Basic Structure and Preparation
Four-carbon POE is synthesized through the copolymerization of ethylene and 1-butene, while eight-carbon POE is the copolymerization product of ethylene and 1-octene. From a molecular structure perspective, both types of POE are random copolymers of ethylene and α-olefins, sharing similar basic structures. However, their performance differences mainly arise from variations in side chains.
Structural Characteristics and Physical Properties
The longer octene side chains in eight-carbon POE result in larger intermolecular distances. This structural characteristic endows eight-carbon POE with excellent elasticity and higher tensile strength. The long side chains of octene enhance the interaction forces between tie molecules, enabling the material to better withstand tensile stress.
In comparison, the shorter side chains of four-carbon POE lead to lower density and relatively higher crystallinity. This gives four-carbon POE higher liquidity during processing, as well as better high-temperature stability and heat resistance.
Downstream Applications
In downstream applications, four-carbon POE and eight-carbon POE are generally considered versatile. However, at the same density, eight-carbon POE exhibits better toughening effects than four-carbon POE. Eight-carbon POE can often be produced at lower densities (e.g., Exxon’s product 9061 achieves 0.86), giving it advantages in toughness and softness, especially under low-temperature conditions (e.g., -40°C).
Applications in Engineering Plastics
In engineering plastic applications, the choice of POE is not solely dependent on material softness. Eight-carbon POE is favored for its excellent low-temperature performance without requiring excessive softness. On the other hand, four-carbon POE, with its lower melting temperature and narrower molecular weight distribution, is more suitable for applications requiring high liquidity and high-temperature stability.
Conclusion
In summary, four-carbon POE and eight-carbon POE each have their own advantages and are suitable for different application scenarios. The high liquidity and high-temperature stability of four-carbon POE make it more marketable in industries with high-temperature demands, while eight-carbon POE’s superior low-temperature toughness and elasticity make it more competitive in the flexible materials field. When selecting a specific type of POE, comprehensive consideration should be given to the specific application requirements.
