Myalski Jerzy, Godzierz Marcin, Olesik Piotr
Silesian University of Technology, Faculty of Materials Engineering, Krasińskiego 8, 40-019 Katowice, Poland.
Polish Academy of Sciences, Centre of Polymer and Carbon Materials, M. Curie-Skłodowskiej 34 street, 41-819 Zabrze, Poland.
Polymers (Basel). 2020 Oct 1;12(10):2264. doi: 10.3390/polym12102264.
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.
在本研究中，展示了不同碳填料对热塑性聚酰胺PA6的摩擦学和制造性能的影响。以下材料用作碳添加剂：玻璃碳（GC）、由聚合物废料热解得到的碳（BC）和氧化石墨烯（GO）。通过在酒精中机械搅拌将填料引入PA6基体，以使碳颗粒沉降到颗粒表面。由生产的颗粒通过注塑成型制成样品。测定了制备材料的微观结构、硬度和熔体流动指数（MFI）。此外，通过差示扫描量热法（DSC）和X射线衍射（XRD）检查了样品的结晶度。使用DSC检查熔点（Tm），其结果有助于选择对PA6进行正确的热处理以提高所得材料的结晶度。通过针对铸铁配对件的销盘试验评估了复合材料的干滑动摩擦学行为。试验在室温下进行，滑动速度为0.1 m/s，滑动距离为250 m，法向力为40 N。所得结果表明，将GO引入PA6基体可提供良好的磨损行为，例如形成碎屑，这些碎屑起到滚子的作用，从而减少磨损并降低摩擦系数。含氧化石墨烯的样品中的摩擦系数比其他样品低近两倍。然而，与GC或BC填料相比，这种材料的制造难度大幅增加。磨损轨迹的微观结构研究表明，聚合物基体与碳填料（GC和BC）的微晶之间的附着力较差，因此与氧化石墨烯相比，它们对摩擦学性能的影响较小。
