polyisobutyleenin

Polyisobutylene, often abbreviated as PIB, is a synthetic polymer derived from the polymerization of isobutylene, also known as 2-methylpropene. It is a branched aliphatic hydrocarbon. PIB exists in a range of molecular weights, from low-viscosity liquids to rubbery solids. Its properties are significantly influenced by its molecular weight and degree of branching.

The primary applications of polyisobutylene stem from its excellent barrier properties, particularly against gases and moisture. Low molecular weight PIB is commonly used as a lubricant additive, a viscosity modifier, and as a component in adhesives and sealants. Higher molecular weight PIB is employed in chewing gum bases, as a tackifier in pressure-sensitive adhesives, and in some types of protective coatings. Its inertness and resistance to chemical degradation contribute to its versatility.

Polyisobutylene is produced through cationic polymerization. The physical state and characteristics of PIB are highly dependent on its molecular weight. For example, very low molecular weight grades are oily liquids, while higher molecular weight grades exhibit elastomeric properties. Its non-polar nature means it is insoluble in water but soluble in many organic solvents. The specific grade of PIB used in an application is chosen based on the desired performance characteristics, such as viscosity, tack, or barrier efficiency.