Tribological properties of potential bio-based lubricants from RBD palm stearin and palm fatty acid distillate

Abstract

Palm-based oil properties, which consist of long fatty acid chains, have the potential to replace current mineral oils. Recent studies have shown that palm-based oil has comparable lubricating properties to those of commercial engine oil. However, several palm oil products yet to be discover as lubricants such as RBD Palm Stearin (RBD PS) and Palm Fatty Acid Distillate (PFAD) due to its solid form properties. In this study, both RBD PS and PFAD has been tested for the suitability as lubricant in the tribological experiments consists of anti-wear test and extreme pressure test according to ASTM standards of D4172 B and 2783 respectively. In ASTM D4172 B, test has been conducted with 40kg load and 1200 rpm speed at 75°C in duration of 60 minutes while in ASTM 2783 the temperature and speed are remain constant at 45°C and 1760 rpm in duration of 10 minutes with increasing loads until failure detected. Mineral Oil (MO) has been used as a direct comparison between commercial engine oil and bio-based palm oil. Results shows PFAD has recorded lowest average coefficient of friction (COF), wear scar diameter (WSD) and surface roughness at 0.038, 433µm and 0.188µm in anti-wear test. In the extreme pressure test, RBD PS shows the earliest failure of 4mm wear scar diameter at 126kg followed by palm fatty acid distillate and mineral oil at 130kg and 146kg load.