The solubility and kinetics of moisture transport mechanisms in type of resin and
fibers have been investigated the physical tests group comprised the determination of
diffusion coefficient (D) of (0.3 salt water), (0.5 NaOH), (0.5 KOH). The study has
been oriented to investigate a theme that has a crucial interest in most industrial
applications, also the effect of (Salt water, NaOH, KOH) on the composites. The
composite plate contains two type of fibers, the first type: polyester-woven fiber and
the second type: polyester–(random+woven) fibers. The result shows the solution
would be absorbed in the first type more than that in second type. Because of the
fiber/matrix interface plays the role of a channel for a solution to penetrate into the
composite; this penetration normally starts at cut edges. This type of channels found in
the composites, , while alkaline solutions has effect on the composites. Salt water and
NaOH, in composites are more than their identical in KOH, Since polyester has high
resistance to alkine as. The diffusivity coefficient of saltwater in UP s is larger than
that of NaOH and KOH