Materials
·
2024
·Vol. 17
·期 7
·1680
·
IF 3.1
Xiao Sang,Ke Han,Manfu Zhu,Liran Ma
Controlling friction by light field is a low-cost, low-energy, non-polluting method. By applying ultraviolet light on the surface of photosensitive materials, the properties of the friction pairs or lubricant can be influenced, thus achieving the purpose of reducing friction. In this study, TiO2, an inorganic photosensitive material, was selected to investigate the modulating effect of light fields on friction lubrication when using polyalphaolefin (PAO) base oil as a lubricant, and the modulation law of light fields on the friction lubrication behavior was investigated under different loads (1–8 N), different speeds (20–380 mm/s), and different viscosities (10.1–108.6 mPa·s) of PAO base oil. The experimental results showed that light treatment could reduce the friction coefficient of PAO4 base oil lubrication from 0.034 to 0.016, with a reduction of 52.9% under conditions of 3 N-load and 56.5 mm/s-speed, and the best regulation effect could be achieved under the mixed lubrication condition. After TiO2was treated with ultraviolet light, due to its photocatalytic property, PAO molecules were oxidized and adsorbed on the TiO2surface to form an adsorption layer, which avoided the direct contact of rough peaks and thus reduced the friction coefficient. This study combines photosensitivity, photocatalysis, and friction, presenting a method to reduce the friction coefficient by applying a light field without changing the friction pairs or lubricants, which provides a new direction for friction modulation and gives new ideas for practical applications.
研究领域:
材料科学
·
摩擦学
·
光化学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
COLLOIDS AND SURFACES A-PHYSICOCHEMICAL AND ENGINEERING ASPECTS
·
2024
·
IF 4.9
Siwei Chen,Qingqing Chen,Baogang Wang,Hongsheng Lu
The application of carbon dots (CDs) as lubricant additives of nonpolar oils such as poly-α-olefins (PAOs) has been greatly hindered because most of CDs derived from the bottom-up method were water-soluble. In this work, the oil-soluble polymer brushes grafted CDs were synthesized by the surface-initiated atom transfer radical polymerization of bis-alkyl chain monomers. As expected, the polymer grafted CDs exhibited the excellent long-term dispersion stability in PAO owing to the principle of similar compatibility. As the lubricant additives of PAO4, the CDs showed the best friction-reducing and anti-wear properties when the polymerization time was 2 h. Adding 1 wt% of CDs could make the coefficient of friction and wear volume of PAO4 reduce by 64.1 % and 49.6 %, respectively. Moreover, both the tribological properties and anti-rust performance of CDs were superior to the commercially used ZDDP. The distinguished friction-reducing and anti-wear properties of CDs were attributed to the synergistic lubrication of carbon cores and polymer brushes. The rolling, repairing and polishing action of carbon cores, together with the tribo-reactions of polymer brushes, resulted in the formation of tough lubricating films on the rubbing surfaces, thereby tremendously alleviating the friction and wear of tribopair. The impressive anti-rust performance of CDs could be assigned to their strong adsorption ability on metallic surfaces. The above results are hopeful to provide useful information for the design and development of efficient multifunctional additives such as polymer-grafted metallic or inorganic nanomaterials.
研究领域:
材料科学
·
润滑工程
·
表面化学
✓ 已验证
产品关联
DOI
高影响因子
ACS Omega
·
2020
·
IF 2.87
Ruida Zhao,Puke Mi,Sheng Xu,Suqin Dong
In this paper, poly-α-olefins (PAO) containing quaternary carbon centers were prepared by two-step oligomerization using a metallocene catalyst followed by a Ziegler–Natta catalyst. First, the 1-decene dimer was oligomerized with [t-BuN(Me)2C(η5-C5H4)]ZrCl2, and the effects of the oligomerization temperature, Al/Zr molar ratio, and catalyst loading on the oligomerization were investigated. In the second step, the obtained 1-decene dimers were copolymerized with 1-decene with TiCl4/Et2AlCl, and the effects of the catalysts, monomer/dimer ratio, and α-olefin species on the copolymerization were investigated. The composition and structure of the dimers and copolymerization products were characterized by gas chromatography (GC) and 1H NMR and 13C NMR spectroscopy. The results of GC and 13C NMR analyses indicated that the metallocene catalyzed the formation of the 1-decene oligomerization product, resulting in the branched olefin dimer being the major product, and the existence of quaternary carbons in the 1-decene/1-decene dimer copolymerization product could also be found. The polymerization mechanism for the formation of the quaternary carbon centers is proposed. The 1-decene/1-decene dimer copolymerization product containing quaternary carbon centers has a kinematic viscosity of 10.8 mm2/s at 100 °C, a viscosity index of 165, and a pour point of −52 °C; thus, the product with quaternary carbon centers has a better viscosity–temperature performance and low-temperature fluidity than those of the 1-decene oligomerization product and typical PAO products, but the kinematic viscosity is similar.
