Abstract:
In this study, the relationship between skin structure and shear strength distribution of thin-wall
injection molded polypropylene (PP) molded at different molecular weight and molecular distribution
was investigated. Skin-core structure, cross-sectional morphology, crystallinity, crystal
orientation, crystal morphology and molecular orientation were evaluated by using polarized
optical microscope, differential scanning calorimeter, X-ray spectroscopic analyzer and laser Raman
spectroscopy, respectively, while the shear strength distribution was investigated using a
micro cutting method called SAICAS (Surface And Interfacial Cutting Analysis System). The results
indicated that the difference of molecular weight and molecular weight distribution showed own
skin layer thickness. Especially, high molecular weight sample showed thicker layer of the lamellar
orientation and molecular orientation than low molecular weight sample. In addition, wide
molecular distribution sample showed large crystal orientation layer.
