Article
Engineering, Chemical
Yu Cheng, Yingbin Bu, Pengxi Guan, Yujie Yang, Jianbo Qing
Summary: The friction and anti-wear properties of hexagonal boron nitride (h-BN) nanoparticles as a lubricating grease additive for lithium grease were studied under sliding conditions. The addition of 3 wt% 60 nm h-BN particles and 1 wt% 500 nm h-BN particles resulted in reductions of 22.34% and 20.18% in wear scar diameter, respectively, although the friction coefficients slightly decreased. The formation of layer-crystal structure boric acid H3BO3 during friction, combined with the synergistic effect of h-BN nanoparticles, led to friction reduction and enhanced wear resistance. Furthermore, the 60 nm h-BN particles filled the asperity valleys on the friction surface, creating a rolling effect and establishing a protective film, while the 500 nm h-BN particles shielded the asperity contact between the friction pairs and produced a polishing effect.
LUBRICATION SCIENCE
(2023)
Article
Engineering, Mechanical
Chunming Xu, Yuxing Peng, Zhencai Zhu, Wei Tang, Kun Huang
Summary: The study investigated the effect of different mineral particles on the wear of steel wires through wear tests. It was found that the friction coefficient between steel wires decreases with increasing mineral particle concentrations, with coal particles and ore particles affecting steel wire wear differently.
Article
Engineering, Mechanical
Chunming Xu, Yuxing Peng, Zhencai Zhu, Wei Tang, Kun Huang
Summary: Mineral particles in mine air exacerbate wire rope wear, threatening its lifespan. Wear of steel wire under mixed grease conditions increases with loading force, while wear coefficient decreases. Wear mechanisms include abrasive, adhesive, and fatigue wear, with peak friction pair exhibiting more severe wear characteristics.
ENGINEERING FAILURE ANALYSIS
(2021)
Article
Engineering, Mechanical
Yanshuang Wang, Xudong Gao, Jianghai Lin, Pu Zhang
Summary: The addition of few-layer graphene to lithium complex grease can improve its microstructure, increase viscoelasticity, enhance viscosity-temperature properties, and optimize friction and wear performance.
Article
Engineering, Mechanical
Seyedmohammad Vafaei, Dennis Fischer, Max Jopen, Georg Jacobs, Florian Koenig, Ralf Weberskirch
Summary: This research presents the design and evaluation of three different bio-based polymer thickener systems for lubricants. Tribological tests were conducted to characterize the lubrication properties of developed bio-based greases. The effect of thickener type on film thickness and friction behavior was evaluated and compared to a commercial petrochemical grease as benchmark.
Article
Polymer Science
Monika C. Wehrli, Anna Weise, Tim Kratky, Thomas Becker
Summary: The mechanical properties of hydrated vital gluten were studied under thermomechanical stress. With increasing temperature, the linear viscoelastic moduli decreased, indicating material softening. However, protein polymerization and new cross-link formation led to higher elastic moduli.
Article
Materials Science, Multidisciplinary
Raisa E. D. Rudge, Karlijn Theunissen, Jason R. Stokes, Elke Scholten, Joshua A. Dijksman
Summary: Soft PDMS surfaces lubricated by hard glass spheres exhibit different frictional regimes due to deformability, including rolling friction, sliding friction, and PDMS-PDMS contact regime, which are interpreted in terms of Hertzian contact deformation effects on the surfaces.
PHYSICAL REVIEW MATERIALS
(2021)
Article
Chemistry, Multidisciplinary
Jun Zhao, Tong Gao, Jie Dang, Weiyu Cao, Ziqi Wang, Shuangxi Li, Yijun Shi
Summary: This study successfully improved the lubrication and anti-wear performance of grease under high temperature and high load conditions by using modified talc nanosheets, providing guidance for developing natural lubricant additives and showing great potential in sustainable lubrication.
