Zeolite nanocrystals were used as proactive agents to extend the lifetime of commercial lubricants by protecting the performance additives from depletion and adsorbing the acid formed during oxidation. The nanosized zeolites were introduced into four lubricants and subjected to oxidation (90 °C and 150 °C). A strong affinity towards protection of zinc dialkyldithiophosphate (ZDDP) additive was demonstrated by 31P NMR (nuclear magnetic resonance) and FTIR (fourier-transform infrared) spectroscopy even after heating at 150 °C for 24 h. FTIR profiles of lubricants aged in the presence of LTL (Linde Type L zeolite) showed lower oxidation degree while the formed oxidation products (aldehydes, ketones, and acids) were adsorbed on the zeolite crystals acting as scavengers.
Keywords: FTIR; NMR; additive protection; anti-oxidant; lubricants; zeolite.