研究领域:
材料科学
·
化学工程
✓ 已验证
DOI
高影响因子
WEAR
·
2023
·
IF 5
Hua Jiang,Xianjun Hou,Qifan Yu,Mohamed Kamal Ahmed Ali
This study comprehensively investigated physicochemical and tribological performance of polyalphaolefin (PAO4) oil introducing oleic acid (OA)-functionalized SiC/TiN hybrid nanomaterials . The dispersion stability , wettability , thermal stability, and friction properties of the nanolubricants (NL) system were greatly improved following the application of hybrid NL. Additionally, the anti-wear and reducing-friction behavior were assessed via a four-ball tribometer. The results showed that the COF and WSD values of wear scar lubricated by hybrid NL were greatly reduced by approximately 32.7% and 35.1%, respectively, compared with the base oil. Finally, it is strongly confirmed that the significant improvement of friction performance is mainly due to improved interfacial effect of NL, the stable chemical tribo-film generated onto the friction surface , and the synergistic effect among SiC, TiN nanoparticles , and OA surfactant .
研究领域:
材料科学
·
摩擦学
·
化学工程
✓ 已验证
产品关联
DOI
高影响因子
ENERGY & FUELS
·
2019
·
IF 3.021
Su Q. Dong,Pu K. Mi,Sheng Xu,Jun Zhang,Rui D. Zhao
In this paper, a single-component poly-α-olefin (PAO) oil base stock of an α-olefin tetramer was prepared via two-step oligomerization using a metallocene catalyst and a Ziegler–Natta catalyst in sequence. The structure was characterized, the performance was investigated, and the effects of the molecular structure and composition on performance were evaluated. First, the α-olefins were dimerized with different metallocenes as the catalyst, and the effects of the oligomerization conditions (amount of catalyst, temperature, and ratio of Al/Zr) on the molecular weight distribution of the obtained polymers were investigated. The dimerization selectivity reached 83.1%, and the content of branched α-olefin was 91.7%. In the second step, the obtained α-olefin dimer was polymerized by a Ziegler–Natta catalyst, and the dimerization reaction was dominant. A PAO with a tetramer content of 89.6% was obtained, and at 100 °C, the kinematic viscosity was 6.4 cSt and the viscosity index was 148. Further results suggested that both molecular structure parameters (the length of the main chain and the length of the branches) affect the PAO properties when the number of branches and the branch position on the molecular skeleton are the same. It was also found that, as the length of the main chain and the length of the branches increased, the kinematic viscosity and viscosity index increased, while the pour point decreased; however, when the length of the main chain, the number of branches, and the length of the branches were the same, the presence of quaternary carbons in the main chain lowered the viscosity index and increased the pour point.
研究领域:
化学工程
·
材料科学
✓ 已验证
DOI
高影响因子
JOURNAL OF MATERIALS SCIENCE
·
2016
·Vol. 52
·期 8
·4483-4492
·
IF 2.302
Lu Hongsheng,Tang Weiwei,Liu Xiang,Wang Baogang,Huang Zhiyu
The oleylamine (OA)-modified carbon nanoparticles (CPs -OA ) with particle sizes of 25–35 nm were synthesized by a facile one-pot pyrolysis method. As the OA molecules were covalently attached on the surfaces of CPs -OA , the CPs -OA exhibited good dispersibility in polyalphaolefin (PAO). Then the tribological behaviors of CPs -OA as the lubricating additives of PAO were investigated in detail. Under the four-ball mode and the load of 392 N, the CPs -OA showed the best friction-reducing and antiwear properties at the optimal concentration of 1.0 wt%. Specifically, in comparison with that of pure PAO, the mean friction coefficient and mean wear scar diameter of the 1.0 wt% CPs -OA /PAO suspension reduced by 47 and 30%, respectively. The friction-reducing and antiwear capabilities of CPs -OA strengthened with increasing load from 200 to 392 N and increasing test time from 240 to 480 min. In addition, the CPs -OA -based additives could work for a long time without weakening the lubrication capability. The synergistic effect of tribofilm, including PAO molecules and the CPs -OA layer, might account for the outstanding friction-reducing and antiwear capabilities of CPs -OA -based additives under boundary lubrication.
