Developing functional additive resistant to space atomic oxygen (AO) irradiation through simple molecular design and chemical synthesis to enhance the lubricating performance of multialkylated cyclopentanes (MACs) oil is a significant challenge. Herein, sulfur-containing polyhedral oligomere silsesquioxane (POSS) were synthesize via a click-chemistry reaction of octavinyl polyhedral oligomeric with alkyl sulfide. The reduce-friction (RF), anti-wear (AW) properties and anti-AO irradiation of POSS-S-R as MACs base oil additives in atmospheric and simulated space environments were systematically investigated for the first time. Results demonstrate that POSS-S-R not only possesses outstanding anti-AO irradiation capacity but also effectively improves the RF and AW of MACs in atmospheric or simulated space surroundings. This improvement is due to the excellent anti-AO irradiation properties of the POSS structure itself and the high load-carrying ability of silicon-containing and sulfur-containing compounds generated by tribo-chemical reactions, which effectively separates the direct contact of the friction interface. We believe that this synthesized POSS-S-R is a promising additive for space lubricants.

A new type of lubricating material (BTA-P₄₄₄₄-Lig) was synthesized by combining lignin with tetrabutylphosphorus and benzotriazole. The tribological properties, corrosion resistance, and anti-oxidation properties of BTA-P₄₄₄₄-Lig as a lubricant were investigated. The lubricating material exhibits excellent friction reduction and wear resistance, as well as good thermal stability and excellent oxidation resistance. Mechanistic analysis reveals that the active elements N and P in the lubricating material react with the metal substrate, and the reaction film effectively blocks direct contact between the friction pairs, affording excellent friction reduction and wear resistance. At the same time, the phenolic hydroxyl group in lignin reacts with oxygen free radicals to form a resonance-stable semi-quinone free radical, which interrupts the chain reaction and affords good anti-oxidant activity.

In this study, the direct intercalation of gemini ionic liquids (ILs) with different alkyl chains into the bentonite (BT) interlayer as a high-performance lubricating additive for base oil 500SN was investigated. The purpose of modifying BT with an IL is to improve the dispersion stability and lubricity of BT in lubricating oil. The dispersibility and tribological properties of IL–BT as oil-based additives for 500SN depend on the increase in interlamellar space in BT and improve as the chain length is increased. More importantly, the IL–BT nanomaterial outperforms individual BT in improving wear resistance, owing to its sheet layers were deformed and sprawled in furrows along the metal surface, thereby resulting in low surface adhesion. Because of its excellent lubrication performance, IL-modified BT is a potential candidate for the main component of drilling fluid. It can be used as a lubricating additive in oil drilling and oil well construction to reduce equipment damage and ensure the normal operation of equipments.