Low Molecular Weight Polyisobutene (LMW PIB) is a synthetic hydrocarbon polymer made by the polymerization of isobutylene (C₄H₈), with a low molecular weight range, typically between 300 and 2,000 g/mol. It is also referred to as polyisobutylene oligomer or polybutene in some contexts.
Chemical Structure:
Repeating unit: –[CH₂–C(CH₃)₂]ₙ–
It's an alkyl-substituted hydrocarbon polymer, consisting mainly of isobutylene units.
The degree of polymerization is low, resulting in short chains and low viscosity compared to high MW PIB.
Key Properties:
| Property | Description |
|---|---|
| Appearance | Clear, viscous, colorless to pale yellow liquid |
| Molecular Weight Range | ~300 to 2,000 g/mol |
| Viscosity | Medium to high (but lower than high-MW PIBs) |
| Solubility | Soluble in mineral oils and hydrocarbons |
| Reactivity | Chemically inert, but terminal groups can be modified |
Applications:
Lubricants and Additives
Used as tackifiers and ashless dispersants in four-stroke and two-stroke engine oils, as well as industrial gear oils. Improves viscosity index, enhances oil film strength, and reduces smoke emissions. Common molecular weight grades are 950, 1300, and 2400.
Adhesives and Sealants
Used as tackifiers in pressure-sensitive adhesives, hot-melt adhesives, and sealants to provide durable adhesion, excellent aging resistance, and airtight sealing, particularly suitable for moisture-sensitive environments.
Cosmetics and Personal Care Products
Due to its structural similarity to natural squalane, it is commonly used in lipsticks, creams, and other products as a squalane substitute. It provides moisturizing, lubricating, and non-greasy skin feel with excellent hydration properties.
Food and Pharmaceuticals
Food-grade polyisobutylene serves as a gum base for chewing gum and a pharmaceutical excipient, meeting relevant safety standards.
Other Industrial Applications
Used in coatings, plastic modification, fuel additives (reducing VOC emissions), and other fields.
Conclusion
PIB polymer (Polyisobutylene) is a versatile and high-performance industrial polymer widely used in lubricants, adhesives, sealants, and rubber compounds.
When sourcing PIB raw materials, partnering with a reliable PIB polymer supplier and manufacturer is essential. Tianjin Gnee Biotech Co. Ltd., with its own production facilities and strict quality control systems, provides consistent product quality and the ability to offer custom PIB molecular weight solutions to meet diverse industrial requirements, ensuring long-term supply stability for global markets.