Composites based on nylon 6/clinoptilolite by ultrasound-assisted extrusion for enhanced flame retardant and mechanical properties

Safe, lightweight, high-strength and sustainable materials are required for automotive parts and electrical components. In this paper, a polymeric composite based on nylon 6 and clinoptilolite (green fire retardant) was obtained by ultrasound-assisted extrusion. The materials were analyzed by Fourier transform infrared spectroscopy (FT-IR), thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), scanning electron microscopy (SEM) and cone calorimetry. From the FT-IR results, the presence of elements corresponding to the composition of the clinoptilolite that was used as an additive and nylon 6 was observed. TGA analysis showed that thermal stability improved, and in DSC analysis, we observed a slight increase in the crystallinity of the clinoptilolite polymer compounds, which was reflected in the flame retardation tests and by the mechanical properties. Significant improvement in the stiffness mechanical properties of nylon 6 with increasing clinoptilolite content was observed. For clinoptilolite contents of 1, 5 and 10% weight, the Young’s modulus increased by 3352.79, 3675.53 and 4327.06 MPa, respectively, compared to that of nylon 6, with a value of 2997.45 MPa. Meanwhile, the flexion resistance of nylon 6 increased from 84.75 to 95.05, 99.9 and 105.4 N/mm2 for the compounds obtained. The homogeneous distribution of clinoptilolite in the polymeric matrix due to processing by ultrasonic-assisted melt extrusion prevents the formation of stress concentration points. Flame retardant properties were studied with cone calorimetry, and a reduction in the peak heat release rate (HRR) was observed.