Optimization of FFF process parameters to improve the tensile strength and impact energy of polylactic acid/carbon nanotube composite

In this study, the process parameters of fused filament fabrication are optimized to improve the tensile strength and impact energy of polylactic acid/carbon nanotube (PLA/CNT) composite. Hence, the utility function (UF) technique and response surface method (RSM) are applied to explore the optimal levels of the effective parameters of print speed, nozzle temperature, and CNT content. The differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), and SEM analyses are employed to examine the thermal properties of the printed samples. The results of DSC and TGA analyses exhibited that the incorporation of CNT into PLA enhanced the thermal strength of PLA/CNT composite. The addition of CNTs in the composite improved the tensile strength by 37%, while the addition of CNTs up to 4 wt% improved the impact energy by 29%. Moreover, an increment of the print speed to 60 mm/s reduced the impact energy (12%) and tensile strength (22%), while an increment of the nozzle temperature to 200 degrees C enhanced the impact energy (9%) and tensile strength (12%). The optimization results demonstrated that the strength and impact energy of PLA/CNT composite optimized at CNT content of 2.8 wt%, print speed of 20 mm/s, and nozzle temperature of 209 degrees C. Additionally, the impact energy and tensile strength of the PLA/CNT composite enhanced up to 62.5 MPa and 2.14 J at the optimum conditions. Highlights<br /> Application of FFF process for producing the PLA/CNT composite<br /> Investigating the impact of FFF parameters on the mechanical properties<br /> Estimating the optimal conditions of the FFF process