Tailored Crystalline Structure and Mechanical Properties of Isotactic Polypropylene/High Molecular Weight Polyethylene Blend

In this work, isotactic polypropylene and high density polyethylene blends with tailored crystalline structures were prepared through an accessible injection-molding method. Two hierarchic structures, i.e., shish-kebab structures and epitaxy structures, were both successfully obtained among the whole range of samples, which were carefully characterized through polarized light microscopy, scanning electron microscopy, differential scanning calorimetry and small-angle X-ray scattering. It was found that the special epitaxy crystalline structure showed better mechanical properties than the shish-kebab one. The inclined polyethylene lamellae among the oriented polypropylene matrix not only enhances the interfacial adhesion but also facilitates the transmission of external force within matrix. Consequently, the tensile strength of the sample with epitaxy structures is around 46.58 MPa and its impact strength reaches up to 63.33 kJ/m(2). These results provide a new method to industrially manufacture samples with tailored crystalline structures, making it possible for preparing general polymer materials with advanced properties.