Structure and mechanical properties of fast cooled and annealed poly(phenylene sulfide)/Vectra A blends

Poly(phenylene sulfide) (PPS)/Vectra A blends were directly injection molded and obtained throughout the composition range both as molded, low crystallinity, and annealed highly crystalline materials. The blends were immiscible, but, contrary to an earlier work on PPS/Vectra A blends, they showed a clear fibrous morphology that was a consequence of the higher viscosity of the matrix compared with that of the Vectra A at the shear strain rate used. The mechanical properties of the annealed blends showed that when highly crystalline materials are sought, annealing post‐cold molding is a valid alternative to molding at high mold temperatures. The fracture properties of the as‐molded blends, such as ductility and tensile strength, were higher than in annealed blends, as a consequence of the higher deformability of the less crystalline structure. The presence of the LCP in the as‐molded low‐crystallinity PPS blends counteracts their intrinsic lower stiffness by means of a faster stiffness increase when Vectra A was added, compared with that which took place in annealed blends. These facts rendered the as‐molded PPS/Vectra A blends alternative materials to the usual highly crystalline ones.