Preparation and tribological properties of inclusion complex of β-cyclodextrin/dialkyl pentasulfide as additive in PEG-600 aqueous solution

Guan, Jiju; Xu, Xuefeng; Gan, Li; Peng, Wei

doi:10.1016/j.apsusc.2013.10.176

Cited by 14 publications

(10 citation statements)

References 30 publications

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“…The rGO dispersed PEG200 was used as synthetic lube base oil for tribology evaluation. Neat PEG itself is considered useful for lubricating additives 41 42 43 . Before the tribology test, the PEG functionalized rGO powder sample was thoroughly dispersed in the PEG medium by ultrasonication process for 1 hour and their dispersion stability was monitored for 4 hours.…”

Section: Methodsmentioning

confidence: 99%

Energy efficient reduced graphene oxide additives: Mechanism of effective lubrication and antiwear properties

Gupta

Kumar

Panda

et al. 2016

Sci Rep

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Optimized concentration of reduced graphene oxide (rGO) in the lube is one of the important factors for effective lubrication of solid body contacts. At sufficiently lower concentration, the lubrication is ineffective and friction/wear is dominated by base oil. In contrast, at sufficiently higher concentration, the rGO sheets aggregates in the oil and weak interlayer sliding characteristic of graphene sheets is no more active for providing lubrication. However, at optimized concentration, friction coefficient and wear is remarkably reduced to 70% and 50%, respectively, as compared to neat oil. Traditionally, such lubrication is described by graphene/graphite particle deposited in contact surfaces that provides lower shear strength of boundary tribofilm. In the present investigation, graphene/graphite tribofilm was absent and existing traditional lubrication mechanism for the reduction of friction and wear is ruled out. It is demonstrated that effective lubrication is possible, if rGO is chemically linked with PEG molecules through hydrogen bonding and PEG intercalated graphene sheets provide sufficiently lower shear strength of freely suspended composite tribofilm under the contact pressure. The work revealed that physical deposition and adsorption of the graphene sheets in the metallic contacts is not necessary for the lubrication.

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Section: Methodsmentioning

confidence: 99%

Energy efficient reduced graphene oxide additives: Mechanism of effective lubrication and antiwear properties

Gupta

Kumar

Panda

et al. 2016

Sci Rep

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“…In the 1 H NMR spectrum of β-CD, the peaks at 4. 83, 3.39, 3.82, 3.30, 3.49, and 3.65 ppm are attributed to H-1, H-2, H-3, H-4, H-5, and H-6 of D-pyran glucose units; the peaks recorded between 5.0 and 5.5 ppm are ascribed to the hydrogen atoms of hydroxyl groups, and the peak at 3.6 ppm is attributed to the O-H group (Guan et al 2014). Compared to β-CD, the β-CD-CS exhibited an additional peak at nearby 3.19 ppm, which can be ascribed to the CH 3 -N + group substituted cationic group from cationic starch (Wang and Xie 2010).…”

Section: Scheme 1 Schematic Representation Of β-Cd Grafted Onto Polymentioning

confidence: 99%

β-Cyclodextrin Grafted Cellulose and Cationic Starch for Antibacterial Paper Products: A Comparative Study

Dong¹,

Li²,

Xiao³

et al. 2014

BioResources

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Two kinds of macromolecules applied in papermaking were modified with β-cyclodextrin (β-CD) and loaded with ciprofloxacin hydrochloride (CipHCl) in an attempt to compare their potential applications in antimicrobial paper. β-CD grafted cellulose (β-CD-Cel) and β-CD grafted cationic starch (β-CD-CS) were prepared by grafting β-CD onto cellulose fiber and cationic starch using citric acid (CA) and epichlorohydrin (ECH) as crosslinking agents, respectively. β-CD-Cel and β-CD-CS were both loaded with an antimicrobial agent (CipHCl) to form inclusion complexes, namely β-CD-Cel-CipHCl and β-CD-CS-CipHCl. Furthermore, the inclusion complexes were added to the pulp to prepare antibacterial paper. The antimicrobial activity and physical properties of the paper were investigated. The results showed that the paper with both inclusion complexes exhibited excellent antibacterial activity, and the antibacterial activity with β-CD-CS-CipHCl was higher than that with β-CD-CelCipHCl. Moreover, the addition of both β-CD-Cel-CipHCl and β-CD-CSCipHCl affected the tensile and tear strengths of the paper. The paper with β-CD-CS-CipHCl had better physical properties than that with β-CDCel-CipHCl because the CS acts as a reinforcing agent in papermaking. These prepared antibacterial paper sheets may be useful for preventing wound and nosocomial infections in the medical and packaging fields.

