摘要
The performance demands of mechanical lubricants are intrinsically linked to the operational reliability, efficiency, and service life of machinery, encompassing critical aspects such asextreme condition adaptability, longterm stability, and environmental compatibility. However, conventional lubricants exhibit limitations in fulfilling these multifaceted operational requirements. In this study, we developed a bifunctional metallocenecatalyzed polyalphaolefin (mPAO) base oil integrating antioxidant and antiwear characteristics. Two sulfurphosphorus additives-diphenyldithiophosphoric acid phenyl ester (DPDTP) and butyl phosphorothioate derivative (BPSD)-were synthesized. A series of functionalized mPAO alkylation products were successfully prepared by grafting selected organophosphorus compounds onto mPAO via alkylation. Oxidation stability was assessed through pressurized differential scanning calorimetry (PDSC) and thermogravimetric analysis (TGA). Compared with mPAO, m-DPDTP demonstrated remarkable antioxidant enhancement, exhibiting a 74 degrees C higher initial oxidation temperature and a 61.6 degrees C increase in onset decomposition temperature. Tribological performance was systematically investigated using four-ball wear tests, UMT tribometer measurements, and TE77 reciprocating friction evaluations. The m-DPDTP exhibited reductions in average friction coefficients of 35.91 %, 56.85 %, and 47.78 %. Additionally, a 56.85 % reduction in wear scar diameter was observed during the fourball evaluations. Additionally, m-DPDTP demonstrated the highest PB (212 N) and PD (250 N). These findings substantiate that DPDTP-grafted alkylation products possess superior friction reduction, antiwear capabilities, and extreme-pressure performance. This work establishes a molecular engineering strategy combining structural design and composite modification to develop mPAO alkylation products with concurrent thermal-oxidative stability and tribological enhancement. This breakthrough overcomes the functional singularity of conventional base oils and provides a novel paradigm for advanced lubricant formulation.
