Effect of Carbon Fillers on the Wear Resistance of PA6 Thermoplastic Composites

Abstract

In this study, the influence of different carbon fillers on the tribological and manufacturing properties of the thermoplastic polyamide PA6 is presented. The following materials were used as carbon additives: glassy carbon (GC), carbon obtained from the pyrolysis of polymer wastes (BC), and graphene oxide (GO). Fillers were introduced into the PA6 matrix by mechanical stirring in alcohol to settle carbon particles onto the granule surface. Samples were made by injection molding from the produced granules. The microstructure, hardness, and melt flow index (MFI) of the prepared materials were determined. Also, the degree of crystallinity of the samples was examined by Differential Scanning Calorimetry (DSC) and X-ray Diffraction (XRD). The melting point (Tm) was examined using DSC, the results from which allowed the correct heat treatment of PA6 to increase the crystallinity of the obtained material to be selected. The dry sliding tribological behavior of the composites was evaluated via pin-on-block tests against cast iron counterparts. The tests were performed at room temperature, with a sliding speed 0.1 m/s, a sliding distance of 250 m, and a normal force of 40 N. The obtained results revealed that the introduction of GO into the PA6 matrix provides favorable wear behavior, such as the formation of debris that acts as rollers that give a decrease in wear and a lower coefficient of friction. The coefficient of friction in samples with graphene oxide was nearly two times lower than with other samples. However, the ease of manufacture of this material was drastically reduced compared to GC or BC fillers. Microstructural investigations of wear tracks revealed poor adhesion between the polymer matrix and micrograins of carbon fillers (GC and BC), and therefore their influence on tribological properties was less compared to graphene oxide.

Lightweight, Flexible Cellulose-Derived Carbon Aerogel@Reduced Graphene Oxide/PDMS Composites with Outstanding EMI Shielding Performances and Excellent Thermal Conductivities

“…which are 25.8, 362.5 and 163.9 °C higher than The T 5 , T 30 and T HRI of the pure PDMS (292.3, 362.5 and 163.9 °C). It is mainly attributed to the fact that the introduction of rGO with excellent heat resistance can help improve the heat resistance of CCA@rGO/PDMS EMI shielding composites [ 64 ]. Meanwhile, the good interfacial compatibility between CCA@rGO and PDMS matrix can effectively prevent the oxygen penetration and thermal degradation behavior of CCA@rGO/PDMS EMI shielding composites [ 65 , 66 ].…”

“…This is mainly attributed to the fact that the hard two-phase interfacial layer between CCA@rGO and PDMS matrix increases with the increase in CCA@rGO loading, which restricts the movement of PDMS molecular chains and makes T g increase [63]. As shown in [64]. Meanwhile, the good interfacial compatibility between CCA@rGO and PDMS matrix can effectively prevent the oxygen penetration and thermal degradation behavior of CCA@rGO/PDMS EMI shielding composites [65,66].…”

Structure and Mechanical Properties of High-Density Polyethylene Composites Reinforced with Glassy Carbon

“…Combined, these effects lead to a slightly higher strength nanocomposite with a highly limited elastic deformation of the material [ 15 ]. In contrast, the addition of 1 wt% of graphene oxide (GO) in a polyamide 6 (PA6) matrix favors crystallization of γ-modification of PA6 [ 16 ]. However, there is a large difference in the chain structure of polypropylene (PP) and PA6, which could impede proper comparison.…”

Tribological Performance of Composites Reinforced with the Agricultural, Industrial and Post-Consumer Wastes: A Review

“…Another material—carbon obtained from the pyrolysis of polymer wastes—was used in the study by Myalski et al to reinforce polyamide (PA) thermoplastic composites [ 105 ]. The 10 wt % addition of this modified waste material, however, lead to an increase in COF as compared to neat PA variant (although the differences were not statistically significant), suggesting its poor performance as a reinforcement.…”

“…Biocarbon obtained from the pyrolysis of polymer wastes can be an example of it. In the investigation carried out in Myalski et al, the wear of the PA composite with this filler was characterized by much lower wear in the sliding test on cast iron than standard PA6 and other PA composites [ 105 ]. This “paves the way” for PA composites with waste fillers for the production of plain bearings as well as gears.…”