Fabrication of thermoplastic polymer-fiber-reinforced polymer composites through automated powder dispersion and compression molding

This work explores a novel method for fabricating lightweight thermoplastic polymer-fiber-reinforced polymer (PFRP) composites, often referred to as self-reinforced composites (SRCs), using automated powder dispersion followed by compression molding. A representative PFRP was fabricated using plain-weave ultra-high-molecular-weight polyethylene (UHMWPE) fabrics embedded in a high-density polyethylene (HDPE) powder matrix. In the dispersion process, various parameters including sweeping speed, vibration voltage, sieve mesh size, and dispersion paths were studied for their effects on powder distribution, powder amount, and processing speed, aiming to achieve better control over fiber volume fraction ( <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:mrow> <mml:msub> <mml:mi>V</mml:mi> <mml:mi>f</mml:mi> </mml:msub> </mml:mrow> </mml:math> ) and improve mechanical properties of PFRP composites. In addition, the tensile behavior of the PFRPs with a fiber volume fraction of 30% fabricated using the proposed method with different dispersion paths was investigated, and the highest average elastic modulus, tensile strength, and failure strain reached 7.2 GPa, 375 MPa, and 5.8%, respectively. Moreover, their specific tensile properties (normalized by composite density) are comparable to those of glass- or aramid-fiber-reinforced polymer composites. This work was motivated by the search for a diverse automated manufacturing method to fabricate lightweight thermoplastic PFRPs with enhanced mechanical properties.