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“…The selection of this liquid was based on its chemical compatibility with rGO as the resultant dispersion constituted polar groups for effective interaction. Furthermore, from application and comparison point of view, PEG had been widely used in several investigations for lubrication purpose . Before the tribology test, PEG was thoroughly dispersed in the certain amount of already synthesized composite by ultrasonication and its dispersion stability was monitored for two weeks.…”

Section: Methodsmentioning

confidence: 99%

Molecular‐Pillar‐Supported Functionalized Reduced Graphene‐Oxide for Energy Efficient Lubrication

Gupta

Kumar

Panda

et al. 2016

Adv Materials Inter

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of anisotropic crystal structure, signifying strong covalent intralayer and weak van der Waals interlayer interactions. The layered lattice structure of graphene and its derivatives in lube oil provide an effective lubrication and antiwear properties. [9][10][11][12][13] However, it is a hydrophobic material and dispersion in a polar hydrophilic lube is unfavorable. In the light of this, oxygen functionalization converts graphene into graphene oxide/reduced graphene oxide (GO/rGO), providing a hydrophilic nature. The GO/rGO is a derivative of graphene containing abundant oxygen functional groups such as carboxyl, hydroxyl, and ether on the basal plane of carbon sheet. [ 14 ] Oxygen functionalization and chemically modifi ed graphene sheet is widely utilized to engineer molecular selfassemblies of organic ingredient for wide range of applications. [15][16][17][18] The presence of hydrophilic oxygen containing groups and hydrophobic aromatic frameworks in GO/rGO makes it an amphiphilic copolymer system, retaining a 2D feature in solution. [ 19 ] Baoli et al. proposed successful grafting of graphene with polyaniline (PANI) through the self assembled amino-propylsilane monolayer and chemical oxidative graft polymerization. [ 20 ] Feng et al. and Fan et al. prepared graphene-PANI composite fi lms by electrochemical process for the use in supercapacitor electrodes. [ 21,22 ] In this composite, the van der Waals interaction dominates between graphene and the conductive polymer. It is well-known that the large surface area of graphene and strong van der Waals force causes severe aggregation in the composite matrix. Therefore, strong interfacial adhesion and compatibility between graphene and the matrix involves dispersion of graphene a prerequisite for its reliable performance. To address these issues, graphene must be functionalized using both covalent and noncovalent approaches. However, covalently bonded polyaniline-graphene hybrids are rarely reported. [ 23,24 ] Kumar et al. reported a chemically bonded graphene-polyaniline hybrid, in which a carboxylic acid ester group linked graphene and PANI. [ 23 ] Novel graphene-polyaniline hybrid based on the PANI nanofi ber was formed through van der Waals interaction. [ 24 ] An et al. reported amide groups linkage between graphene-polyaniline-grafted PANI nanofi bers and graphene. [ 25 ] Presently, there is no report of grafted graphene-polyaniline dispersed in a lube medium for tribology Molecular-pillar-supported basal plane of reduced graphene oxide (rGO)is fabricated by polymerizing polyaniline (PANI). In the presence of poly(ethylene glycol) (PEG200), the γ -radiolysis is used for modifying the functionalization and improving the structural symmetry of PANI and PEG grafted rGO (PANI-PEG-g-rGO). The PANI is covalently and noncovalently grafted onto the surface of the graphene sheets. Carboxyl groups of rGO are linked to the nitrogen atoms in the PANI backbone and an accompanying noncovalent interaction between alkyl chains of grafted PANI and hydrooxylated rGO is formed. ...

show abstract

Preparation and tribological properties of inclusion complex of β-cyclodextrin/dialkyl pentasulfide as additive in PEG-600 aqueous solution

Cited by 14 publications

References 30 publications

Energy efficient reduced graphene oxide additives: Mechanism of effective lubrication and antiwear properties

Energy efficient reduced graphene oxide additives: Mechanism of effective lubrication and antiwear properties

β-Cyclodextrin Grafted Cellulose and Cationic Starch for Antibacterial Paper Products: A Comparative Study

Molecular‐Pillar‐Supported Functionalized Reduced Graphene‐Oxide for Energy Efficient Lubrication

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