Article
Polymer Science
Max Jopen, Patrick Degen, Stephan Henzler, Bastian Grabe, Wolf Hiller, Ralf Weberskirch
Summary: This study investigates the influence of polymerization on polyurea lubricating systems and provides a theoretical basis for further development. The results show that by optimizing the degree of polymerization, comparable extreme pressure and anti-wear properties can be achieved without the need for additives.
Article
Engineering, Mechanical
Hasan Bas, Onur Ozen, Muhammet Ali Besirbeyoglu
Summary: This study investigated the effects of MoS2 and CaF2 additives on the friction, wear, and contact temperature of lithium soap grease. The results showed that both additives improved wear resistance and reduced friction coefficient. The suitable additive ratio for both additives was found to be in the range of 1-1.5 wt%.
TRIBOLOGY INTERNATIONAL
(2022)
Article
Chemistry, Physical
Revaz Chachanidze, Kaili Xie, Hanna Massaad, Denis Roux, Marc Leonetti, Clement de Loubens
Summary: Controlling the assembly of polyelectrolytes and surfactant at liquid-liquid interfaces is important for fabricating soft materials with specific physical properties. The kinetics and properties of the assembly process of a positively charged biopolymer, chitosan, with an anionic fatty acid at the water-oil interface were studied. The results revealed that the interfacial complexation is a multi-step process.
JOURNAL OF COLLOID AND INTERFACE SCIENCE
(2022)
Article
Nanoscience & Nanotechnology
Jingjie Pan, Chang Liu, Xinxin Gao, Kan Zhang, Weitao Zheng, Changfeng Chen
Summary: By developing a dual-phase nanocomposite material, researchers have created a self-lubricating material with extremely low friction coefficient and wear rate, solving the challenges faced by traditional lubrication systems. Even after annealing, this material maintains excellent performance, aiming to meet the most challenging lubrication needs.
ACS APPLIED MATERIALS & INTERFACES
(2021)
Article
Biochemistry & Molecular Biology
A. Basak Kayitmazer, Fatih Comert, Henning H. Winter, Phillip B. Messersmith
Summary: Rheological experiments showed that the linear viscoelasticity of HA/CHI coacervates depends on the molecular weight of the polymers. Catechol-conjugated HA and CHI exhibited a significant increase in moduli, suggesting their potential as injectable tissue scaffolds or medical adhesives.
Article
Energy & Fuels
He Yifeng, Sun Hongwei, Liu Xinyang
Summary: The study demonstrated that the vacuum lubricating grease prepared using perfluoropolyether as base oil exhibited excellent performance for long life lubrication of moving parts in a vacuum environment.
CHINA PETROLEUM PROCESSING & PETROCHEMICAL TECHNOLOGY
(2021)
Article
Engineering, Mechanical
B. P. Ferrer, L. Biazon, A. Zuin, P. Tayer, A. Toro, T. Cousseau
Summary: The effect of rail grease formulation on friction, wear, and grease loss due to centrifugal force was evaluated. Six greases were used to isolate the effects of thickener and base oil viscosity, which had the same consistency and additive package but different base oil viscosities and thickener types. The results showed that lithium greases have lower friction but higher wear than calcium greases, higher kinematic viscosity reduces wear but increases friction regardless of the thickener type, the critical speed at which grease is expelled from the disc increases with viscosity for lithium-thickened greases and does not depend on viscosity for calcium greases, and lithium greases with high base oil viscosity are best suited for wheel-rail interface lubrication.
TRIBOLOGY TRANSACTIONS
(2023)
Article
Polymer Science
Antonio M. Borrero-Lopez, Concepcion Valencia, Jose M. Franco
Summary: This review provides a comprehensive overview of the latest techniques and procedures for treating and modifying lignocellulosic materials to be used as precursors for biomaterials, biochemicals, and biofuels, with a focus on lignin and lignin-based products. Four main pretreatment types, including thermal, mechanical, chemical, and biological, are discussed, with particular attention given to the biological action of fungi and bacteria. The review highlights the vast possibilities of obtaining different final products depending on the selected microorganism and biomass. It extensively describes biofuels, biochemicals, and biomaterials derived from lignocellulose, covering not only the whole lignocellulosic structure but also the main biopolymers, cellulose, hemicellulose, and lignin. Moreover, the formulation of bio-polyurethanes from lignocellulosic materials is emphasized, especially in their applications in lubricant, adhesive, and cushioning material fields. The review also presents high-performance alternatives to petroleum-derived products such as adhesives, lubricating greases, and elastomers with improved properties.
