Fabrication and characterization of mechanical properties of stacked hybrid composites reinforced with natural fibers and groundnut shell powder as biochar

The growing trend of adopting natural composites for lightweight engineering applications has necessitated exploring the effect of stacking sequence on the mechanical and morphological properties of natural-based composite materials. The primary aim of this study is to explore the mechanical and morphological behavior of hybrid natural composite comprising of jute (J) and banana (B) fibers mixed with groundnut shell biochar as reinforcement in an epoxy resin matrix. Four different samples of containing jute and banana fiber in four different laminate stacking sequences, i.e., S1: J2-B1-J2, S2: J1-B1-J1-B1-J1, S3: B1-J1-B1-J1-B1, and S4: B2-J1-B2, were prepared using the hand lay-up method with the biochar content varying from 12% to 21%. The study reveals that the stacking sequence significantly affects the mechanical and morphological properties of natural composites. A maximum compressive strength of 22.37 MPa was achieved for sample S4. The tensile test shows that sample S2 has a maximum tensile strength of 32.58 MPa. Sample S1 possesses the highest flexural strength of 38.52 MPa. Sample S2 had the highest Rockwell Hardness of 67. Experimental observations indicate that composites with jute in the outermost layer exhibit better mechanical properties, including tensile, flexural, and hardness. However, banana fiber at the outermost layer yields better compressive strength. SEM characterization indicates that composite having banana fiber at outermost layer shows serious damage in terms of matrix cracks, delamination, and fibers pull out whereas composite samples with jute at the outermost part exhibits better interfacial bonding leading to effective load transfer efficiency. The FTIR analysis reveals that the mixing of biochar in all the fabricated composite yields better intermolecular interactions without altering the basic chemical structure of the natural fibers.