Development of CNT Modified GFRP Composite and Assessment of Its Elevated Temperature Mechanical Performance

Abstract

Matrix modification in fiber reinforced polymer (FRP) composite by a scientifically structured nano-filler is a current trend of research which has been globally acknowledged to enhance the transverse mechanical performance of the FRP composites. In the present investigation, modification of epoxy resin has been done by multi-walled carbon nanotube (MWCNT) by a sequential process comprising of stirring, sonication followed by vacuum degassing (VD). The potential improvement due to MWCNT modification in the polymer matrix lies in the efficient dispersion of MWCNT in the epoxy matrix with introduction of least possible defects in the final material. Hence, initially emphasis has been focused on the effect of varying the VD time (4, 12, 18 and 50 hours) of MWCNT/epoxy mixture. After optimising the VD time, effect of MWCNT content (0.1 and 0.3 wt. %) in the epoxy resin on flexural properties of MWCNT embedded glass/epoxy-composite (MWCNT-GE) with respect to the control glass/epoxy (GE) composites were evaluated. The flexural test results revealed that maximum strength in the MWCNT (0.1%)-GE composite was obtained with a vacuum degassing time of 18 hours, which was about 27% higher than the control GE sample. In the next phase of the work, emphasis has been focused on elevated temperature durability of MWCNT/GE, functionalized CNT modified FRP composite and control GE composite. In-situ 3-point bend tests were carried out for control GE, 0.1wt% pristine CNT embedded GE (CNT/GE) and 0.1wt% COOH functionalized CNT embedded GE (FCNT/GE) at room temperature (25°C), 70°C, 90°C and 110°C. It has been observed that addition of 0.1% CNT in polymer matrix enhances the flexural strength and flexural modulus by 22.22% and by 7.24% respectively than control GE composite at room temperature whereas addition of 0.1% FCNT enhances flexural strength and flexural modulus by 40.21% and 15.05% respectively than control GE composite. Post failure fractured surface was analysed by SEM to study different fracture mechanism.