Rheological and tribological properties of poly-hexylnaphthalene/ poly-α-olefin lithium grease

doi:10.11949/0438-1157.20230173

Abstract

Abstract:

Poly-hexylnaphthalene base oil was synthesized with 1-hexene and naphthalene catalyzed by ionic liquid (Et₃NHCl-AlCl₃). Lithium grease prepared by poly-α-olefin (PAO8) base oil was used as reference. Lithium grease with different soap contents was prepared by adjusting the complex ratio of poly-hexylnaphthalene and PAO8 in the base oil (10∶90, 20∶80, 30∶70 and 40∶60). The physicochemical properties of different grease samples were tested and characterized. Meanwhile, the rheometer and SRV-V friction and wear tester were used to systematically evaluate the effects of poly-hexylnaphthalene added on the rheological and tribological properties of lithium grease. And with the help of 3D white light interference analyzer, the worn surface of the steel disc was analyzed. The experimental results show that the combination of poly-hexylnaphthalene and PAO8 had excellent synergistic effect at the mass ratio of 20∶80. The addition of poly-hexylnaphthalene can significantly improve the thickening ability of PAO8 base oil and save the amount of thickener. At the same time, poly-hexylnaphthalene can improve the rheological and tribological properties of PAO8 lithium grease under the condition of higher temperature (85℃).

Key words: poly-hexylnaphthalene, base oil, lithium grease, rheological properties, tribological properties

摘要：

离子液体（Et₃NHCl-AlCl₃）催化1-己烯和萘合成了多己基萘基础油，以聚α-烯烃（PAO8）基础油制备的锂基润滑脂作为参照，通过调节基础油中多己基萘与PAO8的复配比（10∶90、20∶80、30∶70和40∶60）制备了不同皂分含量的锂基润滑脂。对不同润滑脂样品的理化性能进行测试表征，利用流变仪和SRV-V摩擦磨损试验机系统地评价了加入的多己基萘对锂基润滑脂的流变学和摩擦学性能的影响，并借助3D白光干涉仪对钢盘磨损表面进行了分析。实验结果表明：基础油中多己基萘与PAO8复配质量比为20∶80时具有良好的协同效应，添加多己基萘可以显著提高PAO8基础油的稠化能力，节约稠化剂的用量，同时在较高温度（85℃）的工况下，多己基萘可以提高PAO8锂基润滑脂的流变和摩擦学性能。

关键词: 多己基萘, 基础油, 锂基润滑脂, 流变性能, 摩擦学性能

CLC Number:

TH 117

Zhiping ZHAO, Chen CHEN, Qiong TANG, Hong XU, Lei LIU, Jinxiang DONG. Rheological and tribological properties of poly-hexylnaphthalene/ poly-α-olefin lithium grease[J]. CIESC Journal, 2023, 74(6): 2555-2564.

赵志萍, 陈晨, 汤琼, 徐红, 刘雷, 董晋湘. 多己基萘/聚α-烯烃锂基润滑脂的流变学和摩擦学性能[J]. 化工学报, 2023, 74(6): 2555-2564.

Figures/Tables 11

Fig.1 Gas chromatogram of the hexylnaphthalene

Fig.2 Dropping point and oil separation of grease samples

Table 1 The oxidation onset temperature of grease samples with different soap contents （8%，10%）

润滑脂	氧化起始温度/℃
润滑脂	8%	10%
PAO8	281.8	288.1
PHN10	290.0	288.4
PHN20	292.4	291.2
PHN30	297.3	298.8
PHN40	319.0	323.1

Fig.3 Modulus curves of lithium grease with PAO8 and PHN20 as base oil with different soap contents

Fig.4 Modulus curves of lithium grease with different poly-hexylnaphthalene contents at different temperatures

Fig.5 tanδ curves of lithium grease with different poly-hexylnaphthalene contents at different temperatures

Fig.6 SEM images of soap fibers in different lithium greases (30k×)

Fig.7 Friction curves and average friction coefficient of lithium grease prepared from PAO8, PHN20 and PHN40 as base oil at 85℃ and 105℃

