Weld Line Morphology in Injection-Molded General Purpose and High Impact Polystyrene

Abstract

The occurrence of weld lines throughout the field of polymer processing has been recognized as one of that discipline's unsolved problems [1]. A recent review has been made of this phenomenon which occurs wherever molten polymer flow fronts meet [2]. The mechanical properties of weld regions have been determined to be very sensitive to processing conditions in both amorphous and semicrystalline injection-molded thermoplastics [3–8].