Abstract
In this paper presents the flexural properties of composites made from natural fibers (Coir fibers) as reinforcing phase in polyester matrix. The chemical treated of fibers with KOH solution at different concentrations (1, 5, 10 % KOH) with different times (0.25, 1, 18, 72, 168, 240 Hours) are used. Flexural strength reached the maximum values of (2.81 MPa) at immersed time (18 Hours) with (10 % KOH) concentration, whereas the composites containing fibers treated with (10 % KOH) decreased to (0.312 MPa) at immersed time (240 Hours). This was attributed to degradation of coir fiber when using high concentrations of alkali.