Fig.8 Wear volume of steel disc

Fig.9 3D images and profiles of wear scar of steel disc lubricated by different lithium grease prepared with PAO8，PHN20 andPHN40 as base oil at 85℃

Fig.10 3D images and profiles of wear scar of steel disc lubricated by different lithium grease prepared with PAO8，PHN20 andPHN40 as base oil at 105℃

References 35

1	Holmberg K, Erdemir A. Global impact of friction on energy consumption, economy and environment[J]. FME Transactions, 2015, 43(3): 181-185.
2	Cai M R, Guo R S, Zhou F, et al. Lubricating a bright future: lubrication contribution to energy saving and low carbon emission[J]. Science China Technological Sciences, 2013, 56(12): 2888-2913.
3	Farré-Lladós J, Westerberg L G, Casals-Terré J, et al. On the flow dynamics of polymer greases[J]. Lubricants, 2022, 10(4): 66.
4	曾晖, 李少飞, 刘涛, 等. 功能性润滑脂的开发进展[J]. 化工学报, 2015, 66(8): 2878-2887.
	Zeng H, Li S F, Liu T, et al. Functional lubricating materials-engineering research and development progress of lubricating grease[J]. CIESC Journal, 2015, 66(8): 2878-2887.
5	Pan J B, Cheng Y H, Yang J Y. Effect of heat treatment on the lubricating properties of lithium lubricating grease[J]. RSC Advances, 2015, 5(72): 58686-58693.
6	Ren G L, Li W, Li H, et al. Regulating performance characteristics of lithium complex greases via dibasic acids[J]. Lubrication Science, 2020, 32(6): 261-272.
7	Wu C, Yang K, Chen Y, et al. Investigation of friction and vibration performance of lithium complex grease containing nano-particles on rolling bearing[J]. Tribology International, 2021, 155: 106761.
8	He Q, Wang Z G, Li A, et al. Tribological properties of nanometer Al₂O₃ and nanometer ZnO as additives in lithium-based grease[J]. Industrial Lubrication and Tribology, 2018, 70(6): 953-960.
9	Zhang J, Li J T, Wang A L, et al. Improvement of the tribological properties of a lithium-based grease by addition of graphene[J]. Journal of Nanoscience and Nanotechnology, 2018, 18(10): 7163-7169.
10	Wang Z Y, Chang J, Cai C. Tribological performance of phosphonium ionic liquids as additives in lithium lubricating grease[J]. Lubricants, 2018, 6(1): 23.
11	Fan X Q, Li W, Li H, et al. Probing the effect of thickener on tribological properties of lubricating greases[J]. Tribology International, 2018, 118: 128-139.
12	Hao H, Liu Z W, Zhao F Q, et al. Material flow analysis of lithium in China[J]. Resources Policy, 2017, 51: 100-106.
13	Jiang H B, Xu X L, Hong X Z, et al. Preparation of high viscosity PAO from mixed alpha-olefins over metallocene catalyst[J]. China Petroleum Processing & Petrochemical Technology, 2018, 20(2): 90-96.
14	Hanifpour A, Bahri-Laleh N, Mohebbi A, et al. Oligomerization of higher α-olefins to poly(α-olefins)[J]. Iranian Polymer Journal, 2022, 31(1): 107-126.
15	Gajewski J B, Głogowski M J. Anti-wear additive content in fully synthetic PAO and PAG base oils and its effect on electrostatic and tribological phenomena in a rotating shaft-oil-lip seal system[J]. Journal of Physics: Conference Series, 2013, 418: 012045.
16	Porfiryev Y, Shuvalov S, Popov P, et al. Effect of base oil nature on the operational properties of low-temperature greases[J]. ACS Omega, 2020, 5(21): 11946-11954.
17	de Laurentis N, Cann P, Lugt P M, et al. The influence of base oil properties on the friction behaviour of lithium greases in rolling/sliding concentrated contacts[J]. Tribology Letters, 2017, 65(4): 128.
18	Zhang E H, Li W M, Zhao G Q, et al. A study on microstructure, friction and rheology of four lithium greases formulated with four different base oils[J]. Tribology Letters, 2021, 69(3): 1-9.
