Effect of NaOH treatment on mechanical strength of banana/epoxy laminates

The present study is focused on studying the effect of alkali treatment on the mechanical properties of banana fiber-reinforced epoxy composites. Four batches of samples were prepared with respect to the percentage of sodium hydroxide (NaOH) in the treatment solution (0%, 2.5%, 4.5%, and 6.5%). Later mechanical tests such as tensile, compressive, and interlaminar shear tests were conducted on the prepared composite specimens to determine the influence of alkali treatment on the mechanical characteristics. The test results indicate an overall improvement in all the mechanical properties due to the fiber treatment. Moreover, the samples made from the fiber treated with 4.5% of NaOH solution indicated the highest tensile strength and compressive strength, with an overall increment of 24.2% and 34.8% in tensile and compressive strengths, respectively, when compared with the untreated sample. A linear increment in interlaminar strength is observed with a maximum value of 25.4 N/mm2 for the sample made from the fiber treated with 6.5% of NaOH solution. This increase is due to the fiber flattening process which increases the bonding surface at the interface.