Overview of Polyisobutylene (PIB)
Polyisobutylene (PIB), is a synthetic elastomer and polymer hydrocarbon produced by the polymerization of isobutylene (isobutene).
It is widely used in rubber compounds, sealants, adhesives, lubricants, fuels, and pharmaceutical applications due to its excellent impermeability, chemical stability, and flexibility.
polyisobutylene chemical structure
Polyisobutene (also known as polyisobutylene, PIB) is a class of organic polymers produced by the polymerization of isobutene. The resulting polymers typically have the general formula:
Me₃C[CH₂CMe₂]ₙH (where Me = CH₃)
Polyisobutylene usually appears as a colorless, gummy or rubber-like solid, depending on its molecular weight.
Basic Structural Unit
Polyisobutylene is composed of repeating isobutylene units:
- Monomer: Isobutylene (C₄H₈)
- Repeating unit: –[–CH₂–C(CH₃)₂–]ₙ–
This structure features:
- A carbon–carbon saturated backbone
- Methyl side groups attached to every other carbon atom
Because the polymer chain is fully saturated, PIB shows excellent resistance to oxidation, heat, and chemical attack.
Properties of Polyisobutylene (CAS 9003-27-4)
| Property | Description |
|---|---|
| Chemical Name | Polyisobutylene |
| CAS Number | 9003-27-4 |
| Molecular Structure | Saturated hydrocarbon polymer |
| Appearance | Colorless to pale viscous liquid / semi-solid |
| Odor | Odorless |
| Solubility in Water | Insoluble |
| Solubility in Oils | Soluble |
| Density (20°C) | ~0.90–0.93 g/cm³ |
| Glass Transition Temperature (Tg) | Approx. −70 °C |
| Volatility | Very low |
| Chemical Stability | Excellent |
| Film-Forming Ability | High |
| Gas Permeability | Very low |
polyisobutylene (CAS 9003-27-4) Uses
- Petroleum Additives: Polyisobutylene (PIB) serves as a lubricant additive to enhance lubricant performance.
- Adhesives: PIB exhibits excellent adhesion and elasticity, making it suitable for manufacturing pressure-sensitive adhesives, sealants, and similar products.
- Wires and Cables: Polyisobutylene can be used to manufacture insulation layers for wires and cables, enhancing electrical insulation properties.
- Plasticizer: Polyisobutylene (PIB) can serve as a plasticizer for plastics, improving processing properties and flexibility.
- Other Applications: Polyisobutylene (PIB) is also used in the production of rubber products, coatings, inks, and other fields.