Effect of calcium nitrate application on the structural behavour of okra (cv.Kirikou) fibre reinforced epoxy composite

Abstract

This experimental research was carried out to determine the effect of pre-harvest fibre treatment, on the structural behaviour of the epoxy composite. The okra (cv Kirikou) plants, from where the fibre, used for the production of the composite was obtained, was pre-harvest treated with calcium nitrate Ca(NO₃)₂. Five treatments, which were (0 mg/l, 100 mg/l, 200 mg/l, 300 mg/l and 400 mg /l) Ca(NO₃)₂, were used in this research. The 0 mg/l Ca(NO₃)₂ was taken as the control experiment. The Okra stem were cut at 60 days after planting, and fibre extracted through retting method. The epoxy composite samples were produced by partial replacement of the matrix with 20% (by weight), of the processed okra fibre. The composites production and testing were conducted according to the ASTM International recommended procedures. Results obtained from the laboratory tests showed that pre-harvest treatment had significant (p ≤0.05) effect on the mechanical behaviour (tensile strength and flexural strength) of the composite samples. Tensile strength of the composite increased linearly, with increment in the treatment concentration. The untreated okra fibre reinforced epoxy composite recorded tensile strength of 34.73 MPa, while the okra fibre treated with 400 mg/l Ca(NO₃)₂ had a tensile strength of 57.87 MPa. Likewise, the untreated okra fibre reinforced epoxy composite had the lowest flexural strength (126 MPa), when compared the flexural strength of composite samples reinforced with treated okra fibre. These results showed the relevance of pre-harvest fibre treatment, on the mechanical properties of composites. This research will be useful in composite production and utilization, and had opened a new front in plant fibre production and management.