Effect of Curing Temperature on Nanomodified Fiber-Reinforced Polymer Composites

Abstract

Dispersion of pristine and functionalized-COOH carbon nanotubes (CNTs) into the resin matrix used to develop fiber-reinforced polymer (FRP) composites is known to improve FRP properties such as shear strength, UV resistance, strength, and stiffness. Nanomodification of the FRP matrix with CNTs is also known to improve bonds within the FRP. However, there is still a gap in knowledge on the effect of temperature on curing characteristics when CNTs are incorporated. In this study, mechanical testing and material characterization of nanomodified FRP composites was conducted to identify the effects of curing under room temperature (30 °C) and elevated temperature (110 °C). The resin for FRP composites was nanomodified with pristine and functionalized multi-walled carbon nanotubes using a standard dispersion protocol. FRP composites were fabricated using vacuum assisted hand layup techniques and prepared for ASTM standard testing. Static tensile testing and interfacial adhesion tests were conducted to evaluate the mechanical performance. Differential scanning calorimetry and thermogravimetric analysis were performed to determine curing characteristics to inform on the polymerization of nanomodified resins cured under the two temperature conditions. Scanning electron microscopy was performed to identify CNT dispersion characteristics. It was found that curing FRP composites with nanomodified resins at elevated temperatures increased the tensile and interfacial adhesion strength and stiffness and also reduced ductility. It can be understood from this study how target performance metrics in a wide range of structural applications can be achieved in FRP composites by incorporating nanomodified resins cured at varying temperatures.