus and dynamic properties. The experimental fracture surfaces were also observed by scanning electron microscopy (SEM). Significant weakening of fiber-matrix interface and matrix softening were major factors affecting the strength and modulus reduction at high temperature.