Compatibility analysis of metal-oxide nanofillers on ASA polymer for additive manufacturing to achieve multi-functionality

Fused filament fabrication (FFF) is increasingly used for manufacturing outdoor functional components; however, the long-term performance of FFF-manufactured polymer parts is often limited by inadequate thermal stability, ultraviolet (UV) resistance, and process reliability. In this context, the present study addresses the research question of how different inorganic metal-oxide nanofillers and their stage-dependent incorporation influence the multifunctional performance of acrylonitrile styrene acrylate (ASA) for FFF applications. ASA-based nanocomposites reinforced with 2 wt% silicon dioxide (SiO 2 ), zinc oxide (ZnO), and titanium dioxide (TiO 2 ) were developed using a hybrid processing route that combines solution blending with melt extrusion, including a powder-based pre-mixing step via ball milling to improve nanoparticle dispersion and interfacial bonding. The resulting materials were systematically characterized through morphological (FE-SEM/EDX), structural (XRD), thermal (DSC/TGA), ultraviolet–visible (UV–Vis), and rheological (MFI) analyses to evaluate dispersion quality, thermal behavior, UV shielding performance, and processability. The powder-based blending approach produced markedly improved nanoparticle dispersion and stronger interfacial interactions, with TiO 2 exhibiting the highest compatibility with the ASA matrix. Among the investigated nanofillers, ASA–TiO 2 nanocomposites demonstrated superior thermal stability, significantly enhanced UV absorption in the UV-A and UV-B regions, and stable melt flow behavior with negligible compromise in processability. These findings establish a clear processing–structure–property relationship and identify ASA–TiO 2 nanocomposites as a promising, weather-resistant material system for FFF-manufactured end-use components intended for prolonged outdoor exposure.