Preparation and Laser Marking Properties of Poly(propylene)/Molybdenum Sulfide Composite Materials

In this study, using molybdenum sulfide (MoS2) as laser-sensitive particles and poly(propylene) (PP) as the matrix resin, laser-markable PP/MoS2 composite materials with different MoS2 contents ranging from 0.005 to 0.2% were prepared by melt-blending. A comprehensive analysis of the laser marking performance of PP/MoS2 composites was carried out by controlling the content of laser additives, laser current intensity, and the scanning speed of laser marking. The color difference test shows that the best laser marking performance of the composite can be obtained at the MoS2 content of 0.02 wt %. The surface morphology of the PP/MoS2 composite material was observed after laser marking using a metallographic microscope, an optical microscope, and a scanning electron microscope (SEM). During the laser marking process, the laser energy was absorbed and converted into heat energy to cause high-temperature melting, pyrolysis, and carbonization of PP on the surface of the PP/MoS2 composite material. The black marking from carbonized materials was formed in contrast to the white matrix. Using X-ray diffraction (XRD), Fourier transform infrared (FT-IR) spectroscopy, and Raman spectroscopy, the composite materials before and after laser marking were tested and characterized. The PP/MoS2 composite material was pyrolyzed to form amorphous carbonized materials. The effect of the laser-sensitive MoS2 additive on the mechanical properties of composite materials was investigated. The results show that the PP/MoS2 composite has the best laser marking property when the MoS2 loading content is 0.02 wt %, the laser marking current intensity is 11 A, and the laser marking speed is 800 mm/s, leading to a clear and high-contrast marking pattern.