Low molecular weight polyisobutylene (MW ~1,350) is a viscous, tacky polymer with superior barrier properties and chemical inertness. It is widely used as a plasticizer, thickener, and adhesion promoter in industrial formulations.
Key Properties of Low Molecular Weight Polyisobutene
Physical State
At room temperature, low molecular weight polyisobutylene is a high-viscosity liquid. Products with a molecular weight below 3,500 are usually fully liquid, featuring a very low pour point (below −50 °C) and a high flash point ranging from 110 °C to 263 °C, making PIB base oil suitable for high-temperature lubrication systems.
Chemical Properties
Low molecular weight PIB is odorless, non-toxic, and highly chemically inert. It demonstrates excellent heat resistance, oxidation resistance, UV stability, and resistance to acids and alkalis, along with outstanding electrical insulation properties. These characteristics make polyisobutylene fluid ideal for long-term industrial use.
Solubility
Low molecular weight polyisobutene is soluble in non-polar solvents such as benzene, diisobutylene, chlorinated hydrocarbons, and mineral oils. However, it is insoluble in polar solvents including water, alcohols, and acetone-an essential feature of saturated hydrocarbon polymers like PIB.
Reactivity Classification
Based on terminal group structure, polyisobutylene polymers are classified into high-reactivity PIB (with more than 80% α-terminal vinyl groups) and conventional low-reactivity PIB. Highly reactive polyisobutylene is particularly suitable for further chemical modification, such as the production of PIB succinimide dispersants.
Applications of Low Molecular Weight Polyisobutene
Lubricant Additives
Low molecular weight PIB is widely used as a viscosity modifier and oil-film strength enhancer in two-stroke and four-stroke engine oils, as well as industrial gear oils. It improves viscosity index, reduces shear loss, and can partially replace high-viscosity base oils in lubricant formulations.
Chewing Gum Base
In food-grade polyisobutylene applications, low molecular weight PIB enhances softness, elasticity, and temperature stability of chewing gum bases, ensuring consistent texture during mastication.
Adhesives and Sealants
As a key tackifying component, low molecular weight polyisobutylene is used in pressure-sensitive adhesives, sealants, and cable impregnation compounds, offering strong adhesion, flexibility, and excellent weather resistance.
Polymer Modification
PIB fluid is commonly applied as an impact modifier in plastics and thermoplastic elastomers, improving toughness and flexibility without compromising chemical stability.
Pharmaceutical and Cosmetic Packaging
Thanks to its non-toxic, odorless, and inert nature, low molecular weight polyisobutylene is used in pharmaceutical packaging seals, closures, and controlled-release systems, as well as in cosmetic packaging applications.
Conclusion
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.