Thermal and Mechanical Properties of Cementitious Waste-Coated Polyamide 6 Composites

The study investigates pozzolanic materials, silica fume, and fly ash as reinforcement agents in a polyamide 6 (PA6) matrix with cement. The materials were combined in various proportions and applied via ultrasonic coating before being extruded into composite filament samples. Different characterization techniques, including thermogravimetric analysis (TGA) and Differential Scanning Calorimetry (DSC), were employed for evaluation of the samples. Results showed that PA6 composites with silica fume had the highest modulus of elasticity (MOE) but relatively low modulus of rupture (MOR) values for the samples. The addition of cement and fly ash enhanced their overall mechanical properties, increasing MOR and MOE by 24.4% and 81.5%, respectively. TGA indicated improved thermal stability with silica fume, while fly ash displayed the highest residual mass. Neat PA6 maintained a high maximum decomposition temperature (Tmax) but minimal residue. DSC results suggested that while melting temperature remained largely unchanged, cement reduced enthalpy change, indicating limited crystallization. Neat PA6's low heat deflection temperature (HDT) due to amorphous content led to reduced mechanical strength at high temperatures. Cement enhanced the deformation resistance of the samples, while silica fume provided limited reinforcement. Having fly ash in the samples significantly improved their HDT, thermal stability, and rigidity. Based on the findings in this study, pozzolanic materials demonstrated their potential use as effective fillers for PA6 composites in various applications.