Development of a Polyolefin Elastomer Modified Hybrid Inorganic Filler System for Enhanced Performance in HDPE Double-Wall Corrugated Pipe Production

This study presents the design and performance evaluation of an advanced inorganic filler system composed of calcite (CaCO₃) and talc (Mg₃Si₄O₁₀(OH)₂), modified with a polyolefin elastomer (POE), and integrated into a high-density polyethylene (HDPE) carrier resin with process additives such as erucamide, montan wax, pe wax, and PIB. The composite was developed to improve the structural integrity and longevity of HDPE double-wall corrugated pipes. Comprehensive characterization of the filler was performed using TGA–DSC, FTIR, SEM–EDX, XRD, and XRF analyses, confirming the presence of every individual component and homogeneous dispersion in the compound. Pilot-scale extrusion pipe trials confirmed uniform filler dispersion when evaluated by SEM-EDX analysis. The filler addition increased both the density and MFI values up to 1.03 g/cm³ and 1.5 g/10 min, respectively, while test results indicated oxidation induction times (OIT) reaching up to 40 min. The developed filler-added pipes demonstrated a significantly higher ring stiffness value of 12.20 kN/m², exceeding the minimum requirement of 8 kN/m² specified for the SN8 class pipes. The POE effectively attenuated rigidity and brittleness typically induced by mineral fillers, yielding this superior stiffness while maintaining adequate ring flexibility. These findings highlight the potential of this tailored filler system to advance the production of lightweight, mechanically robust corrugated piping solutions for demanding infrastructure applications.