Weldline morphology of injection molded modified poly(phenylene-oxide)/polyamide-6 blends

The weldline morphology of modified-poly(phenylene-oxide)/polyamide-6 blend s has been investigated. A distinct contacting layer consisting of fine sph erical particles was observed from the V-notch at the surface to the center of the molded part for the low viscosity ratio blend. In contrast, such sm all particles were not found and a slight deformation was observed near the part's surface for the high viscosity ratio blend. The weldline morphology was found to be dominated by the deformation, the breakup, and the relaxat ion of the dispersed modified-poly(phenylene oxide) phase. The effect of in jection conditions on the weldline morphology has also been investigated. T he morphology of the meldline was quite complicated. Distorted multi-layere d structures were observed. It was found that those structures arise from t he subsequent flow after merging of the two flow fronts. Weldlines and meld lines have been studied separately, and their formation mechanisms were fou nd to be basically similar.