polyalphaolefin

Polyalphaolefin (PAO) denotes a family of synthetic hydrocarbon base oils used primarily in lubricants. PAOs are produced by polymerizing alpha-olefin monomers and then saturating the resulting polymer with hydrogen, yielding clean, stable hydrocarbons with performance characteristics similar to mineral oils but superior in some respects. They are widely used as synthetic base stocks in automotive, industrial, and aerospace lubricants.

Production involves polymerizing short-chain alpha-olefins such as 1-decene, 1-dodecene, or 1-tetradecene. The polymerization is typically carried out with catalysts such as Ziegler-Natta or metallocene systems to give predominantly linear, high-molecular-weight polyalphaolefins. The product is then hydrogenated to convert any residual unsaturation into fully saturated hydrocarbons, improving oxidation stability, color, and additive compatibility. The resulting PAO base oils have a narrow molecular weight distribution and minimal aromatic content.

Key properties of PAOs include a high viscosity index, low volatility, and excellent oxidative and thermal stability. They maintain viscosity over a wide temperature range and exhibit good low-temperature behavior, making them suitable for use in extreme operating conditions. PAOs are essentially hydrocarbon fluids with predictable performance and good compatibility with common lubricant additives.

Applications cover automotive engine oils, transmissions, hydraulic fluids, and industrial gear oils, as well as specialty lubricants for aerospace and high-performance machinery. As synthetic base oils, PAOs often enable longer service intervals and improved oxidation resistance compared with conventional mineral oils, albeit at a higher cost.

Compared with mineral oils, PAOs offer superior stability, higher viscosity index, and better low-temperature performance, while their performance depends on the choice of monomers and processing.