Article
Biochemistry & Molecular Biology
Luisa Garcia-Fuentevilla, Jose F. Rubio-Valle, Raquel Martin-Sampedro, Concepcion Valencia, Maria E. Eugenio, David Ibarra
Summary: This study focuses on the structural features and physicochemical properties of different Kraft lignins and their influence on the electrospinning process to obtain nanostructures. The results show that under appropriate conditions, Kraft lignins can form fibrous structures at the nanoscale.
INTERNATIONAL JOURNAL OF BIOLOGICAL MACROMOLECULES
(2022)
Article
Polymer Science
M. Borrego, J. E. Martin-Alfonso, C. Valencia, M. C. Sanchez, J. M. Franco
Summary: This work focuses on improving the electrospinnability of low-sulfonate lignin/polyvinylpyrrolidone solutions by adding surfactants and studying the resulting nanofibers' ability to structure castor oil. The addition of surfactants improves electrospinnability, producing more compact and uniform fiber mats in certain systems. These nanofiber mats dispersed in castor oil can generate physically stable strong oleogels, which exhibit excellent lubrication performance and potential applications as lubricants.
Article
Chemistry, Multidisciplinary
Alba Blanquez, Antonio M. Borrero-Lopez, Gabriela Dominguez, Concepcion Valencia, Jose M. Molina-Guijarro, Maria E. Eugenio, David Ibarra, Manuel Hernandez
Summary: This study analyzed the compositional and structural modification of extracted lignins from barley and wheat straws that were biologically pretreated with Streptomyces. The results showed that the MDG301 strain exhibited better ligninsolubilization and higher hydrolytic enzymatic profile compared to the MDG147 strain. Soda pulping also caused structural changes in the lignins, resulting in excellent adhesive properties. The lignins extracted from barley straw showed the best performance in shear strength tests, while those from wheat straw performed well in peeling essays.
ACS SUSTAINABLE CHEMISTRY & ENGINEERING
(2022)
Article
Engineering, Chemical
Isabel Dianez Amores, Joamin Gonzalez-Gutierrez, I. Martinez Garcia, Jose M. Franco, Crispulo Gallegos
Summary: This paper explores the meeting points between Chemical Engineering and 3D printing, as well as the new techniques and applications that could benefit from this collaboration in the future.
CHEMICAL ENGINEERING RESEARCH & DESIGN
(2022)
Article
Agricultural Engineering
J. F. Rubio-Valle, M. C. Sanchez, C. Valencia, J. E. Martin-Alfonso, J. M. Franco
Summary: In this study, electrospun lignin/cellulose acetate fiber-bead nanostructures were developed as structuring agents for vegetable oils to be used as eco-friendly lubricating oleogels. The morphology of the electrospun nanostructures was found to be strongly dependent on the rheological properties of the biopolymer solution. The rheological properties of these gel-like dispersions can be tailored through concentration and ratio, and the resulting oleogels have comparable properties to conventional lubricants.
INDUSTRIAL CROPS AND PRODUCTS
(2022)
Article
Chemistry, Physical
E. Cortes-Trivino, J. Cubero-Cardoso, A. Tenorio-Alfonso, M. A. Fernandez-Recamales, C. Valencia, J. Urbano, J. M. Franco
Summary: This study investigates the usage of natural deep eutectic solvents (NADESs) with different hydroxyl group content as a matrix base in reactions involving lignin-enriched fraction. The NADESs were prepared by mixing citric acid with glycerol, xylitol, and sucrose as the hydrogen bond donor compounds. Waste lignocellulose was additionally epoxidised to be used as a thickening agent for the NADESs. The research successfully achieved chemical interaction between NADESs and epoxidised lignocellulose, resulting in various rheological responses.