研究领域:
材料科学
·
润滑工程
✓ 已验证
产品关联
DOI
高影响因子
CHINESE JOURNAL OF CHEMICAL ENGINEERING
·
2022
·
IF 3.898
Chen Chen,Yujie Liu,Qiong Tang,Hong Xu,Mingxing Tang,Xuekuan Li,Lei Liu,Jinxiang Dong
A new category of lithium greases was synthesized by using poly- α -olefin (PAO8) and alkyl-tetralin as base oil, where the alkyl-tetralins were synthesized by the alkylation of tetralin and olefins. The influence of thickener concentration, alkyl-tetralin content and type of blend oils on the rheological and tribological performance of lithium grease was investigated. The microstructures of soap fibers were measured to reveal the structure–property correlations. The concentration of thickener and alkyl-tetralin content obviously affect the lubricating performance of lithium grease, while the molecular structure of alkyl-tetralin has no obvious impact on their properties. It was found that alkyl-tetralin could significantly enhance the thickening ability of PAO8 base oils, and decrease the amount of thickeners by 1.5% (mass). Lithium greases prepared using 20% (mass) alkyl-tetralin as co-base oil exhibited high colloidal stability, excellent rheological behaviors and tribological properties.
研究领域:
材料科学
·
化学工程
·
机械工程
✓ 已验证
产品关联
DOI
高影响因子
INDUSTRIAL & ENGINEERING CHEMISTRY RESEARCH
·
2018
·
IF 3.141
Ruochong Zhang,Dan Qiao,Xuqing Liu,Zhiguang Guo,Litian Hu,Lei Shi
The dispersibility of TiO2 nanoparticles in polyalphaolefin (PAO) are improved by the interaction between the chemically modified TiO2 (denoted as TTO) and 1-methyl-2,4-bis (N-octadecylurea) benzene (MOB) gelator. Tribological tests show the outstanding friction-reducing and antiwear performances of PAO10–MOB–TTO under the common friction condition and higher temperature friction condition, respectively. The lubricating property of PAO10–1% MOB–0.5% TTO is further enhanced after UV irradiation for 40 min, which might be attributed to the photocatalytic effect of TTO under UV. The physical adsorption film is enhanced by the immobilization function of MOB. The chemical reaction film including various organic oxides and nitrides are produced for the active element in TTO and MOB. The antiwear performance is further improved by the “mending effect” of TTO with the good dispersibility. The combined effects of various factors promote the excellent lubricating performances of PAO10–1% MOB–0.5% TTO.
研究领域:
材料科学
·
机械工程
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF INDUSTRIAL AND ENGINEERING CHEMISTRY
·
2023
·
IF 6.1
Chuan Li,Xinxin Wang,Qiangqiang Zhang,Xu Tan,Yefeng Liu,Honglin Li,Hao Liu,Enzhu Hu,Xianguo Hu
This study fabricated nano-CeO 2 /biodiesel carbon soot (BCS) composites using the raw material BCS, which is the byproduct of biodiesel combustion and cerium salt and used as a novel lubricant additive to PAO6 for steel/steel contact. Oleylamine modified nano-CeO 2 /BCS composites comprise abundant lipophilic groups, and thus nano-CeO 2 /BCS composites exhibit good dispersion in PAO6. The tribological results showed that nano-CeO 2 /BCS composites significantly improved the lubricating performances of PAO6. In case of 0.1 wt% nano-CeO 2 /BCS composites dispersed in PAO6, the friction coefficient and wear volume were reduced by 17.3 and 35.2%, respectively. The improved tribological properties were attributed to the composites rolling and forming of a lubricating film on the friction surface and the presence of BCS and CeO 2 in composites exerting a synergistic lubricating effect, which simultaneously improved the tribological properties of PAO6. This discovery contributes to the conversion of BCS into valuables and promotes the high value utilization of BCS as a lubricating additive.
