Elevated Temperature Performance of Hybrid Polymer Composites

Abstract

FRP composites are the most promising and reliable materials in today’s world. Their outstanding properties make them unique and distinct. Apart from many advantages, during application, they start degrading when exposed to harsh environmental condition like elevated temperature. Hybridising a composite using two different reinforcements has proved to be a method for improving their performance in such conditions. Present study aims at evaluating the mechanical performance of GFRP and Glass/Carbon/epoxy (G/C hybrid) composites at ambient and in-situ elevated conditions. When tested for in-situ at +70 oC and +100 oC, significant reduction in inter-laminar shear strength (ILSS) was observed for both the composites as compared to that at room temperature. The ILSS of G/C hybrid was found out to be 28.2 % more than that of GFRP at room temperature, which became nearly equal for both the composite systems when tested at +100 oC and thus the fiber hybridisation effect was completely diminished. On the other hand, incorporation of carbon nanotubes (CNTs) in epoxy resin has also caused drastic improvement in strength over conventional GFRP. In the present study, epoxy of GFRP composite was modified with 0.1 wt. %, 0.3 wt. % and 0.5 wt. % of CNT and laminates were fabricated. Testing was done for these composites at room temperature, 70 oC, 90 oC and 110 oC. Composite with 0.1 wt. % CNT showed the maximum increment in strength by 32.74 % over GFRP at room temperature. Decrease in flexural properties was noted at elevated temperatures for all the composites. Composite with 0.3 wt. % CNT showed the maximum strength at 70 oC and 90 oC among all the fabricated composites. It was found that testing near glass transition temperature caused high reduction in properties and also confirms the ineffectiveness of hybridisation at such temperature.