19	Chen C, Liu Y J, Tang Q, et al. Tribological and rheological performance of lithium grease with poly-α-olefin and alkyl-tetralin as base oils[J]. Chinese Journal of Chemical Engineering, 2023, 56: 180-192.
20	Hourani M J, Hessell T, Abramshe R A, et al. Alkylated naphthalenes as high-performance synthetic lubricating fluids[J]. Tribology Transactions, 2007, 50(1): 82-87.
21	Xu N, Wang X B, Ma R, et al. Insights into the rheological behaviors and tribological performances of lubricating grease: entangled structure of a fiber thickener and functional groups of a base oil[J]. New Journal of Chemistry, 2018, 42(2): 1484-1491.
22	Mazzo-Skalski S. Alkylated naphthalene basestocks advance high-performance lubricants[J]. Tribology & Lubrication Technology, 2009, 65(11): 38-40.
23	刘谋, 罗勇, 刘勇, 等. 一种由烷基萘基础油制备的高温锂基润滑脂及其制备方法: 110283638A[P]. 2019-09-27.
	Liu M, Luo Y, Liu Y, et al. High-temperature lithium base grease prepared from alkylnaphthalene base oil and preparation method of lithium base grease: 110283638A[P]. 2019-09-27.
24	Belov P S, Grigor’eva E N, Nikonorov E M, et al. Alkylnaphthalenes as components of high-temperature lubricants[J]. Chemistry and Technology of Fuels and Oils, 1984, 20(4): 208-210.
25	Yang T, Wang F J, Huang J P, et al. Efficient continuous-flow synthesis of long-chain alkylated naphthalene catalyzed by ionic liquids in a microreaction system[J]. Reaction Chemistry & Engineering, 2021, 6(10): 1950-1960.
26	Li L, Zhao X R, Chen C, et al. Highly selective synthesis of polyalkylated naphthalenes catalyzed by ionic liquids and their tribological properties as lubricant base oil[J]. ChemistrySelect, 2019, 4(18): 5284-5290.
27	韩路坤, 牛文星, 徐红, 等. 有机柱撑型层状硅铝酸钠的合成及摩擦学性能研究[J]. 润滑与密封, 2022, 47(2): 109-115.
	Han L K, Niu W X, Xu H, et al. Synthesis and tribological properties of lamellar aluminosilicates-C₁₈N⁺Me₃ [J]. Lubrication Engineering, 2022, 47(2): 109-115.
28	Paszkowski M. Assessment of the effect of temperature, shear rate and thickener content on the thixotropy of lithium lubricating greases[J]. Proceedings of the Institution of Mechanical Engineers, Part J: Journal of Engineering Tribology, 2013, 227(3): 209-219.
29	Wang Y S, Wu B J. Friction characteristics and mechanisms of two lithium greases in elastohydrodynamic lubrication[J]. Journal of Failure Analysis and Prevention, 2020, 20(4): 1266-1273.
30	Zhou W G, Huang L, Wang C F, et al. A study on the effects of temperature changes on the rheological properties of lithium lubricating grease and data processing[C]//Liang Q, Wang W, Liu X, et al. International Conference in Communications, Signal Processing, and Systems. Singapore: Springer, 2022: 514-522.
31	Delgado M A, Sánchez M C, Valencia C, et al. Relationship among microstructure, rheology and processing of a lithium lubricating grease[J]. Chemical Engineering Research and Design, 2005, 83(9): 1085-1092.
32	Delgado M A, Valencia C, Sánchez M C, et al. Influence of soap concentration and oil viscosity on the rheology and microstructure of lubricating greases[J]. Industrial & Engineering Chemistry Research, 2006, 45(6): 1902-1910.
33	Lin B, Rustamov I, Zhang L, et al. Graphene-reinforced lithium grease for antifriction and antiwear[J]. ACS Applied Nano Materials, 2020, 3(10): 10508-10521.
34	Fan M J, Ai J, Hu C H, et al. Naphthoate based lubricating oil with high oxidation stability and lubricity[J]. Tribology International, 2019, 138: 204-210.
35	Wang Y S, Zhang P, Lin J H, et al. Rheological and tribological properties of lithium grease and polyurea grease with different consistencies[J]. Coatings, 2022, 12(4): 527.

