Large-scale formation of shish-kebab in water-assisted injection-moulded high-density polyethylene with a high-molecular weight

摘要

To promote flow-induced orientation and reserve the formation of the shish-kebab structure, a modified injection-moulding technology named water-assisted injection moulding (WAIM), was applied to provide twice the shear flow and a rapid cooling rate on high-molecular weight high-density polyethylene (HDPE) melt in a mould cavity. Large-scale distribution of highly oriented shish-kebab was successfully achieved in a WAIM sample with a high-molecular weight. More importantly, the high-orientation degree of lamellae (larger than 0.4) in the thickness direction for a high-molecular weight WAIM sample is 60%, which is much more than a conventional injection-moulded sample (15%). This work provides a new insight to achieve injection-moulded products with enhanced oriented structures.