Unveiling the dual role and regulatory mechanism of stearic acid in enhancing interface compatibility in high-filled coal gangue-polyethylene composites

Abstract

Stearic acid (SA) modification of coal gangue (CG) presents a promising avenue for producing high-filled, high-performance composites. This study aimed to elucidate the influence of SA on composite interfacial compatibility and its control mechanism. The composite, consisting of polyethylene (PE) and SA-modified CG (80 wt%), was fabricated via hot-pressing to establish the correlation between SA quantity and composite properties, uncovering SA's role in property enhancement and interface formation mechanism. Findings revealed the dual role of SA in composite compatibility. At lower SA concentrations (≤1.0 %), it facilitated enhanced interfacial compatibility. However, this effect plateaued and declined at higher SA concentrations (>1.0 %). This decline was attributed to SA's lubricating effect, where a high SA content on the CG surface acted more as a lubricant than a component enhancing interfacial properties. Moreover, sustainability analyses highlighted the simplicity, environmental friendliness, and economic viability of the process for producing high-filled CG composites using SA-modified CG. This study provides both scientific insight and practical guidance for leveraging high-filled CG composites in industrial applications.