In‐situ grafted POE for reduction of flow marks on injection molding of PP

Flow mark phenomenon is one of the typical and common surface defects that affect industrial desired surface and long‐life mechanical properties of the injection molding of polypropylene (PP). The effect of in‐situ grafted polyolefin elastomer (POE) on the flow marks on injection molding of PP was investigated by combining experimental methods with dissipative particle dynamics (DPD) simulations. It was found that 1,6‐hexanediol diacrylate‐grafted POE (POE‐g‐HD) facilitated the reduction of the flow marks under an optimized grafting condition, a screw speed of 250 rpm at 185°C. The DPD simulations indicated that the reduction of the flow marks via POE‐g‐HD was related to the emergence of POE‐g‐HD quasi‐clusters. In addition, increasing melt strength of PP resulted in a melt fracture phenomenon and an increase of the flow marks. The limiting grafting degree of POE led to a finite reduction of the flow marks.