Experimental evaluation and numerical comparisons of pine tree leaves, graphene oxide loaded, and E-glass fiber reinforced sandwich composites

The research aim is to develop pure epoxy composites (PEC), PTL-reinforced epoxy composites (PTLEC), PTL-loaded and E-glass fiber- incorporated epoxy composites (PTLEIEC), and PTL- and E-glass fabric and graphene oxide-incorporated epoxy composites (PTLEIEGO) were fabricated through an open molding hand layup technique, and structural, mechanical, and thermal stability were carried out and results were compared. Functional groups such as OH, -C-H, C=O, C=C, and C-OH, were found in PTL. Similarly, the OH, C-H, Si-O-Si, C=O, and C-H present in the PTLEIEGO composites were found through Fourier transform infrared spectroscopy (FTIR). The crystal plane orientations (110) and (220) in the PTLEIEGO composites were found through XRD. The surface morphology and elemental compositions of PTLEIEGO composites were found through field emissions electron microscopy (FESEM) and found the presence of different organic and inorganic elemental compositions such as C, O, Si, Ca, Zn, K, and Br as 77.85, 20.78, 0.33, 0.45, 0.05, 0.05, and 0.50 wt.% through energy dispersive X-ray (EDX) spectroscopy. The DSC and TGA were carried out and found the thermal stability of the composites and the onset melting temperature was found to 353.1˚ C. The maximum tensile strength of PTL, PEC, PTLEC, PTLEIEC, and PTLEIEGO composites was found to be 1.25 MPa, 25 ± 0.5 MPa, 55 ± 0.5 MPa, 93 ± 0.5 MPa, and 120 ± 0.5 MPa as per ASTM D 638. The tensile strength was improved from 1.25 MPa for PTL to 120 ± 0.5 MPa for PTLEIEGO. The FEM results revealed a minimum error of 0 % and a maximum error of 21.38 % compared to the experimental results. The maximum shore D hardness of PEC, PTLEC, PTLEIEC, and PTLEIEGO composites was found to be 55 ± 0.5 SHN, 59 ± 0.5 SHN, 76.1 ± 0.5 SHN, and 81.4 ± 0.5 SHN, respectively, as per ASTM D2240. The flexural strengths of PEC, PTLEC, PTLEIEC, and PTLEIGO composites were found to be 37 ± 0.5 MPa, 43 ± 0.5 MPa, 94 ± 0.5 MPa, and 131 ± 0.5 MPa, respectively, as per ASTM D 790. The new composites would be employed in low-strength structural applications such as panels, cabins, doors, and laptop stands.