Study on Adhesive Property of Insert Injection Molded Glass Fiber Reinforced Polypropylene Composites

This study focused on insert injection molding process, which is molded the melted polymer around an inserted part placed in the molded cavity of injection molding. The interfacial adhesive property between the inserted part and an injected polymer was investigated. The glass fiber reinforced polypropylene (GF/PP) with various adhesive lengths of 0, 5, 10 and 15 mm was prepared as the inserted part. Polypropylene was injected to the mold. The effects of the inserted parts surface roughness, pre-heated the inserted parts and the barrel temperature on the adhesive property of GF/PP-PP injection molded were studied. It was found that interfacial adhesive property of GF/PP-PP insert injection molded increased according with increasing of surface roughness, pre-heated the insert part and increasing the barrel temperature. In addition, the effect of vent barrel on the adhesive property was evaluated. It was found that the adhesive property of GFPP-PP insert injection molded was unchanged by using the vent barrel system. The fracture mode of the insert injection molded specimens was depended on the adhesive length of the inserted part. The interfacial strength of the GF/PP-PP insert injection molded would be considering on the length at L=0 mm, which was attributed to the adhesive normal strength of the specimens.