Enhancing the Mechanical Performance of Recycled Polyolefins Through Stainless Steel Mesh Reinforcement Processed by Injection Molding

ABSTRACT Mechanical degradation during recycling limits recycled plastics in structural applications, perpetuating reliance on virgin polymer. This study introduces PolyMesh, a manufacturable reinforcement concept in which SS304 stainless steel woven wire mesh is embedded within recycled high‐density polyethylene (rHDPE) and recycled polypropylene (rPP) via insert injection molding. The influence of mesh density on tensile (ASTM D3039/D3039M; using 4 × 4, 5 × 5, 20 × 20, and 30 × 30 mesh counts) and flexural (ASTM D790; introducing an intermediate 8 × 8 density) mechanical performance was systematically investigated. Mesh reinforcement produced modest tensile stiffness improvements (maximum Young's modulus increase: +12.4% for rHDPE with 30 × 30 mesh; +3.7% for rPP with 20 × 20 mesh). In contrast, flexural testing revealed substantially stronger reinforcement effects: rHDPE achieved up to 13.46% improvement in flexural modulus (8 × 8 mesh) and 13.77% in flexural strength (4 × 4 mesh), while rPP exhibited a flexural modulus gain of 61.40% (8 × 8 mesh) and flexural strength improvements of up to 15.06%. The divergent tensile–flexural response indicates PolyMesh acts primarily through geometric bending stiffness enhancement rather than interfacial load transfer, consistent with the elastic modulus mismatch between SS304 and the polymer matrix. These findings establish PolyMesh as a viable, scalable strategy for upgrading recycled polyolefins in flexure‐dominated, non‐critical structural applications.