The aim of the present research work is to enhance the thermal and dynamic mechanical properties of Kevlar/Cocos nucifera sheath (CS)/epoxy composites with graphene nano platelets (GNP). Laminates were fabricated through the hand lay-up method followed by hot pressing. GNP at different wt.% (0.25, 0.5, and 0.75) were incorporated with epoxy resin through ultra-sonication. Kevlar/CS composites with different weight ratios (100/0, 75/25, 50/50, 25/75, 0/100) were fabricated while maintaining a fiber/matrix weight ratio at 45/55. Thermal degradation and viscoelastic properties were evaluated using thermogravimetric analysys (TGA), differential scanning calorimetric (DSC) analysis, and a dynamic mechanical analyser (DMA). The obtained results revealed that Kevlar/CS (25/75) hybrid composites at 0.75 wt.% of GNP exhibited similar thermal stability compared to Kevlar/epoxy (100/0) composites at 0 wt.% of GNP. It has been corroborated with DSC observation that GNP act as a thermal barrier. However, DMA results showed that the Kevlar/CS (50/50) hybrid composites at 0.75 wt.% of GNP exhibited almost equal viscoelastic properties compared to Kevlar/epoxy (100/0) composites at 0 wt.% GNP due to effective crosslinking, which improves the stress transfer rate. Hence, this research proved that Kevlar can be efficiently (50%) replaced with CS at an optimal GNP loading for structural applications.
Delamination factor in drilling represents the maximum spread of imperfections around the drilled hole in a polymer composite. Df can directly affect the performance of the drilled component. This study focuses on investigating the influence of nanofillers, titanium dioxide and graphene, with epoxy in varying quantities ranging from 1 to 4 wt%, on the delamination behavior of the glass fiber-reinforced composites. The parameters, such as spindle speeds (600, 1200, and 1800 rpm), feed rates (30, 40, and 50 mm/min), and drill bit diameter (4, 6, and 8 mm), were considered. A high-resolution camera was used to capture the images of the drilled hole, which were processed using MATLAB to compute the delamination factor at top and rear faces of the composite. Additionally, thrust force obtained from the dynamometer at various nanofiller quantities was analyzed. The thrust force decreased with an increase in the spindle speed and the feed rate. Spindle speed and feed rate contributed the least to delamination, while filler percentage contributed the least to thrust. The mean GRG showed that GT1, a drill bit diameter of 4 mm, a spindle speed of 1800 rpm and a feed rate of 50 mm/min were the optimum parameters.