Injection molding of PPO/PA blends

The effect of injection molding conditions on the morphology of poly (phenylene oxide) (PPO) and polyamide blends was investigated. We found the four distinct regions across the thickness of molded part: skin layer, transient region, subskin layer and core region. The skill layer and/or the transient region is formed by the elongational fountain flow of the polymer flow front and the subskin layer is generated by high shear flow on top of the frozen skin/transient layer. We also noted that the elongation of dispersed PPO phase in the subskin layer and the subskin layer thickness are influenced by the injection conditions such as speed and temperature. The dispersed phase in core region is, however, not deformed by various injection conditions.