An enhancement in the tensile modulus and bending resistance of polylactic acid/carbon nanotube composite by optimizing FFF process parameters

Fused-filament fabrication (FFF) is one of the most common 3D printing methods for thermoplastic polymers and composite materials because it is easy to use and is low-cost. The printed polymer parts for industrial applications require desirable mechanical properties. Therefore, in the present research, the process parameters of fused filament fabrication are optimized to enhance the Young’s modulus and bending resistance of polylactic acid/carbon nanotube (PLA/CNT) composite. For this purpose, the response surface method (RSM) and desirability function technique (DFT) are applied to find the optimal values of the effective parameters of CNT content, printing speed and nozzle temperature. The printed samples were examined by using DSC, TGA and SEM analyses. The results of DSC and TGA analyses indicated that the addition of CNT into PLA enhanced the thermal stability of PLA/CNT composite. It was also observed from the optimization results that the Young’s modulus and bending resistance of PLA/CNT composite improved at CNT content of 2.9 wt%, printing speed of 20 mm/s and nozzle temperature of 210°C.