Insights into Researches on the Tribological, Microstructural and Micromechanical Properties of Thermoplastic Based Composites

Two disjoint filler materials in a powder form are added to a polycarbonate (PC) matrix. The micro sized additives are Graphite (Gr) and molybdenum disulfide (MoS₂) introduced as layered solid lubricants. Two distinct development methodologies are employed in order to prepare the composites; the first process is industrial by using directly an injection molding machine, while the second process is composite preparation in a laboratory scale. The experimental results of the two process are compared. From friction and wear tests, it is established that MoS₂ particles improved the wear resistance and reduced the coefficient of friction of steel/PC contact with both development methodologies. On the contrary, Gr decreases the tribological properties of PC. Fracture morphologies and x-ray micro-tomography are performed to characterize the microstructural aspects of PC/solid lubricant composites. Micrographs show microcracking, filler agglomeration and the presence of voids with direct injection molding. Besides, the composites present poor scratch resistance properties. The different results are improved with the second development methodology including the powders surface treatment by an amino-silane and mechanical mixing with the PC matrix.