The Polymer Society of Korea

Abstract

This study examines the foaming behavior of biodegradable polylactic acid (PLA)/low-density polyethylene (LDPE) blends to clarify the link between rheology and morphology. While polymer blending can tailor material properties, foaming in immiscible systems remains poorly understood. LDPE shows strain-hardening from its long-chain branched structure, influencing melt processability and foam stability. Fillers with different shapes and surface hydrophobicities were added to tune interfacial interactions and enhance compatibility. Their effects on viscoelasticity were analyzed by small-amplitude oscillatory shear (SAOS) and uniaxial extensional viscosity tests, and morphology was examined by SEM and TEM. Correlation of rheological and structural data revealed that interfacial morphology critically governs foam density and stability. These results demonstrate that controlling interfacial structure is essential to improve the foaming performance and processability of PLA/LDPE blends.