研究领域:
材料科学
·
摩擦学
·
能源与环境
✓ 已验证
产品关联
DOI
高影响因子
Lubricants
·
2024
·Vol. 12
·期 7
·255
·
IF 3.1
Jian Xu,Qidi Hu,Jiusheng Li
With the continuous advancement of industrial technology, higher demands have been placed on the properties of gear oils, such as oxidation stability and shear resistance. Herein, the oxidation stability of high-viscosity metallocene poly-α-olefins (mPAOs) was improved by chemical modification via aromatic amine alkylation. The modified mPAO base oils were synthesized separately with diphenylamine (mPAO-DPA) and N-phenyl-α-naphthylamine (mPAO-NPA), and their applicability in industrial gear oil formulations was evaluated. The composition and physicochemical properties of the obtained samples were assessed using1H NMR spectroscopy, Fourier transform infrared spectroscopy, gel permeation chromatography, and the American Society for Testing and Materials standards (ASTM D445, ASTM D2270, ASTM D92, etc.) confirming the successful completion of the alkylation reaction. The oxidation stability of the samples was also evaluated using pressurized differential scanning calorimetry. The initial oxidation temperature of mPAO-NPA (230 °C) was 53 °C higher than that of mPAO, and the oxidation induction period of mPAO-DPA was nearly twice that of mPAO-NPA. Thermogravimetric analysis in air revealed the increased thermal decomposition temperature and improved thermal stability of modified mPAO. ISO VG 320 industrial gear oils were formulated using mPAO alkylated with N-phenyl-α-naphthylamine(Lub-2) and commercially purchased PAO100 (Lub-1) as base oil components. The antioxidant performance of two industrial gear oils was evaluated through oven oxidation and rotating oxygen bomb tests. The oxidation induction period of Lub-2 was 30% higher than that of Lub-1, with the latter having a lower acid number and a smaller increase in viscosity at 40 °C. Finally, the friction performance of the samples was assessed on a four-ball friction tester, revealing the synergistic effect of the mPAO-NPA base oil with the HiTEC 3339 additive, forming a more stable oil film with a smaller wear scar diameter.
研究领域:
化学工程
·
材料科学
·
工业润滑
✓ 已验证
产品关联
DOI
高影响因子
CARBOHYDRATE POLYMERS
·
2019
·
IF 6.044
Ke Li,Xiao Zhang,Chen Du,Jinwan Yang,Bolang Wu,Zhiwei Guo,Conglin Dong,Ning Lin,Chengqing Yuan
With the increasing requirement of environmental protection, the development of lubricating materials with non-toxicity and good biodegradability becomes more and more significant. As the novel green nanomaterial derived from natural cellulose, cellulose nanocrystals (CNCs) in the present work were prepared from native cotton and added into polyalphaolefin (PAO) base oil as the lubricant additive. To improve the compatibility of CNCs with PAO, the surface of CNCs were grafted by stearoyl chains, which entangled with polyolefin chains and led to a good dispersibility and stability of the colloidal solution. This hybrid oil with the elevated viscosity improved the formation of lubricant film in the boundary lubrication regime. Combining with the mending effect of CNC particles on the surface roughness and scars, both the friction and the wear were dramatically reduced. Specifically, the introduction of 2 wt% modified nanocrystals (mCNC) in PAO base oil reduced the coefficient of friction (COF) by 30%. The results of this study suggest that cellulose nanocrystal is a promising ecofriendly and effective lubricant additive.
研究领域:
材料科学
·
环境科学
·
生物工程
✓ 已验证
DOI
PubMed
高影响因子
Lubricants
·
2024
·Vol. 12
·期 12
·416
·
IF 3.1
Haiyang Wang,Zhongyi He,Liping Xiong,Liang Qian,Lili Li,Qiyang Long
This research thoroughly examined the tribological characteristics of polyalphaolefin (PAO4) oil, both with and without the incorporation of methyl silicone resin. The evaluation of anti-wear properties and friction reduction was conducted using a four-ball tester for friction and wear. The incorporation of methyl silicone resin into PAO4 at 25 °C significantly reduced the wear scar diameter (WSD), achieving minimum values at a concentration of 0.02 wt.%. PAO4 with 0.02 wt.% methyl silicone resin shows excellent wear resistance at different temperatures. A detailed analysis of the wear scar surfaces and wear debris was conducted using scanning electron microscope (SEM), energy dispersive spectrometer (EDS), X-ray photoelectron spectroscopy (XPS), Raman spectroscopy, 3D surface profiler and TEM. The results compellingly demonstrate that the remarkable improvement in wear resistance is predominantly due to the strategic formation of SiO2nanoparticles during the friction process. These SiO2particles not only adeptly fill the surface gaps at the friction interface but also crucially contribute to the formation of a robust tribochemical film, which is instrumental in enhancing wear performance.
研究领域:
材料科学
·
表面工程
·
化学工程
✓ 已验证
产品关联
DOI
高影响因子
危险品化学品经营许可证（带存储）