Abstract: This study is aimed at to investigate the effect of surface
modification through NaOH (Sodium hydroxide) treatment and fiber length on the
tensile strength of coir fiber of reinforced epoxy composites. The coir fibers
was treated with 2, 4, 6, 8 and 10% concentration of NaOH separately for 10
days.The tensile strength of untreated and alkali treated fiber was measured.
For each group of the coir fiber experiments were conducted on different fiber
lengths, namely; 10, 20 and 30 mm. The experimental results showed that increasing
NaOH concentration leads to a decrease in fiber diameter in a linear fashion.
This reduction in diameter naturally ends up with reduced tensile strengths.
The treated coir fiber was used as a reinforcement and epoxy as a matrix to
fabricate the composites. The tensile strength of different samples of composites
was measured. Increased NaOH concentration in fibers treatment was found to
increase the tensile strength up to 4% and further increase in NaOH concentration
reduces the tensile strength and also increased fiber length was found to increase
in tensile strength. Maximum tensile strength of the composite was found to
be uniformly accruing for 4% NaOH treated samples. Based on the nonlinear regression
analysis the tensile strength equation was proposed for coir fiber reinforced