Health & Environmental Research Online (HERO)


Print Feedback Export to File
4493360 
Journal Article 
Tribological studies of some SAPS-free Schiff bases derived from 4-aminoantipyrine and aromatic aldehydes and their synergistic interaction with borate ester 
Jaiswal, V; Kalyani; Rastogi, RB; Kumar, R 
2014 
1 
Journal of Materials Chemistry A
ISSN: 2050-7488
EISSN: 2050-7496 
2 
27 
10424-10434 
WOS:000338124500014 
Tribological performance of sulfur, phosphorous and metal-free Schiff bases of 4-aminoantipyrine with benzaldehyde (AAPB), salicylaldehyde (AAPS), p-chlorobenzaldehyde (AAPC) and p-methoxybenzaldehyde (AAPM) and their synergistic formulations with borate ester (BE) in paraffin oil has been evaluated using a four-ball tester at optimized concentrations of Schiff bases (1% w/v) and their synergistic formulations with BE (0.5% w/v for each) by varying loads for 30 min duration and varying test durations at 392 N load. Synergistic formulations effectively enhance antiwear properties of oil and possess high load carrying capacity in comparison to the conventional zinc dibutyldithiophosphate (ZDDP)/BE/Schiff bases alone. The best efficiency is shown by AAPM, followed by AAPC, AAPS and then AAPB. The same order is observed in their corresponding synergistic formulations. AFM and SEM micrographs of the wear scar lubricated with synergistic formulations show a drastic decrease in surface roughness in comparison to borate ester/ZDDP alone. EDX analysis of the worn surface in the presence of AAPM + BE exhibits nitrogen, boron and oxygen indicating adsorption of the additive on the surface. XPS of the tribofilm shows B2O3, BN, Fe2O3, Fe3O4 and adsorbed carbon in the form of -C-C- and -C(O)O- moieties. Quantum chemical calculations (DFT) for interactions of Schiff bases with surfaces show good agreement with experimental results.