PIB Polymer Specifications Guide: Viscosity, Molecular Weight, and Purity
PIB polymer (Polyisobutylene) is widely used in lubricants, adhesives, sealants, rubber compounds, and specialty chemical formulations. In raw material selection, viscosity, molecular weight, and purity are the key specifications that directly affect processing behavior, product consistency, and long-term performance in practical applications.
Viscosity Ranges (Reference Values)
| Molecular Weight Range | Viscosity (100°C) | Processing Characteristics |
|---|---|---|
| Low MW PIB | Low to medium | Easy blending, good flow |
| Medium MW PIB | Medium to high | Strong tack, controlled flow |
| High MW PIB | Very high | Elastic, requires heating |
PIB Molecular Weight
Molecular Weight: The molecular weight of PIB can range from hundreds to millions, and it is usually classified into several categories according to its molecular weight:
- Low molecular weight polyisobutylene: Molecular weight is usually between 350 and 3500, sometimes defined as 200-10000, and it is a viscous liquid.
- Medium molecular weight polyisobutylene: Molecular weight ranges from approximately 10,000 to 100,000, sometimes defined as 20,000-45,000, and it is a semi-solid at room temperature.
- High molecular weight polyisobutylene: Molecular weight is between 100,000 and 1,000,000, sometimes defined as 75,000-600,000, and it is a rubbery elastomer.
- Ultra-high molecular weight polyisobutylene: Molecular weight is greater than 760,000.
Purity of PIB Polymer
The purity specifications of PIB polymers vary depending on the application, with common industrial-grade products reaching 98% or 99% purity. For example, PIB (PB950) with a purity of 99% is used as a petroleum additive and plasticizer.
Properties of PIB Polymer
| Property | Typical Characteristics |
|---|---|
| Appearance | Colorless to light yellow viscous liquid or rubbery solid |
| Odor | Odorless or slightly hydrocarbon-like |
| CAS Number | 9003-27-4 |
| Density | ~0.91–0.93 g/cm³ (depending on MW) |
| Solubility | Insoluble in water; soluble in hydrocarbons |
| Chemical Resistance | Excellent resistance to acids, alkalis, and oxidation |
| Gas Permeability | Extremely low |
| Thermal Stability | Stable under typical industrial processing conditions |
Industrial Applications of PIB Polymer
Lubricants and Fuel Additives
PIB polymer is widely used as a thickener and viscosity modifier in engine oils, gear oils, and industrial lubricants.
Adhesives and Sealants
Common applications include construction sealants, insulating tapes, and automotive sealing materials.
Rubber and Elastomer Compounds
It is frequently used in butyl rubber modification and specialty rubber products.
Industrial and Specialty Uses
Additional applications include:
- Electrical insulation materials
- Waterproof coatings
- Chewing gum base (food-grade PIB)
- Medical stoppers and packaging (special grades)
Conclusion
Viscosity, molecular weight, and purity are the key specifications that define the performance of PIB polymer (Polyisobutylene) across industrial applications. Understanding how these parameters interact helps industrial buyers select the most suitable PIB polymer grade for lubricants, adhesives, sealants, and rubber formulations.
When sourcing PIB raw materials, working with a reliable PIB polymer supplier and PIB polymer manufacturer is critical. Tianjin Gnee Biotech Co. Ltd. offers consistent quality and custom PIB molecular weight options through controlled in-house production, supporting stable long-term supply for global markets.