A Study on the Strength of the Weld Region of an Injection Molded Article of Poly (oxy-2, 6-dimethyl-1, 4-phenylene) and Polyamide Alloy

Abstract

The strength and the microstructure of the weld region of injection molded test pieces of a polymer alloy of PPE (poly(oxy-2, 6-dimethyl-1, 4-phenylene)) and polyamide were studied. A distinctive weld line was observed at the weld region of an injection molded test piece. The strength of the weld region strongly depended on the width of the weld line. The effects of the molecular weights of the polymers, the types of the elastomer, the conditions of the reactive processing and the composition of PPE and PA on the weld strength were also examined. A microscopic observation of the weld region as well as the strength of the molded test pieces suggested that the dispersed phase, which is composed of PPE and the elastomer dispersed within the PPE phase, was strongly stretched near the weld region while it was molded, and subsequently moved apart from the weld region partially being displaced by polyamide during the cooling procedure.