Carbon nanotubes (CNTs) are attracting great interest in enhancing rheological behavior and thermal performance of lubricating grease. In this study, CNTs were synthesized by catalytic chemical vapor deposition (CCVD) method using low-density polyethylene (LDPE) waste as a cheap carbon source and Co/MgO as an effective catalyst. The effect of temperature on the catalytic pyrolysis of LDPE to produce CNTs has been studied. Catalytic pyrolysis of LDPE waste was conducted in a temperature range of 350–600 °C using the H-ZSM-5 catalyst. The structure and quality of CNTs were fully characterized using HR-TEM, XRD, and Raman spectroscopy. On the other hand, various concentrations of CNTs (0.2, 0.4, 0.6, 0.8, and 1.0 wt%) were mixed with pure lithium grease to determine the optimum percentage that improves the properties of nano-grease. The results showed that a high yield of multiwalled carbon nanotubes (MWCNTs) was obtained with high quality at temperatures ranging from 400 to 550 °C. Also, the addition of CNTs enhanced the rheological behavior of lithium grease, and the optimum percentage of CNTs was 0.8 wt%. Furthermore, the apparent viscosity and shear stress of lithium nano-grease increased by increasing the concentration of CNTs up to 0.8%. At this concentration, the penetration value of lithium nano-grease was greater than pure grease, and the dropping point increased by 12.5%. These results suggested that CNTs prepared from LDPE waste were an excellent additive to enhance the physicochemical properties of lithium grease.

碳纳米管（CNT）在增强润滑脂的流变行为和热性能方面引起了极大的兴趣。在这项研究中，碳纳米管通过催化化学气相沉积（CCVD）方法合成，使用低密度聚乙烯（LDPE）废物作为廉价碳源，而Co / MgO作为有效催化剂。研究了温度对LDPE催化热解制备CNT的影响。使用H-ZSM-5催化剂，在350–600°C的温度范围内对LDPE废物进行了催化热解。碳纳米管的结构和质量已使用HR-TEM，XRD和拉曼光谱进行了全面表征。另一方面，将各种浓度的CNT（0.2、0.4、0.6、0.8和1.0 wt％）与纯锂油脂混合，以确定改善纳米油脂性能的最佳百分比。结果表明，在400至550°C的温度范围内，高质量的多壁碳纳米管（MWCNT）的产量很高。另外，CNT的添加增强了锂润滑脂的流变行为，并且CNT的最佳百分比为0.8重量％。此外，通过将CNT的浓度提高到0.8％，可以提高锂纳米润滑脂的表观粘度和剪切应力。在该浓度下，锂纳米油脂的渗透值大于纯油脂，并且滴点增加了12.5％。这些结果表明，由LDPE废料制备的CNT是增强锂润滑脂理化性能的极好的添加剂。碳纳米管的加入增强了锂基润滑脂的流变性能，碳纳米管的最佳百分含量为0.8 wt％。此外，通过将CNT的浓度提高到0.8％，可以提高锂纳米润滑脂的表观粘度和剪切应力。在该浓度下，锂纳米油脂的渗透值大于纯油脂，并且滴点增加了12.5％。这些结果表明，由LDPE废料制备的CNT是增强锂润滑脂理化性能的极好的添加剂。碳纳米管的加入增强了锂基润滑脂的流变性能，碳纳米管的最佳百分含量为0.8 wt％。此外，通过将CNT的浓度提高到0.8％，可以提高锂纳米润滑脂的表观粘度和剪切应力。在该浓度下，锂纳米油脂的渗透值大于纯油脂，并且滴点增加了12.5％。这些结果表明，由LDPE废料制备的CNT是增强锂润滑脂理化性能的极好的添加剂。锂纳米脂的渗透值大于纯脂，滴点提高了12.5％。这些结果表明，由LDPE废料制备的CNT是增强锂润滑脂理化性能的极好的添加剂。锂纳米脂的渗透值大于纯脂，滴点提高了12.5％。这些结果表明，由LDPE废料制得的CNT是一种出色的添加剂，可增强锂润滑脂的理化性能。