Properties of Insert Injection Molded Polypropylene Single-Polymer Composites With Uniaxial Fibers

This paper introduces the production of polypropylene (PP) single-polymer composites (SPCs) with uniaxial fibers by insert injection molding. PP fiber bundles are stuck on the cavity wall then the molten PP is injected into the cavity to prepare PP SPCs. The fiber mass fraction is about 1.9%, 2.4%, and 1.2% for the tensile, flexural, and impact PP SPC specimens, respectively. Differential scanning calorimetry (DSC) results shows that fibers could maintain their thermal properties after injection molding. The mechanical properties including tensile, flexural, and impact properties are all tested. The maximum of tensile strength, flexural strength, and impact strength of the PP SPCs could reach 31.0 MPa, 46.5 MPa, and 12.25 kJ m⁻², respectively. Especially, the impact properties of the PP SPCs improved obviously than that of nonreinforced PP. The effects of processing conditions are discussed by orthogonal analysis. The influences of different processing parameters on mechanical properties are discussed. Numerical simulation results are also applied in the analysis.