[1]	Jingze CUI, Qiong TANG, Chen CHEN, Yujie LIU, Hong XU, Lei LIU, Jinxiang DONG. Synthesis of high viscosity alkylated acenaphthene and investigation of their lubrication property [J]. CIESC Journal, 2022, 73(8): 3659-3668.
[2]	Zichao JIANG, Jianhua FANG, Zeqi JIANG, Xin WANG, Yanhan FENG, Jianhua DING. Tribological properties ofnano-WS₂ lubricating oil additives under DC magnetic field [J]. CIESC Journal, 2019, 70(7): 2636-2644.
[3]	YU Lei, DAI Kangxu, LU Hao, FANG Yanxiong, CAO Hua, HAN Lifen, ZHAO Hongbin, LI Shijuan. Preparation and tribological properties of nitrogen-containing heterocyclic ester or amide derivatives [J]. CIESC Journal, 2018, 69(9): 4083-4089.
[4]	ZHANG Shanshan, ZHAO Jianguo, ZHANG Jin, XING Baoyan, QIAN Rui, CAO Yu, YANG Xiaofeng, WANG Baojun. Effect of crumpled graphene balls on friction performance of base oil [J]. CIESC Journal, 2018, 69(10): 4479-4485.
[5]	ZHAO Yongqing, CHEN Fuquan, FENG Yanhong, QU Jinping. Properties of poly(lactic acid)/epoxidized soybean oil blends [J]. CIESC Journal, 2014, 65(10): 4197-4202.
[6]	LONG Wenyu1，LI Xiaoou1，LI Dongsheng1，LIU Baozhu2，SHI Yan3. Solution to high acid value lubricating base oil of Dalian Petrochemical Company [J]. Chemical Industry and Engineering Progree, 2014, 33(08): 2219-2223.
[7]	XU Zijun, ZHAO Liang, HE Wangli, LI Zhihao, QIAN Feng. Base oil supply chain modeling method based on revenue sharing contract [J]. CIESC Journal, 2013, 64(12): 4454-4460.
[8]	WU Chunlin，ZHANG Xiaosheng，XU Hong，DONG Jinxiang. Synthesis of N,N-didodecylethylenediamine and its tribological properties [J]. Chemical Industry and Engineering Progree, 2013, 32(08): 1893-1897.
[9]	SU Leijing，DING Xuejia，LEI Xiaohui，HE Jinying，WANG Linsheng，LI Xiran. Structure and thermal properties of phase change materials based on polyolefin cladded paraffin wax blends [J]. Chemical Industry and Engineering Progree, 2013, 32(04): 853-856.
[10]	MA Xiuyuan， DUAN Yufeng， LIU Meng， LI Huafeng. Wall slip behavior and rheological characteristics of coke/water slurry [J]. CIESC Journal, 2012, 63(1): 51-58.
[11]	JIN Gang，ZHAO Xinliang，LEI Yucai. Measuring rheological properties of polymer with torque-rheometer [J]. , 2011, 30(2): 371-.
[12]	ZHANG Yu，DING Xuejia，GUO Tiantian，ZHOU Kebin，HAN Haijun，ZHANG Lijuan. Rheology study on PC/PETG blends [J]. , 2011, 30(12): 2685-.
[13]	XIONG Chu’an，WANG Yonggang，XU Deping. Development of rheological properties of Chinese coal-oil slurry and liquefaction residue in direct liquefaction [J]. , 2009, 28(4): 597-.
[14]	LU Peizhong，ZHANG Fute，YE Wenyu. Tribological behavior of a novel S-N style 1,3,4-thiadiazole-2- thione derivative as additive in rapeseed oil [J]. , 2008, 27(2): 294-.