In the immiscible blends of poly(phenylene sulfide) (PPS) and polyarylate (PAR), absorbed moisture partitioned into each phase according to the equilibrium value of the homopolymers. The water diffusivity was observed to decrease with increasing PPS concentration and at >45%, when PPS became the major component in the skin region, the diffusivity was equal to that of neat PPS. The molecular weight of the PAR fraction was found to degrade linearly with time due to hydrolysis.