Examining thermal, structural, and morphological properties of aluminium/TPU composite filaments

Abstract In this study, thermoplastic polyurethane (TPU)/0.25 wt% of aluminium filler was successfully fabricated using single screw extruder machine. The fabricated filaments were examined for differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), Fourier-transform infrared spectroscopy (FTIR), scanning electron microscopy with energy-dispersive X-ray spectroscopy (SEM-EDS), and X-ray diffraction (XRD). During filament fabrication, the parameters for pure TPU, such as die temperature (160–190 °C), screw speed (400 to 450 rpm), extruder current (2.1 to 2.2 A), were chosen. Similarly, for TPU/aluminium filaments, die temperature (190 –160 °C), screw speed (60 rpm), and extruder current (2.9 A) were chosen. Regarding the experimental results, the TGA of TPU/aluminium samples showed higher degradation than pure TPU samples at 850 °C. DSC results showed a minor effect from adding aluminium fillers in the first cycle. However, there was a significant change observed in the melting behavior in the subsequent cycles, which showed enhanced thermal stability and dimensional control at elevated temperatures. FTIR results confirmed interactions between aluminum fillers and TPU, as evidenced by the reduction in the intensity of C = O and N–H stretching bands, which indicated disrupted hydrogen bonds. SEM images showed that aluminium fillers were well embedded in the TPU matrix without any voids, which help in effective load transfer across the matrix. EDS results confirmed the presence of aluminium and oxygen and indicated the formation of Al2O3 during filament extrusion. Besides, XRD results exhibited a sharp crystalline peak and indicated improved structural stability due to adding aluminium fillers into TPU matrix.