Poly-alpha-olefins (PAO)

Properties and Applications

Poly-α-olefins (sometimes abbreviated as PAO) are colorless liquid oligomers manufactured by catalytic polymerization of linear alpha-olefins such as 1-butene, 1-pentene, 1-hexene, 1-octene, 1-decene an 1-dodecene. These monomers are often copolymerized with each other and with other monomers such as ethylene to achieve certain properties. The flexible alkyl branches on every other carbon atom of the polymer backbone result in a very low packing density and fully amorphous structure which explains why these polymers do not crystallize and remain oily viscous liquids even at very low temperatures.

PAO’s find many uses as automotive and industrial lubricants including synthetic gear oils, hydraulic fluids, compressor oils, greases, engine oils and other functional fluids.¹ PAOs have many advantages over ordinary mineral oils, including superior oxidative and thermal stability, excellent low-temperature properties and well-defined viscosity index. Some grades have received food-grade approval because PAO’s are generally considered non-toxic.

One of the most important applications of alpha-olefins is the copolymerization with ethylene. Even small amounts of alpha-olefins such as 1-hexene or 1-octene will greatly increase the flexibility of linear high-density polyethylene (HDPE) which would be very brittle without any branching.

¹According to a new report by Grand View Research, the global poly-alpha-olefin (PAO) market is expected to reach about USD 1.6 billion by 2025.