JOURNAL OF MOLECULAR LIQUIDS
(2022)
Article
Materials Science, Multidisciplinary
M. Borrego, J. E. Martin-Alfonso, C. Valencia, Maria del Carmen Sanchez Carrillo, J. M. Franco
Summary: The development of environment-friendly natural polymer gel-like dispersions in oil media, with functional properties, in terms of formulation design and synthesis protocol, is still a cutting-edge research area. This study focuses on the manufacture of electrospun ethylcellulose (EC) nanofibrous webs and their usage as thickeners for vegetable oils. The concentration, molecular weight, and binary solvent systems of EC were found to affect the electrospinnability and rheological properties of the nanofiber dispersions. The morphology of the EC nanofiber web plays a crucial role in their physical stabilization and rheological behavior. This work proposes an innovative approach to produce bio-based oleogel-like dispersions that have potential applications in various sectors.
ACS APPLIED POLYMER MATERIALS
(2022)
Article
Materials Science, Paper & Wood
J. F. Rubio-Valle, C. Valencia, M. Sanchez, J. E. Martin-Alfonso, J. M. Franco
Summary: In this study, electrospun Kraft lignin/cellulose acetate nanostructures were produced and investigated as structuring or thickening agents in castor oil for lubricating applications. The morphology of the electrospun nanofibers was influenced by the rheological properties, electrical conductivity, and surface tension of KL/CA solutions, which were in turn affected by the chemical structure and composition of the Kraft lignins. The resulting oleogels, based on KL/CA electrospun nanostructures, exhibited desirable rheological and tribological properties, making them a promising sustainable alternative to conventional lubricating greases.
Article
Polymer Science
Maria Borrego, Jose E. Martin-Alfonso, Concepcion Valencia, M. Carmen Sanchez, Jose M. Franco
Summary: This study introduced a novel strategy for manufacturing thickened gel-like castor oil formulations by dispersing electrospun lignin/ethylcellulose nanostructures, potentially serving as eco-friendly lubricating greases. By controlling the ratio and concentration of lignin and ethylcellulose, the morphology and dispersibility of the nanostructures in oil can be adjusted, demonstrating satisfactory frictional response comparable to traditional lithium-lubricating greases.
Article
Biochemistry & Molecular Biology
Antonio M. Borrero-Lopez, Ling Wang, Haiming Li, Tainise Lourencon, Concepcion Valencia, Jose M. Franco, Orlando J. Rojas
Summary: Acetylated Kraft lignins were used to structure vegetable oils into oleogels. Microwave-assisted acetylation at higher temperatures resulted in gel-like oil dispersions with improved viscoelastic properties and stronger shear-thinning character, along with enhanced long-term stability. The modified lignins enhanced the stability of water-in-oil Pickering emulsions by enhancing hydrogen bonding between the oil and nanoparticles.
INTERNATIONAL JOURNAL OF BIOLOGICAL MACROMOLECULES
(2023)
Article
Chemistry, Multidisciplinary
Maria Borrego, Erik Kuhn, Jose E. Martin-Alfonso, Jose M. Franco
Summary: In this study, different lignin nanostructures were obtained through electrospinning and used as thickeners in bio-based lubricating greases. The impact of nanofibrous network morphology on friction and wear was investigated. The results showed that homogeneous bead-free nanofiber mats as thickeners can effectively reduce friction and wear.
Article
Engineering, Environmental
J. F. Rubio-Valle, C. Valencia, M. C. Sanchez, J. E. Martin-Alfonso, J. M. Franco
Summary: This study explores the use of spent coffee grounds and post-consumer PET bottles to produce electrospun composite nanofibers, aiming to develop a new route for upcycling them into high-value oil-based products. By adjusting the ratio of coffee grounds and PET bottles, the properties of the fibers and oleogels can be modified.
RESOURCES CONSERVATION AND RECYCLING
(2023)
