Superb Glass Fiber‐Reinforced Polypropylene Composites With Low Warpage and Enhanced Mechanical Properties for Screw Extrusion Additive Manufacturing

ABSTRACT Polypropylene (PP), a semi‐crystalline thermoplastic, faces significant challenges in additive manufacturing due to pronounced warpage and inadequate mechanical properties. This study developed an innovative polypropylene random copolymer (PPR)‐based composite system by incorporating maleic anhydride‐grafted polyethylene‐octene (POE‐g‐MAH), calcium carbonate masterbatch (Ca), and glass fiber (GF) to achieve a composite with low warpage and superb mechanical strength for 3D printing. Furthermore, a screw extrusion pellet‐based additive manufacturing approach was implemented to enhance both processing efficiency and mechanical performance of printed components. The results demonstrated remarkable improvements in material properties: incorporation of 10 phr POE‐g‐MAH reduced the warpage deformation from 127.30% (neat PP) to 5.27%, simultaneously achieving an enhanced notched impact strength of 25.4 kJ/m 2 , a 408% improvement compared to neat PP. Optimal tensile strength was achieved at 50.8 MPa with 6 phr POE‐g‐MAH incorporation, approximately twice that of neat PP. Although the Z‐direction tensile strength of the composite reached 76% of the neat PP value, the developed composites demonstrated superior printability and stability for large‐scale additive manufacturing.