Polymer Engineering and Science, Vol.39, No.11, 2159-2171, 1999
Bonding strength at solid-melt interface for polystyrene in a sequential two-staged injection molding process
The effects of processing parameters, such as melt temperature, mold temperature and cooling time, on the bonding strength of the interface in a sequential two-staged injection molding process were investigated both theoretically and experimentally. A theoretical bonding strength model, which accounts for the cooling profile through the thickness of the part and the interpenetration depth of polymer chains across the interface, was proposed. Under various mold and melt temperatures, experiments of sequential two-staged injection molding processes for polystyrene (PS) were also conducted to verify the validity of the model. Finally, an interrelationship between the average extent of reaching an effective interpenetration depth and the degree of bonding has been constructed. The model proposed in this research would be useful in the CAE analysis for a two-staged injection molding process in which distortions or even fractures might occur at the interface.