Polybutene

Polybutene is a family of polymers derived from butene monomers. The two principal commercially important polybutenes are polyisobutylene (PIB), the polymer of isobutylene, and polybutene-1 (PB-1), the polymer of but-1-ene. They are part of the polyolefin family and share general hydrocarbon backbones with distinct industrial roles.

PIB is typically produced by cationic polymerization of isobutylene using strong Lewis acid catalysts in hydrocarbon solvents. This method yields high-molecular-weight polymers that are extremely viscous and resistant to oxidation. PB-1 is produced by anionic or coordination polymerization of but-1-ene with suitable catalysts, enabling control of molecular weight and architecture.

PIB is a colorless, highly viscous liquid or wax with very low gas permeability and strong chemical resistance. It remains flexible over a wide temperature range and is tacky at room temperature. PB-1 is generally a solid elastomer or waxy polymer with a very low glass transition temperature, imparting elasticity at low temperatures.

Common applications reflect these properties. PIB is widely used as a tackifier and thickener in adhesives, sealants, and lubricants, and it also serves in gas- and moisture-barrier films and protective coatings. PB-1 finds use as an elastomeric modifier and component in soft plastics, sealants, and various high-tlex applications where flexibility and adhesion are important.

Safety and handling follow standard practices for hydrocarbon polymers. Polybutenes are generally regarded as chemically inert and low in toxicity under normal handling conditions, though industrial hygiene and proper containment are advised.