Use of an Acylated Chitosan Schiff Base as an Ecofriendly Multifunctional Biolubricant Additive

Two acylated chitosan Schiff base samples ACSB-1 and -2 were synthesized via a two-step reaction pathway. First the chitosan Schiff base (CSB) was prepared utilizing 3,5-di-tert-butyl-4-hydroxybenzaldehyde. In the second step, esterification with lauroyl chloride catalyzed by 4-(dimethylamino)pyridine (DMAP) in N,N-dimethylacetamide (DMAc) solvent affords the final product acylated chitosan Schiff base (ACSB-1 and -2). The products were identified and characterized by Fourier transform infrared (FT-IR) spectroscopy, CHN analysis, thermogravimetry (TG), X-ray diffraction (XRD), etc. The synthesized compounds were evaluated as multifunctional additives for antioxidant and lubricity properties in N-butyl palmitate/stearate. A rotating pressure vessel oxidation test (ASTM D2272) was used for evaluating antioxidant property. The thermo-oxidative stability of the N-butyl palmitate/stearate oil was increased 1.5 times by using this additive in 3000 ppm concentration of ACSB-2 at 150 °C. Lubricity property was ev...